JP2005164758A - Multichannel array waveguide diffraction grating type optical multiplexer/demultilplexer and method for connecting array waveguide and output waveguide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a configuration to obtain low-loss multiplexing/demultiplexing characteristics, by reducing the connection loss due to a mode mismatch between the second slab and output waveguides, inside the array waveguide diffraction grating type optical multiplexer/demultilplexer. <P>SOLUTION: The array waveguide diffraction grating type optical multiplexer/demultilplexer has the array waveguide 13 disposed in the prescribed position of a substrate, the slab waveguide 16 disposed on the output side of the array waveguide, and the output waveguides 14<SB>-n</SB>to 14<SB>n</SB>(excluding 14<SB>0</SB>), which are connected to the slab waveguide 16 and in which the angle formed with the normal of a Rowland circle is such that the angle formed by the central lines of cores, situated at both neighbors of the core situated in the central part and the normal of the Rowland circle, are successively increased from the central core toward the cores on both sides in accordance with the positions from the core. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical multiplexer / demultiplexer used in the field of optical communications, and in particular, to a multi-channel array waveguide diffraction grating type multiplexer / demultiplexer used for wavelength division multiplexing, and to connection between an array waveguide and an output waveguide. Regarding the method.

  In the field of optical communication, a method (wavelength division multiplexing) for increasing transmission capacity by transmitting a large-capacity signal using a carrier wave having a higher frequency has already been put into practical use.

  In this system, an optical multiplexer / demultiplexer that multiplexes or demultiplexes signals of different wavelengths plays an important role.

  Among these, an arrayed waveguide diffraction grating type optical multiplexer / demultiplexer using an arrayed waveguide diffraction grating (AWG) is useful for increasing the number of channels. In addition, an arbitrary number of channels can be created with the same process and the same number of steps regardless of the number of channels, and in principle there is a feature that loss and characteristic deterioration are small.

  In addition, when connecting an arrayed-waveguide diffraction grating (AWG) and the optical fiber which is an output waveguide, it is requested | required that there should be little coupling loss.

For example, an M-channel first and an N-channel second connected to arcuate planar waveguides having a pair of ends, one end centered at the center of the other end. In the coupler consisting of the waveguide array of N, the N-channel second waveguide array is radially arranged from the center point of the circular arc located near the center of the end of the first waveguide array. Has been proposed (for example, Patent Document 1).
JP 11-271557 A

  However, in general, when a plurality of (N-channel) waveguides (waveguides) are arranged on the circumference of a Roland circle, which is a circle drawn so as to be in contact with the surface of the curved diffraction grating at its midpoint. Is the transmission characteristic of the waveguide (waveguide) located near the center of the N-channel waveguide (waveguide) and the transmission of the waveguide (waveguide) located at the end (both ends). It is known that the asymmetry is different from the characteristic.

  If the asymmetry of the transmission characteristics is different within the passband width, there is a problem that the PDL is locally degraded (the worst value of the PDL is increased). In addition, the arrayed waveguide having the flat-top type transmission characteristic has a problem that the ripple within the pass bandwidth increases.

  Note that Patent Document 1 does not suggest any method for solving these problems.

  The object of the present invention is to reduce the connection loss due to mode mismatch between the second slab waveguide and the output waveguide in the arrayed waveguide diffraction grating (AWG) type multiplexer / demultiplexer, and to achieve a low-loss coupling / demultiplexing characteristic. Is to get.

  The present invention comprises an arrayed waveguide comprising a core laminated on a substrate and a clad covering the core, each of which is given a predetermined curvature, and light which is laminated on the substrate and inputted through an input waveguide. A multi-channel comprising: an input-side slab waveguide that inputs signals to the arrayed waveguide; and an output-side slab waveguide that is stacked on a substrate and outputs an optical signal output from the arrayed waveguide to an output waveguide In the arrayed waveguide diffraction grating type multiplexer / demultiplexer, the output waveguide is given a predetermined shape changed in accordance with the shape of the field distribution at the condensing point of the output slab waveguide, and the output slab is given. A multi-channel arrayed waveguide grating type multiplexer / demultiplexer characterized by being connected to a waveguide.

