JP2005326561A - Optical wavelength multiplexer / demultiplexer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical wavelength multiplexer / demultiplexer which is small and has a small loss.
An optical wavelength multiplexer / demultiplexer according to the present invention includes at least one input channel waveguide, an input side slab waveguide connected to the input channel waveguide, and at least one. A plurality of output channel waveguides 16, an output slab waveguide 15 connected to the output channel waveguide 16, and a plurality of phase shifts connecting the input slab waveguide 13 and the output slab waveguide 15. Each phase-shifting channel waveguide 14 is made of a quartz-based material having a higher refractive index than the input-side slab waveguide 13 and the output-side slab waveguide 15. Is.
[Selection] Figure 1

Description

  The present invention relates to an optical wavelength multiplexer / demultiplexer, and more particularly to an optical wavelength multiplexer / demultiplexer used for wavelength division multiplexing optical communication.

  In the field of optical communication, a wavelength division multiplexing (WDM) system is used in which a plurality of signals are placed on signal lights of different wavelengths and transmitted through a single optical fiber to increase information capacity. In this WDM system, an optical wavelength multiplexer / demultiplexer that multiplexes / demultiplexes signal light of different wavelengths plays a major role. In particular, an optical wavelength multiplexer / demultiplexer (AWG (Arrayed Waveguide Grating) optical multiplexer / demultiplexer) using a Mach-Zehnder interferometer or an arrayed waveguide grating multiplexes / demultiplexes a plurality of signal lights with narrow wavelength intervals. Therefore, there is an advantage that the number of multiplexed communication wavelengths can be easily increased and the communication capacity can be increased.

  As shown in FIG. 7, an optical wavelength multiplexer / demultiplexer using a general arrayed waveguide grating is provided on a substrate 71 with an input side slab waveguide 73, an output side slab waveguide 75, and an input side slab. An input channel waveguide 72 connected to one end of the waveguide 73, an output channel waveguide 76 connected to one end of the output slab waveguide 75, the input slab waveguide 73, and the output slab guide The optical circuit 77 includes a plurality of phase-shifting channel waveguides 74 that connect the other ends of the waveguide 75 to each other.

  The light wave input from the input channel waveguide 72 propagates through the input-side slab waveguide 73 and enters each phase-shifting channel waveguide 74. The light wave undergoes a phase change when propagating through each phase-shifting channel waveguide 74 and enters the output-side slab waveguide 75. The light wave in the output-side slab waveguide 75 interferes, reaches the output channel waveguide 76, and is output. At this time, since the interference pattern of the light wave varies depending on the wavelength, optical multiplexing / demultiplexing is realized.

  When an optical circuit is configured using a normal material, when the temperature changes, the refractive index of the material changes due to the thermo-optic effect. This changes the equivalent refractive index of each phase-shifting channel waveguide. Further, the length of each phase-shifting channel waveguide changes due to thermal expansion accompanying temperature change. As a result, the amount of phase change received by each phase-shifting channel waveguide fluctuates due to temperature changes. Since the amount of phase change varies depending on the wavelength, as a result, the output demultiplexing wavelength changes. As an example, considering the case where the optical circuit is made of a quartz-based material, the change of the demultiplexing wavelength due to the temperature in the vicinity of the wavelength of 1.55 μm is 0.01 nm / ° C. For example, when this optical circuit is used in a temperature environment of 0 ° C. to 60 ° C., the wavelength is shifted by a maximum of 0.6 nm, so that it cannot be used in a practical system as it is. Therefore, it is necessary to control the temperature of the optical circuit or make the temperature independent of the optical circuit.

  As a method for making the optical circuit temperature independent, a groove is provided in a part of the optical circuit, and a material whose refractive index has a temperature coefficient different from that of the optical circuit is filled therein, and the wavelength dependency of the phase change due to temperature is compensated. (For example, refer nonpatent literature 1).

