WO2024047707A1

WO2024047707A1 - Optical signal processing device

Info

Publication number: WO2024047707A1
Application number: PCT/JP2022/032437
Authority: WO
Inventors: 雅太田; 賢哉鈴木; 慶太山口; 毅伺梅木; 啓渡邉
Original assignee: 日本電信電話株式会社
Priority date: 2022-08-29
Filing date: 2022-08-29
Publication date: 2024-03-07

Abstract

Provided is an optical signal processing device having low crosstalk. An optical signal processing device according to one embodiment of the present disclosure comprises: at least one first input-output waveguide; a wavelength demultiplexer that is connected to the first input-output waveguide; a plurality of wavelength multiplexers; at least one second input-output waveguide that is connected to each of the plurality of wavelength multiplexers; and a connection circuit that connects the wavelength demultiplexer and the plurality of wavelength multiplexers. The connection circuit includes a plurality of waveguides. One end of each of the plurality of waveguides in the connection circuit is connected to the wavelength demultiplexer. The other ends of the plurality of waveguides in the connection circuit are divided into a plurality of subsets. The other end of one or a plurality of adjacent waveguides in a kth (k is the integer 2) subset among the plurality of subsets is connected to the kth wavelength multiplexer among the plurality of wavelength multiplexers.

Description

Optical signal processing device

The present disclosure relates to an optical signal processing device, and more specifically to an optical signal processing device having a plurality of arrayed waveguide gratings.

With the further increase in capacity of wavelength division multiplexing optical communications, research and development on optical waveguide devices such as optical wavelength multiplexing/demultiplexing circuits and optical switch circuits that support this is being actively conducted. Optical wavelength multiplexing and demultiplexing circuits are used for multiplexing and demultiplexing optical signals, and narrowing the guard band width, which determines the multiplexing and demultiplexing performance, is an important issue that determines the performance of optical communications.

A high-performance optical wavelength multiplexing/demultiplexing circuit (hereinafter also referred to as "tandem AWG") that has a configuration in which two arrayed waveguide gratings (AWG) are connected in cascade is known (for example, a non-patent (See Reference 1). The tandem AWG has the advantage of a narrow guard band, that is, a highly rectangular transmission spectrum characteristic.

A tandem AWG samples the wavelength of light in a first AWG at narrow intervals, and by adjusting the input position of the second AWG, light of a desired wavelength is transmitted to an arbitrary output of the second AWG. It has a function. Therefore, the tandem AWG is effective as an optical wavelength division filter having narrow guard band width and highly rectangular transmission spectrum characteristics. Based on the principle of backward propagation of light, tandem AWGs are also effective as optical wavelength multiplexing filters.

In a tandem AWG, the first AWG and the second AWG need to be connected through a connection circuit. Until the optical signal propagates from the output of the first AWG to the input of the second AWG via the connection circuit, it is necessary to maintain the phase difference of the optical waves in order to prevent deterioration of the interference characteristics.

The first AWG and the second AWG each include an array waveguide composed of a plurality of waveguides having different optical path lengths. A connection circuit connecting the first AWG and the second AWG is also composed of a plurality of waveguides. In a tandem AWG including a first AWG, a second AWG, and a connection circuit, each of which is composed of a plurality of waveguides, there is a path between the input of the first AWG and the output of the second AWG. There are many light paths of different lengths. The phase error of light waves occurring in each of the first AWG, second AWG, and connection circuit deteriorates the interference characteristics in each of the first AWG, second AWG, and connection circuit. Deterioration of interference characteristics increases crosstalk noise, which is one of the optical characteristics of optical wavelength multiplexing/demultiplexing circuits, and becomes a factor that leads to deterioration of optical signal transmission quality.

The present disclosure has been made in view of such problems, and its purpose is to provide an optical signal processing device with low crosstalk noise.

In order to achieve such an objective, an optical signal processing device according to an embodiment of the present disclosure includes at least one first input/output waveguide and a wavelength demultiplexer connected to the first input/output waveguide. a plurality of wavelength multiplexers, at least one second input/output waveguide connected to each of the plurality of wavelength multiplexers, a wavelength demultiplexer and a plurality of wavelength multiplexers; a connection circuit, the connection circuit includes a plurality of waveguides, one end of the plurality of waveguides in the connection circuit is connected to a wavelength demultiplexer, and the other end of the plurality of waveguides in the connection circuit is connected to a plurality of subsets. The other end of one of the k-th subset (k is an integer of 2) of the plurality of subsets or the adjacent plurality of waveguides is connected to the k-th wavelength multiplexer of the plurality of wavelength multiplexers. connected to the wave generator.

