JP2007094063A - Light wavelength multiplexer and demultiplexer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a miniaturized light wavelength multiplexer and demultiplexer for demultiplexing, multiplexing and demultiplexing or demultiplexing optical signals propagating in a two-system optical communication network respectively by hardly deteriorating optical characteristics. <P>SOLUTION: The light wavelength multiplexer and demultiplexer comprises two first optical waveguides adjacent at a distance multiplying a prescribed length by (0.5+N) and passing an intermediate point between the two first optical waveguides by an extension line of a center line of a first slab waveguide, and a plurality of second optical waveguides adjacent at a distance of a half of a prescribed length. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical wavelength multiplexer / demultiplexer in which an arrayed waveguide composed of a plurality of channel waveguides having a constant optical waveguide length difference and a slab waveguide formed on both ends of the arrayed waveguide are formed in the core.

  2. Description of the Related Art Conventionally, an optical wavelength multiplexer / demultiplexer using an arrayed waveguide is expected as a main component that is a key component of a wavelength multiplexing technique required for an optical fiber communication network or the like.

  A conventional optical wavelength multiplexer / demultiplexer will be described with reference to FIG. 6 using the conventional optical wavelength multiplexer / demultiplexer 90 as an example. FIG. 6 is a conceptual diagram of the optical wavelength multiplexer / demultiplexer 90. FIG. 6 shows the first optical waveguide 21, the first slab waveguide 22, the channel waveguide 23, the arrayed waveguide 24, the second slab waveguide 25, the second optical waveguide 26, the first chip 92a, and the second chip 92b. And a package 94 is shown.

  The first optical waveguide 21, the first slab waveguide 22, the channel waveguide 23, the second slab waveguide 25, and the second optical waveguide are formed as core patterns stacked on the substrate on the first chip 92 a and the second chip 92 b. A waveguide 26 is formed. The arrayed waveguide 24 is composed of a plurality of channel waveguides 23. The package 94 includes two chips, a first chip 92a and a second chip 92b.

  The optical wavelength multiplexer / demultiplexer 90 can multiplex the optical signals input to the second optical waveguide 26 of the first chip 92a and output the combined optical signals from the first optical waveguide 21. Further, the optical wavelength multiplexer / demultiplexer 90 can demultiplex an optical signal input to the first optical waveguide 21 of the second chip 92b and output it from the second optical waveguide 26. Since two chips are formed in the package 94, the optical wavelength multiplexer / demultiplexer 90 can simultaneously multiplex and demultiplex.

  With reference to FIG. 7, another conventional optical wavelength multiplexer / demultiplexer will be described using the optical wavelength multiplexer / demultiplexer 91 disclosed in Patent Document 1 as an example. FIG. 7 is a conceptual diagram of the optical wavelength multiplexer / demultiplexer 91. FIG. 7 shows the first optical waveguide 21, the first slab waveguide 22, the channel waveguide 23, the arrayed waveguide 24a, the arrayed waveguide 24b, the second slab waveguide 25, the second optical waveguide 26, and the chip 93. Has been.

  Two sets of the first optical waveguide 21, the first slab waveguide 22, the channel waveguide 23, the second slab waveguide 25, and the second optical waveguide 26 are formed on the chip 93 as a core pattern laminated on the substrate. Is done. In other words, the chip 93 is formed with two patterns that can be multiplexed and demultiplexed simultaneously. Since two patterns are formed on the chip 93, the optical wavelength multiplexer / demultiplexer 91 can simultaneously combine and demultiplex.

JP 2002-14245 A

  Since the optical wavelength multiplexer / demultiplexer 90 shown in FIG. 6 includes two chips, there is a problem that the manufacturing cost is increased due to the large size. The optical wavelength multiplexer / demultiplexer 91 of FIG. 7 is made to solve the problem of the optical wavelength multiplexer / demultiplexer 90 of FIG.

  However, the optical wavelength multiplexer / demultiplexer 91 shown in FIG. 7 has a problem that the optical characteristics are deteriorated due to the difference between the center wavelengths of the two patterns. The above-described problem will be described with reference to FIGS.

  FIG. 8 is a cross-sectional view of the substrate in the etching process. FIG. 8 shows a light source 95, a substrate 96, an under cladding layer 97a, a pattern 98a, a pattern 98b, and a photoresist 99.

