Optical device, phase shifter and optical communication device

Abstract

To provide an optical device capable of reducing insertion loss of light while suppressing a drive current amount to a heater electrode.SOLUTION: An optical device has a substrate, a dielectric laminated on the substrate; an optical waveguide surrounded by the dielectric; and a heater electrode arranged on the optical waveguide, and surrounded by the dielectric. The optical waveguide is a rib type optical waveguide provided with a rib on a slab and below the heater electrode, and has a structure in which a width of the slab is 11 times or less a width of the rib.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an optical device, a phase shifter, and an optical communication apparatus. [Background technology]

[0002] Optical modulators and optical receivers in optical communication devices used for high-speed optical communication have built-in phase shifters. The phase shifter uses heater heat to increase the temperature inside the optical waveguide, which changes the refractive index inside the optical waveguide, and shifts the phase of the signal light passing through the optical waveguide in response to the change in refractive index.

[0003] Fig. 15 is a schematic plan view showing an example of a conventional phase shifter 200, and Fig. 16 is a schematic cross-sectional view of the phase shifter 200 taken along line HH shown in Fig. 15. The phase shifter 200 shown in Fig. 15 has a Si substrate 201, a dielectric 202, an optical waveguide 203, a heater electrode 204, and an electrode pad 205. The dielectric 202 is stacked on the Si substrate 201, and surrounds the periphery of the optical waveguide 203 arranged on the Si substrate 201 and the periphery of the heater electrode 204 arranged on the optical waveguide 203.

[0004] The dielectric 202 is a cladding layer made of, for example, SiO2. The optical waveguide 203 is a channel-type waveguide made of, for example, Si, through which signal light passes. The heater electrode 204 is made of, for example, a resistive metal such as Ti, and generates heater heat in response to a drive current, thereby increasing the temperature inside the optical waveguide 203. The electrode pad 205 is connected to the heater electrode 204 and includes an input-side electrode pad 205A that inputs current to the heater electrode 204 and an output-side electrode pad 205B that outputs current from the heater electrode 204.

[0005] The phase shifter 200 generates heater heat in response to a drive current to the heater electrode 204, and this heater heat increases the temperature inside the optical waveguide 203. Furthermore, the refractive index inside the optical waveguide 203 changes in response to the thermo-optic effect of Si caused by the temperature increase. Furthermore, the phase shifter 200 shifts the phase of the signal light passing through the optical waveguide 203 in response to the change in the refractive index. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] US Patent Application Publication No. 2019 / 258094 [Patent Document 2] International Publication No. 2016 / 92829 [Patent Document 3] U.S. Patent No. 9,477,039 [Patent Document 4] Japanese Patent Application Laid-Open No. 2003-228031 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the conventional phase shifter 200, the use of a channel-type optical waveguide increases the propagation loss of light, which leads to a need to increase the amount of drive current to the heater electrode 204. Therefore, it is conceivable to increase the electrode length of the heater electrode 204 in order to reduce the amount of drive current to the heater electrode 204, but increasing the electrode length of the heater electrode 204 increases the insertion loss of light.

[0008] In one aspect, an object is to provide an optical device or the like that can reduce the insertion loss of light while suppressing the amount of drive current to a heater electrode. [Means for solving the problem]

[0009] An optical device according to one embodiment includes a substrate, a dielectric layered on the substrate, an optical waveguide surrounded by the dielectric, and a heater electrode disposed on the optical waveguide and surrounded by the dielectric. The optical waveguide is a rib-type optical waveguide having ribs on a slab below the heater electrode. The optical waveguide has a structure in which the width of the slab is 11 times or less the width of the rib. [Effects of the Invention]

