JP2009180836A - Optical signal processor and control method of the optical signal processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical signal processor which can obtain a rectangular transmission spectrum, has a low power consumption regarding the drive and can control a transmission band region and transmission intensity, independently with respect to a plurality of channels, and to provide a control method of the optical signal processor. <P>SOLUTION: The optical signal processor includes: an array waveguide grid 101 which separates an optical signal into a plurality of optical signals having different wavelengths at an emission angle, according to the wavelength of the optical signal; lenses 102, 103 for condensing the optical signals emitted from the array waveguide grid; and a spatial optical modulator 104 for modulating the optical signals condensed, wherein the spatial optical modulator is provided with a plurality of phase imparting cells according to the optical signals of respective wavelengths, and the plurality of phase imparting cells contain at least one element that imparts a phase change which is ≥0 and ≤π, to the condensed optical signal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical signal processing device and an optical signal processing device control method, and more particularly to an optical signal processing device and an optical signal processing device control method capable of arbitrarily setting a transmission band and transmission intensity.

  In recent years, the construction of large-capacity optical communication networks that show rapid development is shifting from the mainstream point-to-point type to the ring mesh type. ROADM (Reconfigurable Optical Add / Drop Multiplexer), which is a typical example of a ring mesh type network, adds / drops a specific channel without converting wavelength multiplexed signal light into an electrical signal at a node relaying each ring network. Need to do. In constructing such a flexible optical network, a filtering device capable of arbitrarily setting a transmission band and a transmission intensity is very important. Examples of this device include an optical wavelength tunable filter that can arbitrarily set the center wavelength and transmission band, an optical gain equalizer that equalizes the gain spectrum in an optical fiber amplifier regardless of wavelength, and the spectral characteristics of each frequency channel. An optical channel monitor and an optical performance monitor for monitoring can be mentioned, and a wavelength blocker capable of controlling the transmission intensity for each channel can be regarded as one form of the filtering device. It has great significance for the development of large-capacity optical communications.

  Among the devices described above, for example, reports of wavelength tunable filters include a type using a dielectric multilayer film (see Non-Patent Document 1), a type using a fiber Bragg grating (see Non-Patent Document 2), and the like.

N. Mekada et al., “Polarization independent, linear-tuned interference filter with constant transmission characteristics over 1530-1570-nm tuning range”, IEEE Photonics Technology. Letters, Vol. 9, No. 6, June 1997, pp. 782. -784. A. Iocco et al., “Tension and compression tuned Bragg grating filter”, Proceeding of ECOC 1998, Vol.1, September 1998, pp.229-230.

  In the case of a conventional wavelength tunable filter, for example, a filter using a dielectric multilayer film disclosed in Non-Patent Document 1 has a method of changing the angle of the dielectric multilayer film with respect to incident light, or a film thickness that is inclined. A method of changing the incident position of signal light with respect to a special dielectric multilayer film has been reported. In these types of filters, the insertion loss varies due to the transmission band tuning. Accordingly, there is a problem that the transmission spectrum becomes broad and the transmission spectrum does not become rectangular unless the dielectric multilayer film is used in multiple stages. In addition, in a filter using a fiber Bragg grating, a method of changing a temperature or applying a tension is generally used as a means for tuning a transmission band. However, when the temperature is changed, an enormous amount of electric power for driving a heater is retained. In order to apply tension, it is necessary to take measures against mechanical vibration, so there are various barriers to practical use.

  In any method, single channel operation is the main function, and it is extremely difficult to realize a device capable of controlling a plurality of channels simultaneously.

  As described above, the characteristics used for the wavelength tunable filter are important in that 1: a rectangular transmission spectrum can be obtained, 2: low power consumption is required for driving, and 3: multi-channel operation is possible. is there. It is also important that it can function as a wavelength blocker. These points are not limited to the wavelength tunable filter, but are concerns common to all filtering devices that simultaneously control the transmission band and the transmission intensity.

  The present invention has been made in view of such a problem, and an object of the present invention is to obtain a rectangular transmission spectrum and to reduce the transmission power and the transmission intensity for a plurality of channels with low power consumption for driving. An object of the present invention is to provide an optical signal processing device that can be controlled independently and a method for controlling the optical signal processing device.