  That is, according to the above-described multi-channel arrayed waveguide grating multiplexer / demultiplexer, the output waveguide is given a predetermined shape that is changed in accordance with the shape of the field distribution at the condensing point of the output slab waveguide. Since it is connected to the output side slab waveguide, the connection loss is reduced and the asymmetry of the transmission characteristics is reduced.

  Further, the present invention is connected to the arrayed waveguide provided at a predetermined position of the substrate, the slab waveguide provided on the output side of the arrayed waveguide, and the slab waveguide. When the angle between the normal and the center line of the core located on both sides of the core located in the center and the normal of the Roland circle is α, the angle according to the position from the center core And an output waveguide including a core defined by α, 2α, 3α,..., (N−1) α, Nα from the core to the cores at both ends. A waveguide diffraction grating type multiplexer / demultiplexer is provided.

  That is, according to the multi-channel arrayed waveguide grating multiplexer / demultiplexer described above, the core formed for an arbitrary number of channels has an angle formed with the normal of the Roland circle at the center. When the angle formed by the center line of the core located on both sides of the core and the normal line of the Roland circle is α, α, 2α, 3α,..., (N−1) α, Nα is connected to the output-side slab waveguide at an angle defined by α, Nα, so that the output uniformity of each channel when multi-channel light is demultiplexed Is increased.

  Further, according to the present invention, each of the output ports of the slab waveguide has an angle formed between the normal line of the Roland circle and the center line of the core positioned on both sides of the core positioned in the center and the normal line of the Roland circle. , Α, 2α, 3α,..., (N−) from the central core toward the cores at both ends according to the position from the central core on the circumference of the Roland circle. 1) Connected to an slab waveguide provided on the output side of an arrayed waveguide provided at a predetermined position of the substrate, wherein an arbitrary number of cores are connected at an angle defined by α and Nα. This is a method of connecting an output waveguide to a slab waveguide.

  That is, according to the connection method described above, an arbitrary number of cores provided for a plurality of channels are directed from the central core to the cores at both ends according to the position from the central core on the circumference of the Roland circle. Then, since it is connected to the slab waveguide at angles defined by α, 2α, 3α,..., (N−1) α, Nα, the output for each channel is made uniform.

  According to the present invention, an increase in the asymmetry of the transmission characteristics within the passband width is suppressed, and an arrayed waveguide grating type optical multiplexer / demultiplexer with low connection loss can be obtained.

  Further, according to the present invention, an arrayed waveguide diffraction grating type optical multiplexer / demultiplexer with little crosstalk can be obtained.

  In addition, the signal waveform is made uniform, and the bandwidth capable of securing a predetermined level of PDL is improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, an arrayed waveguide type optical multiplexer / demultiplexer 10 includes an input waveguide 12, an arrayed waveguide 13, an output waveguide 14, and an input waveguide, which are provided at predetermined positions on a substrate 11, respectively. 12 and the arrayed waveguide 13 and first and second slab waveguides 15 and 16 for optically connecting the arrayed waveguide 13 and the output waveguide 14.

  The arrayed waveguide 13 is formed with a predetermined curvature between the first slab waveguide 15 and the second slab waveguide 16.

As shown in FIG. 2, the core 14 -n _~ cores 14 _n output waveguides 14, except for the center of the core 14 _0, respectively on the circumference of the Rowland circle defining the output terminal of the second slab waveguide 16 _Are connected to the individual output ports 16 _-n and 16 _{n of} the second slab waveguide 16 in a state where the central axis is inclined by a predetermined angle with respect to the normal of the Roland circle. .

In particular, the central core 14 ₀ is perpendicular to the circumference of the normal line of the Rowland circle, is connected to the output port 16 _0. Accordingly, the center line of the center line and the center of the core 14 ₀ of the output ports 16 ₀ is positioned on the same straight line with one another.