  There is an optical wavelength multiplexer / demultiplexer that realizes wavelength dependence compensation by applying this method (see, for example, Non-Patent Document 2). Specifically, the input side slab waveguide 73 shown in FIG. 7 is provided with a plurality of wedge-shaped grooves 78. Here, simply providing one groove 78 causes a large diffraction loss because there is no light confinement structure in a direction perpendicular to the substrate 71. Therefore, by providing a plurality of grooves 78 to reduce diffraction loss per one step of each groove, and adjusting the arrangement interval of each groove 78 to an optimum interval to cause the entire groove 78 to collect light, the groove 78 A method of reducing the diffraction loss as a whole is commonly employed. FIG. 8 shows the relationship between the groove spacing and the loss when the relative refractive index difference Δ between the core material and the clad material constituting the optical circuit is 0.8%. It can be seen that there is an optimum groove arrangement interval that minimizes the loss.

  On the other hand, in addition to making the optical wavelength multiplexer / demultiplexer independent of temperature, downsizing of the optical circuit is an important consideration for further cost reduction. Here, by increasing the relative refractive index difference Δ between the core material and the clad material constituting the optical waveguide, the curvature radius of the bent waveguide is generally reduced, and the device (optical waveguide) is reduced in size and cost. Is known (see, for example, Non-Patent Document 3).

Y. Inoue et al., “Athermal silica-based arrayed-waveguide grating (AWG) multiplexer”, ECOC 97 Technical Digest, 1997, p.33-36. Maru et al., “Athermal and center wavelength adjustable arrayed-waveguide grating”, OFC 2000 Technical Digest, W3, 2000, p. .130-132 Hida et al., “Fabrication of low-loss and polarisation-insensitive 256 channel arrayed-256 channel arrayed wave guide grating with 25 GHz spacing using 1.5% Δ waveguide grating with 25GHz Spacing using 1.5% Δ waveguides) ”, Electron. Letter (Electron. Lett.), 2000, Vol. 36, No. 9, p.820-821

  However, in a temperature-independent type optical wavelength multiplexer / demultiplexer using an arrayed waveguide type diffraction grating, the relative refractive index difference Δ between the core material and the clad material constituting the optical circuit is to be reduced in size and cost. When is increased, there is a problem that radiation loss in the groove increases. For example, as shown in FIG. 9, when the relative refractive index difference Δ between the core material and the clad material is 1.5%, it can be seen that the loss is clearly increased as compared with FIG.

  An object of the present invention created in view of the above circumstances is to provide an optical wavelength multiplexer / demultiplexer that is small in size and low in loss.

  To achieve the above object, an optical wavelength multiplexer / demultiplexer according to the present invention includes at least one input channel waveguide, an input side slab waveguide connected to the input channel waveguide, and at least one input channel waveguide. An output channel waveguide, an output side slab waveguide connected to the output channel waveguide, and a plurality of phase shift channel waveguides connecting the input side slab waveguide and the output side slab waveguide In the arrayed waveguide type optical wavelength multiplexer / demultiplexer, each of the phase-shifting channel waveguides is made of a silica-based material having a higher refractive index than the input-side slab waveguide and the output-side slab waveguide. It is.

  The optical wavelength multiplexer / demultiplexer according to the present invention includes at least one input channel waveguide, an input side slab waveguide connected to the input channel waveguide, and at least one output channel waveguide. An array waveguide comprising a waveguide, an output slab waveguide connected to the output channel waveguide, and a plurality of phase shift channel waveguides connecting the input slab waveguide and the output slab waveguide Type optical wavelength multiplexer / demultiplexer, wherein the input slab waveguide and output slab waveguide formation layers and the phase shift channel waveguide formation layers are provided in different layers, and each phase shift channel The waveguide is made of a quartz material having a refractive index larger than that of each slab waveguide.

  Here, the connection end of each phase-shifting channel waveguide is formed in a tapered shape, and these phase-shifting channel waveguides are connected to the input-side slab waveguide and the output-side slab waveguide to adiabatically. It is preferable to optically couple.

  In addition, it is preferable that a plurality of grooves intersecting with the light wave propagating in the slab waveguide is formed in the input side slab waveguide.

  As described above, each phase-shifting channel waveguide is made of a silica-based material having a refractive index larger than that of the input-side slab waveguide and the output-side slab waveguide, so that the bent portion of the optical circuit, that is, each shift The radius of curvature of the bent portion of the phase channel waveguide can be reduced, so that the optical circuit can be downsized, and the optical wavelength multiplexer / demultiplexer can be downsized.