As described above, according to an embodiment of the present disclosure, by connecting a plurality of wavelength multiplexers in parallel to a wavelength demultiplexer via a connection circuit, light with a low crosstalk noise value is It becomes possible to provide a wavelength multiplexing/demultiplexing circuit.

FIG. 2 is a schematic configuration diagram showing a tandem AWG. 1 is a schematic configuration diagram showing an optical signal processing device according to an embodiment of the present disclosure, in which (a) is a diagram showing the overall configuration, (b) is a diagram showing the configuration of a wavelength demultiplexer, and (c) is a diagram showing the configuration of a wavelength demultiplexer. It is a figure showing the composition of a wave device. FIG. 2 is a diagram illustrating light input to a wavelength demultiplexer of an optical signal processing device according to an embodiment of the present disclosure. FIG. 2 is a diagram illustrating light propagating through a wavelength demultiplexer of an optical signal processing device according to an embodiment of the present disclosure. FIG. 2 is a diagram illustrating light propagating through a wavelength demultiplexer of an optical signal processing device according to an embodiment of the present disclosure. FIG. 2 is a diagram illustrating light input to a wavelength multiplexer of an optical signal processing device according to an embodiment of the present disclosure. FIG. 2 is a diagram illustrating light input to the wavelength multiplexer of the optical signal processing device according to an embodiment of the present disclosure, (a) is a diagram illustrating light input to the wavelength multiplexer, and (b) is a diagram illustrating light input to the wavelength multiplexer. FIG. 2 is a diagram illustrating the transmission characteristics of a wavelength multiplexer. FIG. 3 is a schematic configuration diagram showing a modified form of an optical signal processing device according to an embodiment of the present disclosure, in which (a) is a diagram showing the overall configuration, (b) is a diagram showing the configuration of a wavelength demultiplexer, (c) FIG. 2 is a diagram showing the configuration of a wavelength multiplexer.

Optical signal processing devices according to various embodiments of the present disclosure will be described below with reference to the drawings. The same or similar symbols indicate the same or similar elements, and repeated description may be omitted. Numerical values and materials in the following description are illustrative, and the optical signal processing device according to the embodiment of the present disclosure can be implemented using other numerical values and materials without departing from the spirit of the present disclosure.
Prior to describing an optical signal processing device according to an embodiment of the present disclosure, a tandem AWG will be described.

(Tandem AWG)
FIG. 1 is a schematic configuration diagram showing a schematic configuration of a tandem AWG. As shown in FIG. 1, the tandem AWG 100 includes a first AWG 110, a second AWG 120, one input waveguide 111 connected to the input of the first AWG 110, and one input waveguide 111 connected to the output of the second AWG 120. It includes two output waveguides 121-1 and 121-2, and a connection circuit 130 that connects the output of the first AWG 110 and the input of the second AWG 120. The tandem AWG 100 wavelength-demultiplexes a wavelength-multiplexed signal input via an input waveguide 111, and sends an optical signal with a wavelength λ ₁ and an optical signal with a wavelength λ ₂ included in the wavelength-multiplexed signal to two output waveguides. It is configured to output from each of 121-1 and 121-2.

In the tandem AWG 100, the first AWG 110 receives a wavelength-multiplexed signal (an optical signal with a wavelength λ _{1 and an optical signal with a wavelength λ 2) inputted via the input waveguide 111, and separates the wavelength-multiplexed signal (an optical signal with a wavelength λ 1} and an optical signal with a wavelength λ ₂ ) into different wavelengths of the first AWG 110 depending on the wavelength. It is configured to be split into different positions.

The second AWG 120 is configured to multiplex lights of the same wavelength out of a plurality of input wavelengths at different positions of the second AWG 120 depending on the wavelength.