In contrast, (except 14 ₀₎ core ₁₄ -n _{to 14} n connected to the output port ₁₆ -n ~ 16 _n other than the output ports 16 _0, which is positioned on the center line, the respective center line, moves away from the core 14 ₀ is located in central, so angle increases relative to the normal of the Rowland circle, are connected to a predetermined position of the second slab waveguide 16.

That is, the cores 14 _-n and 14 _n connected to both ends of the second slab waveguide 16 have the second slab guide so that the angle α × n (−n) with respect to the normal of the center line is maximized. Connected to the waveguide 16. The core 14 -1 _(shown simplified) with the core 14 1 _(shown simplified), which is located on both sides of the core 14 ₀ is located in the central portion, the angle alpha × n relative to the normal of the respective center line (- It is connected to the second slab waveguide 16 so that n) is minimized. Incidentally, the angle α between the normal of the center line and the Rowland circle of the respective cores, as defined in the center of the core 14 ₀ side. Therefore, in each of the core 14- _n at one end and the core _14n at the other end, the angle Nα formed by the center line and the normal of the Roland circle is equal, and the polarity (direction) is opposite.

More particularly, angle alpha × n of the normal to the individual cores 14 _-n to 14 _n centerline Rowland circle except the core 14 ₀ is located in central (-n) are shown in Figure 2 As described above, when the light is input from the second slab waveguide 16 to the arrayed waveguide 13, “the two lights collected from the both ends of the input side of the slab waveguide 16 to the center of the output side should travel. The distance (the sum of the optical path lengths of the “optical paths marked with a circle”) and the distance (“Δ” and “the two light beams to be collected from one end on the input side to the both ends on the output side of the slab waveguide 16”). The effect of “Distance Difference” between the sum of the optical path lengths of “the optical path with II”, that is, the sum of the optical path length through which the light with the longest optical path length passes and the optical path length through which the light with the shortest optical path length passes. Is set so as to be reduced. In this case, the angle between the normal of the center line and the Rowland circle of the individual cores 14 _-n to 14 _n is the core that is positioned in the core 14 ₀ on both sides which are located in central center line of the Rowland circle when the angle between the normal and alpha, according to the position of the center of the core 14 _0, toward both ends of the core from the center of the core, α, 2α, 3α, ··· , (N-1) α, It is easily defined by Nα. As described above, in each of the core at an arbitrary position on one end side and the core positioned at the same position on the other end side, the angle α formed by the center line and the normal of the Roland circle is equal. Needless to say, the polarity (direction) is reversed.

  In this way, the core connected to each of the plurality of output ports at the output end of the (output) slab waveguide connected to the output side of the arrayed waveguide is set in accordance with the distance from the center of the slab waveguide. By connecting by changing the angle formed with the normal line of the circle, it is possible to suppress an increase in the asymmetry of the transmission characteristics within the passband width. That is, PDL described later with reference to FIG. 7 is locally degraded (the worst value of PDL is increased). Further, it is possible to reduce the magnitude of the ripple within the passband width in which it is confirmed that the transmission characteristics described later in FIG. 8 occur in a flat-top arrayed waveguide having a substantially flat shape.

In the present invention described above, as a principle capable of suppressing an increase in the asymmetry of the transmission characteristics within the passband width,
A) When considering the field distribution at the condensing point of the second (output side) slab waveguide, “the optical path length through which the light with the longest optical path length is transmitted and the optical path length through which the light with the shortest optical path length is transmitted. It is difficult to completely eliminate the “difference”, and the resulting “degradation of field distribution symmetry” is reduced.
B) Reduction of “effect of connection mismatch” due to the distance from the center of each core (element of output waveguide) connected to the second slab waveguide;
Can be guessed.

In other words, as in the present invention described above, the "(excluding 14 ₀₎ core ₁₄ -n _{to 14} n connected to the output port ₁₆ -n ~ 16 _n other than the output ports 16 _0, which is positioned on the center line , respective center lines, moves away from the core 14 ₀ is located in central, as the angle between the normal line of the Rowland circle is increased, connected to a predetermined position of the second slab waveguide 16 " Thus, it can be considered that the transmission characteristics can be matched with the field distribution shape at the condensing point of the second (output side) slab waveguide.

