JP4168778B2 - Optical function device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical apparatus that performs add / drop of wavelength multiplexed light in an optical network node using wavelength demultiplexing / multiplexing technology.
[0002]
[Prior art]
With the rapid expansion of optical communication transmission capacity, the spread of wavelength multiplexing technology is progressing. The wavelength-multiplexed signal is extracted (or inserted) at a node provided on the network, and only a certain wavelength signal is extracted (or inserted), and the remaining wavelength signal is transmitted as light to the network without being converted into an electric signal (OADM) Optical Add Drop Multiplexer) is drawing attention. In recent OADMs, there is an expectation for ROADM (Reconfiguable OADM) that can freely change the wavelength signal selected at each node as needed.
[0003]
In general, the ROADM is composed of two optical elements, a wavelength multiplexer / demultiplexer and a spatial optical switch array. Its function is to spatially separate a signal in a certain wavelength band propagating through an optical fiber transmission line for each wavelength by a wavelength demultiplexer, and then selectively extract only a desired wavelength signal by a spatial switch array or insert it in reverse. The desired wavelength signal is multiplexed by a wavelength multiplexer and returned to the optical fiber transmission line.
[0004]
In a conventional optical ADM apparatus, a plurality of AWGs (Arrayed Waveguide Gratings) are used as wavelength multiplexers / demultiplexers, and a 2 × 2 Mach-Zehnder TO switch (thermo-optic switch) is used as a spatial switch array. Arranged configurations are common.
For example, a 16-channel AWG add / drop multiplexer has been proposed in which two types of components of four sets of AWGs and Mach-Zehnder type 2 × 2TO switches are monolithically integrated on the same optical waveguide substrate (for example, Non-Patent Document 1). reference).
FIG. 5 is a schematic diagram showing an outline of this conventional optical add / drop multiplexer. As a wavelength multiplexer / demultiplexer for multiplexing and branching, a double gate TO switch 51 in which four AWGs 71, 72, 73, and 74 and TO switches are connected in two stages is arranged in an array. In this configuration, the main signal light that has been transmitted through the optical transmission line is demultiplexed after being incident on the AWG 74 and is input to each double gate TO switch to be used as a main passing signal or a drop signal. Switching takes place. Each port of the switch is connected to AWG 71 and AWG 72 for multiplexing, and is multiplexed there and output as main passing signal light or drop signal light. On the other hand, the plurality of wavelength signal lights to be inserted are demultiplexed by the AWG 73, pass through the corresponding double gate switches 51, are combined by the AWG 72, and are emitted as part of the main passing signal light. .
[0005]
However, the conventional example described above has problems in reducing the element size and improving the element yield. As shown in this example, in order to integrate four AWGs as a multiplexer / demultiplexer and to function as an add / drop multiplexer, the center wavelengths of the AWGs must match. If the center wavelength of the AWG is shifted, the optical insertion loss and add / drop function characteristics of the device will be significantly deteriorated. However, it is normally expected that the center wavelength of the AWG will shift to some extent within the wafer surface. Therefore, the temperature of each AWG is individually adjusted to match the center wavelength. However, since four AWGs are close to each other, a problem of thermal crosstalk accompanying temperature adjustment is newly generated. Therefore, the integrated elements having the same center wavelength of the four AWGs are selected on the wafer. In this case, the element yield per single wafer is remarkably deteriorated.
[0006]
There is also disclosed an OADM in which two AWGs each having a loop connection between input and output optical waveguides are connected by a loopback optical path, and a 2 × 2 optical switch for switching between the two loop connections is inserted in the loopback optical path (for example, a patent) Reference 1) has not yet solved the above problem.
[0007]
[Non-Patent Document 1]
K. Okamoto et al., “16-channel optical add / drop multiplexer composed of arrayed waveguide grating and double gate switch”, Electronics Letter, August 1, 1996, Vol. 32, No. 16, p1471-1472
[Patent Document 1]
JP-A-7-270640 (page 5-7, FIG. 1)
[0008]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical functional device having an OADM function and capable of reducing the element size and improving the element manufacturing yield.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, an optical functional device of the present invention is an optical functional device for inserting / separating a signal of a predetermined wavelength from wavelength multiplexed signal light, and is an arrayed waveguide type having a plurality of optical input / output terminals. Connecting a diffraction grating, a first optical circulator connected to one of the plurality of light input ends, a second optical circulator connected to one of the plurality of light output ends, and an optical circulator at the plurality of light input ends An arrayed-waveguide-type diffraction grating having a transmission / reflection switching optical switch that switches between transmission and reflection of light, which is inserted between the remaining optical input end not connected to the remaining output end not connecting the optical circulators of the plurality of output ends The arrayed waveguide includes a reflecting mirror that reflects on both sides at a position that bisects the arrayed waveguide at the center in the optical axis direction.