  In order to achieve the above object, an optical signal processing device according to the present invention splits an optical signal into a plurality of optical signals having different wavelengths, and performs optical signal processing on the optical signals of the respective wavelengths. A processing device, a spectroscopic unit that splits a plurality of optical signals having different wavelengths at an emission angle corresponding to the wavelength of the optical signal, a unit that condenses the optical signal output from the spectroscopic unit, and the collection unit Signal processing means for modulating the emitted optical signal. The signal processing means includes a plurality of signal processing elements arranged in the direction of intersection with the spectral plane formed by the signal light from the spectroscopic means corresponding to the optical signal of each wavelength. The plurality of signal processing elements include at least one element that gives a phase change of 0 to π to the collected optical signal, and the element can freely set the amount of phase change given to the optical signal. .

  In addition, the control method of the optical signal processing device according to the present invention includes selecting at least two signal processing elements from a plurality of signal processing elements provided in the optical signal processing device, and each of the selected signal processing elements is Setting the phase change amount of the element of the selected signal processing element so as to independently give a phase change of greater than 0 and less than π to the collected optical signal; and a signal processing element excluding the selected signal processing element Includes setting the phase change amount of the elements of the signal processing elements other than the selected signal processing element so as to alternately give a phase change of 0 and π to the collected optical signal. Alternatively, all of the plurality of signal processing elements included in the optical signal processing device provide the elements of all the signal processing elements so as to give the collected optical signal a phase change greater than 0 and less than π. Setting the amount of phase change.

  An embodiment of the optical signal processing device of the present invention is an optical signal processing device capable of arbitrarily setting a transmission wavelength range and a transmitted light intensity, and includes at least one input port, at least one output port, and the input port. A wavelength demultiplexing element as a spectroscopic means for demultiplexing a wavelength multiplexed signal that is more incident, at least one lens as a condensing means, and a spatial light modulator as a signal processing means.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments. In the following description and the drawings, the same reference numerals indicate the same or corresponding elements, and duplicate descriptions are omitted.

(First embodiment)
FIG. 1 is a diagram showing a configuration of a first embodiment of an optical signal processing device according to the present invention, in which (a) is a top view and (b) is a side view.

  As shown in FIG. 1, the optical signal processing apparatus according to this embodiment includes a circulator 106 to which an input fiber 105, a connection fiber 107 and an output fiber 108 are connected, and an arrayed waveguide grating 101 connected to the connection fiber 107. The first Y cylindrical lens 102 having a focal length of fY, the condensing lens 103 having a focal length of fX, and the spatial light modulator 104 are arranged in this order. In the description of the present embodiment, the Y cylindrical lens 102 and the condenser lens 103 are used in this order as the lens system. However, any number of lenses may be used as long as they have the same optical characteristics. There is no problem even if such an arrangement is used.

  Here, the horizontal direction of the signal light emission end face of the substrate of the first arrayed waveguide grating 101 is X, the vertical direction is Y, and the traveling direction of the light wave, that is, the optical axis is Z.

  FIG. 2 is a diagram showing a detailed configuration of the arrayed waveguide grating 101 as a wavelength demultiplexer and a multiplexer. As shown in FIG. 2, the arrayed waveguide grating 101 includes a first slab waveguide 202 connected to the input side optical waveguide 201, an arrayed waveguide 203 connected to the first slab waveguide, and an arrayed waveguide 203. And a second slab waveguide 204 connected to the. The second slab waveguide 204 may or may not be provided.

  FIG. 3A is a diagram showing a detailed configuration of the spatial light modulator 104. As shown in FIG. 3A, the spatial light modulator 104 has a structure in which phase imparting cells 302 that can impart an arbitrary phase shift to incident light are arranged one-dimensionally on a substrate 301. In this spatial light modulator 104, the pitch between cells is defined as P, the gap amount between cells is defined as G, and the number of arranged cells is defined as N, which will be used in the following description. In this embodiment, the signal processing means of the optical signal processing device is configured by N cells, and a signal corresponding to an optical signal having a certain wavelength is formed by a part of N cells (including at least one cell). A description will be given assuming that the processing element is configured. In the present invention, the minimum amount of phase shift that can be modulated with respect to signal light by each cell is π, but this is a spatial light modulator that can modulate at least 2π from the viewpoint of use in an actual device. Preferably there is. Also, as a general means for giving a phase shift to each cell, one using a micro-electro-mechanical system (MEMS) and one using a refractive index modulation element represented by a liquid crystal or the like is used. For example, an element called LCOS (Liquid Crystal on Silicon) is used. Spatial light modulators that use MEMS as a means for providing a phase shift have a structure in which each cell has a movable mirror structure and can reflect light in either direction. In the example, a structure in which the mirror is movable parallel to the Z axis is most preferable. Further, even in the case where a refractive index modulation element is used as a means for giving a phase shift, a structure in which the phase-modulated signal light is reflected in the Z-axis direction as in the feature by the MEMS is preferable.