  When a pattern is formed on the core described above by photolithography and etching, the photoresist 99 is exposed through a photomask (not shown in FIG. 8) on which a desired circuit is drawn. If the angle between the exposure surface of the photoresist 99 and the output light of the light source 95 is the same, the shapes of the pattern 98a and the pattern 98b are substantially the same (not shown in FIG. 8). However, the angle between the exposure surface of the photoresist 99 and the output light of the light source 95 may vary depending on the position of the substrate 96 (see FIG. 8). In particular, the angle formed between the exposure surface of the photoresist 99 and the output light of the light source 95 may be different at places such as the arrayed waveguide 24a and the arrayed waveguide 24b shown in FIG. If the photoresist 99 is exposed and etched in a state where the angle formed by the exposure surface of the photoresist 99 and the output light of the light source 95 is different, the shapes of the pattern 98a and the pattern 98b may be different. For example, the cross section of the pattern 98a is a parallelogram, but the cross section of the pattern 98b is a rectangle.

  Further, depending on the etching conditions, the thickness of the pattern 98a and the pattern 98b may be different (not shown in FIG. 8). When the pattern 98a and the pattern 98b have different shapes and thicknesses, the optical wavelength multiplexer / demultiplexer 91 may have different optical path lengths between the two patterns. If the optical path lengths of the two patterns are different, the optical wavelength multiplexer / demultiplexer 91 has a difference in center wavelength.

  FIG. 9 is a cross-sectional view of the substrate after the overcladding layer is laminated. FIG. 9 shows a substrate 96, an under cladding layer 97a, an over cladding layer 97b, a pattern 98a, and a pattern 98b.

  As shown in FIG. 9, when an over clad layer 97b is laminated on a substrate 96 on which patterns 98a and 98b having different shapes and thicknesses are formed, the thickness of the clad layer composed of the over clad layer 97b and the under clad layer 97a is as follows. , Not uniform. If the thickness of the cladding layer is not uniform, the internal stress is not uniform and the refractive index inside the cladding layer changes. When the refractive index inside the cladding layer changes, the optical wavelength multiplexer / demultiplexer 91 may have different optical path lengths for the two patterns. If the optical path lengths of the two patterns are different, the optical wavelength multiplexer / demultiplexer 91 has a difference in center wavelength.

  It is known that the center wavelength can be adjusted by heating or cooling the substrate. For example, the substrate can be heated or cooled using a heater or a Peltier element. However, since the optical wavelength multiplexer / demultiplexer 91 has two patterns formed on the chip 93, it is difficult to adjust the center wavelength by heating or cooling.

  To summarize the above, the optical wavelength multiplexer / demultiplexer 91 in FIG. 7 differs in the etching conditions and the like in the shape and thickness of the pattern formed in the core, and the thickness of the cladding layer is not uniform. May have a difference. The optical wavelength multiplexer / demultiplexer 91 having the difference in the center wavelength has a problem that the optical characteristics deteriorate.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an optical wavelength multiplexer / demultiplexer that is small in size and hardly deteriorates in optical characteristics. It is another object of the present invention to provide an optical wavelength multiplexer / demultiplexer capable of demultiplexing, multiplexing and demultiplexing or demultiplexing the optical signals propagating through two systems of optical communication networks.

  In order to achieve the above object, the first invention of the present application is adjacent to a distance obtained by multiplying (0.5 + N) by a predetermined length, and the extension line of the central axis of the first slab waveguide is the two extension lines. An optical wavelength multiplexer / demultiplexer comprising the two first optical waveguides that pass through an intermediate point of the first optical waveguides and the plurality of second optical waveguides that are adjacent to each other at a half distance of a predetermined length.

  Specifically, the first invention of the present application includes a clad layer formed on a substrate and a core having a refractive index higher than that of the clad layer surrounded by the clad layer, and the core pattern has a plurality of wavelengths. Two first optical waveguides that propagate an optical signal, a first slab waveguide that is connected to one end of the first optical waveguide and diffracts the optical signal, and has a certain optical waveguide length difference, An end of the first slab waveguide is connected to the side opposite to the side where the first optical waveguide is positioned, and is connected to the other end of the arrayed waveguide; A second slab waveguide that diffracts an optical signal, and a plurality of second optical waveguides that are connected to the side of the second slab waveguide that faces the side where the arrayed waveguide is located, and that propagates the optical signal are formed. An optical wavelength multiplexer / demultiplexer, wherein the two first optical waveguides are (0.5 + N) adjacent to each other by a predetermined length, and an extension line of the central axis of the first slab waveguide passes through an intermediate point of the two first optical waveguides, The second optical waveguide is an optical wavelength multiplexer / demultiplexer (where N is zero or an arbitrary natural number) characterized by being adjacent to each other at a distance of half of the predetermined length.