  According to the present invention, it is possible to obtain an excellent effect that an optical wavelength multiplexer / demultiplexer that is small and has a small loss can be obtained.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of the invention will be described with reference to the accompanying drawings.

(First embodiment)
FIG. 1 shows a plan view of an optical wavelength multiplexer / demultiplexer according to a preferred embodiment of the present invention.

  As shown in FIG. 1, the optical wavelength multiplexer / demultiplexer according to the present embodiment is provided with an optical circuit 17 on a quartz substrate 11. The optical circuit 17 is composed of two types of core materials having different refractive indexes, and a layer of a core material having a lower refractive index (hereinafter referred to as a low refractive index core material) is provided on the quartz substrate 11, and the low refractive index. A layer of a core material having a higher refractive index (hereinafter referred to as a high refractive index core material) is provided on the refractive index core material. The quartz substrate 11 and each core layer are covered with a cladding layer.

  The input side slab waveguide 13 and the output side slab waveguide 15, at least one input channel waveguide 12 connected to one end side of the input side slab waveguide 13, and the output side slab by the low refractive index core material A plurality of (four shown in FIG. 1) output channel waveguides 16 connected to one end of the waveguide 15 are configured. Also, a plurality of (5 in FIG. 1) phase-shifting channel waveguides 14 connecting the other end sides of the input-side slab waveguide 13 and the output-side slab waveguide 15 with the high refractive index core material. Composed. Both end portions (connection end portions) 20a, 20b of each phase-shifting channel waveguide 14 are formed in a tapered shape (tapered shape). A plurality of wedge-shaped grooves 18 are formed in the middle of the input-side slab waveguide 13 so as to intersect with the light wave propagating in the slab waveguide 13, and all the grooves 18 are filled with the optical resin 19. .

  Each phase-shifting channel waveguide 14 is made of a silica-based material having a higher refractive index than the input-side slab waveguide 13 and the output-side slab waveguide 15. For example, the refractive index of the clad material is 1.457, and the low refractive index core material of the input channel waveguide 12, the input side slab waveguide 13, the output side slab waveguide 15, and the output channel waveguide 16 is used. The refractive index is 1.469 (relative refractive index difference Δ1 = 0.8% relative to the cladding material), and the refractive index of the high refractive index core material constituting the phase-shifting channel waveguide 14 is 1.480 (relative refractive index relative to the cladding material). The rate difference Δ2 = 1.5%). Further, the layers of the slab waveguides 13 and 15 and the layer of the phase shift channel waveguide 14 are provided in different layers, and the layer of the phase shift channel waveguide 14 is provided on the layer of the slab waveguides 13 and 15. Provided. The difference (%) between the relative refractive index difference Δ2 of the high refractive index core material relative to the cladding material and the relative refractive index difference Δ1 of the low refractive index core material relative to the cladding material is 0 to 2%, preferably 0 to 1.5. %, Particularly preferably 0.5 to 1.0%.

  The temperature dependency of the refractive index of the optical resin 19 filled in the groove 18 is more effective for making the temperature independent as the material is different from the material constituting the optical circuit 17. For example, when the optical circuit 17 is made of a quartz-based material, the temperature dependency of the refractive index of the optical circuit 17 is a positive value, so that the optical resin 19 has a negative temperature dependency of the refractive index. Silicone resin, epoxy resin and the like are preferable.

  Next, a method for manufacturing the optical wavelength multiplexer / demultiplexer 10 according to the present embodiment will be described with reference to FIGS. 2 (a) to 2 (h). In addition, the same code | symbol is attached | subjected about the member similar to FIG. 1, and detailed description is abbreviate | omitted about these members.

  First, as shown in FIG. 2A, a low refractive index core layer 22 having a refractive index of 1.469 is formed on a quartz substrate 11. Thereafter, using the photolithography technique and the etching technique, as shown in FIG. 2B, the non-mask portion 22a of the low refractive index core layer 22 is removed by etching to form the low refractive index core materials 23a and 23b. . The low refractive index core material 23a forms the input side slab waveguide 13 and the input channel waveguide 12, and the low refractive index core material 23b forms the output side slab waveguide 15 and the output channel waveguide 16.