Next, the operation of the optical signal processing apparatus of this embodiment will be described. First, the signal light input to the input fiber 105 is input to the arrayed waveguide grating 101 via the circulator 106. The input signal light passes through the input side optical waveguide 201, the first slab waveguide 202, the arrayed waveguide 203, and the second slab waveguide 204 in this order. The arrayed waveguide grating 101 is designed to have a demultiplexing characteristic with an operating center wavelength λ ₀ and a free spectral range FSR. The optical signal output from the arrayed waveguide grating 101 diverges in the direction perpendicular to the substrate immediately after being emitted from the substrate, but is converted into parallel light in the Y direction by the Y cylindrical lens 102 disposed at the position fY from the end face of the arrayed waveguide grating. Conversion is performed (FIG. 2B). The optical signal that has passed through the Y cylindrical lens 102 is demultiplexed for each wavelength by passing through the condensing lens 103 disposed at a position separated by fX from the end face of the arrayed waveguide grating 101 in the Z-axis direction. The light is condensed on the spatial light modulator 104 disposed at a position fX from the main surface of the condenser lens (FIG. 2A). As will be described in detail later, the collected light is reflected after being subjected to an arbitrary phase change by the spatial light modulator 104 for each wavelength, and connected to the connecting fiber 107 and the circulator 106 via the same arrayed waveguide grating 101. And output from the output fiber 108.

  In the present invention, it operates as an optical signal processing device by generating a wavelength-dependent phase change amount applied on the spatial light modulator 104. When each of the light of a plurality of wavelengths demultiplexed by the arrayed waveguide grating 101 is condensed so as to straddle a plurality of adjacent phase providing cells 302 of the spatial light modulator 104, the phase change which is different in each phase providing cell 302 The received light interferes with each other. Therefore, the intensity of light recombined with the arrayed waveguide grating 101 varies depending on the phase setting provided by each phase providing cell 302 in the spatial light modulator 104. When the intensities after being subjected to a phase change by cells 1 and 2 having a certain wavelength and incident on adjacent cells 1 and 2 of spatial light modulator 104 are I1 and I2, respectively, the phase difference between cells 1 and 2 is obtained. If φ, the interference light intensity I is expressed by the following equation (1).

When the equation (1) is modified and an equation for obtaining the intensity of the interference light is derived from the phase difference between the cells 1 and 2, the following equation (2) is obtained.

When the phase difference φ is π in the equations (1) and (2), a completely destructive interference condition is satisfied, so that the light intensity recombined with the arrayed waveguide grating 101 is minimized, and ideally I ₁ = completely extinguished when I ₂ holds. Therefore, when a phase periodic structure in which the phase difference between adjacent cells is always π is set under the condition that I ₁ = I ₂ is satisfied, the light incident on the spatial light modulator 104 is retransmitted to the arrayed waveguide grating 101. It does not bond and the transmission intensity is the lowest.

Here, regarding the phase control method of the spatial light modulator 104 in FIG. 3A, as shown in FIG. 3B, the phase difference between the adjacent cells is π with respect to some of the phase-giving cells. A phase difference that does not become necessary is set to φ ₀ (in this specification, a phase-giving cell group that sets such a phase difference is called a phase defect portion). When the phase difference of the cell is φ ₀ ≠ π, interference based on the formula (1) is applied to light having a wavelength collected near the cell among light demultiplexed by the arrayed waveguide grating 101. Is generated, and is modulated and reflected to an intensity different from the modulation intensity in the phase periodic structure portion of the frequency. That is, the light irradiated to the phase periodic structure portion is quenched, and only the light irradiated to the intentionally generated phase defect portion is not completely quenched, and a part or all of the light is coupled to the arrayed waveguide grating 101. . In particular, when the phase difference φ ₀ = 0 of the phase defect portion is established, in principle, it is coupled to the arrayed waveguide grating 101 with an intensity equal to the intensity I of the incident light.

