CN107870397B

CN107870397B - Wavelength selective optical switch

Info

Publication number: CN107870397B
Application number: CN201610852485.6A
Authority: CN
Inventors: 涂鑫
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2016-09-26
Filing date: 2016-09-26
Publication date: 2020-02-21
Anticipated expiration: 2036-09-26
Also published as: CN107870397A; WO2018054075A1

Abstract

A wavelength selective optical switch is proposed, comprising a polarizing beam splitting unit and a wavelength selection unit, the wavelength selection unit comprising: the polarization beam splitting unit is used for splitting an input light beam into a first polarization light beam and a second polarization light beam, transmitting the first polarization light beam to the input ends of the first group of micro-ring resonators, and transmitting the second polarization light beam to the input ends of the second group of micro-ring resonators; the first group of micro-ring resonators are used for coupling a first target light beam in the first polarized light beam into the first group of micro-ring resonators and outputting the first target light beam to the polarization beam combination unit; the second group of micro-ring resonators are used for coupling a second target beam in the second polarized beam into the second group of micro-ring resonators and outputting the second target beam to the polarization beam combination unit; and the polarization beam combination unit is used for combining the first target beam and the second target beam. Thus, the polarization state conversion times of the first polarized light beam and the second polarized light beam are the same, and the polarization-dependent loss can be reduced.

Description

Wavelength selective optical switch

Technical Field

The present invention relates to the field of communications, and in particular, to a wavelength selective optical switch in the field of communications.

Background

With the application of Dense Wavelength Division Multiplexing (DWDM) technology in optical fiber communication systems and data center systems, all-optical switching has become a trend to meet the increasing bandwidth. In the dense wavelength division multiplexing system, each different optical wavelength bears a different optical signal, and the optical signals with different wavelengths are transmitted in the same optical fiber, so that high-capacity and low-loss data communication is realized. The optical switch is a key device for realizing an all-optical switching system, and can realize the functions of routing selection, wavelength selection, optical cross connection, self-healing protection and the like of an all-optical layer. Optical switches that have been implemented to date include conventional mechanical structure optical switches, micro-opto-electro-mechanical systems based switches, liquid crystal optical switches, waveguide type optical switches and semiconductor optical amplifier optical switches. The waveguide type optical switch is usually prepared On a Silicon-On-Insulator (SOI) platform or an Indium Phosphide (InP) platform On an insulating substrate by means of a mature Complementary Metal Oxide Semiconductor (CMOS) process, and the switching speed can reach nanosecond to microsecond by utilizing the thermo-optic effect or the plasma dispersion effect of a Silicon material, and the waveguide type optical switch is small in size, high in integration level and compatible with the CMOS process, so that the mass production with low cost can be realized. The waveguide type micro-ring resonator is a selective conducting device sensitive to wavelength, has the advantages of compact structure, high integration level, low power consumption, simple design and the like, and can be used for realizing the functions of filtering, multiplexing, demultiplexing, routing, wavelength conversion, optical modulation, optical switching and the like. When the wavelength division multiplexing optical signal passes through the micro-ring resonator, if the wavelength of the optical signal conforms to the resonance wavelength of the micro-ring resonator, the optical signal is coupled into the micro-ring resonator to generate resonance, so that the routing function of the optical signal with the specified wavelength is realized. Compared with a cascade Mach-Zehnder-interferometer (MZI for short) type silicon-based optical switch matrix, the optical switch array formed by the micro-ring resonators is simple in topological structure, few in stage number and selective in wavelength, so that optical signals with penetrating wavelengths cannot be affected by coupling of the micro-ring resonators, and through insertion loss is low. In particular, in a metropolitan area convergence ring of a metropolitan area optical network, the optical switch of the micro-ring resonator type has the functions of filtering and loading and unloading signals at the same time, so that the switching node equipment is simple and efficient.

However, the existing micro-ring resonators can only support single polarization state signal light uploading and downloading, because the resonance wavelength of the micro-ring resonator is very sensitive to the effective refractive index and the structural size of the waveguide. Generally, the effective refractive indexes of the TE mode and the TM mode of the waveguide are different, so that the resonant wavelengths of the TE mode and the TM mode are also different, and thus the micro-ring resonator cannot process a polarization-multiplexed optical signal. Even if some specially designed waveguide structures with square or ridge cross sections are adopted, so that the effective refractive indexes or group refractive indexes of the TE mode and the TM mode of the waveguide are equal, the resonance wavelengths of the TE mode and the TM mode are different due to the change of the wavelength structure size caused by process errors. This will limit the application scenarios of the micro-ring resonator in the metro optical network. How to design a micro-ring resonator optical switch with low polarization dependent loss is one of the key technologies of a convergence ring optical switching node in a metropolitan area optical network.

Disclosure of Invention

In view of this, embodiments of the present invention provide a wavelength selective optical switch, which can reduce polarization dependent loss during the selection process of a polarization independent optical signal.

In a first aspect, an embodiment of the present invention provides a wavelength selective optical switch, including a polarization beam splitting unit and a wavelength selection unit, where the wavelength selection unit includes two sets of micro-ring resonators and a polarization beam combining unit,

the polarization beam splitting unit is used for splitting an input light beam into a first polarization light beam and a second polarization light beam, transmitting the first polarization light beam to the input end of a first micro-ring resonator in the two groups of micro-ring resonators, and transmitting the second polarization light beam to the input end of a second micro-ring resonator in the two groups of micro-ring resonators;

the first set of micro-ring resonators are used for coupling a first target beam in the first polarized beam transmitted to the input end of the first set of micro-ring resonators into the first set of micro-ring resonators and outputting the first target beam coupled into the first set of micro-ring resonators from the output end of the first set of micro-ring resonators to the polarization beam combining unit, and the wavelength of the first target beam is equal to the target wavelength corresponding to the wavelength selection unit;

the second group of micro-ring resonators are used for coupling a second target beam in the second polarized beam transmitted to the input end of the second group of micro-ring resonators into the second group of micro-ring resonators and outputting the second target beam coupled into the second group of micro-ring resonators from the output end of the second group of micro-ring resonators to the polarization beam combination unit, and the wavelength of the second target beam is equal to the target wavelength;

the polarization beam combining unit is configured to combine the first target light beam received from the output end of the first group of micro-ring resonators and the second target light beam received from the output end of the second group of micro-ring resonators, and output a light beam obtained by combining the first target light beam and the second target light beam.

Therefore, the wavelength selective optical switch performs the same wavelength selection processing on the two polarized light beams, so that the polarization state conversion times of the first polarized light beam and the second polarized light beam are the same, and therefore, the polarization dependent loss can be reduced, and the performance of the optical switching node is facilitated.