One end of the plurality of waveguides constituting the connection circuit 130 is connected to a position of the first AWG 110 where the optical signal of wavelength λ ₁ and the optical signal of wavelength λ ₂ are demultiplexed. The other ends of the plurality of waveguides constituting the connection circuit 130 are provided with a gap for separating the position of the second AWG 120 where the optical signal of wavelength λ ₁ is inputted and the position where the optical signal of wavelength λ ₂ is inputted. and is connected to the second AWG 120.

The two output waveguides 121-1 and 121-2 are each connected to a position where the light from the second AWG 120 is multiplexed.

In the tandem AWG 100 shown in FIG. 1, an optical signal with a wavelength λ ₁ and an optical signal with a wavelength λ ₂ are each demultiplexed to different positions of the first AWG 110. The optical signal with wavelength λ ₁ is branched to a position above the first AWG 110, and coupled to a waveguide connected to the first AWG 110 at that position among the plurality of waveguides forming the connection circuit 130. The signal propagates to the second AWG 120. The optical signal with wavelength λ ₂ is branched to a position below the first AWG 110 and coupled to a waveguide connected to the first AWG 110 at that position among the plurality of waveguides forming the connection circuit 130. and propagates to the second AWG 120. The optical signal of wavelength λ ₁ and the optical signal of wavelength λ ₂ input to different positions of the second AWG 120 are multiplexed to different positions of the second AWG 120, respectively. The optical signals of wavelength λ ₁ are multiplexed at a position above the second AWG 120, and coupled to the output waveguide 121-1 connected to the second AWG 120 at this position and output. The optical signals of wavelength λ ₂ are multiplexed at a position below the second AWG 120, and coupled to the output waveguide 121-2 connected to the second AWG 120 at that position and output.

The tandem AWG 100 configured as described above samples the wavelength of light at narrow intervals in the first AWG 110 and adjusts the input position of the second AWG 120 to send light of a desired wavelength to an arbitrary position of the second AWG 120. It has the function of transmitting.

The gap of the waveguide forming the connection circuit 130 at the connection position with the second AWG 120 corresponds to a guard band. The higher the resolution of the wavelength demultiplexing function of the first AWG 110, the smaller the gap can be, that is, the guard band can be reduced. In the tandem AWG 100, by increasing the resolution of the first AWG 110, a highly rectangular transmission spectrum characteristic with a narrow guard band width can be achieved. On the other hand, the reduction of the guard band is accompanied by an increase in crosstalk noise, which becomes a factor that leads to deterioration of the transmission quality of optical signals.

Hereinafter, optical signal processing devices according to various embodiments of the present disclosure will be described. An optical signal processing device according to an embodiment of the present disclosure includes a first AWG that configures a wavelength demultiplexer, a plurality of second AWGs that configure a plurality of wavelength multiplexers, a wavelength demultiplexer, and a plurality of second AWGs that configure a wavelength demultiplexer. and a connection circuit for connecting the wavelength multiplexer. The connection circuit includes a plurality of waveguides. One end of the plurality of waveguides in the connection circuit is connected to the output of the wavelength demultiplexer. The other ends of the plurality of waveguides in the connection circuit are divided into a plurality of subsets, and the other ends of one of the k-th (k is an integer of 2) subset or the adjacent plurality of waveguides are divided into a plurality of subsets. It is connected to the input of the k-th wavelength multiplexer among the wavelength multiplexers. According to one embodiment of the present disclosure, an optical signal processing device with low crosstalk noise is provided.

(First embodiment)
The optical signal processing device according to the first embodiment will be described with reference to FIG. 2. FIG. 2(a) is a diagram showing the overall configuration of the optical signal processing device 200. As shown in FIG. 2(a), the optical signal processing device 200 includes a first AWG 210 that constitutes a wavelength demultiplexer, and two second AWGs 220-1 and 220-1 that constitute two wavelength multiplexers. , one input waveguide 111 connected to the input of the first AWG 110, one output waveguide 221-1 connected to the output of the second AWG 120-1, and the other second AWG 120-2. and a connection circuit 230 that connects the output of the first AWG 110 and the input of each of the two second AWGs 220-1 and 220-2. Similar to the tandem AWG 100 shown in FIG. 1, the optical signal processing device 200 wavelength-demultiplexes the wavelength-multiplexed signal input via the input waveguide 111, and generates light with wavelength λ ₁ included in the wavelength-multiplexed signal. It is configured to output a signal and an optical signal of wavelength λ ₂ from two output waveguides 221-1 and 221-2, respectively.