Based on the above principle, the optical signal processing apparatus according to the present invention is controlled to realize a desired function. For example, it is possible to change the center wavelength by controlling the position of the phase defect portion and change the transmission band by controlling the range of the phase defect portion. Further, as is apparent from the above-described equation for determining the light intensity after interference, the transmission intensity can be changed by controlling the phase difference φ ₀ in the phase defect portion.

  Further, the configuration of the present invention will be examined in detail. As shown in FIG. 3A, when the pitch between cells in the spatial light modulator 104 is defined as P, the gap amount between cells is defined as G, and the number of cells used is defined as N, the cell filling rate in the X-axis direction Fill factor can be defined by the following formula.

When the value defined by the fill factor is less than 1, leakage light is generated due to the existence of a gap portion to which an arbitrary phase change cannot be imparted. As the leakage light intensity increases, the diffraction loss increases, the insertion loss increases, and there is a concern that the crosstalk increases without being completely extinguished. Therefore, a spatial light modulator with a fill factor of 1 is used. It is best to use. In addition, if a spatial light modulator having a fill factor value of 0.5 is used and the amount of phase change when the leaked light is reflected is assumed to be 0 (that is, the substrate 301 between cells sets the phase change amount to 0). It should be noted that when configured to function as a set phase providing cell), it is possible to obtain characteristics similar to the above principle by setting the phase change amount in the phase providing cell to π. In such a spatial light modulator, although the set wavelength resolution is lowered, the spatial light modulator can be created with a relatively simple configuration, so that it is effective to promote cost reduction.

  Further, the beam size when light of a certain wavelength is collected on the spatial light modulator 104 will be considered. As the beam size (beam radius) is smaller, the shape of the transmission spectrum is rectangular, and good characteristics as a filter can be obtained. However, if the beam size (beam radius) is too small with respect to the inter-cell pitch P, the light irradiated to the center of the cell is reflected without substantially interfering with it, so that the array waveguide grating 101 is hardly quenched. There is concern about the effect of coupling or causing fluctuations in transmission characteristics. On the other hand, when the beam size is too large, the influence of the phase defect portion is reduced, and there is a concern that the extinction ratio is deteriorated or the shape of the transmission spectrum becomes broad with respect to the frequency axis. For this reason, it is most preferable that the beam size is designed to be about 1 to 2 times P. By designing the beam size in this way, the beam is irradiated across at least two cells, and the shape of the transmission spectrum becomes more rectangular. Further, with respect to the free spectral range FSR of the arrayed waveguide grating 101, the center wavelength can be set with a higher resolution with respect to the frequency as the number N of the cells 302 in the spatial light modulator 104 increases, and the transmission spectrum. Since N can be made close to a rectangle, N is preferably as large as possible.

  FIG. 4 shows a setting example of the phase defect portion in the spatial light modulator of the optical signal processing device according to the present embodiment. In FIG. 4, the phase is set so that the left and right 40 pixels (total of 80 pixels) of the center frequency have a phase defect structure in which the phase setting is 0, and the other part has a phase periodic structure.

FIG. 5 shows a characteristic example of the optical signal processing apparatus according to the present embodiment. In FIG. 5, as specific values, the FSR of the arrayed waveguide grating 101 is designed to be 100 GHz, the center wavelength is 1.55 μm, and the inter-pixel pitch P is 5 μm so that the fill factor of the spatial light modulator is 1. , The gap amount G between cells is 0 (pixel width W = P, height H is larger than the beam diameter), the number of cells is 256 pixels / FSR, and the beam size of a certain wavelength is 2 pixels worth The characteristic of the transmission spectrum of one signal light demultiplexed by the arrayed waveguide grating 101 when the radius is set (that is, twice P) is shown. FIG. 5 shows the characteristics of the transmission spectrum with respect to the frequency of the signal light when the phase defect portion is set to 2 pixels, 80 pixels, 160 pixels, and 240 pixels, respectively. From this result, it can be seen that the transmission band can be changed by controlling the range of the phase defect portion in the phase periodic structure. In this embodiment, the 3 dB band is 1.6 GHz, and the setting wavelength resolution is 3.28 × 10 ⁻³ nm. Further narrowing of the 3 dB band and improvement of the set wavelength resolution can be achieved by increasing N. Further, in the characteristic example of FIG. 5, only the transmission wavelength is selected (that is, only functions as a wavelength blocker), but the intensity is changed by changing the value of the phase difference φ ₀ in the phase defect portion as will be described later. Note that modulation can occur simultaneously.