In addition, in the wavelength selective optical switch, the transmission paths of the first polarized light beam and the second polarized light beam in the optical waveguide are equal or close, so that the differential group velocity delay can be reduced while the polarization dependent loss is further reduced.

Optionally, in an implementation manner of the first aspect, the polarization beam splitting unit transmits the first polarized light beam to the input ends of the first group of micro-ring resonators through a first optical waveguide connecting the polarization beam splitting unit and the input ends of the first group of micro-ring resonators, and light beams of the first polarized light beam that are not coupled into the first group of micro-ring resonators continue to be transmitted along the first optical waveguide;

the polarization beam splitting unit transmits the second polarization beam to the input end of the second group of micro-ring resonators through a second optical waveguide connecting the polarization beam splitting unit and the input ends of the second group of micro-ring resonators, and the second polarization beam which is not coupled to the second group of micro-ring resonators continues to be transmitted along the second optical waveguide.

It should be understood that the wavelength selective optical switch may be used for selection of polarized light having any polarization state, that is, the first polarized light beam and the second polarized light beam may be polarized light beams having any polarization mode, and in particular, the first polarized light beam may be an optical signal of a TE mode or a TM mode, and the second polarized light beam may be an optical signal of a TE mode or a TM mode.

Optionally, in an implementation manner of the first aspect, the first polarized light beam and the second polarized light beam are polarized light beams of a same mode, where the micro-ring resonators in the first set of micro-ring resonators and the micro-ring resonators in the second set of micro-ring resonators are micro-ring resonators matched with the same mode.

For example, if the first polarized light beam is a polarized light beam of a TM mode, the microring resonators in the first set of microring resonators may be designed as microring resonators that match the TM mode; if the second polarized light beam is a polarized light beam of the TE mode, the microring resonators in the second set of microring resonators may be designed as microring resonators that match the TE mode.

Optionally, in an implementation manner of the first aspect, the polarization beam splitting unit includes a polarization beam splitting rotator, and the polarization beam combining unit includes a polarization beam combining rotator.

Therefore, the polarization state conversion times of the first polarized light beam and the second polarized light beam are the same, and the paths of the first polarized light beam and the second polarized light beam transmitted in the optical waveguide are equal, so that the polarization dependent loss and the differential group velocity time delay can be reduced.

Moreover, the micro-ring resonators in the first group of micro-ring resonators and the micro-ring resonators in the second group of micro-ring resonators are micro-ring resonators aiming at the same polarization mode, so the same micro-ring resonators for processing the same polarized light beam can be used, two different sets of micro-ring resonators do not need to be designed, the complexity of the system is reduced, and the control complexity is reduced.

It should be understood that the polarization beam splitting unit in this embodiment may further include other devices capable of splitting and rotating the input optical signal to split the input optical signal into two polarized optical beams, for example, a TE mode optical signal and a TM mode optical signal, and convert one of the polarized optical beams, for example, the TM mode optical signal, into the TE mode optical signal. For example, the polarization beam splitting element may include a polarization beam splitter and a polarization converter, or other optical structures capable of performing this function. Similarly, the polarization beam combining unit may also include other devices capable of combining and rotating the input optical signal.

Optionally, in an implementation manner of the first aspect, the first polarized light beam and the second polarized light beam are polarized light beams of different modes, where a micro-ring resonator in the first group of micro-ring resonators is a micro-ring resonator matched with the mode of the first polarized light beam, and a micro-ring resonator in the second group of micro-ring resonators is a micro-ring resonator matched with the mode of the second polarized light beam.

Optionally, in an implementation manner of the first aspect, the polarization beam splitting unit includes a polarization beam splitter, and the polarization beam combining unit includes a third optical waveguide, and the third optical waveguide is configured to couple the first target beam and the second target beam.

That is, here, the combination of the first target beam and the second target beam is performed in the coupled optical waveguide without adding other wave combining devices.

Therefore, the first polarized light beam and the second polarized light beam do not need to be subjected to polarization state conversion, and polarization dependent loss is greatly reduced. In addition, the difference of the transmission paths of the first polarized light beam and the second polarized light beam in the optical waveguide is obviously reduced, so that the differential group velocity time delay can be reduced while the polarization-dependent loss is further reduced.

Optionally, in an implementation manner of the first aspect, the first group of micro-ring resonators includes one micro-ring resonator or a plurality of cascaded micro-ring resonators, and the second group of micro-ring resonators includes one micro-ring resonator or a plurality of cascaded micro-ring resonators.

Therefore, the wavelength selective optical switch can expand the operating spectral bandwidth of the optical switch by using a plurality of micro-ring resonators cascaded.

Further, the number of the microring resonators in the first set of microring resonators is equal to the number of the microring resonators in the second set of microring resonators. Therefore, the structural complexity of the wavelength selection unit is reduced, the path difference of two paths of polarized light beams during transmission in the optical waveguide is reduced, and the polarization-related loss is reduced.

Optionally, in an implementation manner of the first aspect, the wavelength-selective optical switch further includes a wavelength detection unit corresponding to the wavelength selection unit, and the wavelength detection unit is configured to detect a wavelength of the first target light beam and a wavelength of the second target light beam.

Optionally, in an implementation manner of the first aspect, the wavelength detection unit includes a first optical coupler located at the output ends of the first group of micro-ring resonators, and a first optical detector connected to the first optical coupler, and a second optical coupler located at the output ends of the second group of micro-ring resonators, and a second optical detector connected to the second optical coupler.

In the wavelength selection unit, an optical coupler may be disposed at each output end of the two groups of micro-ring resonators, and is used for extracting a small amount of optical signal energy from the trunk and transmitting the optical signal energy to the optical detector for monitoring. The optical detector feeds the extracted optical signals back to the electrode drive of the two groups of micro-ring resonators through an external feedback circuit respectively, and the wavelength of the downloaded optical signals is stabilized by compensating the change amount of the resonant wavelength of the two groups of micro-ring resonators in real time.

Therefore, the wavelength of the optical signal downloaded by the wavelength selection unit can be stabilized by arranging the wavelength monitoring unit in the wavelength selective optical switch to monitor and compensate the target wavelength in real time.

In a second aspect, there is provided a wavelength selective optical switch, which includes the polarization beam splitting unit described in the first aspect and various implementation manners, and at least one wavelength selecting unit described in the first aspect and various implementation manners, wherein target wavelengths corresponding to each of the at least one wavelength selecting unit are different

For example, the wavelength selective optical switch may include the above-mentioned polarization beam splitting unit, and n of the above-mentioned wavelength selecting units, wherein a light beam which does not satisfy the target wavelength in the first polarized light beam output by the ith wavelength selecting unit and a light beam which does not satisfy the target wavelength in the second polarized light beam respectively enter the (i + 1) th wavelength selecting unit. The beams of the first polarized beam which do not meet the target wavelength pass through the first group of micro-ring resonators in the (i + 1) th wavelength selection unit to realize the aim of meeting the target wavelength lambda_i+1The light beam which does not meet the target wavelength in the second polarized light beam passes through a second group of micro-ring resonators in the (i + 1) th wavelength selection unit to realize the selection of the light beam which meets the target wavelength lambda_i+1Selection of the light beam of (1).