Note that, based on the principle of light beam reversal, the optical signal processing device 200 can also combine the input optical signal with wavelength λ ₁ and the optical signal with wavelength λ ₂ and output a wavelength multiplexed signal. That is, the input waveguide 111 and the output waveguides 221-1 and 221-2 each constitute an input/output waveguide. Further, the

AWGs

210 and 220 constitute a wavelength multiplexer.

FIG. 2(b) is a diagram showing the configuration of the first AWG 210 that constitutes the wavelength demultiplexer. As shown in FIG. 2(b), the AWG 210 includes a first slab 210a, an arrayed waveguide 210b, and a second slab 210c. The array waveguide 210b is composed of a plurality of waveguides having different waveguide lengths. The array waveguide 210b is connected to the output side termination surface of the first slab 210a and the input side termination surface of the second slab 210c. An input waveguide 111 is connected to the input side termination surface of the first slab 210a. A connection circuit 230 is connected to the output side termination surface of the second slab 210c.

FIG. 2(c) is a diagram showing the configuration of the second AWG 220 (220-1 or 220-2) that constitutes the wavelength multiplexer. As shown in FIG. 2(c), the AWG 220 includes a first slab 220a, an arrayed waveguide 220b, and a second slab 220c. The array waveguide 220b is composed of a plurality of waveguides having different waveguide lengths. The array waveguide 220b is connected to the output side termination surface of the first slab 220a and the input side termination surface of the second slab 220c. A connection circuit 230 is connected to the input-side termination surface of the first slab 220a. An output waveguide 221 is connected to the output side termination surface of the second slab 210c.

In the optical signal processing device 200, the first AWG 210 converts the wavelength-multiplexed signal (the optical signal with the wavelength λ ₁ and the optical signal with the wavelength λ ₂ ) inputted via the input waveguide 111 into the first AWG 210 according to the wavelength. The signal is configured to be split into different positions of the AWG 210.

Each of the two second AWGs 220-1 and 220-2 is configured to multiplex input lights of the same wavelength. The second AWG 220 differs from the AWG 120 in FIG. 1 in that it inputs and multiplexes light with the same wavelength and multiplexes the lights with the same wavelength. The free spectral range (FSR) of the second AWG 220, into which light of one wavelength is input/output, is greater than the FSR of the first AWG 210, into which light of multiple wavelengths is input/output, and the second AWG 120 in FIG. can also be made smaller.

The plurality of waveguides making up the connection circuit 230 are divided into two subsets. Each subset includes one or more adjacent waveguides. The upper side of the connection circuit 230 in FIG. 2A is a subset 1, and the lower side is a subset 2. One end of the waveguide in subset 1 is connected to a position in the first AWG 210 where the optical signal of wavelength λ ₁ is demultiplexed (a position above the output side end face of the second slab 210c). One end of the waveguide in subset 2 is connected to a position in the first AWG 210 where the optical signal of wavelength λ ₂ is demultiplexed (a position below the output side end face of the second slab 210c). On the other hand, the other end of the waveguide in subset 1 is connected to the second AWG 220-1 (the end face on the input side of the first slab 220a). The other end of the waveguide in subset 2 is connected to the second AWG 220-2 (the end face on the input side of the first slab 220a).

In the optical signal processing device 200 shown in FIG. 2, an optical signal with a wavelength λ ₁ and an optical signal with a wavelength λ ₂ are input to the first slab 210a of the first AWG 210 via the input waveguide 111. FIG. 3 is a diagram showing the intensity distribution of the optical signal at the boundary between the first slab 210a and the input waveguide 111. In FIG. 3, the position of the first slab 210a to which the input waveguide 111 is connected is defined as _x0 . The intensity distribution shown in FIG. 3 is that of monochromatic light. When the wavelength multiplexed signal input to the first AWG 210 via the input waveguide 111 includes optical signals of a plurality of wavelengths, the optical signals of each wavelength have an intensity distribution similar to that shown in FIG. 3.