  Further, as an advantage of the present embodiment, since an arrayed waveguide grating is used as the wavelength demultiplexing element, it is possible to realize an optical signal processing apparatus having a high set wavelength resolution with a small optical system. In addition, since the arrayed waveguide grating is easy to connect directly to the optical fiber, it is highly mountable. Further, in this embodiment, since the operation is performed only by controlling the phase modulation amount of the spatial light modulator, generally the power consumption of the spatial light modulator can be kept low. Furthermore, by using, for example, a refractive index modulation element typified by liquid crystal as the spatial light modulator, there are no movable parts, and high reliability can be ensured.

  Also, the operation as a notch filter that suppresses transmission of only a specific wavelength can be easily performed as described above.

(Second Embodiment)
The optical signal processing device of the present invention can change the applied frequency band and the number of channels basically by changing the design of the arrayed waveguide grating 101, and can be very flexible in the production of optical signal processing devices of different specifications. It is. For example, by controlling the position of the phase defect portion described with reference to FIG. 3 to be variable, the optical signal processing device can function as a wavelength tunable filter that supports multiple channels.

  FIG. 6 is a diagram illustrating an example in which phase defect portions are arranged so that the optical signal processing device functions as a wavelength tunable filter. As shown in FIG. 6, only the light incident on the phase defect portion is coupled to the AWG, and the light incident on the phase periodic structure portion cancels and does not couple to the AWG. It can function as a wavelength tunable filter that can operate. FIG. 7 shows an example of characteristics when the FSR of the above-described arrayed waveguide grating is 1000 GHz. FIG. 7 shows the characteristics of the transmission spectrum of 10-ch signal light having different center frequencies from each other. The central wavelengths of these signal lights differ by 100 GHz. If 100 GHz is defined as one channel, FIG. 7 shows an example of simultaneous independent operation of 10 channels by controlling the application range of the phase defect portion. It is also possible to realize a wavelength tunable filter corresponding to multiple channels. In FIG. 7, the phase defect portion is set to 240 pixels for each signal light having a center wavelength of −450, −50, and 350 GHz, and the phase defect portion is set for each signal light having a center wavelength of −350, 250 GHz. Is set to 160 pixels, the phase defect portion is set to 80 pixels for signal light having a center wavelength of 150 GHz, and the phase defect portion is set to 2 pixels for signal light having a center wavelength of −250, 50 GHz. In this example, the phase defect portion is set to 0 pixels for signal light having a center wavelength of −150, 450 GHz.

  Furthermore, the shape of the transmission spectrum is not limited to the rectangular spectrum shown in FIG. 5 and FIG. 7 as an example of the characteristics in this embodiment, and the intensity can be controlled independently for each wavelength. realizable. By using this feature, it can be applied to an optical gain equalizer.

  Further, in addition to the configuration of FIG. 1, an optical detector is connected to the output fiber 108, the phase setting of the spatial light modulator 104 is changed, the position of the phase defect portion is kept constant, and the position is continuously changed to increase the detector intensity. By monitoring, a transmission intensity sweep in a specific frequency region is possible.

  FIG. 8 is a diagram illustrating a state in which the position of the phase defect portion is controlled so as to sweep the transmission intensity in a specific frequency region. In FIG. 8, only light having a wavelength that irradiates the phase defect portion is transmitted and coupled to the AWG in a certain time zone, and the light intensity is measured by the photodetector. Next, when the position is moved in the direction of the arrow (that is, on the high frequency side) while maintaining the width of the phase defect portion, only the light having the wavelength irradiated to the phase defect portion after the movement is transmitted and coupled to the AWG. The light intensity is measured with a photodetector. By repeating the position at a high speed over a period of −50 GHz to 50 GHz while maintaining the width of the phase defect portion, it is possible to apply to an optical performance monitor or the like that can measure the light intensity of each wavelength almost in real time.