  The optical wavelength multiplexer / demultiplexer can form the pattern on one chip while reducing the difference in center wavelength. Accordingly, it is possible to provide an optical wavelength multiplexer / demultiplexer that is small in size and hardly deteriorates in optical characteristics.

  In order to achieve the above object, according to a second invention of the present application, a second slab waveguide is formed at a part or all of a coupling point and a part or all of an intermediate point, and one first optical waveguide and the other first slab waveguide are formed. The extension line of the central axis of the first slab waveguide passes through an intermediate point between one of the first optical waveguide and the other first optical waveguide, and an optical signal propagating through the first optical waveguide is coupled. A second optical waveguide coupled with a second optical waveguide formed at a part or all of a point, and an optical signal propagating through the other first optical waveguide formed at a part or all of an intermediate point; It is the optical wavelength multiplexer / demultiplexer formed so that it may couple | bond together.

  Specifically, the second invention of the present application includes a clad layer formed on a substrate and a core having a refractive index higher than that of the clad layer surrounded by the clad layer, and the core pattern has a predetermined wavelength interval. A first slab waveguide that is connected to one end of the first optical waveguide and diffracts the optical signal, and has a certain optical waveguide length difference. One end connected to the other end of the arrayed waveguide and an arrayed waveguide comprising a plurality of channel waveguides connected to the side of the first slab waveguide facing the side where the first optical waveguide is located And a second slab waveguide that diffracts the optical signal and a plurality of the second slab waveguides that are connected to the side of the second slab waveguide that faces the side where the arrayed waveguide is located, and each of which propagates an optical signal having a single wavelength. A second optical waveguide and an optical wavelength multiplexer / demultiplexer formed with Thus, the second optical waveguide has a part or all of a coupling point where the optical signal propagating through one of the first optical waveguides is coupled to a surface of the second slab waveguide connected to the second optical waveguide. And the one first optical waveguide and the other first optical waveguide are formed at a part or all of an intermediate point that is an intermediate point between the coupling points of the second slab waveguide. And an extension of the central axis of the first slab waveguide passes through an intermediate point of the other first optical waveguide, and the optical signal propagating through the first optical waveguide is part or all of the coupling point. The optical signal propagating through the other first optical waveguide is coupled to the second optical waveguide formed at a part or all of the intermediate point. This is an optical wavelength multiplexer / demultiplexer.

  The optical wavelength multiplexer / demultiplexer can form the pattern on one chip while reducing the difference in center wavelength. Accordingly, it is possible to provide an optical wavelength multiplexer / demultiplexer that is small in size and hardly deteriorates in optical characteristics.

  In the second invention of the present application, the one first optical waveguide receives the optical signal having the constant wavelength interval, and the second optical waveguide formed at the coupling point of the second slab waveguide is The optical signal having the single wavelength that has been demultiplexed is output, and the optical signal having the constant wavelength interval is input to the other first optical waveguide, and the second slab waveguide The second optical waveguide formed at the intermediate point preferably outputs the optical signal having the single wavelength that has been demultiplexed.

  The optical wavelength multiplexer / demultiplexer demultiplexes the optical signal input to the one first optical waveguide, outputs the optical signal from the second optical waveguide, and inputs the light input to the other first optical waveguide. A signal can be demultiplexed and output from the second optical waveguide. Accordingly, it is possible to provide an optical wavelength multiplexer / demultiplexer capable of demultiplexing the optical signals propagating through the two systems of optical communication networks.

  In the second invention of the present application, the second optical waveguide formed at the coupling point of the second slab waveguide is inputted with the optical signal having the single wavelength, and the one first optical waveguide. Outputs the combined optical signal having the constant wavelength interval, and the other first optical waveguide receives the optical signal having the constant wavelength interval, and the second slab waveguide The second optical waveguide formed at the intermediate point preferably outputs the optical signal having the single wavelength that has been demultiplexed.

  The optical wavelength multiplexer / demultiplexer multiplexes the optical signal input to the second optical waveguide, outputs the optical signal from the first optical waveguide, and inputs the light input to the other first optical waveguide. A signal can be demultiplexed and output from the second optical waveguide. Therefore, it is possible to provide an optical wavelength multiplexer / demultiplexer capable of multiplexing and demultiplexing the optical signals propagating through the two systems of optical communication networks.