In the first AWG 210, the optical signal with the wavelength λ ₁ and the optical signal with the wavelength λ ₂ each propagate through the first slab 210a while spreading in a direction perpendicular to the propagation axis. FIG. 4 is a diagram showing the intensity distribution of the optical signal at the boundary between the first slab 210a and the arrayed waveguide 210b. The array waveguide 210b is connected to the position of the first slab 210a where the intensity of the optical signal shown in dark color in FIG. 4 appears.

In the first AWG 210, a plurality of optical signals with a wavelength λ ₁ input to the second slab 210c via a plurality of waveguides having different waveguide lengths constituting the array waveguide 210b are transmitted through the waveguides through which they propagated. It has different phases depending on its length. Similarly, the plurality of optical signals of wavelength λ ₂ input to the second slab 210c also have a phase depending on the length of the waveguide through which they propagate. The optical signals of each wavelength input to the first AWG 210 are multiplexed at a position according to the wavelength. Specifically, optical signals of wavelength λ ₁ interfere with each other, are combined, and appear above the AWG 210 (second slab 210c). The optical signals of wavelength λ ₂ interfere with each other, are combined, and appear at a position below the AWG 210 (second slab 210c). One or more waveguides of subset 1 of connection circuit 230 are connected to the position where the optical signal of wavelength λ ₁ appears. Furthermore, one or more waveguides of subset 2 of connection circuit 230 are connected to the position where the optical signal of wavelength λ ₂ appears.

FIG. 5 is a diagram showing the transmission loss at the boundary between the second slab 210c of the first AWG 210 and the connection circuit 230. As shown in FIG. 5, crosstalk noise occurs due to the phase error occurring in the first AWG 210. Therefore, it is desirable to configure the connection circuit 230 so that the waveguide forming the connection circuit 230 is not connected to a position where the crosstalk of the second slab 210c is high. As a result, crosstalk occurring between subset 1 and subset 2 of connection circuit 230 is reduced compared to the case where no subset is provided.

FIG. 6 shows the connection circuit 230 for an arbitrary integer k (k=1, 2), assuming that there is a random variation of about 10 ⁻⁵ in the effective refractive index of the arrayed waveguide 210b of the first AWG 210. This is the optical signal intensity distribution of subset k of connection circuit 230 when an optical signal of a wavelength different from λ _k is coupled to any one waveguide in subset k of λ k . Each broken line in FIG. 6 corresponds to each waveguide included in subset k. As can be seen from FIG. 6, the crosstalk noise within subset k of connection circuit 230 is approximately −40 dB.

FIG. 7(a) shows the intensity distribution of the optical signal of λ1 (wavelength different from λ _k=2 ) input to the second AWG 220-2 when k=2. The peak intensity of the optical signal at λ1 is approximately -40 dB. FIG. 7B is a diagram showing the transmission loss at the boundary between the second slab 210c of the second AWG 220-2 and the waveguide of the subset 2 of the connection circuit 230. It can be seen that the crosstalk of connection circuit 230 to subset 2 is −80 db or less.

In this way, in the optical signal processing device 200, the optical signal with the wavelength λ ₁ and the optical signal with the wavelength λ ₂ are each demultiplexed to different positions of the first AWG 210 (second slab 210c). The optical signal of wavelength λ ₁ is branched to the upper position of the first AWG 210 (second slab 210c), and connected to the first AWG 210 at that position among the plurality of waveguides that constitute the connection circuit 230. The signal is coupled to the waveguide of Subset 1 and propagated to the second AWG 220-1. The optical signal of wavelength λ ₂ is branched to a position below the first AWG 210 (second slab 210c), and connected to the first AWG 110 at the corresponding position among the plurality of waveguides forming the connection circuit 130. The signal is coupled to the waveguide of Subset 2 and propagated to the second AWG 120.

The plurality of waveguides constituting the connection circuit 230 have the same length or have an optical wave length difference that is an integral multiple of the wavelength of the propagating optical signal. This maintains the phase difference of the light waves and prevents deterioration of the interference characteristics in the first AGW. On the other hand, the spacing between adjacent waveguides constituting the connection circuit 230 may or may not be constant. For example, when demultiplexing wavelength λ ₁ in the C wavelength band and wavelength λ ₂ in the L wavelength band from a wavelength multiplexed signal, the distance between adjacent waveguides in subset 1 of the connection circuit 230 and the distance between adjacent waveguides in subset 2 The intervals between the two can be made different.