  In the arrayed waveguide optical multiplexer / demultiplexer 10 described above with reference to FIG. 1, a multiplexed optical signal is input to the input waveguide 12 from a single mode fiber (SMF), for example, although not described in detail. On the other hand, although not described in detail, the output waveguide 14 outputs demultiplexed optical signals toward a plurality of single mode fibers (SMF) connected to the output side of the arrayed waveguide optical multiplexer / demultiplexer 10. The The optical signal input to the output waveguide 14 is separated from the multiplexed signal input via the input waveguide 12 by the first slab waveguide 15, the arrayed waveguide 13 and the second slab waveguide 16. Needless to say, these are the individual outputs of a given wavelength interval. In this case, for the reason described with reference to FIG. 2, the connection loss (coupling loss) between the individual cores of the output waveguide 14 and the second slab waveguide 16 is minimized.

  Further, due to the difference in transmission characteristics between the core located at the center and the core located at both ends of the individual output waveguides 14 connected to the second slab waveguide 16, the well-known PDL is In a flat-top output waveguide that is reduced (the worst value of PDL is increased) or has a flat transmission characteristic, an increase in ripple is reduced.

  FIG. 3 illustrates another embodiment in which the output-side slab waveguide and the output waveguide described above with reference to FIG. 2 are connected. The same components as those previously described with reference to FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

In the array waveguide diffraction grating multiplexer-demultiplexer shown in FIG. 3, any number of cores except the central core 114 ₀ output waveguide 114 defines the output end of the second slab waveguide 16, respectively Roland Each output of the second slab waveguide 16 is tilted at a predetermined angle α × n (−n) with respect to the normal of the Roland circle at an arbitrary position on the circumference of the circle. port ₁₆ is connected to the _-n and 16 _n (as in the example shown in FIG. 2).

The connecting portion of the slab waveguide 16 of each of the cores 114 _-n to 114 _n, tapers the cross-sectional diameter of the slab waveguide side defined largely is formed. Incidentally, taper, relative to the circumference of the normal line of the Rowland circle except the central core 114 _0, are formed asymmetrically. Further, a taper provided in each core except the central core 114 ₀ increasing distance from the center of the core 114 _0, with respect to the normal line of the Rowland circle, the center of the core 114 becomes ₀ on the opposite side portion increases It is prescribed as follows.

In other words, the cores 114 _-n and 114 _n connected to both ends of the second slab waveguide 16 have a portion on the opposite side of the core located in the center with respect to the normal of the center line. A taper defined to be the largest is given. Further, taper given to each core 114 located on both sides of the core 114 ₀ located in the center -1 _(shown simplified) of the core 114 1 _(shown simplified), based on the normal of the center line, Although the part on the opposite side of the core located in the center is formed larger, the size (size of the asymmetric part) compared to the size of the asymmetric part of the taper of the other core Smallest.

  FIG. 4 illustrates another embodiment in which the output-side slab waveguide and the output waveguide described above with reference to FIG. 2 are connected. The same components as those previously described with reference to FIGS. 1 to 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

In the array waveguide diffraction grating multiplexer-demultiplexer shown in FIG. 4, any number of cores except the central core 214 ₀ output waveguide 214 defines the output end of the second slab waveguide 16, respectively Roland Each output of the second slab waveguide 16 is tilted at a predetermined angle α × n (−n) with respect to the normal of the Roland circle at an arbitrary position on the circumference of the circle. port ₁₆ is connected to the _-n and 16 _n (as in the example shown in FIG. 2).