  In the second invention of the present application, the second optical waveguide formed at the coupling point of the second slab waveguide is inputted with the optical signal having the single wavelength, and the one first optical waveguide. Outputs the combined optical signal having the constant wavelength interval, and the second optical waveguide formed at the intermediate point of the second slab waveguide has the light having the single wavelength. Each of the signals is input, and the other first optical waveguide preferably outputs the combined optical signal having the fixed wavelength interval.

  The optical wavelength multiplexer / demultiplexer can multiplex the optical signals input to the second optical waveguide and output them from the one first optical waveguide and the other first optical waveguide. Accordingly, it is possible to provide an optical wavelength multiplexer / demultiplexer that can multiplex the optical signals propagating through the two systems of optical communication networks.

  The present invention can provide an optical wavelength multiplexer / demultiplexer that is small in size and hardly deteriorates in optical characteristics. Further, it is possible to provide an optical wavelength multiplexer / demultiplexer capable of demultiplexing, multiplexing and demultiplexing or demultiplexing the optical signals propagating through the two systems of optical communication networks.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to embodiment shown below.

(Embodiment 1)
The first embodiment of the present application includes a clad layer formed on a substrate and a core having a refractive index higher than that of the clad layer surrounded by the clad layer, and an optical signal having a plurality of wavelengths is used as the pattern of the core. Two first optical waveguides that propagate, a first slab waveguide that is connected to one end of the first optical waveguide and diffracts an optical signal, and has a certain optical waveguide length difference. An arrayed waveguide composed of a plurality of channel waveguides connected to the side of the first slab waveguide facing the side where the first optical waveguide is located, and the other end of the arrayed waveguide, Light formed by a second slab waveguide that diffracts, and a plurality of second optical waveguides that are connected to the side of the second slab waveguide that faces the side where the arrayed waveguide is located, and that propagates optical signals A wavelength multiplexer / demultiplexer, wherein the two first optical waveguides are (0 5 + N) multiplied by a predetermined length and an extension line of the central axis of the first slab waveguide passes through an intermediate point of the two first optical waveguides, and the plurality of second optical waveguides The waveguides are optical wavelength multiplexers / demultiplexers (where N is zero or any natural number) characterized in that they are adjacent to each other at a distance of half the predetermined length.

  The optical wavelength multiplexer / demultiplexer 10 according to the first embodiment will be described with reference to FIGS. FIG. 1 is a conceptual diagram of an optical wavelength multiplexer / demultiplexer 10. The optical wavelength multiplexer / demultiplexer 10 includes a first optical waveguide 21, a first slab waveguide 22, a channel waveguide 23, an arrayed waveguide 24, a second slab waveguide 25, and a second optical waveguide 26.

  FIG. 2 is an enlarged view of a connection portion between the first optical waveguide 21 and the first slab waveguide 22. FIG. 2 shows the first optical waveguide 21, the first slab waveguide 22, the distance 40 of the first optical waveguide, and the extension 41 of the central axis of the first slab waveguide.

  FIG. 3 is an enlarged view of a connection portion between the second slab waveguide 25 and the second optical waveguide 26. FIG. 3 shows the distance 42 between the second slab waveguide 25, the second optical waveguide 26, and the second optical waveguide.

The manufacture of the optical wavelength multiplexer / demultiplexer 10 will be described. The optical wavelength multiplexer / demultiplexer 10 may be formed on a substrate (not shown in FIGS. 1 to 3). For example, the substrate material can be silicon (Si) or quartz glass (SiO ₂ ). The clad layer may be formed by laminating quartz glass on the substrate described above. The core may be formed by laminating quartz glass mixed with impurities that increase the refractive index on the above-described cladding layer. For example, as a method of laminating a clad layer and a core, a flame accumulation method (FHD method), a CVD method (chemical vapor deposition method), or a sputtering method can be given.

  The clad layer may be formed by laminating quartz glass mixed with impurities that lower the refractive index on the above-described substrate. The core may be formed by laminating quartz glass on the cladding layer described above.

  For example, the first optical waveguide 21, the first slab waveguide 22, the channel waveguide 23, the array waveguide 24, the second slab waveguide 25, and the second optical waveguide 26 are formed as a pattern on the core described above by photolithography and etching. , May be formed.