According to the wavelength selective optical switch provided by the embodiment of the invention, two groups of micro-ring resonators are arranged to respectively perform the same wavelength selective treatment on two polarized light beams, so that the polarization state conversion times of the first polarized light beam and the second polarized light beam are the same, the polarization correlation loss is reduced, and the performance of an optical switching node is facilitated.

And the transmission paths of the two polarized light beams in the optical waveguide are equal or close, so that the differential group velocity time delay can be reduced while the polarization-related loss is further reduced.

In addition, the wavelength selective optical switch in the embodiment of the invention has simple structure and compact volume, and can also form a large-scale optical switch matrix.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic block diagram of a polarization independent microring resonator in the prior art.

Fig. 2 is a schematic structural diagram of a wavelength selective optical switch according to an embodiment of the present invention.

Fig. 3 is a schematic structural view of a wavelength selective optical switch according to another embodiment of the present invention.

Fig. 4 is a schematic structural view of a wavelength selective optical switch according to another embodiment of the present invention.

Fig. 5 is a schematic structural view of a wavelength selective optical switch according to another embodiment of the present invention.

Fig. 6 is a schematic structural view of a wavelength selective optical switch according to another embodiment of the present invention.

Fig. 7 is a schematic structural view of a wavelength selective optical switch according to another embodiment of the present invention.

Fig. 8 is a schematic structural view of a wavelength selective optical switch according to another embodiment of the present invention.

Fig. 9 is a schematic structural view of a wavelength selective optical switch according to another embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, shall fall within the scope of protection of the present invention.

Fig. 1 is a schematic block diagram of a polarization independent microring resonator in the prior art. The microring resonator 100 comprises two parts: a polarization sensitive working cell 110 and a polarization rotating mirror 120. The polarization-multiplexed optical signal includes a TE mode optical signal and a TM mode optical signal, and the input polarization-multiplexed optical signal enters the polarization-independent micro-ring resonator structure from the bus optical waveguide 130, passes through the polarization beam splitter 111, and is output from the optical waveguide 112 and is output from the optical waveguide 113. The optical waveguide 112 is coupled to the micro-ring resonator 114, and the TE mode optical signal that matches the resonant wavelength of the micro-ring resonator 114 is coupled into the micro-ring resonator 114 for transmission in the counterclockwise direction, and is coupled out from the output optical waveguide 115, and enters the polarization combiner 118. The TM mode optical signal in the optical waveguide 113 is transmitted to the polarization rotation mirror 121 at the far end, and is reflected back to be converted into TE mode optical signal TE_TMEnters the optical waveguide 112 and is transmitted in reverse with the TE optical signal. Wherein the polarization rotating mirror 120 comprises a polarization rotator 121 and a curved waveguide 122. Optical signal TE conforming to the resonant wavelength of microring resonator 114_TMThe optical signal is coupled into the micro-ring resonator 114 for transmission in the clockwise direction, is coupled out from the output optical waveguide 115, is converted into a TM mode optical signal through the curved optical waveguide 116 and the polarization rotator 117, and enters the polarization combiner 118. The polarization combiner 118 combines the input TE mode optical signal and TM mode optical signal and outputs the resultant from the bus optical waveguide 140, thereby realizing a polarization-independent filter switching function.

However, in the micro-ring resonator, the lengths of optical waveguides through which the TE mode optical signal and the TM mode optical signal pass are greatly different, and the number of times of polarization state conversion of the TM mode optical signal is large, which may cause serious polarization-dependent loss and differential group velocity delay, and affect the system performance; moreover, the micro-ring resonator has a complex structure and a large volume, and is not suitable for forming a large-scale optical switch matrix.

The polarization dependent loss refers to the difference of energy losses generated after optical signals in different polarization states pass through a system, and in the embodiment of the invention, the difference of energy losses of two polarized light beams in different polarization states after the two polarized light beams pass through the optical switch can be used. The smaller the difference, the less sensitive the optical switch to the polarization state.

A Wavelength Selective optical Switch (WSS) is a subsystem of a Wavelength division system that develops rapidly in recent years, and can Switch optical signals with different wavelengths between any input and output ports, thereby greatly improving the networking capability of the Wavelength division system. In terms of operation, wavelength selective switches can be classified into micro-electromechanical type, planar waveguide type, liquid crystal type, and the like. The wavelength selective optical switch in the embodiment of the present invention is one of planar waveguide type.

Fig. 2 is a schematic structural view of a wavelength selective optical switch of an embodiment of the present invention. The wavelength selective optical switch includes a polarization beam splitting unit 310 and a wavelength selection unit 320, wherein the wavelength selection unit 320 includes two sets of micro-ring resonators including a first set of micro-ring resonators 321 and a second set of micro-ring resonators 322, and a polarization beam combining unit 323.

A polarization beam splitting unit 310 for splitting an input light beam into a first polarization light beam and a second polarization light beam, transmitting the first polarization light beam to an input end of a first set of micro-ring resonators 321 of the two sets of micro-ring resonators, and transmitting the second polarization light beam to an input end of a second set of micro-ring resonators 322 of the two sets of micro-ring resonators;

the first set of micro-ring resonators 321 is configured to couple a first target beam of the first polarized beams transmitted to the input end of the first set of micro-ring resonators 321 into the first set of micro-ring resonators 321, and output the first target beam coupled to the first set of micro-ring resonators 321 to the polarization beam combining unit 323 from the output end of the first set of micro-ring resonators 321, where a wavelength of the first target beam is equal to a target wavelength corresponding to the wavelength selecting unit 320;

the second group of micro-ring resonators 322 is configured to couple a second target beam of the second polarized beam transmitted to the input end of the second group of micro-ring resonators 322 into the second group of micro-ring resonators 322, and output the second target beam coupled into the second group of micro-ring resonators 322 from the output end of the second group of micro-ring resonators 322 to the polarization beam combining unit 323, where the wavelength of the second target beam is equal to the target wavelength;

the polarization beam combining unit 323 is configured to combine the first target beam received from the output end of the first set of micro-ring resonators 321 and the second target beam received from the output end of the second set of micro-ring resonators 322, and output a beam obtained by combining the first target beam and the second target beam.