  Next, as shown in FIG. 2C, a clad layer 24 having a refractive index of 1.457 is deposited on the quartz substrate 11 and the low refractive index core materials 23a and 23b by chemical vapor deposition. Thereafter, as shown in FIG. 2D, the cladding layer 24 is planarized by a CMP (Chemical Mechanical Polishing) method.

  Next, as shown in FIG. 2E, a high refractive index core layer 25 having a refractive index of 1.480 is formed on the low refractive index core materials 23 a and 23 b and the cladding layer 24. Thereafter, using the photolithography technique and the etching technique, as shown in FIG. 2F, the non-mask portion 25a of the high refractive index core layer 25 is removed by etching to form the high refractive index core material 26. Each high-refractive index core material 26 forms each phase-shifting channel waveguide 14. Further, the connecting portions of the high refractive index core material 26 and the low refractive index core materials 23 a and 23 b are formed in the tapered portions 26 a and 26 b, and the tapered portions 26 a and 26 b are formed at both ends of each phase shift channel waveguide 14. Parts 20a and 20b.

  Next, as shown in FIG. 2G, a clad layer having a refractive index of 1.457 is formed on the low refractive index core materials 23a and 23b, the clad layer 24, and the high refractive index core material 26 by chemical vapor deposition. 27 is deposited.

  Finally, as shown in FIG. 2 (h), a plurality of the low refractive index core material 23a reaching the quartz substrate 11 from the surface portion of the cladding layer 27 (only one is shown in FIG. 2 (h)). ) And the optical resin 19 is filled in each groove 18. Thereby, the optical wavelength multiplexer / demultiplexer 10 according to the present embodiment is obtained.

  Here, the tapered portions 26a and 26b of the high refractive index core material 26 are not necessarily formed. However, by forming the tapered portions 26a and 26b, the high refractive index core material 26 and the lower refractive index core material 23a thereunder are formed. , 23b can be easily adiabatically optically coupled. The taper processing in the depth direction (vertical direction in FIG. 2 (f)) is, for example, Kitano et al., “Novel spot size converter for super high Δwaveguides”, CEL 2003. This can be achieved by using the method described in (CLEO 2003).

  Next, the operation of the present embodiment will be described.

  The multi-wavelength signal light incident from the input channel waveguide 12 is radiated and propagated inside the input-side slab waveguide 13 to become demultiplexed signal light. At this time, a groove 18 filled with an optical resin 19 is provided in the middle of the input side slab waveguide 13. The refractive index temperature coefficient of the optical resin 19 is opposite to the refractive index temperature coefficient of the quartz-based material constituting the optical circuit 17, so that even if the temperature of the optical circuit 17 changes, the phase of each demultiplexed signal light The variation in the amount of change can be completely compensated (cancelled) by the optical resin 19 filled in the groove 18.

  Each demultiplexed signal light compensated for the variation in the phase change amount is incident on each phase-shifting channel waveguide 14 and propagates therethrough. Thereafter, each demultiplexed signal light reaches the output-side slab waveguide 15 and is emitted. At the time of this radiation, since there is a radiation angle specific to the wavelength of each demultiplexed signal light, each demultiplexed signal light radiated from each phase-shifting channel waveguide 14 is output to the output-side slab waveguide 15. Then, the light is condensed and coupled to each output channel waveguide 16 corresponding to each wavelength.

  In the optical wavelength multiplexer / demultiplexer 10 according to the present embodiment, the relative refractive index difference Δ2 between the cladding materials 24 and 27 and the high-refractive index core material 26 in the optical circuit 17 is low as compared with the cladding materials 24 and 27. It is formed to be larger than the relative refractive index difference Δ1 with respect to the refractive index core materials 23a and 23b. As a result, the radius of curvature of the bent portion of the optical circuit 17 (the bent portion of each phase-shifting channel waveguide 14) can be reduced, and the optical circuit 17 can be downsized, and thus the optical wavelength multiplexer / demultiplexer 10 Miniaturization is possible. Actually, when Δ = 0.8%, the minimum radius of curvature without substantial loss is 5 mm, whereas by setting Δ = 1.5%, the minimum radius of curvature is 2 mm. be able to.