  As shown in FIG. 2, the two first optical waveguides 21 are formed so that the extension line 41 of the central axis of the first slab waveguide passes through the intermediate point between the two first optical waveguides 21. Also good.

  The two first optical waveguides 21 may be formed such that the distance 40 between the first optical waveguides is a distance obtained by multiplying (0.5 + N) by a predetermined length A. N is zero or any natural number. The predetermined length A is also related to the formation of the second waveguide described later.

  The predetermined length A may be estimated from the center wavelength, the number of channels, and the wavelength interval of the optical wavelength multiplexer / demultiplexer 10. For example, the predetermined length A may be 10 micrometers, 20 micrometers, or the like. Further, the distance 40 of the first optical waveguide may be 30 micrometers or 60 micrometers. The predetermined length A and the first optical waveguide distance 40 are not limited to the above.

  The first slab waveguide 22 may be formed so as to be connected to one end of the first optical waveguide 21.

  The plurality of channel waveguides 23 may be formed so that one end thereof is connected to the side of the first slab waveguide 22 facing the side where the first optical waveguide 21 is located. Each of the channel waveguides 23 has a certain optical waveguide length difference. The arrayed waveguide 24 is composed of a plurality of channel waveguides 23.

  The second slab waveguide 25 may be formed so as to be connected to the other end of the arrayed waveguide 24 opposite to the end connected to the first slab waveguide 22.

  The second optical waveguide 26 may be formed so as to be connected to the side of the second slab waveguide 25 that faces the side where the arrayed waveguide 24 is located. As shown in FIG. 3, the second optical waveguide 26 may be formed such that the distance 42 of the second optical waveguide is half of the predetermined length A.

  After the first optical waveguide 21, the first slab waveguide 22, the channel waveguide 23, the arrayed waveguide 24, the second slab waveguide 25, and the second optical waveguide 26 are formed on the core as a pattern, the cladding layer is formed again. You may laminate.

  When the clad layer is again laminated, the above-described substrate may be heated at 1000 ° C. or more. If the refractive index of the clad layer laminated on the upper surface of the substrate and the clad layer laminated again are the same, a single clad layer is formed after heating.

  In addition, if it does as follows, the optical wavelength multiplexer / demultiplexer 11 which concerns on 2nd Embodiment mentioned later can be manufactured. The second optical waveguide 26 may be formed at all the coupling points where the optical signal propagating through the first optical waveguide 21 is coupled to the surface of the second slab waveguide 25 to which the second optical waveguide 26 is connected. . Further, the second optical waveguide 26 may be formed at a part of the coupling point described above. Further, the second optical waveguide 26 may be formed at all of the intermediate points that are the surfaces of the second slab waveguides 25 to which the second optical waveguides 26 are connected and are in the middle of the above-described coupling points. The second optical waveguide 26 may be formed at a part of the intermediate point of the second slab waveguide 25 described above.

  The extension line of the central axis of the first slab waveguide 22 passes through an intermediate point between the first optical waveguide 21 and the first optical waveguide 21 of the first optical waveguide 21 and the other first optical waveguide 21. To be formed. One first optical waveguide 21 is formed such that an optical signal propagating through one first optical waveguide 21 is coupled with the second optical waveguide 26 formed at a part or all of the coupling points described above. The The other first optical waveguide 21 includes a second optical waveguide 26 in which an optical signal propagating through the other first optical waveguide 21 is formed at a part or all of an intermediate point of the second slab waveguide 25 described above. Formed to bond between the two.

  That is, the above-described coupling point is a portion where an optical signal propagating through one first optical waveguide 21 is demultiplexed and coupled to a surface of the second slab waveguide 25 to which the second optical waveguide 26 is connected. The intermediate point of the second slab waveguide 25 described above is a surface where the optical signal propagating through the other first optical waveguide 21 is demultiplexed and the second optical waveguide 26 of the second slab waveguide 25 is connected. It becomes a place to join to. As described above, the optical wavelength multiplexer / demultiplexer 11 according to the second embodiment can be manufactured.