Specifically, the polarization-multiplexed and wavelength-multiplexed input light beam is split into two polarized light beams having different polarization states, i.e., a first polarized light beam and a second polarized light beam, by the polarization beam splitting unit. The two polarized light beams enter the wavelength selection unit 320 through the input component, as shown in fig. 2, the first polarized light beam enters the first set of micro-ring resonators 321 in the wavelength selection unit 320, and the second polarized light beam enters the second set of micro-ring resonators 322, where in the embodiment of the present invention, the direction of the arrow in the figure is an illustration of the propagation direction of the light beam in the optical waveguide.

The first target beam of the first polarized beam transmitted to the input terminal of the first set of micro-ring resonators 321 is coupled into the first set of micro-ring resonators 321 to generate resonance, thereby realizing a designated wavelength λ_iThe first set of micro-ring resonators 321 directs the first polarized beam to meet the target wavelength λ_iIs coupled into the first set of micro-ring resonators 321, where λ_iIs the resonant wavelength of the first set of micro-ring resonators 321. The second polarized light beam entering the second set of micro-ring resonators 322 is coupled into the second set of micro-ring resonators 322 to generate resonance, thereby achieving a specified wavelength λ_iThe second micro-ring resonator group 322 will satisfy the target wavelength λ in the second polarized light beam_iTo (1) aThe two target beams are coupled into a second set of micro-ring resonators 322, wherein the resonance wavelength of the second set of micro-ring resonators 322 is also λ_i. The resonance wavelength of the first set of micro-ring resonators 321 is equal to the resonance wavelength of the second set of micro-ring resonators 322, and is equal to the target wavelength λ_i。

The first target beam coupled out from the first polarized beam by the first micro-ring resonator 321 is transmitted to the polarization beam combining unit 323 through the optical waveguide between the first micro-ring resonator 321 and the polarization beam combining unit 323, and the optical waveguide between the first micro-ring resonator 321 and the polarization beam combining unit 323 is coupled to the first micro-ring resonator 321, so that the beam output from the first micro-ring resonator 321 can enter the optical waveguide and be transmitted to the polarization beam combining unit 323.

Similarly, the first target beam coupled out from the first polarized beam by the second set of micro-ring resonators 322 is transmitted to the polarization beam combining unit 323 through the optical waveguide between the second set of micro-ring resonators 322 and the polarization beam combining unit 323, and the optical waveguide between the second set of micro-ring resonators 322 and the polarization beam combining unit 323 is coupled to the second set of micro-ring resonators 322, so that the output beam of the second set of micro-ring resonators 322 can enter the optical waveguide and be transmitted to the polarization beam combining unit 323.

The polarization beam combining unit 323 combines the first target beam coupled by the first set of micro-ring resonators 321 and the second target beam coupled by the second set of micro-ring resonators 322 and outputs a combined beam of the first target beam and the second target beam, thereby completing a wavelength selection process. The single wavelength optical signal output by the wavelength selection unit 320 satisfies the target wavelength λ_i。

It can be seen that, in the wavelength selective optical switch according to the embodiment of the present invention, the two polarized light beams are simultaneously subjected to the wavelength selection process, so that the polarization state conversion times of the first polarized light beam and the second polarized light beam are the same, and therefore, the polarization dependent loss can be reduced, which is beneficial to the performance of the optical switching node.

Moreover, the processing processes of the first group of micro-ring resonators and the second group of micro-ring resonators on the two polarized light beams are consistent, so that the transmission paths of the first polarized light beam and the second polarized light beam in the optical waveguide are equal or close, the polarization correlation loss can be further reduced, and the differential group velocity delay can be reduced.

In addition, compared with the wavelength selective optical switch in the prior art, the wavelength selective optical switch in the embodiment of the invention has the advantages of simple structure and compact volume, and is suitable for forming a large-scale optical switch matrix.

As another embodiment, the polarization beam splitting unit 310 transmits the first polarization beam to the input end of the first set of micro-ring resonators 321 through a first optical waveguide connecting the polarization beam splitting unit 310 and the input end of the first set of micro-ring resonators 321, and the light beam of the first polarization beam that is not coupled into the first set of micro-ring resonators 321 continues to be transmitted along the first optical waveguide;

the polarization beam splitting unit 310 transmits the second polarization beam to the input end of the second set of micro-ring resonators 322 through the second optical waveguide connecting the polarization beam splitting unit 321 and the input end of the second set of micro-ring resonators 322, and the second polarization beam which is not coupled to the second set of micro-ring resonators 322 continues to be transmitted along the second optical waveguide.

It should be understood that when the edge of the microring resonator and other devices (e.g., straight waveguides) are close to each other in space until the distance between the two reaches the same order of magnitude (e.g., micrometer order) or smaller (e.g., nanometer order) as the wavelength, the optical fields in the two interact, which we refer to as coupling.

When the input end of the first micro-ring resonator 321 and the first optical waveguide are close to each other in space until the distance between the input end and the first optical waveguide reaches the same order of magnitude as or smaller than the target wavelength, optical fields in the first micro-ring resonator 321 and the first optical waveguide interact with each other to realize the coupling between the first micro-ring resonator 321 and the first optical waveguide; when the input end of the second group of micro-ring resonators 322 and the second optical waveguide are close to each other in space until the distance between the input end and the second optical waveguide reaches the same order of magnitude as or smaller than the target wavelength, the optical fields in the two interact with each other, and the coupling between the second group of micro-ring resonators 322 and the second optical waveguide is realized.

Specifically, in the first polarized beam transmitted to the input end of the first set of micro-ring resonators 321, the first set of micro-ring resonators 321 will satisfy the target wavelength λ_iIs coupled into the first set of micro-ring resonators 321; in the second polarized beam transmitted to the input end of the second set of micro-ring resonators 322, the second set of micro-ring resonators 322 will satisfy the target wavelength λ_iIs coupled into the second set of micro-ring resonators 322, and the first target beam and the second target beam are output after being combined in the polarization beam combining unit 323 without being coupled into the first set of micro-ring resonators 321 at the non-target wavelength λ_iContinues to propagate in the first optical waveguide without being coupled to the non-target wavelength λ of the second set of micro-ring resonators 322_iThe remaining light beam continues to travel in the second optical waveguide.

It should be understood that, in the embodiment of the present invention, the light beam may also be referred to as an optical signal, each different optical wavelength carries a different optical signal, and the optical signals with different wavelengths are transmitted together in the optical waveguide, for example, in the same optical fiber, so that data communication with large capacity and low loss can be implemented.

As another embodiment, the wavelength selective optical switch of the embodiment of the present invention includes a polarization beam splitting unit 310, and at least one wavelength selection unit 320, wherein the target wavelength corresponding to each wavelength selection unit 320 is different.