  In the optical wavelength multiplexer / demultiplexer 10 according to the present embodiment, both end portions 20a and 20b of each phase-shifting channel waveguide 14 are each tapered (tapered). Thus, each phase-shifting channel waveguide 14, the input-side slab waveguide 13, and the output-side slab waveguide 15 can be optically coupled in an adiabatic manner. As a result, it is possible to suppress fluctuations in the amount of phase change received by each phase-shifting channel waveguide 14 due to temperature changes. Therefore, the temperature independence of the optical wavelength multiplexer / demultiplexer 10 is further improved.

  Further, in the optical wavelength multiplexer / demultiplexer 10 according to the present embodiment, the relative refractive index difference Δ between the groove 18 filled with the optical resin 19 for temperature independence and the clad materials 24 and 27 is small. It is formed in the low refractive index core material 23 a, that is, the input side slab waveguide 13. As a result, in the optical circuit 17, it is possible to suppress an increase in radiation loss in the groove 18 while keeping the refractive index of each phase-shifting channel waveguide 14 large.

  In the optical wavelength multiplexer / demultiplexer 10 according to the present embodiment, the high refractive index core material 26 and the low refractive index core materials 23a and 23b are stacked, and the high refractive index core layer 25 and the low refractive index core layer 22 are stacked. The phase shift channel waveguide 14 is formed by the high refractive index core material 26, and the input side slab waveguide 13 and the output side slab waveguide 15 are formed by the low refractive index core materials 23a and 23b. . Accordingly, the optical wavelength multiplexer / demultiplexer can be obtained by a relatively easy manufacturing process conventionally used for manufacturing an optical wavelength multiplexer / demultiplexer as shown in FIGS. 2 (a) to 2 (h). 10 can be manufactured. As a result, it is possible to obtain an optical wavelength multiplexer / demultiplexer 10 that is small in size and low in loss with substantially the same manufacturing cost as that of a conventional optical wavelength multiplexer / demultiplexer.

  Next, another embodiment of the present invention will be described with reference to the accompanying drawings.

(Second Embodiment)
FIG. 3 shows a plan view of an optical wavelength multiplexer / demultiplexer according to another preferred embodiment of the present invention. In addition, the same code | symbol is attached | subjected about the member similar to FIG. 1, and detailed description is abbreviate | omitted about these members.

  The optical wavelength multiplexer / demultiplexer 10 according to the previous embodiment shown in FIG. 1 is configured such that only each phase-shifting channel waveguide 14 is composed of a high refractive index core material 26 (see FIG. 2 (h)). It was.

  As shown in FIG. 3, the basic configuration of the optical wavelength multiplexer / demultiplexer 30 according to the present embodiment is the same as that of the optical wavelength multiplexer / demultiplexer 10 according to the previous embodiment, and each phase-shift channel The waveguide 14, the input channel waveguide 12, and each output channel waveguide 16 are made of a high refractive index core material.

  Further, together with both ends 20a and 20b of each phase-shifting channel waveguide 14, an end portion (connection end portion) 32a of the input channel waveguide 12 and an end portion (connection end portion) 36a of each output channel waveguide 16 are provided. Are each tapered (tapered).

  A method of manufacturing the optical wavelength multiplexer / demultiplexer 30 according to the present embodiment will be described with reference to FIGS. 4 (a) to 4 (h). In addition, the same code | symbol is attached | subjected about the member similar to Fig.2 (a)-FIG.2 (h), and detailed description is abbreviate | omitted about these members.

  First, as shown in FIG. 4A, the low refractive index core layer 22 is formed on the quartz substrate 11. Thereafter, using the photolithography technique and the etching technique, as shown in FIG. 4B, the non-mask portion 22a of the low refractive index core layer 22 is removed by etching to form the low refractive index core materials 23a and 23b. . The low refractive index core material 23a forms the input side slab waveguide 13, and the low refractive index core material 23b forms the output side slab waveguide 15.