[0010] According to one aspect, the amount of drive current to the heater electrode can be suppressed while reducing the insertion loss of light. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is an explanatory diagram showing an example of an optical communication device according to this embodiment. [Figure 2] FIG. 2 is a schematic plan view illustrating an example of the phase shifter according to the first embodiment. [Figure 3] FIG. 3 is a schematic cross-sectional view of the phase shifter taken along line AA in FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view of a phase shifter of a comparative example. [Figure 5] FIG. 5 is an explanatory diagram showing an example of the relationship between the amount of drive current of the phase shifter and the slab width / rib width. [Figure 6] FIG. 6 is a schematic plan view illustrating an example of a phase shifter according to the second embodiment. [Figure 7] FIG. 7 is a schematic cross-sectional view of the phase shifter taken along line BB in FIG. [Figure 8] FIG. 8 is a schematic plan view showing an example of a phase shifter according to the third embodiment. [Figure 9] FIG. 9 is a schematic cross-sectional view of the phase shifter taken along line CC shown in FIG. [Figure 10] FIG. 10 is a schematic cross-sectional view of the phase shifter taken along line DD in FIG. [Figure 11] FIG. 11 is a schematic plan view showing an example of a phase shifter according to the fourth embodiment. [Figure 12] FIG. 12 is a schematic cross-sectional view of the phase shifter taken along line EE shown in FIG. [Figure 13] FIG. 13 is a schematic cross-sectional view of the phase shifter taken along the line FF shown in FIG. [Figure 14] FIG. 14 is a schematic cross-sectional view of the phase shifter taken along line GG shown in FIG. [Figure 15] FIG. 15 is a schematic plan view showing an example of a conventional phase shifter. [Figure 16] FIG. 16 is a schematic cross-sectional view of the conventional phase shifter taken along line HH shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the optical device and the like disclosed in the present application will be described in detail with reference to the drawings. Note that the present invention is not limited to these embodiments. Furthermore, the examples shown below may be combined as appropriate within the scope of not causing any contradiction. [Example]

[0013] FIG. 1 is an explanatory diagram showing an example of an optical communication device 1 according to the present embodiment. The optical communication device 1 shown in FIG. 1 is connected to an optical fiber 2A(2) on the output side and an optical fiber 2B(2) on the input side. The optical communication device 1 includes a DSP (Digital Signal Processor) 3, a light source 4, an optical modulator 5, and an optical receiver 6. The DSP 3 is an electrical component that performs digital signal processing. For example, the DSP 3 performs processing such as encoding of transmission data, generates an electrical signal including the transmission data, and outputs the generated electrical signal to the optical modulator 5. The DSP 3 also obtains an electrical signal including reception data from the optical receiver 6 and performs processing such as decoding of the obtained electrical signal to obtain the reception data.

[0014] The light source 4 includes, for example, a laser diode, and generates light of a predetermined wavelength and supplies it to the optical modulator 5 and the optical receiver 6. The optical modulator 5 is an optical device that modulates the light supplied from the light source 4 with an electrical signal output from the DSP 3 and outputs the resulting optical transmission signal to the optical fiber 2A. The optical modulator 5 is an optical modulator including a phase shifter 10, etc. The optical modulator 5 generates an optical transmission signal by modulating the light supplied from the light source 4 with an electrical signal input to the modulation section as the light propagates through the waveguide. The phase shifter 10 shifts the phase of the signal light passing through the optical waveguide 13.

[0015] The optical receiver 6 receives an optical signal from the optical fiber 2B and demodulates the received optical signal using light supplied from the light source 4. The optical receiver 6 then converts the demodulated received optical signal into an electrical signal and outputs the converted electrical signal to the DSP 3. The optical receiver 6 also includes a phase shifter 10 and the like.

[0016] Fig. 2 is a schematic plan view showing an example of the phase shifter 10 of Example 1, and Fig. 3 is a schematic cross-sectional view of the phase shifter 10 taken along line AA shown in Fig. 2. The phase shifter 10 shown in Fig. 2 has a Si substrate 11, a dielectric 12, an optical waveguide 13, a heater electrode 14, and an electrode pad 15.

[0017] The dielectric 12 is stacked on the Si substrate 11 and surrounds the periphery of the optical waveguide 13 arranged on the Si substrate 11 and the periphery of the heater electrode 14 arranged on the optical waveguide 13. The dielectric 12 is made of, for example, SiO2 or the like. The optical waveguide 13 in the dielectric 12 is made of, for example, Si, and is a waveguide through which signal light passes. The heater electrode 14 in the dielectric 12 is made of, for example, a resistive metal such as Ti, and generates heater heat in response to a drive current, which increases the temperature inside the optical waveguide 13. The electrode pad 15 has an input-side electrode pad 15A that inputs current to the heater electrode 14 and an output-side electrode pad 15B that outputs current from the heater electrode 14.