  The point that the optical wavelength multiplexer / demultiplexer 10 is small in size and hardly deteriorates in optical characteristics will be described. The optical wavelength multiplexer / demultiplexer 10 does not need to form the same pattern at a location apart from the core described above. For example, the arrayed waveguide 24 of FIG. 1 is not formed at a distant place like the arrayed waveguide 24a and the arrayed waveguide 24b of FIG. Therefore, the shape and thickness of the core described above are rarely different, the thickness of the clad layer approaches uniformly, and the difference in center wavelength is reduced. The optical wavelength multiplexer / demultiplexer 10 can form the pattern to be formed on the core described above on one chip while reducing the difference in the center wavelength. When the difference between the center wavelengths is reduced, the optical wavelength multiplexer / demultiplexer 10 is less likely to deteriorate the optical characteristics. Accordingly, it is possible to provide an optical wavelength multiplexer / demultiplexer that is small in size and hardly deteriorates in optical characteristics.

(Embodiment 2)
The second embodiment of the present application includes a clad layer formed on a substrate, a core surrounded by the clad layer and having a refractive index higher than that of the clad layer, and light having a constant wavelength interval as the pattern of the core. Two first optical waveguides for propagating signals, a first slab waveguide connected to one end of the first optical waveguide and diffracting an optical signal, and having a certain optical waveguide length difference, An end of the first slab waveguide connected to the side opposite to the side where the first optical waveguide is located, an arrayed waveguide composed of a plurality of channel waveguides, and an end connected to the other end of the arrayed waveguide, A second slab waveguide that diffracts the signal and a plurality of second slab waveguides that are connected to the side of the second slab waveguide that faces the side where the arrayed waveguide is located, each of which propagates an optical signal having a single wavelength. An optical wavelength multiplexer / demultiplexer in which an optical waveguide is formed The second optical waveguide includes a part or all of coupling points where the optical signal propagating through one of the first optical waveguides is coupled to a surface of the second slab waveguide to which the second optical waveguide is connected, and the first optical waveguide. The one first optical waveguide and the other first optical waveguide are formed at a part or all of an intermediate point that is an intermediate point between the coupling points of the two slab waveguides, and the one first optical waveguide and the other An extension of the central axis of the first slab waveguide passes through an intermediate point of the first optical waveguide, and the optical signal propagating through the first optical waveguide is formed at a part or all of the coupling point. The optical signal coupled to the second optical waveguide and propagating through the other first optical waveguide is coupled to the second optical waveguide formed at a part or all of the intermediate point. Is an optical wavelength multiplexer / demultiplexer characterized by

  The optical wavelength multiplexer / demultiplexer 11 according to the second embodiment of the present application will be described with reference to FIG. FIG. 4 is a conceptual diagram of the optical wavelength multiplexer / demultiplexer 11. The optical wavelength multiplexer / demultiplexer 11 includes a first optical waveguide 21, a first slab waveguide 22, a channel waveguide 23, an arrayed waveguide 24, a second slab waveguide 25, and a second optical waveguide 26.

  As described above, the optical wavelength multiplexer / demultiplexer 11 can be manufactured in the same manner as the optical wavelength multiplexer / demultiplexer 10 in FIG.

  For example, an optical signal having a certain wavelength interval is input to the first optical waveguide 21. The optical signal output from the first optical waveguide 21 is diffracted by the first slab waveguide 22 and input to the channel waveguide 23. Since each channel waveguide 23 has a constant optical waveguide length difference, the phase of the optical signal output from the channel waveguide 23 is shifted by a certain amount. Optical signals whose phases are shifted by a certain amount interfere with each other when diffracted by the second slab waveguide 25. As a result of the interference, the optical signal is demultiplexed for each wavelength and output to the specific second optical waveguide 26.

  An optical signal having a single wavelength is input to the specific second optical waveguide 26. The optical signal output from the second optical waveguide 26 is diffracted by the second slab waveguide 25 and input to the channel waveguide 23. Since each channel waveguide 23 has a constant optical waveguide length difference, the phase of the optical signal output from the channel waveguide 23 is shifted by a certain amount. Optical signals whose phases are shifted by a certain amount interfere with each other when diffracted by the first slab waveguide 22. As a result of the interference, the optical signals are multiplexed at a constant wavelength interval and output to the first optical waveguide 21.

  Similar to the optical wavelength multiplexer / demultiplexer 10 in FIG. 1, the optical wavelength multiplexer / demultiplexer 11 can form the above-described pattern on one chip while reducing the difference in center wavelength. Accordingly, it is possible to provide an optical wavelength multiplexer / demultiplexer that is small in size and hardly deteriorates in optical characteristics.