It should be understood that the target wavelength corresponding to each wavelength selection unit 320 in at least one wavelength selection unit in the wavelength selective optical switch is different, that is, the wavelength of the optical signal output by each wavelength selection unit is different. For example, the wavelengths corresponding to the three wavelength selection units shown in FIG. 3 are λ_i、λ_i+1And λ_n. In the above, one of the wavelength selection units 320 is taken as an example, and the target wavelength corresponding to the wavelength selection unit 320 is λ i.

It should also be understood that in embodiments of the present invention, the input beams are polarization multiplexed and wavelength division multiplexed; the output beam finally output by the polarization beam combining unit 323, i.e., the beam obtained by combining the first target beam and the second target beam, is a single-wavelength polarization-multiplexed beam satisfying the target wavelength. After passing through the polarization beam splitting unit 310 and the wavelength selection unit 320, the original input light beam is changed from the multi-wavelength light beam to the single-wavelength output light beam.

The wavelength selective optical switch according to an embodiment of the present invention is described in detail below with reference to fig. 4 to 9. As shown in fig. 3 to 9, two wavelength selection units 320, i.e., the ith wavelength selection unit 320 (corresponding to the wavelength λ)_i) And the (i + 1) th wavelength selection unit 320 (corresponding to the wavelength λ_i+1) However, the wavelength selective optical switch may further include more wavelength selection units 320, which may be selected according to the actual application. In the following, a detailed description is given with reference to the ith wavelength selective element shown in fig. 3 to 9, and other wavelength selective elements may refer to the relevant description of the wavelength selective element.

Optionally, the first polarized light beam is an optical signal in TM mode or TE mode, and the second polarized light beam is an optical signal in TM mode or TE mode.

In the embodiment of the invention, the mode is an electromagnetic field distribution which can be supported by the waveguide with a specific shape, and mathematically, the mode is a guided mode solution of Maxwell equation of the structure and corresponds to a characteristic value, namely the effective refractive index. The effective refractive index is an important parameter in a waveguide, and is related to the structure of the waveguide, material properties (refractive index), operating wavelength, and mode order. Once these parametric characteristics of the waveguide are determined, the effective index of refraction of a mode of the waveguide will also be determined. The TM mode and TE mode beams will be described as an example.

The wavelength selective optical switch of the embodiment of the present invention can be used for selecting polarized light having any polarization state, that is, the first polarized light beam and the second polarized light beam can be polarized light beams having any polarization mode, and particularly, the first polarized light beam can be an optical signal in a TE mode or a TM mode, and the second polarized light beam can be an optical signal in a TE mode or a TM mode.

In the following, the first polarization beam is an optical signal in TM mode or TE mode, and the second polarization beam is an optical signal in TE mode, but the present invention is not limited thereto.

As another embodiment, the first set of micro-ring resonators 321 may include one micro-ring resonator or a plurality of cascaded micro-ring resonators, and the second set of micro-ring resonators 322 includes one micro-ring resonator or a plurality of cascaded micro-ring resonators.

Further, the number of micro-ring resonators in the first set of micro-ring resonators 321 is equal to the number of micro-ring resonators in the second set of micro-ring resonators 322.

Fig. 4 shows a schematic block diagram of a wavelength selective optical switch according to another embodiment of the present invention. As shown in fig. 4, the first set of micro-ring resonators 321 includes a micro-ring resonator, and the second set of micro-ring resonators 322 includes a micro-ring resonator.

As another embodiment, the first polarized light beam and the second polarized light beam are polarized light beams with different modes, wherein the micro-ring resonators in the first set of micro-ring resonators 321 are micro-ring resonators matched with the mode of the first polarized light beam, and the micro-ring resonators in the second set of micro-ring resonators 322 are micro-ring resonators matched with the mode of the second polarized light beam.

Mode matching means that the effective refractive indices in two adjacent waveguides are close or equal. When the effective refractive indexes of two modes in adjacent waveguides in two spaces are close or equal, the corresponding two modes satisfy the phase matching condition. Energy coupling and mode conversion may occur between modes that satisfy the phase matching condition. The waveguides in a planar waveguide loop are typically of the same height, so the waveguide width of adjacent regions determines the effective refractive index of a certain mode of the waveguide; the waveguide spacing of adjacent regions determines the energy coupling and mode conversion efficiency per unit length; the waveguide length (i.e., coupling length) of adjacent regions determines the overall energy coupling and mode conversion efficiency of the device.

By selecting appropriate waveguide spacing, waveguide width, and waveguide length (i.e., coupling length) of adjacent regions, it is possible to achieve complete coupling (conversion) of optical energy from one mode in one waveguide into a corresponding mode in another waveguide.

For example, as shown in fig. 4, the first polarized light beam is a polarized light beam in the TM mode, and the microring resonators in the first set of microring resonators 321 can be designed as microring resonators matching the TM mode; the second polarized light beam is a polarized light beam of TE mode, and the microring resonators in the second set of microring resonators 322 can be designed as microring resonators matching the TE mode.

At this time, when the optical signal of the TM mode passes through the first set of micro-ring resonators 321, the target wavelength λ is satisfied_iIs coupled into the micro-ring resonator matched with the TM mode, and the target wavelength λ is satisfied when the optical signal of the TE mode passes through the second set of micro-ring resonators 322_iIs coupled into the micro-ring resonator matching the TE mode.

As another embodiment, the polarization beam splitting unit 320 includes a polarization beam splitter, and the polarization beam combining unit 323 includes a third optical waveguide for coupling the first target beam and the second target beam.

That is, the combining of the first target beam and the second target beam is completed in the coupled optical waveguide (or referred to as an optical waveguide), and the first target beam and the second target beam enter the optical waveguide to be combined after being output from the output ends of the corresponding micro-ring resonator groups, and are finally output through the optical waveguide, so that no other wave combining device needs to be added.

Since the microring resonators in the first set of microring resonators 321 are microring resonators matched with the mode of the first polarized light beam, the first set of microring resonators 321 can completely couple (convert) the light energy of the TM mode in the first optical waveguide into the mode corresponding to the first set of microring resonators 321, and output the first target light beam of the TM mode coupled to the first set of microring resonators 321 into the third optical waveguide; the micro-ring resonators in the second group of micro-ring resonators 322 are micro-ring resonators matched with the mode of the second polarized light beam, so that the second group of micro-ring resonators 322 can completely couple the optical energy of the TE mode in the second optical waveguide into the mode corresponding to the second group of micro-ring resonators 322, and output the second target light beam coupled to the TE mode of the second group of micro-ring resonators 322 into the third optical waveguide.