[0018] The optical waveguide 13 is a rib-type optical waveguide having a rib 13A on a slab 13B. The width dimension X2 of the slab 13B is set to be 11 times or less the width dimension X1 of the rib 13A. In the phase shifter 10, the width of the slab 13B of the optical waveguide 13 is limited to prevent heat diffusion and suppress a decrease in the heating efficiency of the optical waveguide 13. Furthermore, to reduce the propagation loss of light, the width of the slab 13B needs to be larger than the width of the rib 13A, but limiting the width of the slab 13B is effective in improving the heating efficiency.

[0019] FIG. 4 is a schematic cross-sectional view of a phase shifter 100 of a comparative example. The phase shifter 100 shown in FIG. 4 includes a Si substrate 11, a dielectric 12, an optical waveguide 130, and a heater electrode 14. The phase shifter 100 shown in FIG. 4 differs from the phase shifter 10 shown in FIG. 3 in the structure of the optical waveguide 130 disposed below the heater electrode 14. The optical waveguide 130 is a rib-type optical waveguide having a rib 130A on a slab 130B, but the width of the slab 130B is more than 11 times the width of the rib 130A. In the phase shifter 100 of the comparative example, a rib-type optical waveguide is used as the optical waveguide 130 instead of a channel-type optical waveguide, thereby reducing the propagation loss of light and the insertion loss of light.

[0020] The optical loss in the heater electrode 14 is αL, where L is the length of the optical waveguide 13 and α is the optical loss per unit length. When the rib thicknesses of the channel-type optical waveguide and the rib-type optical waveguide are the same, the optical loss per unit length is 0.21 dB / mm for the channel-type optical waveguide and 0.14 dB / mm for the rib-type optical waveguide. The length of the optical waveguide 13 is 1.2 mm for the channel-type optical waveguide and 1.44 mm for the rib-type optical waveguide, which is 20% longer. Therefore, the optical insertion loss is 0.25 dB for the channel-type optical waveguide and 0.20 dB for the rib-type optical waveguide. Therefore, the optical insertion loss of the rib-type optical waveguide is 0.05 dB smaller than that of the channel-type optical waveguide.

[0021] However, in the phase shifter 100 of the comparative example, the width of the Si slab is wide and the thermal conductivity of Si is higher than that of SiO2, so the heat generated in the heater electrode 14 is diffused in the slab 130B, reducing the heating efficiency of the optical waveguide 130. As a result, the phase shifter 100 of the comparative example requires a larger amount of drive current than the phase shifter 10.

[0022] 5 is an explanatory diagram showing an example of the relationship between the drive current amount and the slab width / rib width of the phase shifter 10. For example, let the drive current amount of the heater electrode 204 of a channel-type optical waveguide 203 in which the slab width is 1 time the rib width be "1." If the optical waveguide 13 arranged below the heater electrode 14 is changed from a channel-type optical waveguide to a rib-type optical waveguide, the drive current amount of the heater electrode 14 needs to be kept to 1.2 times or less the drive current amount of the channel-type optical waveguide in order to reduce power consumption.

[0023] Therefore, the amount of drive current to the heater electrode 14 of a rib-type optical waveguide in which the width of the slab 130B is more than 11 times the width of the rib 130A, such as the phase shifter 100 of the comparative example, exceeds 1.2 times the amount of drive current to the heater electrode 204 of a channel-type optical waveguide. In contrast, the amount of drive current to the heater electrode 14 of a rib-type optical waveguide in which the width X2 of the slab 13B is 11 times or less the width X1 of the rib 13A, such as the phase shifter 10, can be suppressed to 1.2 times or less the amount of drive current to the heater electrode 204 of a channel-type optical waveguide.

[0024] In the phase shifter 10 of Example 1, the optical waveguide 13 of a rib-type optical waveguide is disposed below the heater electrode 14, and the width X2 of the slab 13B of the optical waveguide 13 is set to be 11 times or less the width X1 of the rib 13A. As a result, the phase shifter 10 can reduce the amount of drive current to the heater electrode 14 and reduce the insertion loss of light, compared to the phase shifter 100 of the comparative example.

[0025] In the optical communication device 1, the optical modulator 5 and the optical receiver 6 are integrated on a single chip, which can greatly contribute to making the entire optical communication device 1 smaller.