As described above, the first AWG 210 has the function of branching the input optical signal to different positions depending on the wavelength, but also has the function of branching the optical signal to different positions depending on the input position. has. When the input position of the optical signal is changed, the wavelength of the optical signal propagated through the subsets 1 and 2 of the connection circuit 230 and input to the second AWGs 220-1 and 220-2 changes. Furthermore, when the wavelength of the optical signal is changed, the position where the optical signals are multiplexed in the second AWGs 220-1 and 220-2 also changes. Therefore, the optical signal processing device 200 may have a configuration in which a plurality of input waveguides are connected to the first AWG 210 and a plurality of output waveguides are connected to each of the second AWGs 220-1 and 220-2.

The first AWG 210, the connection circuit 230, and the second AGW 220 may be configured on the same planar lightwave circuit (PLC), or the first AWG 210 and the second AWG 220 may be configured on the same planar lightwave circuit (PLC). Two AGWs 220 may be connected by a connection circuit 230.

The material of the light wave circuit constituting the first AWG 210 and the second AGW 220 of this embodiment can be silicon oxide (SiO ₂ ), which has low connection loss with an optical fiber. Alternatively, as the material of the light wave circuit, silicon (Si), which can reduce the circuit area, may be used, or silicon nitride (Si ₃ N ₄ ), which has performance between silicon oxide and silicon, may be used.

As described above, according to this embodiment, it is possible to provide the optical signal processing device 200 with low crosstalk noise. In this embodiment, a wavelength multiplexed signal input through the input waveguide 111 is wavelength-demultiplexed, and two optical signals of wavelength λ ₁ and wavelength λ ₂ included in the wavelength multiplexed signal are separated into two optical signals. The optical signal processing device 200 is configured to output from the output waveguides 221-1 and 221-2, respectively. It is also possible to configure an optical signal processing device configured to output.

(Variation 1)
A modification of the optical signal device of this embodiment will be described with reference to FIG. The optical signal processing device of this modification is configured to output optical signals of three or more different wavelengths from a wavelength multiplexed signal from three or more output waveguides.

FIG. 8(a) is a diagram showing the overall configuration of an optical signal processing device 800. As shown in FIG. 8(a), the optical signal processing device 800 includes a first AWG 810 that constitutes a wavelength demultiplexer, and a second AWG 810 that constitutes k (k is an integer of 3 or more) wavelength multiplexers. AWG820-1, 820-2,...820-k, one input waveguide 111 connected to the input of the first AWG810, and the output connected to the output of the kth second AWG820-k. It includes a waveguide 821-k and a connection circuit 830 that connects the output of the first AWG 110 and the input of each of the k second AWGs 820-1, 820-2, . . . 820-k. . The optical signal processing device 800, like the optical signal processing device 200 shown in FIG. It is configured to output optical signals having wavelengths λ _k to λ _k from k output waveguides 221-1 to 221-k, respectively.

Note that, similarly to the optical signal processing device 200, based on the principle of light beam reversal, the optical signal processing device 800 multiplexes an optical signal of wavelength λ _k from an input optical signal of wavelength λ ₁ to generate a wavelength multiplexed signal. It can also be output. That is, the input waveguide 111 and the output waveguides 821-1 to 821-k each constitute an input/output waveguide. Further, AWGs 810 and 820-1 to 820-k constitute a wavelength multiplexer.

FIG. 8(b) is a diagram showing the configuration of the first AWG 810 that constitutes the wavelength demultiplexer. Similar to the first AWG 210 shown in FIG. 2(b), the first AWG 810 includes a first slab 810a, an arrayed waveguide 810b, and a second slab 810c. The array waveguide 210b is composed of a plurality of waveguides having different waveguide lengths. The array waveguide 810b is connected to the output side termination surface of the first slab 810a and the input side termination surface of the second slab 810c. An input waveguide 111 is connected to the input side termination surface of the first slab 810a. Subsets 1 to k of the connection circuit 830 are connected to the output end surface of the second slab 810c.