The connecting portions of the cores 214 _{-n to} 214 _{n with} the slab waveguide 16 are formed in a parabolic shape in which the cross-sectional diameter on the slab waveguide side is largely defined. Incidentally, parabolic-shaped connecting portion, to the circumference of the normal line of the Rowland circle except the central core 214 _0, are formed asymmetrically. Further, parabolic-shaped connecting portions provided in each of the core except the central core 214 ₀ increasing distance from the center of the core 214 _0, with respect to the normal line of the Rowland circle, the opposite side of the central core 214 ₀ It is stipulated that the part becomes larger.

  That is, the parabolic connecting portion described with reference to FIG. 4 can be replaced with the taper shown in FIG.

  As described above, the core connected to each of the plurality of output ports at the output end of the (output) slab waveguide connected to the output side of the arrayed waveguide is set according to the distance from the center of the slab waveguide. Asymmetric taper or parabolic connection with varying angle between normal to the Roland circle and increased size on the opposite side of the core from the core. Providing the portion can also suppress an increase in the asymmetry of the transmission characteristics within the passband width. That is, PDL described later with reference to FIG. 7 is locally degraded (the worst value of PDL is increased). Further, it is possible to reduce the magnitude of the ripple within the passband width in which it is confirmed that the transmission characteristics described later in FIG. 8 occur in a flat-top arrayed waveguide having a substantially flat shape.

  FIG. 5 shows the transmission characteristics of the present invention to which the connection between the slab waveguide and the output waveguide described with reference to FIGS. 2 to 4 is applied. FIG. 5 shows an example in which the transmission characteristic is a Gaussian distribution.

  In FIG. 5, the degree of loss of optical signals from wavelengths λ1 to λn used as from −n to n channel is −n channel and n channel, which are wavelengths located at both ends compared to the center 0 channel. , The loss level is improved, and the difference between the center and both ends, that is, the uniformity (A−B) is improved over the example using the well-known connection method indicated by the dotted line for comparison. (The application is indicated by A and the comparative example is indicated by B).

  FIG. 6 shows transmission characteristics when the connection between the slab waveguide and the output waveguide described with reference to FIGS. 2 to 4 is applied to a flat-top arrayed waveguide having flat transmission characteristics.

  In FIG. 6, the degree of loss of optical signals from wavelengths λ1 to λn used as from −n to n channel is a wavelength located at both ends compared to the center 0 channel, −n channel and n channel. , The loss level is improved, and the difference between the center and both ends, that is, the uniformity (ab), is improved over the example using the well-known connection method shown by the dotted line for comparison. (This application is indicated by a, and a comparative example is indicated by b).

  FIG. 7 shows the transmission characteristics of the present invention to which the connection between the slab waveguide and the output waveguide described with reference to FIGS. 2 to 4 is applied, with one arbitrary wavelength (one channel) extracted. FIG. 7 corresponds to FIG. 5 and shows an example in which the transmission characteristic is a Gaussian distribution. Similarly to FIG. 5, the subscript “A” is attached to the present application, and the same “B” is attached to the comparative example.

  As is apparent from FIG. 7, even when “PDλA = PDλB”, the shifts in the center wavelength are substantially equal, so that “PDLA <PDLB”. Note that “PDLA <PDLB” indicates that the band becomes wider when the band of the passband is managed (defined) with the worst value of PDL. Since this result does not depend on the mode, the TM mode and the TE mode are the same.

  More specifically, AB is approximately 0.7 dB in the 40-channel arrayed waveguide grating optical multiplexer / demultiplexer, and it is confirmed that asymmetry is improved in each channel. .

  FIG. 8 shows the transmission characteristics when the connection between the slab waveguide and the output waveguide described with reference to FIGS. 2 to 4 is applied to a flat-top array waveguide having a flat transmission characteristic. ) Is shown in an extracted state. FIG. 8 corresponds to FIG. 6 and shows an example in which the transmission characteristic is a flat top. Similarly to FIG. 6, the subscript “a” is attached to the present application, and the same “b” is attached to the comparative example.

  As is apparent from FIG. 8, even when “PDλa = PDλb”, the shifts in the center wavelength are substantially equal, and “PDLa <PDLb”. Note that “PDLA <PDLB” is the same as that in FIG. 7, and is used to manage the passband bandwidth. Since this result does not depend on the mode, the TM mode and the TE mode are the same.