[0026] In the phase shifter 10 of Example 1, a case where one rib-type optical waveguide 13 is arranged below the heater electrode 14 is exemplified. However, N rib-type optical waveguides 13 may be arranged in a folded manner below the heater electrode 14, and an embodiment in this case will be described below as Example 2. [Example]

[0027] FIG. 6 is a schematic plan view showing an example of a phase shifter 10A of Example 2. FIG. 7 is a schematic cross-sectional view of the phase shifter 10A taken along line BB shown in FIG. 6. Note that the same components as those in the phase shifter 10 of Example 1 are denoted by the same reference numerals, and redundant descriptions of the components and operations will be omitted. The phase shifter 10 of Example 1 differs from the phase shifter 10A of Example 2 in that the optical waveguide 13 of the rib-type optical waveguide has two folded linear portions 131 arranged in parallel below the heater electrode 14. In addition, the output-side electrode pad 15B1 is arranged on the opposite side of the heater electrode 14 from the input-side electrode pad 15A.

[0028] The optical waveguide 13 has a straight portion 131A (131) on the outgoing path, a straight portion 131B (131) on the returning path, and a folded portion 132 where the straight portion 131A on the outgoing path is folded back to the straight portion 131B on the returning path. Furthermore, the straight portion 131A on the outgoing path and the straight portion 131B on the returning path are arranged in parallel below the heater electrode 14. The optical waveguide 13 has a structure in which the width dimension X2 of the slab 13B is equal to or less than (11 × 2) times the width dimension X1 of the rib 13A. In a rib-type optical waveguide, light is less confined in the optical waveguide 13 than in a channel-type optical waveguide. Therefore, if the folded portion 132 is configured with a small radius of curvature, light will radiate and optical loss will occur. However, since the optical waveguide 13 has a structure in which the width dimension X2 of the slab 13B is equal to or smaller than (11×2) times the width dimension X1 of the rib 13A, even if the folded portion 132 has a small radius of curvature, it is possible to reduce the insertion loss of light while suppressing the amount of drive current to the heater electrode 14. Moreover, the size of the phase shifter 10A can be reduced.

[0029] In the phase shifter 10A of the second embodiment, a straight portion 131A on the outgoing path side and a straight portion 131B on the returning path side of the rib-type waveguide are arranged below the heater electrode 14, and the width dimension X2 of the slab 13B is set to be equal to or less than (11 × 2) times the width dimension X1 of the rib 13A. As a result, in the phase shifter 10A, even when the optical waveguide 13 has a folded structure, the amount of drive current to the heater electrode 14 can be suppressed and the insertion loss of light can be reduced.

[0030] In the phase shifter 10A of the second embodiment, two straight portions 131, a straight portion 131A on the outgoing path side and a straight portion 131B on the returning path side, are arranged in parallel below the heater electrode 14. However, the number of straight portions 131 is not limited to two, and two or more, N, of straight portions 131 may be used. In this case, the optical waveguide 13 may have a structure in which the width of the slab 13B is equal to or less than (11×N) times the width of the rib 13A, and the number N of straight portions 131 can be changed as appropriate. [Example]

[0031] Next, a phase shifter 10B according to a third embodiment will be described. Fig. 8 is a schematic plan view showing an example of the phase shifter 10B according to the third embodiment, Fig. 9 is a schematic cross-sectional view of the phase shifter 10B taken along line CC shown in Fig. 8, and Fig. 10 is a schematic cross-sectional view of the phase shifter 10B taken along line DD shown in Fig. 8. Note that the same components as those in the phase shifter 10A according to the second embodiment are denoted by the same reference numerals, and redundant descriptions of the components and operations will be omitted.

[0032] The optical waveguide 13 has a straight portion 131A on the outgoing path, a straight portion 131B on the returning path, and a folded portion 132. The straight portion 131A on the outgoing path and the straight portion 131B on the returning path are configured as rib-type optical waveguides. The folded portion 132 is configured as a channel-type optical waveguide.

[0033] The straight portion 131A on the outgoing path side and the straight portion 131B on the returning path side in the optical waveguide 13 shown in Fig. 9 are configured by a rib-type optical waveguide. The folded portion 132 in the optical waveguide 13 shown in Fig. 10 is configured by a channel-type optical waveguide.