  Next, as shown in FIG. 4C, a cladding layer 24 is deposited on the quartz substrate 11 and the low refractive index core materials 23a and 23b by chemical vapor deposition. Thereafter, the cladding layer 24 is planarized by CMP as shown in FIG.

  Next, as shown in FIG. 4 (e), the high refractive index core layer 25 is formed on the low refractive index core materials 23 a and 23 b and the cladding layer 24. Thereafter, using a photolithography technique and an etching technique, as shown in FIG. 4F, the non-mask portion 25a of the high refractive index core layer 25 is etched away, and the high refractive index core material 26 and the high refractive index core are removed. Materials 46a and 46b are formed. The high refractive index core material 26 forms each phase-shifting channel waveguide 14, and the high refractive index core materials 46 a and 46 b form the input channel waveguide 12 and the output channel waveguide 16. Further, the tapered portions 26 a and 26 b of the high refractive index core material 26 become both end portions 20 a and 20 b of each phase-shifting channel waveguide 14. Further, the connecting portions of the high refractive index core materials 46 a and 46 b with the low refractive index core materials 23 a and 23 b are formed in the tapered portions 47 a and 47 b, and the tapered portions 47 a and 47 b are the ends of the input channel waveguide 12. The portion 32a and the end portion 36a of each output channel waveguide 16 are provided.

  Next, as shown in FIG. 4G, the clad layer 27 is formed on the low refractive index core materials 23a and 23b, the clad layer 24, and the high refractive index core materials 26, 46a and 46b by chemical vapor deposition. Deposition formation.

  Finally, as shown in FIG. 4 (h), a plurality of low refractive index core materials 23a reaching from the surface portion of the cladding layer 27 to the quartz substrate 11 (only one is shown in FIG. 4 (h)). ) And the optical resin 19 is filled in each groove 18. Thereby, the optical wavelength multiplexer / demultiplexer 30 according to the present embodiment is obtained.

  Also in the optical wavelength multiplexer / demultiplexer 30 according to the present embodiment, the same operational effects as those of the optical wavelength multiplexer / demultiplexer 10 according to the previous embodiment can be obtained.

  Further, in the optical wavelength multiplexer / demultiplexer 30 according to the present embodiment, the relative refractive index difference Δ2 between the cladding materials 24 and 27 and the high refractive index core materials 26, 46a and 46b in the optical circuit 17 is determined by the cladding. It is formed larger than the relative refractive index difference Δ1 between the materials 24 and 27 and the low refractive index core materials 23a and 23b. For this reason, it is possible to reduce the curvature radii of the bent portions of the optical circuit 17 (the bent portions of the phase shift channel waveguides 14, the input channel waveguides 12, and the output channel waveguides 16). The circuit 17 can be further miniaturized, and further the optical wavelength multiplexer / demultiplexer 10 can be further miniaturized.

  Further, in the optical wavelength multiplexer / demultiplexer 30 according to the present embodiment, both end portions 20a and 20b of each phase shift channel waveguide 14, the end portion 32a of the input channel waveguide 12, and each output channel guide. Each end 36a of the waveguide 16 is tapered (tapered). Thereby, each waveguide 12, 14, 16 and the input side slab waveguide 13 and the output side slab waveguide 15 can be optically coupled in an adiabatic manner. As a result, it is possible to suppress fluctuations in the amount of phase change received by each waveguide 12, 14, and 16 due to temperature changes. Therefore, the optical wavelength multiplexer / demultiplexer 30 is further improved in temperature independence compared to the optical wavelength multiplexer / demultiplexer 10 according to the previous embodiment.

(Third embodiment)
A plan view of an optical wavelength multiplexer / demultiplexer according to another preferred embodiment of the present invention is shown in FIG. In addition, the same code | symbol is attached | subjected about the member similar to FIG. 3, and detailed description is abbreviate | omitted about these members.

  As shown in FIG. 5, the basic configuration of the optical wavelength multiplexer / demultiplexer 50 according to this embodiment is the same as that of the optical wavelength multiplexer / demultiplexer 30 according to the previous embodiment, and the input side slab waveguide. In addition, the output side slab waveguide is integrated and formed over the entire surface of the quartz substrate 11.