  In the second embodiment of the present application, when an optical signal having a certain wavelength interval is input to one of the first optical waveguides 21, the optical wavelength multiplexer / demultiplexer 11 is formed at the coupling point of the second slab waveguide 25. From the second optical waveguide 26, it is possible to output an optical signal having a single wavelength that has been demultiplexed. Further, when the optical wavelength multiplexer / demultiplexer 11 inputs an optical signal having a certain wavelength interval to the other first optical waveguide 21, the second optical waveguide 26 formed at the intermediate point of the second slab waveguide 25. It is possible to output an optical signal having a single wavelength that has been demultiplexed. Accordingly, it is possible to provide an optical wavelength multiplexer / demultiplexer capable of demultiplexing optical signals propagating through two systems of optical communication networks.

  In the second embodiment of the present application, when an optical signal having a single wavelength is input to the second optical waveguide 26 formed at the coupling point of the second slab waveguide 25, the optical wavelength multiplexer / demultiplexer 11 From the first optical waveguide 21, it is possible to output a combined optical signal having a certain wavelength interval. Further, when an optical signal having a certain wavelength interval is input to the other first optical waveguide 21, the optical wavelength multiplexer / demultiplexer 11 starts from the second optical waveguide 26 formed at the midpoint of the second slab waveguide 25. It is possible to output an optical signal having a single wavelength that has been demultiplexed. Accordingly, it is possible to provide an optical wavelength multiplexer / demultiplexer capable of multiplexing and demultiplexing optical signals propagating through two systems of optical communication networks.

  In the second embodiment of the present application, when an optical signal having a single wavelength is input to the second optical waveguide 26 formed at the coupling point of the second slab waveguide 25, the optical wavelength multiplexer / demultiplexer 11 From the first optical waveguide 21, it is possible to output a combined optical signal having a certain wavelength interval. When an optical signal having a single wavelength is input to the second optical waveguide 26 formed at the midpoint of the second slab waveguide 25, the optical wavelength multiplexer / demultiplexer 11 starts from the other first optical waveguide 21. The combined optical signal having a constant wavelength interval can be output. Therefore, it is possible to provide an optical wavelength multiplexer / demultiplexer that can multiplex optical signals propagating through two systems of optical communication networks.

  FIG. 5 is a diagram showing the difference between the center wavelengths of the optical wavelength multiplexer / demultiplexer according to the present invention and the conventional optical wavelength multiplexer / demultiplexer. In FIG. 5, the vertical axis represents the center wavelength difference, and the horizontal axis represents the number of prototypes. In FIG. 5, the average absolute value of the difference between the center wavelengths is 0.0012 nm for the optical wavelength multiplexer / demultiplexer according to the present invention, and 0.044 nm for the conventional optical wavelength multiplexer / demultiplexer. . The standard deviation of the difference between the center wavelengths is 0.004 nm for the optical wavelength multiplexer / demultiplexer according to the present invention, and 0.057 nm for the conventional optical wavelength multiplexer / demultiplexer. Therefore, the optical wavelength multiplexer / demultiplexer according to the present invention can reduce the variation in the difference in the center wavelength to about 1/10 as compared with the conventional optical wavelength multiplexer / demultiplexer.

  The optical wavelength multiplexer / demultiplexer of the present invention can be used in an optical fiber communication network as an optical component such as an optical multiplexer / demultiplexer or an optical switch.

It is a conceptual diagram of the optical wavelength multiplexer / demultiplexer which concerns on one Embodiment of this-application 1st invention. FIG. 2 is an enlarged view of a connection portion between the first optical waveguide and the first slab waveguide in FIG. 1. It is an enlarged view of the connection location of the 2nd slab waveguide and 2nd optical waveguide in FIG. It is a conceptual diagram of the optical wavelength multiplexer / demultiplexer which concerns on one Embodiment of this invention 2nd invention. It is the figure which showed the difference of the center wavelength of the optical wavelength multiplexer / demultiplexer which concerns on invention of this application, and the conventional optical wavelength multiplexer / demultiplexer. It is a conceptual diagram of the conventional optical wavelength multiplexer / demultiplexer. It is a conceptual diagram of another conventional optical wavelength multiplexer / demultiplexer. It is sectional drawing of the board | substrate in an etching process. It is sectional drawing of the board | substrate after laminating | stacking an over clad layer.