[0010]
In another optical functional device of the present invention, the light input from the first port is output to the second port, and the light input from the second port is output to the third port. Connected between the circulator and the second optical circulator, and the second port of the first optical circulator and the second port of the second optical circulator, and separates light of a predetermined wavelength in accordance with external control. / Adding (adding / dropping) optical circuit, the first port of the first optical circulator is used as an input port for wavelength-multiplexed optical signals, and the third port of the first optical circulator is light of a predetermined wavelength Is an output port that outputs a new wavelength-multiplexed optical signal that has been separated / inserted, the first port of the second optical circulator is the input port that inserts an optical signal of a predetermined wavelength, and the third port of the second optical circulator The Po Is an output functional port that separates an optical signal having a predetermined wavelength, and an optical circuit includes a first slab conductor having one end connected to a plurality of input / output waveguides and the other end connected to an arrayed waveguide. An array waveguide type diffraction grating having a waveguide and a second slab waveguide, a 1 × 2 optical switch array connected to an input / output optical waveguide of the first slab waveguide, a first reflector, a second The first reflecting mirror is provided at a position that bisects the arrayed waveguide at the center in the optical axis direction, and is a first optical waveguide of two optical waveguides on the two-terminal side of the 1 × 2 optical switch. Is connected to the input / output optical waveguide of the second slab waveguide, the second optical waveguide of the optical switch is connected and terminated to the second reflecting mirror, and a plurality of inputs / outputs at the end of the first slab waveguide Among the optical waveguides, at least one optical waveguide is a second port of the first optical circulator. Connected to, among the plurality of input and output optical waveguides of the second slab waveguide end, at least one optical waveguide, characterized in that connected to the second port of the second optical circulator.
The first reflecting mirror is a reflecting mirror plate that reflects the arrayed waveguide propagation light back to both side waveguides.
The first reflecting mirror is formed by a groove provided so as to cut the arrayed waveguide and a highly reflective film disposed on both side walls of the groove.
The arrayed waveguide includes linearly parallel arrayed waveguides before and after the first reflecting mirror.
The optical switch is a thermo-optic switch.
The optical circuit is formed on the same substrate.
The second reflecting mirror is formed on the end face of the substrate.
The optical functional device is integrated into a module together with a temperature adjusting unit that controls the temperature of the optical functional device and a switch control unit that drives and controls the optical switch array.
[Action]
In the optical functional device of the present invention, the wavelength multiplexed signal light input to one slab end is reflected by a high reflection mirror installed at the center of the arrayed waveguide and returned to the same slab for demultiplexing. Each wavelength signal is controlled by each optical switch, and drop light or passing light is distributed. In this configuration, one AWG is optically divided into two by a highly reflective film at the center of the arrayed waveguide, and the form is one AWG, but logically there are two AWGs. Thus, the function of multiplexing and demultiplexing can be performed independently. Therefore, in the optical functional device of the present invention, since the number of AWGs can be reduced as compared with the above-described conventional example, it is possible to simultaneously improve the yield and reduce the size.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram showing an outline of an optical functional device of the present invention. This optical functional device has a high reflection plate 13 which is inserted in the central portion of the optical waveguide direction of the arrayed waveguide on the quartz substrate 1 and is a means for reflecting light back to the arrayed waveguide in both directions, and the first slab An AWG composed of the waveguide 2, the second slab waveguide 11, and the arrayed waveguides 12 and 14 and a 1-input 2-output directional coupler type (1 × 2) thermo-optic switch array 19 are arranged.
The first slab waveguide 2 is provided with an input / output port 16 for inputting / outputting wavelength multiplexed signal light and a wavelength separation port array 3 for separating wavelength multiplexed signal light for each wavelength. The input / output port 16 is optically connected to the external signal light input port 6 and the external signal light output port 15 via the optical circulator 20. Further, the wavelength separation port array 3 is connected to an input port of the thermo-optic switch array 19.
In the thermo-optic switch array 19, one of the output ports is optically terminated to the highly reflective film 5, and the other is connected to the wavelength separation port array 10 provided in the second slab 10.
The second slab is provided with a wavelength separation port array 10 and an input / output port 9 for inputting / outputting wavelength multiplexed signal light. The input / output port 9 is connected to an add port 8 and a drop port via an optical circulator 17. 18 is optically connected. In the configuration of the present embodiment, the AWG and the optical switch array 19 are monolithically integrated on the quartz substrate 1, but the effects and effectiveness of the present invention are not affected even if these two functions are configured on separate substrates.