  A method for manufacturing the optical wavelength multiplexer / demultiplexer 50 according to the present embodiment will be described with reference to FIGS. 6 (a) to 6 (e). In addition, the same code | symbol is attached | subjected about the member similar to Fig.4 (a)-FIG.4 (h), and detailed description is abbreviate | omitted about these members.

  First, as shown in FIG. 6A, the low refractive index core layer 22 is formed on the quartz substrate 11.

  Next, as shown in FIG. 6B, a high refractive index core layer 25 is formed on the low refractive index core layer 22 by chemical vapor deposition. Thereafter, as shown in FIG. 6C, the non-mask portion 25a of the high refractive index core layer 25 is removed by etching using a photolithography technique and an etching technique, and the high refractive index core material 26 and the high refractive index core are removed. Materials 46a and 46b are formed. The high refractive index core material 26 forms each phase-shifting channel waveguide 14, and the high refractive index core materials 46 a and 46 b form the input channel waveguide 12 and the output channel waveguide 16. Further, the tapered portions 26 a and 26 b of the high refractive index core material 26 become both end portions 20 a and 20 b of each phase-shifting channel waveguide 14. Further, the tapered portions 47 a and 47 b of the high refractive index core materials 46 a and 46 b become the end portion 32 a of the input channel waveguide 12 and the end portion 36 a of each output channel waveguide 16.

  Next, as shown in FIG. 6D, the cladding layer 27 is deposited on the low refractive index core layer 22b and the high refractive index core materials 26, 46a, and 46b by chemical vapor deposition.

  Finally, as shown in FIG. 6E, a plurality (1 in FIG. 6E) reaches a predetermined position of the low refractive index core layer 22 from the surface portion of the cladding layer 27 to the quartz substrate 11. (Only one is shown) 18 is formed, and each groove 18 is filled with an optical resin 19. Thereby, the optical wavelength multiplexer / demultiplexer 50 according to the present embodiment is obtained.

  Next, the operation of the present embodiment will be described.

  The multi-wavelength signal light incident from the input channel waveguide 12 is radiated and propagated inside the slab waveguide (low refractive index core layer 22) to become demultiplexed signal light. At this time, the demultiplexed signal light emitted from each phase-shifting channel waveguide 14 so that the multi-wavelength signal light input from the input channel waveguide 12 reaches each phase-shifting channel waveguide 14. Are adjusted in advance so that each of the waveguides 12, 14, 16 is formed so as to reach each output channel waveguide 16.

  Each demultiplexed signal light that radiates and propagates inside the slab waveguide 22 is compensated for variation in the amount of phase change by the optical resin 19 filled in the groove 18 and is incident on each phase-shifting channel waveguide 14. Propagate inside it. Thereafter, each demultiplexed signal light reaches the slab waveguide 22 again and is emitted. Each demultiplexed signal light emitted from each phase-shifting channel waveguide 14 is condensed and coupled to an output channel waveguide 16 corresponding to each wavelength via a slab waveguide 22.

  The multi-wavelength signal light or each demultiplexed signal light propagating through each waveguide 12, 14, 16 is confined in the thickness direction of the optical wavelength multiplexer / demultiplexer 50 (vertical direction in FIG. 6 (e)). This is done by the difference in refractive index between the lower refractive index core layer 22, the high refractive index core materials 26, 46 a and 46 b, and the uppermost cladding layer 27.

  Further, the taper lengths at both end portions 20a and 20b of each phase-shifting channel waveguide 14, the end portion 32a of the input channel waveguide 12, and the end portion 36a of each output channel waveguide 16 are the same as those in the previous embodiment. The optical wavelength multiplexer / demultiplexer 30 according to the embodiment is formed to be sufficiently longer than the respective taper lengths at the both end portions 20a, 20b, the end portion 32a, and the end portion 36a. As a result, the multi-wavelength signal light radiated from the input channel waveguide 12 and the demultiplexed signal lights radiated from the phase-shifting channel waveguides 14 are radiated in a wide range in the slab waveguide 22 portion. It will not be. That is, the spread of the multiplexed wavelength signal light and each demultiplexed signal light in the slab waveguide 22 can be controlled within a narrow range.