  FIG. 9 shows an example of the transmission characteristics when the position of the phase defect portion is controlled as described with reference to FIG. From this characteristic, it can also be used for an optical performance monitor, and can be used for a very wide range of applications as a filtering device.

(Third embodiment)
FIG. 10 is a diagram showing the configuration of the third embodiment of the optical signal processing device according to the present invention. (A) is a top view, (b) is a side view.

  As shown in FIG. 10, the optical signal processing apparatus according to the present embodiment is characterized in that a reflective spatial light modulator is not used and a transmissive configuration is used. The optical signal processing apparatus according to the present embodiment applies a first arrayed waveguide grating 701 connected to the input connection fiber 708, a first Y cylindrical lens 702 having a focal length of fY, and a focal length of fX in order to apply phase modulation. A first condensing optical system having the first condensing lens 703, a spatial light modulator 704, a second condensing lens 705 having a focal length of fX and a focal length for outputting phase-modulated light. A second condensing optical system having a second Y cylindrical lens 706 of fY and a second arrayed waveguide grating 707 connected to the output connecting fiber 709 are arranged in this order. In the description of the present embodiment, the Y cylindrical lenses 702 and 706 and the condenser lenses 703 and 705 are used in this order as the lens system. However, any number of lenses may be used as long as they have similar optical characteristics. It does not matter if any arrangement is used. In order to couple light emitted from the arrayed waveguide grating 701 most efficiently to the arrayed waveguide grating 709, it is most preferable that the arrayed waveguide gratings 701 and 709 have the same structure.

  The arrayed waveguide gratings 701 and 709 are the arrayed waveguide grating 101 in the first embodiment, the Y cylindrical lenses 702 and 706 are in the Y cylindrical lens 102 in the first embodiment, and the condensing lenses 703 and 705 are the condensed lights in the first embodiment. It corresponds to the lens 103. Therefore, the detailed description about these effects is omitted.

  Details of the spatial light modulator 704 in this embodiment are shown in FIG. The spatial light modulator 704 includes a liquid crystal substrate 801 and a phase-giving cell 802. The input-side transparent electrode 803 and the output-side transparent electrode 804 are sandwiched between the liquid crystal substrate 801 in the z-axis direction in order to form the phase-giving cell 802. N pieces are arranged, respectively, but if the phase applying cells 802 have a structure that changes the phase independently, there is no problem even if, for example, a single ground electrode structure in which all the output side electrodes are connected is used. Moreover, although the most common indium tin oxide was used as the material for the transparent electrode, any material may be used as long as it has a similar function, and a different structure may be used. Furthermore, although a spatial light modulator using liquid crystal is used in this embodiment, an electro-optic crystal such as potassium tantalate niobate or lithium niobate may be used as long as the element has a similar function. Of course, there is no problem even if any element is used as long as the material uses a variable rate material.

  In this embodiment, an example of an optical signal processing apparatus having a transmissive configuration using a spatial light modulator is shown. Unlike the first embodiment, the input light is coupled to an arrayed waveguide grating having a similar structure after a desired phase change is given to each wavelength independently by the spatial light modulator. As for the phase distribution of the spatial light modulator at this time, it is possible to transmit a specific wavelength by providing a phase defect portion in the phase periodic structure, as in the first embodiment. Further, it can function as a wavelength blocker as will be described later. In this embodiment, since the demultiplexing element and the multiplexing element are used separately, it is possible to omit the circulator necessary for the reflective configuration, and to reduce the cost and further reduce the insertion loss. A signal processing device can be realized. Further, in the reflection type, unnecessary reflected light on the end face of each optical element is coupled to the arrayed waveguide grating, which causes deterioration of characteristics. However, in the transmissive configuration in this embodiment, unnecessary reflected light is reflected in the second array. Since it does not couple to the waveguide grating, it greatly contributes to good characteristics closer to the calculation result.