[0034] The optical waveguide 13 in the phase shifter 10B of the third embodiment has a straight portion 131A on the outgoing path, a straight portion 131B on the returning path, and a folded portion 132. The straight portion 131A on the outgoing path and the straight portion 131B on the returning path are rib-type optical waveguides, and the folded portion 132 is a channel-type optical waveguide. As a result, the folded portion 132 of the phase shifter 10B is configured as a channel-type optical waveguide, and therefore, optical loss in the folded portion 132 can be suppressed.

[0035] In the phase shifter 10B of Example 3, the straight portion 131A on the outgoing path side and the straight portion 131B on the returning path side are made of rib-type optical waveguides, and the folded portion 132 is made of channel-type optical waveguides. However, the joint between the straight portion 131A on the outgoing path side and the folded portion 132, and the joint between the straight portion 131B on the returning path side and the folded portion 132 may be made tapered, and such an embodiment will be described below as Example 4. [Example]

[0036] Fig. 11 is a schematic plan view showing an example of a phase shifter 10C of Example 4, Fig. 12 is a schematic cross-sectional view of the phase shifter 10C taken along line EE shown in Fig. 11, Fig. 13 is a schematic cross-sectional view of the phase shifter 10C taken along line FF shown in Fig. 11, and Fig. 14 is a schematic cross-sectional view of the phase shifter 10C taken along line GG shown in Fig. 11. Note that the same components as those in the phase shifter 10B of Example 3 are denoted by the same reference numerals, and redundant descriptions of the components and operations will be omitted.

[0037] The phase shifter 10C of the fourth embodiment differs from the phase shifter 10B of the third embodiment in that the junction 133 between the straight portion 131 and the folded portion 132 is tapered so that the width of the slab 13B gradually narrows from the rib-type optical waveguide toward the channel-type optical waveguide.

[0038] The straight portion 131A on the outgoing path side and the straight portion 131B on the returning path side in the optical waveguide 13 shown in Fig. 12 are configured by a rib-type optical waveguide. The folded portion 132 in the optical waveguide 13 shown in Fig. 14 is configured by a channel-type optical waveguide.

[0039] 13 has an outgoing-side joint 133A between an outgoing-side straight portion 131A and a folded-back portion 132, and a homeward-side joint 133B between the homeward-side straight portion 131B and the folded-back portion 132. The outgoing-side joint 133A has a tapered shape in which the width of the slab 13B gradually narrows from the outgoing-side straight portion 131A, which is a rib-type optical waveguide, toward the folded-back portion 132 of the channel-side optical waveguide, and the rib 13A of the outgoing-side straight portion 131A and the rib of the folded-back portion 132 are joined. The homeward-side joint 133B has a tapered shape in which the width of the slab 13B gradually widens from the folded-back portion 132 of the channel-side optical waveguide toward the homeward-side straight portion 131B, which is a rib-type optical waveguide, and the rib 13A of the homeward-side straight portion 131B and the rib of the folded-back portion 132 are joined.

[0040] The phase shifter 10C of the fourth embodiment has an outgoing-side joint 133A between the outgoing-side straight portion 131A and the turned-back portion 132, and a homeward-side joint 133B between the homeward-side straight portion 131B and the turned-back portion 132. The outgoing-side joint 133A has a tapered shape in which the width of the slab 13B gradually narrows from the outgoing-side straight portion 131A, which is a rib-type optical waveguide, toward the turned-back portion 132 of the channel-side optical waveguide, and the rib 13A of the outgoing-side straight portion 131A and the rib of the turned-back portion 132 are joined. The homeward-side joint 133B has a tapered shape in which the width of the slab 13B gradually widens from the turned-back portion 132 of the channel-side optical waveguide toward the homeward-side straight portion 131B, which is a rib-type optical waveguide, and the rib 13A of the homeward-side straight portion 131B and the rib of the turned-back portion 132 are joined. That is, in the phase shifter 10C of the fourth embodiment, the joint 133 between the straight portion 131 and the folded portion 132 has a tapered structure in which the width of the slab 13B gradually decreases from the rib optical waveguide toward the channel optical waveguide. As a result, the phase shifter 10C can suppress abrupt changes in light by gradually changing the width between the slab 13B and the rib of the channel optical waveguide using a tapered structure.

[0041] The phase shifters 10A, 10B, and 10C of Examples 2 to 4 illustrate the case where two straight line portions 131, a straight line portion 131A on the outgoing path and a straight line portion 131B on the returning path, are arranged in parallel below the heater electrode 14. However, the number of straight line portions 131 is not limited to two, and may be N, which is two or more, and can be changed as appropriate.