FIG. 8(c) is a diagram showing the configuration of the second AWG 820 (820-1 to 820-k) that constitutes the wavelength multiplexer. As shown in FIG. 8(c), the AWG 820 includes a first slab 820a, an arrayed waveguide 820b, and a second slab 820c. The array waveguide 820b is composed of a plurality of waveguides having different waveguide lengths. The array waveguide 820b is connected to the output side termination surface of the first slab 820a and the input side termination surface of the second slab 820c. A subset k of the connection circuit 830 is connected to the input side termination surface of the first slab 820a of the second AWG 820-k. An output waveguide 221-k is connected to the output side termination surface of the second slab 810c of the second AWG 820-k.

As described above, the first AWG 810 has the function of branching the input optical signal to different positions depending on the wavelength, but at the same time, the first AWG 810 has the function of branching the input optical signal to different positions depending on the input position. has. When the input position of the optical signal is changed, the wavelength of the optical signal propagated through subset 1 to k of the connection circuit 830 and input to the second AWGs 820-1 to 820-k changes. Furthermore, when the wavelength of the optical signal is changed, the position where the optical signal is multiplexed in the second AWGs 820-1 to 820-k also changes. Therefore, the optical signal processing device 800 may have a configuration in which a plurality of input waveguides are connected to the first AWG 810 and a plurality of output waveguides are connected to each of the second AWGs 820-1 to 820-k.

The AWG 810, AWG 820, connection circuit 830, and output waveguide 821 in the optical signal processing device 800 correspond to the AWG 210, AWG 220, connection circuit 230, and output waveguide 221 in the optical signal processing device 200 described above, so detailed explanations will be given below. The explanation will be omitted.

As explained above, according to this modification, it is possible to provide an optical signal processing device 200 with low crosstalk noise.

Note that the wavelength λ ₁ to wavelength λ _k in the description of this modification is expanded from the wavelength band λ ₁ to the wavelength band λ _k , and a plurality of wavelengths (wavelengths _λ _1- ₁ , λ _1-2 , ...), multiple wavelengths included in the wavelength band λ ₂ (wavelengths λ _2-1 , λ _2-2 , ...), ... multiple wavelengths included in the wavelength band λ _k The optical signal processing device may be configured to output wavelengths (wavelengths λ _k-1 , λ _k-2 , . . . ) from a plurality of output waveguides, respectively.

As explained above, according to this modification, it is possible to provide an optical signal processing device with low crosstalk noise.

It is possible to provide an optical wavelength multiplexing/demultiplexing circuit with a lower crosstalk noise value than the conventional configuration.

100 tandem AWG
110, 120, 210, 220, 810, 820 AWG
111 Input waveguide 121, 221, 821 Output waveguide 130 Connection circuit, 230, 830

Connection circuit

200, 800 Optical

signal processing device

210a, 210c, 220a, 220c, 810a, 810c, 820a,

820c Slab

210b, 220b, 810b, 820b array waveguide

Claims

An optical signal processing device,
at least one first input/output waveguide;
a wavelength demultiplexer connected to the first input/output waveguide;
multiple wavelength multiplexers,
at least one second input/output waveguide connected to each of the plurality of wavelength multiplexers;
comprising a connection circuit that connects the wavelength demultiplexer and the plurality of wavelength multiplexers,
The connection circuit includes a plurality of waveguides,
One end of the plurality of waveguides in the connection circuit is connected to the wavelength demultiplexer,
The other end of the plurality of waveguides in the connection circuit is divided into a plurality of subsets, and one of the k-th (k is an integer of 2) subset among the plurality of subsets or the other end of the plurality of adjacent waveguides is divided into a plurality of subsets. An optical signal processing device whose end is connected to a k-th wavelength multiplexer among the plurality of wavelength multiplexers.
The optical signal processing device according to claim 1, wherein the wavelength demultiplexer and the wavelength multiplexer are constructed of silicon oxide optical circuits.
The optical signal processing device according to claim 1, wherein the wavelength demultiplexer and the wavelength multiplexer are constructed of silicon optical circuits.
The optical signal processing device according to claim 1, wherein the wavelength demultiplexer and the wavelength multiplexer are constructed of silicon nitride optical circuits.
The optical signal processing device according to claim 1, wherein the wavelength demultiplexer and the wavelength multiplexer include an arrayed waveguide diffraction grating.
The optical signal processing device according to claim 1, wherein the wavelength demultiplexer and the wavelength multiplexer are formed in a plane light wave circuit.