[0012]
The operation of this configuration will be described below. The wavelength multiplexed signal light input to the external signal light input port 6 is guided to the input / output port 16 via the optical circulator 20 and input to the first slab 2. The wavelength multiplexed signal light that has propagated through the first slab 2 propagates through the arrayed waveguide 14 and is reflected by the high reflector 13, and travels back through the arrayed waveguide 14 to return to the first slab 2, and is separated for each wavelength. The wave is input to the optical switch array 19 via the wavelength separation port array 3.
In the optical switch array 19, the wavelength signal light that is output through as external signal light without being separated by the optical functional device is output to the first switch output port 4, reflected by the high reflection film 5, and reverses the optical path. The signal enters the first slab 2 and is multiplexed again to the input / output port 16 through the arrayed waveguide 14 and the high reflection plate 13. The signal light combined with the output port 16 is output as an external output signal light to the output port 15 via the optical circulator 20.
On the other hand, in the optical switch array 19, the wavelength signal light output to the second switch output port 7 is input to the second slab 11 via the wavelength separation port array 10, and passes through the array waveguide 12 and the high reflection plate 13. Then, it returns to the second slab 11 again and is multiplexed to the input / output port 9. The wavelength signal light combined with the input / output port 9 is output from the drop port 18 as drop signal light via the optical circulator 17.
The add signal light having the same wavelength as the drop signal light or the wavelength of any vacant channel of the wavelength multiplexed signal light is input from the add port 8 and output to the input / output port 9 via the optical circulator 17 to be the drop signal. The optical path reverses the same optical path and is output from the external signal light output port 15 to the outside through the optical circulator 20 as a part of the external output signal light.
The optical functional device of the present invention can selectively extract wavelength signal light by the switching function of the optical switch array 19 and can dynamically perform selective insertion into the wavelength signal light.
[0013]
Next, a second embodiment of the present invention will be described.
FIGS. 2A and 2B are schematic views showing a second embodiment of the present invention. Instead of the high reflection plate 13 used in the first embodiment, a high reflection film such as a metal film is formed on both walls of a groove formed so as to cross the arrayed waveguide. Yes. (B) has shown the cross-sectional shape which cut | disconnected the highly reflective groove part 23 of (a) along the AA 'line in the figure.
In the second embodiment of the present invention, the groove portion 21 is formed in the center of the arrayed waveguide between the first slab and the second slab so as to separate the arrayed waveguides 12 and 14, The highly reflective film 22 is formed by an appropriate manufacturing method such as vapor deposition or sputtering. With this configuration, it is not necessary to mount a high reflection plate as in the first embodiment, and a high reflection function can be easily provided at the center of the arrayed waveguide.
[0014]
Next, a third embodiment of the present invention will be described.
FIG. 3 is a schematic diagram showing a third embodiment of the present invention. A linearly parallel array waveguide section 30 is provided between the array waveguides 14 and 12, and a high reflection function section 31 is formed therein. Other configurations are the same as those of the first or second embodiment.
In the configuration of the present embodiment, even if the positional deviation occurs in the optical axis direction when forming the highly reflective functional part 31, the optical waveguide between the waveguides of the arrayed waveguide is within the range of the linearly parallel arrayed waveguide part 30. The phase difference is not affected by this shift. Therefore, in the third embodiment, it is possible to improve the phase error tolerance at the time of manufacture.
[0015]
Next, a fourth embodiment of the present invention will be described.
FIG. 4 is a schematic view showing an embodiment of an optical functional module incorporating the optical functional device of the present invention. To drive the temperature adjustment unit 56 on the mounting substrate 53, the first to third optical functional devices 50 disposed on the temperature adjustment unit 56, and the optical switch array included in the optical functional device 50. The optical switch driving unit 54 and the temperature control unit 52 for controlling the temperature of the temperature adjusting unit 56 are arranged at appropriate positions so as to be controlled by a control signal from the external signal processing unit 55. .
In the optical functional module of the present invention, it is possible to insert and extract a light wave with respect to an arbitrary wavelength signal light in a certain wavelength band by an appropriate external electric signal.
[0016]
【The invention's effect】
As described above, in the configuration of the present invention, the demultiplexing and multiplexing functions can be performed optically independently with an AWG of the same size as the conventional one without causing an increase in size. This makes it possible to reduce the number of AWGs required for each optical functional device such as an optical add / drop multiplexer, wavelength blocker, dynamic level equalizer, etc., and realize an optical functional device that is smaller and less expensive than conventional ones. be able to.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a first embodiment of an optical functional device according to the present invention.