  On the other hand, the ripple specific to the flat top is also “ripple a <ripple b”, and it is recognized that the magnitude of the ripple is suppressed.

  More specifically, it has been confirmed by a-b that the crosstalk level can be improved by about 5 dB in the 40-channel arrayed waveguide grating optical multiplexer / demultiplexer. Moreover, it has been confirmed that the asymmetry is improved in each channel.

  Thus, in the arrayed waveguide grating optical multiplexer / demultiplexer, when connecting the output-side slab waveguide and the output waveguide of an arbitrary number of channels, the output waveguides provided corresponding to the respective channels are By increasing the angle formed with the normal line of the Roland circle according to the distance from the center of the slab waveguide, it is possible to suppress an increase in the asymmetry of the transmission characteristics within the passband width.

  When the end portion of the output waveguide is tapered or parabolic in the portion connected to the slab waveguide, the size of the tapered or parabolic portion depends on the distance from the output waveguide located at the center. The height may be asymmetric and the size of the portion outside the center may be increased.

  As described above, according to the present invention, the connection loss due to the mode mismatch between the second slab waveguide and the output waveguide in the arrayed waveguide grating (AWG) type multiplexer / demultiplexer is reduced, and the passband is reduced. Asymmetry with respect to the center of the transmission characteristic in width is suppressed.

  Therefore, the signal waveform is made uniform, and the bandwidth capable of securing a predetermined level of PDL is improved.

  The present invention is not limited to the above-described embodiments, and various modifications or changes can be made without departing from the scope of the invention when it is implemented. Moreover, each embodiment may be implemented in combination as appropriate as possible, and in that case, the effect of the combination can be obtained.

Schematic explaining an example of an arrayed waveguide diffraction grating type optical multiplexer / demultiplexer to which the embodiment of the present invention is applied. Schematic explaining an example of a structure of the principal part of the arrayed waveguide shown in FIG. Schematic explaining an example of a structure of the principal part of the arrayed waveguide shown in FIG. Schematic explaining an example of a structure of the principal part of the arrayed waveguide shown in FIG. Schematic which shows the transmission characteristic of this invention to which the connection of the slab waveguide and output waveguide which were demonstrated by FIG. 2 thru | or FIG. 4 was applied. FIG. 5 is a schematic diagram illustrating transmission characteristics when the connection between the slab waveguide and the output waveguide described with reference to FIGS. 2 to 4 is applied to a flat-top arrayed waveguide having flat transmission characteristics. Schematic which shows the transmission characteristic of this invention which applied the connection of the slab waveguide and output waveguide which were demonstrated by FIG. 2 thru | or 4 in the state which extracted one arbitrary wavelength (1 channel). Schematic which shows the transmission characteristic of this invention which applied the connection of the slab waveguide and output waveguide which were demonstrated by FIG. 2 thru | or 4 in the state which extracted one arbitrary wavelength (1 channel).

Explanation of symbols

10 ... arrayed waveguide grating type optical demultiplexer, 11 ... substrate (Si), 12 ... input waveguide, 13 ... arrayed waveguide, 14 ... output _waveguides, 14 -n, · · ·, 14 n _... core (Output waveguide), 15 ... first slab waveguide, 16 ... second slab waveguide, SMF ... single mode fiber.

Claims (11)