In this embodiment, the polarization beam splitter 310 is used to split an input optical signal into a first polarized beam and a second polarized beam. The receiving end of the first set of micro-ring resonators 321 receives a first polarized light beam satisfying the target wavelength λ_iThe first target beam of light is coupled into the first set of micro-ring resonators 321 and output from the output terminal of the first micro-ring resonator 321; the receiving end of the second set of micro-ring resonators 322 receives a second polarized beam that satisfies the target wavelength λ_iIs coupled into the second set of micro-ring resonators 322 and is output from the output terminal of the second micro-ring resonator 322. The output end of the first micro-ring resonator 321 outputs the first target light beam to the third optical waveguide, the output end of the second micro-ring resonator 322 outputs the second target light beam to the third optical waveguide, and the first target light beam output by the first micro-ring resonator 321 and the second target light beam output by the second micro-ring resonator 322 are combined in the third optical waveguide. The first target beam and the second target beam combined by the third optical waveguide are output.

In particular, when polarization-multiplexed and wavelength-division-multiplexed input light beams (wavelength λ)₁、λ₂…λ_nAnd) after the input port inputs the polarization beam splitter 310, the input optical signal can be split into an optical signal in TM mode and an optical signal in TE mode in the polarization beam splitter 310, and the two optical signals respectively enter the wavelength selection unit 320. The optical signal of the TM mode is transmitted to the input terminal of the first set of micro-ring resonators 321, and the optical signal of the TE mode is transmitted to the input terminal of the second set of micro-ring resonators 322. If wavelength lambda in TM-mode optical signal_iIn accordance with the resonant wavelength of the first set of micro-ring resonators 321, the first set of micro-ring resonators 321 will satisfy the target wavelength λ in the optical signal of the TM mode_iIs coupled into the first set of micro-ring resonators 321; if wavelength lambda in the optical signal of TE mode_iConforming to a second set of micro-ring resonators322, then the second set of micro-ring resonators 322 will satisfy the target wavelength λ in the TE mode optical signal_iIs coupled into the second set of micro-ring resonators 322.

The first target optical beam in the first set of micro-ring resonators 321 is output from the output end of the first set of micro-ring resonators 321 to the coupling region of the first set of micro-ring resonators 321 and the third optical waveguide; the second target optical beam in the second group of micro-ring resonators 322 is output from the output terminal of the second group of micro-ring resonators 322 to the coupling region of the second group of micro-ring resonators 322 and the third waveguide. The first target beam output from the first micro-ring resonator 321 and the second target beam output from the second micro-ring resonator 322 are combined in the third optical waveguide.

The first target beam and the second target beam combined in the third optical waveguide are output. Combining the first target beam in TM mode and the second target beam in TE mode to form a polarization-multiplexed single-wavelength optical signal, wherein the wavelength of the output beam is lambda_iSatisfying the resonance wavelength λ of the first and second sets of

micro-ring resonators

321 and 322_i。

Therefore, the first polarized light beam and the second polarized light beam do not need to be subjected to polarization state conversion, and polarization dependent loss is greatly reduced.

In addition, the difference of the transmission paths of the first polarized light beam and the second polarized light beam in the optical waveguide is obviously reduced, so that the differential group velocity time delay can be reduced while the polarization-dependent loss is further reduced.

As another embodiment, the wavelength selective optical switch may further include a wavelength detection unit corresponding to the wavelength selection unit, the wavelength detection unit being configured to detect the wavelength of the first target beam and the wavelength of the second target beam.

Specifically, the wavelength selection means 320 is provided with wavelength detection means at the output end of the first group of micro-ring resonators 321 and at the output end of the second group of micro-ring resonators 322, respectively, and detects the wavelength of the first target beam and the wavelength of the second target beam, respectively.

Further, the wavelength detecting unit includes a first optical coupler 341 located at the output end of the first group of micro-ring resonators 321, and a first photodetector 351 connected to the first optical coupler 341, and a second optical coupler 342 located at the output end of the second group of micro-ring resonators 322, and a second photodetector 352 connected to the second optical coupler 342.

Fig. 5 is a schematic structural view of a wavelength selective optical switch according to another embodiment of the present invention. In the ith wavelength selective element, a first optical coupler 341 may be disposed at the output end of the first group of micro-ring resonators 321 for extracting a small amount of optical signal energy from the trunk to be transmitted to the first photodetector 351 for monitoring. The first optical coupler 341 outputs a part of the optical signal in the first target beam to the first optical detector 351, and the first optical detector 351 feeds back the part of the optical signal to the electrode drive of the first micro-ring resonator 321 through an external feedback circuit, thereby compensating the resonance wavelength λ of the first micro-ring resonator in real time_iTo stabilize the wavelength of the downloaded optical signal.

Similarly, a second optical coupler 342 may be disposed at the output end of the second set of micro-ring resonators 322 to output a portion of the optical signal in the second target beam to a second optical detector 352, and the second optical detector 352 feeds back the portion of the optical signal to the electrode driver of the second set of micro-ring resonators 322 through an external feedback circuit, so as to compensate the resonance wavelength λ of the second set of micro-ring resonators in real time_iTo stabilize the wavelength of the downloaded optical signal.

Therefore, by arranging the wavelength monitoring unit, the wavelength of the optical signal downloaded by the wavelength selection unit can be stabilized through real-time monitoring and compensation of the target wavelength.

Fig. 4 and 5 are both illustrated by way of example in which the first set of micro-ring resonators 321 includes one micro-ring resonator, and the second set of micro-ring resonators 322 includes one micro-ring resonator. However, a plurality of microring resonators may be included in the first and second sets of

microring resonators

321 and 322, respectively. As shown in fig. 6, which is a schematic block diagram of a wavelength selective optical switch according to another embodiment of the present invention, the first group of micro-ring resonators 321 may include two cascaded micro-ring resonators, and the second group of micro-ring resonators 322 may include two cascaded micro-ring resonators. That is, one microring resonator in the above-described wavelength selection unit may be replaced with a plurality of microring resonators in cascade, and may be unchanged elsewhere. Thereby the working spectral bandwidth of the optical switch can be enlarged.

Optionally, the number of microring resonators in the first set of microring resonators is the same as the number of microring resonators in the second set of microring resonators. Therefore, the structural complexity of the wavelength selection unit is reduced, the path difference of two paths of polarized light beams during transmission in the optical waveguide is reduced, and the polarization-related loss is reduced.

Fig. 7 shows a schematic block diagram of a wavelength selective optical switch according to another embodiment of the present invention. As shown in fig. 7, the first set of micro-ring resonators 321 includes one micro-ring resonator, and the second set of micro-ring resonators 322 includes one micro-ring resonator.