FIG. 2 is a schematic view showing a second embodiment of the optical functional device according to the present invention.
FIG. 3 is a schematic view showing a third embodiment of the optical functional device according to the present invention.
FIG. 4 is a schematic diagram showing an outline of an optical functional module incorporating the optical functional device of the present invention.
FIG. 5 is a schematic diagram showing an outline of a conventional optical functional device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Quartz substrate 2 First slab waveguide 3 Wavelength separation port array 4 First switch output port 5 High reflection film 6 External signal light input port 7 Second switch output port 8 Add port 9 Input / output port 10 Wavelength separation port array 11 Second slab waveguide 12 Array waveguide 13 High reflector 14 Array waveguide 15 Output port 16 Input / output port 17 Optical circulator 18 Drop port 19 Optical switch array 20 Optical circulator 21 Groove 22 High reflective film 23 High reflective groove 30 Linear parallel Array waveguide section 31 High reflection function section 50 Optical function apparatus 51 Double gate TO switch 52 Temperature control section 53 Mounting substrate 54 Optical switch drive section 55 External signal processing section 56 Temperature adjustment section 71 AWG
72 AWG
73 AWG
74 AWG

Claims (9)

An optical functional device for inserting / separating a signal of a predetermined wavelength from wavelength-multiplexed signal light,
An arrayed waveguide type diffraction grating having a plurality of light input / output terminals;
A first optical circulator connected to one of the plurality of optical input ends;
A second optical circulator connected to one of the plurality of optical output ends;
The light input ends of the plurality of light input ends that are not connected to the optical circulator and the remaining output ends of the plurality of output ends that are not connected to the optical circulator are switched between transmission and reflection of light. It has a transmission / reflection switching light switch,
The arrayed waveguide provided in the arrayed waveguide grating includes a reflecting mirror that reflects on both sides at a position that bisects the arrayed waveguide at the center in the optical axis direction.
An optical functional device. A first optical circulator and a second optical circulator that output light input from the first port to the second port and output light input from the second port to the third port;
Connected between the second port of the first optical circulator and the second port of the second optical circulator, and separates / inserts (adds / drops) light of a predetermined wavelength in accordance with external control And an optical circuit that
A new wavelength-multiplexed optical signal in which the first port of the first optical circulator is used as an input port for wavelength-multiplexed optical signals, and the third port of the first optical circulator is used to separate / insert light of the predetermined wavelength Output port,
The first port of the second optical circulator is used as an input port for inserting the optical signal of the predetermined wavelength, and the third port of the second optical circulator is an output port for separating the optical signal of the predetermined wavelength. An optical functional device,
The optical circuit is
An arrayed waveguide grating having a first slab waveguide and a second slab waveguide, one end of which is connected to a plurality of input / output waveguides and the other end is connected to an arrayed waveguide;
A 1 × 2 optical switch array connected to an input / output optical waveguide of the first slab waveguide;
A first reflector;
A second reflector,
The first reflecting mirror is provided at a position that bisects the arrayed waveguide at the center in the optical axis direction;
Of the two optical waveguides on the two-terminal side of the 1 × 2 optical switch, the first optical waveguide is connected to the input / output optical waveguide of the second slab waveguide, and the second optical waveguide of the optical switch Is connected and terminated to the second reflector,
Among the plurality of input / output optical waveguides at the end of the first slab waveguide, at least one optical waveguide is connected to the second port of the first optical circulator;
Among the plurality of input / output optical waveguides at the end of the second slab waveguide, at least one optical waveguide is connected to the second port of the second optical circulator,
An optical functional device. The first reflecting mirror is a reflecting mirror plate that reflects the arrayed waveguide propagation light back to both side waveguides.
The optical functional device according to claim 2. The first reflecting mirror is formed by a groove provided so as to cut the arrayed waveguide and a highly reflective film disposed on both side walls of the groove.
The optical functional device according to claim 2. The arrayed waveguide includes linearly parallel arrayed waveguides before and after the first reflecting mirror,
The optical functional device according to claim 2. The optical switch is a thermo-optic switch,
The optical functional device according to claim 1. The optical circuit is formed on the same substrate,
The optical functional device according to claim 2. The second reflecting mirror is formed on the end surface of the substrate.
The optical functional device according to claim 7. The optical functional device is integrated into a module together with a temperature adjusting unit that controls the temperature of the optical functional device and a switch control unit that drives and controls the optical switch array.
The optical functional device according to claim 7, wherein:

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