(Fourth embodiment)
In the fourth embodiment, light intensity control that can operate as a wavelength blocker will be described. The basic configuration is the same as that in the first or third embodiment, but the method of providing a phase in the spatial light modulator is different. In the description of the present embodiment, the reflection type configuration shown in FIG. 1 is used. However, there is no problem even if the transmission type configuration shown in FIG. 10 is used.

  The intensity of the signal light subjected to interference by the spatial light modulator 104 is as shown in the above formulas (1) and (2). In these equations, φ corresponds to the phase difference between the two cells, and the extinction ratio is maximum when φ = π, and the extinction ratio is minimum when φ = 0. However, when the phase change φ is set to a value between π and 0, they cannot be completely weakened and a part of the interference light is coupled to the arrayed waveguide grating. From this principle, it is possible to arbitrarily control the transmission intensity by controlling the phase difference φ in the periodic phase structure. Regarding the intensity control mechanism, it should be noted that a filter capable of simultaneously controlling the transmission wavelength and the transmission intensity can be realized by combining with the transmission range control mechanism of the phase defect portion shown in the first and third embodiments.

  FIG. 12 is a diagram illustrating a setting example of the phase defect portion in the spatial light modulator for causing the optical signal processing device to function as a wavelength blocker. As shown in FIG. 12, the phase of the cell of the phase defect portion in the spatial light modulator is set so that 0 and A are alternately arranged. At this time, the transmission intensity changes based on the above formula (1) at all wavelengths. Therefore, by changing the phase A, the optical signal processing device can function as a wavelength blocker.

  FIG. 13 shows an example of characteristics of the optical signal processing apparatus according to the present embodiment. In FIG. 13, as specific values, the FSR of the arrayed waveguide grating 101 is designed to be 100 GHz, the center wavelength is 1.55 μm, the fill factor of the spatial light modulator is 1, and the number of cells is 256 pixels / FSR. The beam size of a certain wavelength is set to a radius of 2 pixels. Further, the transmission intensity is controlled from 0 dB to −35 dB by changing the phase change amount φ (0 ≦ φ ≦ π). The transmission range in FIG. 13 is an example of characteristics when one-channel control is performed, but by increasing the FSR of the arrayed waveguide grating 101 and corresponding the number of cells of the spatial light modulator 104, the transmission range in FIG. It is of course easy to perform a 10-channel collective operation similar to that shown in FIG.

  FIG. 14 is a diagram illustrating an example in which the phase defect portion is arranged so that the optical signal processing device functions as a wavelength blocker that operates in a plurality of channels at once. FIG. 14 is similar to the setting example of the phase defect portion shown in FIG. 12 in that the phase of the cell of the phase defect portion in the spatial light modulator is set so that 0 and A are alternately arranged. By changing the value of A for each frequency and setting it, a plurality of channels can be operated simultaneously and independently. The closer the value of A is to π, the smaller the transmission intensity becomes, and the closer it is to 0, the more completely the light is transmitted.

  FIG. 15 shows an example of the characteristic of the intensity controller for such 10-channel independent operation. In this embodiment, it can be operated as a wavelength blocker capable of controlling the transmission intensity independently for each channel. As a feature of the wavelength blocker of this embodiment, since the configuration between the channels is seamless, it is advantageous in that a wideband wavelength blocker that hardly causes band degradation at the channel end can be realized.