As another embodiment, the first polarized light beam and the second polarized light beam are polarized light beams of the same mode, wherein the micro-ring resonators in the first set of micro-ring resonators 321 and the micro-ring resonators in the second set of micro-ring resonators 322 are micro-ring resonators matched with the same mode.

For example, as shown in fig. 7, the first polarized light beam is a polarized light beam of a TE mode, and the microring resonators in the first set of microring resonators 321 may be designed as microring resonators matching the TE mode; the second polarized light beam is also a polarized light beam of the TE mode, and the microring resonators in the second set of microring resonators 322 are also designed as microring resonators matching the TE mode.

At this time, when the optical signal of the TE mode passes through the first set of micro-ring resonators 321, the target wavelength λ is satisfied_iIs coupled into the micro-ring resonator matched with the TE mode, and when the other optical signal of the TE mode passes through the second set of micro-ring resonators 322, the target wavelength λ is satisfied_iIs coupled into the micro-ring resonator matching the TE mode.

Because the signals carried by the two beams with the same polarization state are different, if the two beams are coupled together for processing, coherent constructive and coherent destructive interference effects occur, which cause signal loss and cannot be demodulated out any more, and therefore, the two TE beams are processed by the first set of micro-ring resonators 321 and the second set of micro-ring resonators 322, respectively.

As another example, the polarization beam splitting unit 310 includes a polarization beam splitting rotator, and the polarization beam combining unit 323 includes a polarization beam combining rotator.

In this embodiment, the input ends of the first set of micro-ring resonators 321 receive a first polarized beam that satisfies the target wavelength λ_iIs coupled into the first set of micro-ring resonators 321, and the second set of micro-ring resonators 322 receives the second polarized light beam at its input and transmits the second polarized light beam with a target wavelength λ_iIs coupled into a second set of micro-ring resonators 322. The output end of the first micro-ring resonator 321 outputs the first target beam to the polarization beam combiner 323, the output end of the second micro-ring resonator 322 outputs the second target beam to the polarization beam combiner 323, and the polarization beam combiner 323 is configured to combine the first target beam and the second target beam, and output a beam obtained by combining the first target beam and the second target beam.

In particular, when polarization-multiplexed and wavelength-division-multiplexed input light beams (wavelength λ)₁、λ₂…λ_nAnd) after the polarization rotation beam splitter 310 is input from the input port, the input optical signal can be divided into two paths of TE mode optical signals in the polarization beam splitter 310, where the first path of TE mode optical signal (first polarization beam) is a TE mode component in the original polarization multiplexed and wavelength division multiplexed optical signal, the second path of TE mode optical signal (second polarization beam) is obtained by converting a TM mode component in the original polarization multiplexed and wavelength division multiplexed optical signal, and the two paths of optical signals respectively enter the wavelength selection unit 320. If the wavelength lambda of the first path of TE mode optical signal_iCorresponding to the resonant wavelength of the first set of micro-ring resonators 321, the first set of micro-ring resonators 321 will be tuned to that path TSatisfying the target wavelength λ in an E-mode optical signal_iIs coupled into the first set of micro-ring resonators 321; if the wavelength lambda of the second path of TE mode optical signal_iIn accordance with the resonant wavelength of the second set of micro-ring resonators 322, the second set of micro-ring resonators 322 will satisfy the target wavelength λ in the optical signal of the TE mode_iIs coupled into the second set of micro-ring resonators 322.

The first target beam in the first set of micro-ring resonators 321 is output from the output end of the first set of micro-ring resonators to the polarization beam combiner rotator 323; the second target beam in the second group of micro-ring resonators 322 is output from the output end of the second group of micro-ring resonators 322 to the polarization beam combiner rotator 323. The polarization beam combiner 323 is configured to combine the first target beam and the second target beam. The first target beam output from the first group of micro-ring resonators 321 and the second target beam output from the second group of micro-ring resonators 322 are combined in the polarization beam combiner 323.

In the first target beam and the second target beam combined by the polarization beam combiner 323, the TE mode optical signal in the original input optical signal is converted into the TM mode optical signal by the polarization beam combiner 323, and the other TE mode optical signal is kept after passing through the polarization beam combiner 323, and then the polarization multiplexed single wavelength optical signal is formed after combining. The polarization beam combiner 323 outputs the combined TE mode optical signal and TM mode optical signal, and the wavelength of the output optical beam is λ_iSatisfying the resonance wavelength λ of the first and second sets of

micro-ring resonators

321 and 322_i。

Therefore, the polarization state conversion times of the first polarized light beam and the second polarized light beam are the same, and the transmission paths of the first polarized light beam and the second polarized light beam from the wave splitting to the wave combining are equal, so that the polarization dependent loss and the differential group velocity time delay can be reduced.

Moreover, since the micro-ring resonators in the first group of micro-ring resonators 321 and the micro-ring resonators in the second group of micro-ring resonators 322 are micro-ring resonators for the same polarization mode, the same micro-ring resonators for processing the same polarized light beam can be used, two different sets of micro-ring resonators do not need to be designed, the complexity of the system is reduced, and the control complexity is reduced.

It should be understood that the polarization beam splitting unit in this embodiment may further include other devices capable of splitting and rotating the input optical signal to split the input optical signal into two polarized optical beams, such as a TE mode optical signal and a TM mode optical signal, and convert the TM mode optical signal into the TE mode optical signal. For example, the polarization beam splitting element may include a polarization beam splitter and a polarization converter, or other optical structures capable of performing this function. Similarly, the polarization beam combining unit may also include other devices capable of combining and rotating the input optical signal. The invention is not limited in this regard.

Optionally, the wavelength selective optical switch in this embodiment may further include a wavelength detection unit corresponding to the wavelength selection unit, and the wavelength detection unit is configured to detect the wavelength of the first target light beam and the wavelength of the second target light beam.

Further, the wavelength detecting unit 320 includes a first optical coupler 341 located at the output end of the first group of micro-ring resonators 321, and a first photodetector 351 connected to the first optical coupler 341, and a second optical coupler 342 located at the output end of the second group of micro-ring resonators 322, and a second photodetector 352 connected to the second optical coupler 342.

Fig. 8 is a schematic structural view of a wavelength selective optical switch according to another embodiment of the present invention. In the ith wavelength selective element, a first optical coupler 341 may be disposed at the output end of the first group of micro-ring resonators 321 for extracting a small amount of optical signal energy from the trunk to be transmitted to the first photodetector 351 for monitoring. The first optical coupler 341 outputs a part of the optical signal in the first target beam to the first optical detector 351, and the first optical detector 351 feeds back the part of the optical signal to the electrode drive of the first micro-ring resonator 321 through an external feedback circuit, thereby compensating the resonance wavelength of the first micro-ring resonator in real timeλ_iTo stabilize the wavelength of the downloaded optical signal.