  Also in the optical wavelength multiplexer / demultiplexer 50 according to the present embodiment, the same effects as those of the optical wavelength multiplexer / demultiplexer 30 according to the previous embodiment can be obtained.

  Further, in the optical wavelength multiplexer / demultiplexer 50 according to the present embodiment, it is not necessary to form the slab waveguides 13 and 15 individually as in the optical wavelength multiplexer / demultiplexer 30 according to the previous embodiment. That is, the low refractive index core layer 22 itself is a slab waveguide on the input side and output side, and the manufacturing process shown in FIGS. 4B to 4D is not necessary. Thus, the optical wavelength multiplexer / demultiplexer 50 can be manufactured by an easier manufacturing process than the optical wavelength multiplexer / demultiplexer 30. As a result, it is possible to obtain an optical wavelength multiplexer / demultiplexer 50 that is smaller, smaller, and less lossy than the optical wavelength multiplexer / demultiplexer 30.

  As described above, the present invention is not limited to the above-described embodiment, and it goes without saying that various other things are assumed.

  The structure and configuration of the optical circuit 17 of the optical wavelength multiplexer / demultiplexers 10, 30, and 50 according to the present embodiment are the same as those of the elements used in the optical wavelength multiplexing transmission system and the optical frequency multiplexing transmission system, for example, M × N. It can also be applied to frequency routing devices, Add / Drop filters, and the like.

1 is a plan view of an optical wavelength multiplexer / demultiplexer according to a preferred embodiment of the present invention. It is sectional drawing for demonstrating the manufacturing method of the optical wavelength multiplexer / demultiplexer of FIG. It is a top view of the optical wavelength multiplexer / demultiplexer which concerns on other suitable one Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the optical wavelength multiplexer / demultiplexer of FIG. It is a top view of the optical wavelength multiplexer / demultiplexer which concerns on another suitable one Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the optical wavelength multiplexer / demultiplexer of FIG. It is a top view of the temperature independent type optical wavelength multiplexer / demultiplexer using the conventional arrayed waveguide type diffraction grating. It is a figure which shows the relationship between the arrangement | positioning space | interval of each groove | channel, and loss in case the relative refractive index difference (DELTA) of a core material and a clad material is 0.8%. It is a figure which shows the relationship between the arrangement | positioning space | interval of each groove | channel, and loss in case the relative refractive index difference (DELTA) of a core material and a clad material is 1.5%.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical wavelength multiplexer / demultiplexer 12 Input channel waveguide 13 Input side slab waveguide (slab waveguide)
14 Phase-shifting channel waveguide 17 Optical circuit

Claims (4)

  At least one input channel waveguide, an input-side slab waveguide connected to the input channel waveguide, at least one output channel waveguide, and an output connected to the output channel waveguide An arrayed waveguide type optical wavelength multiplexer / demultiplexer comprising a side slab waveguide and a plurality of phase shift channel waveguides connecting the input side slab waveguide and the output side slab waveguide. An optical wavelength multiplexer / demultiplexer comprising a channel waveguide made of a silica-based material having a larger refractive index than the input side slab waveguide and the output side slab waveguide.   At least one input channel waveguide, an input-side slab waveguide connected to the input channel waveguide, at least one output channel waveguide, and an output connected to the output channel waveguide An arrayed waveguide type optical wavelength multiplexer / demultiplexer comprising a side slab waveguide and a plurality of phase-shifting channel waveguides connecting the input side slab waveguide and the output side slab waveguide. The formation layer of the waveguide and the output-side slab waveguide and the formation layer of each of the phase-shifting channel waveguides are provided in different layers, and each phase-shifting channel waveguide has a higher refractive index than each slab waveguide. An optical wavelength multiplexer / demultiplexer comprising a quartz-based material.   The connecting end of each phase-shifting channel waveguide is tapered, and the phase-shifting channel waveguide is connected to the input-side slab waveguide and the output-side slab waveguide for adiabatic optical coupling. The optical wavelength multiplexer / demultiplexer according to claim 1 or 2. 4. The optical wavelength multiplexer / demultiplexer according to claim 1, wherein a plurality of grooves intersecting light waves propagating in the slab waveguide are formed in the input-side slab waveguide. 5.

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