[0042] In the phase shifters 10A, 10B, and 10C of Examples 2 to 4, the folded portion 132 of the optical waveguide 13 is disposed at the tip of the output-side electrode pad 15B1. However, the folded portion 132 may be disposed within the output-side electrode pad 15B1, and this can be modified as appropriate. As a result, the folded portion 132 is disposed below the output-side electrode pad 15B1, which allows the overall length of the phase shifters 10A, 10B, and 10C to be shortened.

[0043] The optical communication device 1 of Example 1 is exemplified as having an optical modulator 5 and an optical receiver 6 built in, but the optical communication device 1 may also have only one of the optical modulator 5 and the optical receiver 6 built in, and can be modified as appropriate. [Explanation of symbols]

[0044] 1 Optical communication equipment 3 DSP 4 light source 5 Optical Modulator 6 Optical receiver 10, 10A, 10B, 10C Phase Shifter 11. Si substrate 12 Dielectrics 13 Optical waveguide 14 Heater electrode 131 Straight section 131A Straight section on the outbound side 131B Straight section on the return journey 132 Folded section 133 Joint 133A Junction on the outbound side 133B Junction on the return journey

Claims

1. A substrate; a dielectric layer laminated on the substrate; an optical waveguide surrounded by the dielectric; a heater electrode disposed on the optical waveguide and surrounded by the dielectric; The optical waveguide is An optical device characterized by having a rib-type optical waveguide provided on a slab and located below the heater electrode, wherein the width of the slab is structured to be 11 times or less the width of the rib so that the amount of drive current supplied to the heater electrode is more than 1 time and not more than 1.2 times that when using a channel-type optical waveguide having the same thickness as the rib of the rib-type optical waveguide.

2. The optical waveguide under the heater electrode is 2. The optical device according to claim 1, wherein N straight portions are folded back, the folded N straight portions are arranged in parallel, and the width of the slab is 11N times or less the width of the rib.

3. The optical waveguide is The straight portion and the folded portion that folds back the straight portion are included. The straight portion is It is composed of a rib-type optical waveguide, The folded portion is 3. The optical device according to claim 2, wherein the optical device is formed of a channel-type optical waveguide.

4. The joint between the straight portion and the folded portion is 4. The optical device according to claim 3, wherein the width of the slab gradually narrows from the straight portion toward the folded portion.

5. A substrate; a dielectric layer laminated on the substrate; an optical waveguide surrounded by the dielectric; a heater electrode disposed on the optical waveguide and surrounded by the dielectric; The optical waveguide is A phase shifter comprising a rib-type optical waveguide provided on a slab and located below the heater electrode, the slab having a width that is 11 times or less the width of the rib so that the amount of drive current supplied to the heater electrode is greater than 1 time and not more than 1.2 times the amount when a channel-type optical waveguide having the same thickness as the rib of the rib-type optical waveguide is used.

6. a processor that performs signal processing on the electrical signal; A light source that generates light; an optical modulator that modulates light generated from the light source using an electrical signal output from the processor, The phase shifter in the optical modulator comprises: A substrate; a dielectric layer laminated on the substrate; an optical waveguide surrounded by the dielectric; a heater electrode disposed on the optical waveguide and surrounded by the dielectric; The optical waveguide is An optical communication device characterized in that it has a rib-type optical waveguide provided on a slab and located below the heater electrode, and has a structure in which the width of the slab is 11 times or less the width of the rib so that the amount of drive current supplied to the heater electrode is more than 1 time and not more than 1.2 times that when using a channel-type optical waveguide having the same thickness as the rib of the rib-type optical waveguide.

7. A light source that generates light; an optical receiver that demodulates a received optical signal using light from the light source, The phase shifter in the optical receiver comprises: A substrate; a dielectric layer laminated on the substrate; an optical waveguide surrounded by the dielectric; a heater electrode disposed on the optical waveguide and surrounded by the dielectric; The optical waveguide is An optical communication device characterized in that it has a rib-type optical waveguide provided on a slab and located below the heater electrode, and has a structure in which the width of the slab is 11 times or less the width of the rib so that the amount of drive current supplied to the heater electrode is more than 1 time and not more than 1.2 times that when using a channel-type optical waveguide having the same thickness as the rib of the rib-type optical waveguide.

Images