In this embodiment, fig. 7 and 8 are both illustrated by taking an example in which the first set of micro-ring resonators 321 includes one micro-ring resonator, and the second set of micro-ring resonators 322 includes one micro-ring resonator. However, a plurality of microring resonators may be included in the first and second sets of

microring resonators

321 and 322, respectively. As shown in fig. 9, which is a schematic block diagram of a wavelength selective optical switch according to another embodiment of the present invention, the first group of micro-ring resonators 321 may include two cascaded micro-ring resonators, and the second group of micro-ring resonators 322 may include two cascaded micro-ring resonators. That is, one microring resonator in the above-described wavelength selection unit may be replaced with a plurality of microring resonators in cascade, and may be unchanged elsewhere. Thereby the working spectral bandwidth of the optical switch can be enlarged.

The wavelength selective optical switch described in the above embodiments is described by taking as an example one wavelength selective element included in the wavelength selective optical switch, and actually, the wavelength selective optical switch may include a plurality of such wavelength selective elements to form a large-scale optical switch matrix. The wavelength selective optical switch may further include a polarization beam splitting unit 310 as described in fig. 2 to 9, and n wavelength selecting units as described in fig. 2 to 9, wherein, according to fig. 2 to 9, a light beam which does not satisfy the target wavelength in the first polarization light beam output by the ith wavelength selecting unit, and a light beam which does not satisfy the target wavelength in the second polarization light beam output by the ith wavelength selecting unitAnd the light beams which do not meet the target wavelength in the light beams enter the (i + 1) th wavelength selection unit respectively. The beams of the first polarized beam which do not meet the target wavelength pass through the first group of micro-ring resonators in the (i + 1) th wavelength selection unit to realize the aim of meeting the target wavelength lambda_i+1The light beam which does not meet the target wavelength in the second polarized light beam passes through a second group of micro-ring resonators in the (i + 1) th wavelength selection unit to realize the selection of the light beam which meets the target wavelength lambda_i+1Selection of the light beam of (1). Wherein i is a positive integer greater than zero and less than n.

It can be seen that, in the wavelength selective optical switch in the embodiment of the present invention, the times of polarization state conversion of the first polarized light beam and the second polarized light beam are the same, so that the polarization dependent loss can be greatly reduced, which is beneficial to the performance of the optical switching node.

In addition, the first group of micro-ring resonators and the second group of micro-ring resonators are symmetrically distributed along the input direction of the optical signal, and the processing processes of the two polarized light beams are identical, so that the transmission paths of the first polarized light beam and the second polarized light beam in the optical waveguide are equal or close, the polarization-dependent loss can be further reduced, and the differential group velocity time delay can be reduced.

Compared with the wavelength selective optical switch in the prior art, the wavelength selective optical switch in the embodiment of the invention has the advantages of simple structure, compact volume and suitability for forming a large-scale optical switch matrix.

It should be noted that, based on the wavelength selective optical switch of the embodiment of the present invention, optical switches having other modified connection relationships may be connected and formed. For example, changing the directions of the incident light input port and the target output port in the wavelength selective optical switches in fig. 2 to 9 can be implemented by changing the connection relationship of the wavelength selection unit accordingly, which is not described herein again.

It should be understood that the reference herein to first, second and third and various numerical references is merely a convenient distinction for description and is not intended to limit the scope of embodiments of the invention.

It should also be understood that, in various embodiments of the present invention, the sequence numbers of the above-mentioned processes do not mean the execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

It should also be understood that the term "and/or" herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. A wavelength selective optical switch is characterized in that the wavelength selective optical switch comprises a polarization beam splitting unit and at least one wavelength selection unit, the wavelength selection unit comprises two groups of micro-ring resonators and a polarization beam combining unit,

the polarization beam combining unit is configured to combine the first target light beam received from the output end of the first group of micro-ring resonators and the second target light beam received from the output end of the second group of micro-ring resonators, and output a light beam obtained by combining the first target light beam and the second target light beam; wherein,

the first polarized light beam and the second polarized light beam do not carry out polarization state conversion or have the same polarization state conversion times.

2. The wavelength selective optical switch according to claim 1, wherein the polarization beam splitting unit transmits the first polarized light beam to the input ends of the first set of micro-ring resonators through a first optical waveguide connecting the polarization beam splitting unit and the input ends of the first set of micro-ring resonators, and the light beam of the first polarized light beam which is not coupled into the first set of micro-ring resonators continues to be transmitted along the first optical waveguide;

3. The wavelength selective optical switch according to claim 1 or 2, wherein the first polarized optical beam and the second polarized optical beam are polarized optical beams of the same mode, and wherein the micro-ring resonators of the first set of micro-ring resonators and the micro-ring resonators of the second set of micro-ring resonators are micro-ring resonators matched with the same mode.

4. The wavelength selective optical switch according to claim 3, wherein the polarization beam splitting unit comprises a polarization beam splitting rotator and the polarization beam combining unit comprises a polarization beam combining rotator.

5. The wavelength selective optical switch according to claim 1 or 2, wherein the first polarized optical beam and the second polarized optical beam are polarized optical beams of different modes, wherein the microring resonators of the first set of microring resonators are microring resonators matched with the mode of the first polarized optical beam, and the microring resonators of the second set of microring resonators are microring resonators matched with the mode of the second polarized optical beam.

6. The wavelength selective optical switch of claim 5, wherein the polarization beam splitting unit comprises a polarization beam splitter, and the polarization beam combining unit comprises a third optical waveguide for coupling the first target beam and the second target beam.

7. The wavelength selective optical switch according to claim 1 or 2, wherein the first set of microring resonators comprises one microring resonator or a plurality of microring resonators in cascade, and the second set of microring resonators comprises one microring resonator or a plurality of microring resonators in cascade.

8. The wavelength selective optical switch according to claim 1 or 2, further comprising a wavelength detection unit corresponding to the wavelength selection unit, the wavelength detection unit being configured to detect the wavelength of the first target beam and the wavelength of the second target beam.

9. The wavelength selective optical switch according to claim 8, wherein the wavelength detection unit includes a first optical coupler located at an output end of the first set of micro-ring resonators, and a first photodetector connected to the first optical coupler,

and a second optical coupler located at the output ends of the second group of micro-ring resonators, and a second photodetector connected to the second optical coupler.

10. The wavelength selective optical switch according to claim 1 or 2, wherein the first polarized light beam is an optical signal of TM mode or TE mode, and the second polarized light beam is an optical signal of TE mode or TM mode.

11. The wavelength selective optical switch according to claim 1 or 2, wherein the at least one wavelength selective element comprises a plurality of wavelength selective elements, wherein the target wavelength corresponding to each of the plurality of wavelength selective elements is different.