Explanation of symbols

10, 11, 90, 91 Optical wavelength multiplexer / demultiplexer 21 First optical waveguide 22 First slab waveguide 23 Channel waveguides 24, 24a, 24b Array waveguide 25 Second slab waveguide 26 Second optical waveguide 40 First Optical waveguide distance 41 Extension of central axis of first slab waveguide 42 Second optical waveguide distance 92a First chip 92b Second chip 93 Chip 94 Package 95 Light source 96 Substrate 97a Under clad layer 97b Over clad layer 98a Pattern 98b Pattern 99 photoresist

Claims (5)

A cladding layer formed on a substrate and a core having a higher refractive index than the cladding layer surrounded by the cladding layer,
Two first optical waveguides that propagate optical signals of a plurality of wavelengths;
A first slab waveguide connected to one end of the first optical waveguide and diffracting an optical signal;
An arrayed waveguide comprising a plurality of channel waveguides having a constant optical waveguide length difference and having one end connected to a side of the first slab waveguide opposite to the side where the first optical waveguide is located;
A second slab waveguide connected to the other end of the arrayed waveguide and diffracting an optical signal;
An optical wavelength multiplexer / demultiplexer in which a plurality of second optical waveguides that propagate optical signals are connected to a side of the second slab waveguide that faces the side where the arrayed waveguide is located,
The two first optical waveguides are adjacent to each other at a distance obtained by multiplying (0.5 + N) by a predetermined length, and the extension line of the central axis of the first slab waveguide is the two first optical waveguides. The optical wavelength multiplexer / demultiplexer (where N is zero or an arbitrary natural number), wherein the plurality of second optical waveguides are adjacent to each other at a distance of half the predetermined length. ). A cladding layer formed on a substrate and a core having a higher refractive index than the cladding layer surrounded by the cladding layer,
Two first optical waveguides for propagating optical signals having a constant wavelength interval;
A first slab waveguide connected to one end of the first optical waveguide and diffracting an optical signal;
An arrayed waveguide comprising a plurality of channel waveguides having a constant optical waveguide length difference and having one end connected to a side of the first slab waveguide opposite to the side where the first optical waveguide is located;
A second slab waveguide connected to the other end of the arrayed waveguide and diffracting an optical signal;
A plurality of second optical waveguides that are connected to a side of the second slab waveguide opposite to the side where the arrayed waveguide is located, and each of which propagates an optical signal having a single wavelength, are formed. A duplexer,
The second optical waveguide includes a part or all of coupling points where the optical signal propagating through one of the first optical waveguides is coupled to a surface of the second slab waveguide to which the second optical waveguide is connected, and the first optical waveguide. The one first optical waveguide and the other first optical waveguide are formed at a part or all of an intermediate point that is an intermediate point between the coupling points of the two slab waveguides, and the one first optical waveguide and the other An extension of the central axis of the first slab waveguide passes through an intermediate point of the first optical waveguide, and the optical signal propagating through the first optical waveguide is formed at a part or all of the coupling point. The optical signal coupled to the second optical waveguide and propagating through the other first optical waveguide is coupled to the second optical waveguide formed at a part or all of the intermediate point. An optical wavelength multiplexer / demultiplexer.   The one first optical waveguide is inputted with the optical signal having the predetermined wavelength interval, and the second optical waveguide formed at the coupling point of the second slab waveguide is separated from the single optical waveguide. The optical signal having one wavelength is output, and the other first optical waveguide is input with the optical signal having the constant wavelength interval and is formed at the intermediate point of the second slab waveguide. 3. The optical wavelength multiplexer / demultiplexer according to claim 2, wherein the second optical waveguide outputs the optical signals having the demultiplexed single wavelength. 4.   The second optical waveguide formed at the coupling point of the second slab waveguide is inputted with the optical signal having the single wavelength, and the one first optical waveguide is multiplexed. The optical signal having a constant wavelength interval is output, and the other first optical waveguide is input with the optical signal having the constant wavelength interval and formed at the intermediate point of the second slab waveguide. 3. The optical wavelength multiplexer / demultiplexer according to claim 2, wherein the second optical waveguide outputs the optical signals having the demultiplexed single wavelength. 4. The second optical waveguide formed at the coupling point of the second slab waveguide is inputted with the optical signal having the single wavelength, and the one first optical waveguide is multiplexed. The optical signal having a constant wavelength interval is output, and the second optical waveguide formed at the intermediate point of the second slab waveguide is input with the optical signal having the single wavelength. 3. The optical wavelength multiplexer / demultiplexer according to claim 2, wherein the other first optical waveguide outputs the multiplexed optical signal having the constant wavelength interval.

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