It is a figure which shows the structure of the optical signal processing apparatus of 1st Embodiment, (a) is a top view, (b) is a side view. It is a figure which shows the structure of the arrayed-waveguide grating | lattice of the optical signal processing apparatus of 1st Embodiment. (A) is a figure which shows the detailed structure of the spatial light modulator of the optical signal processing apparatus of 1st Embodiment, (b) is a figure which shows an example of the phase modulation amount in a spatial light modulator. It is a figure which shows the example of 1 setting of the phase defect part in the spatial light modulator of the optical signal processing apparatus by this embodiment. It is a figure which shows the example of a characteristic as a wavelength variable filter of the optical signal processing apparatus by 1st Embodiment. It is a figure which shows an example which has arrange | positioned the phase defect part so that the optical signal processing apparatus by 2nd Embodiment may function as a multi-channel wavelength variable filter. It is a figure which shows the example of a characteristic as a 10ch wavelength variable filter of the optical signal processing apparatus by 2nd Embodiment. It is a figure for demonstrating a mode that the position of a phase defect part is controlled so that the optical signal processing apparatus by 2nd Embodiment sweeps the transmission intensity of a specific frequency area | region. It is a figure which shows the example of a characteristic as an optical performance monitor of the optical signal processing apparatus by 2nd Embodiment. It is a figure which shows the structure of the optical signal processing apparatus of 3rd Embodiment, (a) is a top view, (b) is a side view. It is a figure which shows the detailed structure of the spatial light modulator of the optical signal processing apparatus of 3rd Embodiment, (a) is a top view, (b) is a side view. It is a figure which shows one setting example of the phase defect part in the spatial light modulator for functioning the optical signal processing apparatus of 4th Embodiment as a wavelength blocker. It is a figure which shows the characteristic as a wavelength blocker of the optical signal processing apparatus of 4th Embodiment. It is a figure which shows the example of 1 setting of the phase defect part in the spatial light modulator for functioning the optical signal processing apparatus by 4th Embodiment as a wavelength blocker which carries out multiple channel collective operation. It is a figure which shows the characteristic as a 10ch wavelength blocker of the optical signal processing apparatus of 4th Embodiment.

Explanation of symbols

101,701,707 Array waveguide grating 102,702,706 Cylindrical lens 103,703,705 Condensing lens 104,704 Spatial light modulator 302,802 Phase assignment cell 803,804 Electrode

Claims (8)

An optical signal processing device that splits an optical signal into a plurality of optical signals of different wavelengths and performs signal processing on the optical signals of each wavelength,
A spectroscopic means for splitting a plurality of optical signals having different wavelengths at an emission angle according to the wavelength of the optical signal;
Condensing means for condensing the optical signal emitted from the spectroscopic means;
Signal processing means for modulating the collected optical signal,
The signal processing means includes a plurality of signal processing elements arranged in a direction intersecting with a spectral plane formed by signal light from the spectroscopic means corresponding to the optical signals of the respective wavelengths, and the plurality of signals The processing element includes at least one element that gives a phase change of 0 to π to the collected optical signal, and the element can freely set the amount of the phase change. apparatus.   A part of the plurality of signal processing elements gives a phase change greater than 0 and less than π to the collected optical signal, and a signal processing element excluding a part of the plurality of signal processing elements is the collected light. The optical signal processing apparatus according to claim 1, wherein the amount of phase change of the element can be set so as to alternately give a phase change of 0 and π to the signal. The intensities after an optical signal of a certain wavelength incident on the adjacent first element and second element of the signal processing means undergoes a phase change by the first element and the second element are I ₁ and I, respectively. ₂ , the difference Φ of the amount of phase change set in the first element and the second element in order to set the intensity of the interference optical signal by the first element and the second element to I,

The optical signal processing apparatus according to claim 1, wherein an amount of phase change of the first element and the second element is set so as to satisfy the above.   4. The optical signal processing apparatus according to claim 1, wherein an arrayed waveguide grating including an input waveguide, a slab waveguide, and an arrayed waveguide is used as the spectroscopic means.   5. The optical signal processing apparatus according to claim 1, wherein the signal processing means has a structure in which refractive index modulation elements as the elements are arranged.   2. The signal processing element is configured such that a pitch between the elements is ¼ to ½ times a diameter of the beam of the collected optical signal. The optical signal processing device according to any one of 1 to 5. A method for controlling an optical signal processing device according to any one of claims 1 to 6,
Selecting at least two signal processing elements from the plurality of signal processing elements;
Setting a phase change amount of the selected signal processing element so that each of the selected signal processing elements independently gives a phase change of greater than 0 and less than π to the collected optical signal; And the signal processing elements other than the selected signal processing element are configured to alternately apply a phase change of 0 and π to the collected optical signal, so that the signal processing elements other than the selected signal processing element A method for controlling an optical signal processing device, comprising: setting a phase change amount. A method for controlling an optical signal processing device according to any one of claims 1 to 6,
Including setting a phase change amount of each of the signal processing elements so that all of the plurality of signal processing elements give a phase change of greater than 0 and less than π to the collected optical signal. A method for controlling an optical signal processing device.

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