An arrayed waveguide composed of a core laminated on a substrate and a clad covering the core, each of which is given a predetermined curvature, and an optical signal laminated on the substrate and inputted via the input waveguide Multi-channel array waveguide diffraction comprising: an input-side slab waveguide that is input to a waveguide; and an output-side slab waveguide that is stacked on a substrate and outputs an optical signal output from the arrayed waveguide to an output waveguide In the lattice type multiplexer / demultiplexer,
The output waveguide is connected to the output slab waveguide by being given a predetermined shape that is changed in accordance with the shape of the field distribution at the condensing point of the output slab waveguide. Channel array waveguide grating type multiplexer / demultiplexer.   A plurality of the output waveguides are arranged on an arc unique to the output-side slab waveguide, and are positioned at the center on the arc of the output waveguide when connected to the output-side slab waveguide. The angle between the center of the output waveguide and the normal line of the arc is increased in a predetermined direction as the distance from the output waveguide to the output waveguide located at the center on the arc increases with respect to the output waveguide. The multi-channel arrayed waveguide grating type multiplexer / demultiplexer according to claim 1.   3. The multi-channel array conductor according to claim 2, wherein a direction in which an angle formed by a center of the output waveguide and a normal line of the arc is increased is on the output waveguide side positioned at the center. Waveguide diffraction grating type multiplexer / demultiplexer.   The angle formed between the center of the output waveguide and the normal line of the arc is an angle formed between the output waveguide side positioned at the center and the output waveguide positioned on both sides thereof and the normal line of the arc. 4. The multi-channel arrayed waveguide grating type multiplexer / demultiplexer according to claim 2, wherein the size of is increased in proportion to a distance from the center to an arbitrary output waveguide.   A plurality of the output waveguides are arranged on an arc unique to the output-side slab waveguide, and the output-side slab waveguide is connected to the output-side slab waveguide through a connection portion formed in a tapered or parabolic shape. As the distance from the output waveguide located at the center on the arc increases with reference to the output waveguide located at the center on the arc of the output waveguide, 2. The multi-channel arrayed waveguide grating multiplexer / demultiplexer according to claim 1, wherein the size of the asymmetric part of the connecting portion formed in the tapered shape or the parabolic shape is increased.   6. The direction in which the size of the asymmetrical portion of the connection portion formed in the tapered shape or the parabolic shape is increased is on a side opposite to the output waveguide located at the center. A multi-channel arrayed waveguide grating multiplexer / demultiplexer as described. An arrayed waveguide provided at a predetermined position of the substrate;
A slab waveguide provided on the output side of the arrayed waveguide;
Connected to the slab waveguide, the angle formed between the normal line of the Roland circle and the normal line of the Roland circle located on both sides of the core positioned at the center is When α is set, the output including the cores defined by α, 2α, 3α,..., (N−1) α, Nα from the center core toward the cores at both ends according to the position from the center core. A waveguide;
A multi-channel arrayed waveguide diffraction grating type multiplexer / demultiplexer comprising:   The angle formed by the center of the core other than the core positioned at the central portion of the output waveguide and the normal line of the Roland circle is increased toward the core side positioned at the central portion, respectively. The multi-channel arrayed waveguide grating type multiplexer / demultiplexer according to claim 7.   Each of the cores of the output waveguide has a connection region formed in a tapered shape or a parabolic shape on a side connected to the slab waveguide, and each of the connection regions is located at the central portion. 9. The multi-channel arrayed waveguide diffraction according to claim 8, further comprising an asymmetric region that is increased on a side opposite to the center of the core located at the center as the distance to the core is increased. Lattice type multiplexer / demultiplexer.   Each of the output ports of the slab waveguide has an angle between the normal of the Roland circle and the angle between the center line of the core located on both sides of the core located at the center and the normal of the Roland circle. Then, according to the position from the central core on the circumference of the Roland circle, from the central core toward the cores at both ends, α, 2α, 3α, ..., (N-1) α, Nα The slab guide is connected to the output waveguide connected to the slab waveguide provided on the output side of the arrayed waveguide provided at a predetermined position of the substrate, wherein an arbitrary number of cores are connected at a specified angle. How to connect to the waveguide.   Each core has a connection region formed in a tapered shape or a parabolic shape on the side connected to the slab waveguide, and each connection region increases as the distance from the core located in the central portion increases. 11. An arrayed waveguide provided at a predetermined position of the substrate according to claim 10, further comprising an asymmetric region that is increased to a side opposite to the center of the core located at the center. A method of connecting an output waveguide connected to a slab waveguide to the slab waveguide.

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