WO2016092829A1 - 光変調器 - Google Patents
光変調器 Download PDFInfo
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- WO2016092829A1 WO2016092829A1 PCT/JP2015/006112 JP2015006112W WO2016092829A1 WO 2016092829 A1 WO2016092829 A1 WO 2016092829A1 JP 2015006112 W JP2015006112 W JP 2015006112W WO 2016092829 A1 WO2016092829 A1 WO 2016092829A1
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- 230000003287 optical effect Effects 0.000 title claims abstract description 254
- 239000004065 semiconductor Substances 0.000 claims abstract description 176
- 238000005253 cladding Methods 0.000 claims abstract description 34
- 239000000758 substrate Substances 0.000 claims abstract description 15
- 238000000034 method Methods 0.000 description 21
- 229910004298 SiO 2 Inorganic materials 0.000 description 18
- 230000001902 propagating effect Effects 0.000 description 16
- 230000005684 electric field Effects 0.000 description 15
- 230000000694 effects Effects 0.000 description 11
- 230000008033 biological extinction Effects 0.000 description 10
- 238000009826 distribution Methods 0.000 description 7
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 6
- 229910052710 silicon Inorganic materials 0.000 description 6
- 239000010703 silicon Substances 0.000 description 6
- 230000008859 change Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 239000000969 carrier Substances 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 238000013459 approach Methods 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 2
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 2
- 229910013641 LiNbO 3 Inorganic materials 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- 230000005697 Pockels effect Effects 0.000 description 2
- 229910052785 arsenic Inorganic materials 0.000 description 2
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000005468 ion implantation Methods 0.000 description 2
- 230000031700 light absorption Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000005701 quantum confined stark effect Effects 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 230000010365 information processing Effects 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
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Classifications
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/21—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour by interference
- G02F1/225—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour by interference in an optical waveguide structure
- G02F1/2257—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour by interference in an optical waveguide structure the optical waveguides being made of semiconducting material
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/015—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on semiconductor elements having potential barriers, e.g. having a PN or PIN junction
- G02F1/025—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on semiconductor elements having potential barriers, e.g. having a PN or PIN junction in an optical waveguide structure
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/21—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour by interference
- G02F1/212—Mach-Zehnder type
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F2201/00—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00
- G02F2201/06—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00 integrated waveguide
- G02F2201/063—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00 integrated waveguide ridge; rib; strip loaded
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F2201/00—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00
- G02F2201/12—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00 electrode
- G02F2201/127—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00 electrode travelling wave
Definitions
- the present invention relates to an optical modulator used in an optical communication system and an optical information processing system, and more particularly to a Mach-Zehnder optical modulator that operates at a low voltage and has a small waveguide loss.
- a Mach-Zehnder type (MZ type) optical modulator splits light incident on an optical waveguide into two waveguides by means of an optical splitter, propagates the branched light for a certain length, and then combines it again by an optical multiplexer. Has a wave structure.
- Each of the two branched optical waveguides is provided with a phase modulator, which changes the phase of the light propagating to each optical waveguide, changes the interference condition of the combined light, and changes the light intensity or the light phase. Modulate.
- a dielectric such as LiNbO 3 and a semiconductor such as InP, GaAs and Si are used, and a voltage is applied to the optical waveguide by a traveling wave electrode disposed in the vicinity of the optical waveguide. Applying it changes the phase of the light.
- the Pockels effect is mainly used in LiNbO 3
- the Pockels effect and the quantum confined Stark effect (QCSE) are mainly used in InP and GaAs
- the carrier plasma effect is mainly used in Si.
- an optical modulator having a high modulation speed and a low driving voltage In order to perform optical modulation with an amplitude voltage of several volts at a high speed of 10 Gbps or higher, the high-speed electrical signal and the speed of light propagating through the phase modulator are matched, and the interaction is performed while propagating.
- a traveling wave electrode is required.
- an optical modulator in which the electrode length of a traveling wave electrode is several millimeters to several tens of millimeters has been put into practical use (for example, Non-Patent Document 1).
- An optical modulator using a traveling wave electrode is required to have an electrode structure and an optical waveguide structure with low optical loss and low reflection so as to be able to propagate without reducing the intensity of an electric signal or light propagating through a waveguide.
- the MZ type optical modulator includes a silicon optical modulator in which an optical waveguide is made of silicon.
- the silicon optical modulator uses a thin wire of Si so that light can be guided through an SOI layer from an SOI (Silicon on Insulator) substrate in which a Si thin film is bonded onto an oxide film (BOX) layer obtained by thermally oxidizing the surface of the Si substrate.
- a dopant is injected so that the processed thin wire becomes a p-type / n-type semiconductor, and SiO 2 serving as a light cladding layer is deposited and a traveling wave electrode is formed.
- it is necessary to design and process the optical waveguide so as to reduce the optical loss.
- the p-type / n-type doping of the processed thin wire and the production of the traveling wave electrode suppress the generation of optical loss to a small extent. Therefore, it is necessary to design and process so as to suppress reflection and loss of high-speed electrical signals.
- FIG. 1 is a top perspective view showing a configuration of a conventional MZ type optical modulator 100.
- the MZ-type optical modulator 100 is a silicon optical modulator, and includes an input optical waveguide 101, an optical splitter 102 that branches the light incident from the input optical waveguide 101 in a 1: 1 ratio, and light from the optical splitter 102.
- Incoming optical waveguides 103 and 104 are provided.
- the MZ optical modulator 100 includes a phase modulation unit 111 that modulates the phase of light propagating through the optical waveguide 103, a phase modulation unit 112 that modulates the phase of light propagating through the optical waveguide 104, and the phase modulation unit 111.
- the optical waveguide 105 that propagates the light from the optical waveguide 106 and the optical waveguide 106 that propagates the light from the phase modulation unit 112 are provided.
- the MZ type optical modulator 100 includes an optical multiplexer 107 that multiplexes light whose phases are modulated from the optical waveguides 105 and 106, and an output optical waveguide 108 that emits the light combined by the optical multiplexer 107.
- the phase modulation unit 111 includes traveling wave electrodes 121 and 122 extending in the x-axis direction and an optical waveguide 123. By applying a voltage to the traveling wave electrodes 121 and 122, the phase modulation unit 111 transmits light guided through the optical waveguide 123. Change the phase.
- the phase modulation unit 112 includes traveling wave electrodes 124 and 125 extending in the x-axis direction and an optical waveguide 126, and light that is guided in the optical waveguide 126 by applying a voltage to the traveling wave electrodes 124 and 125. Change the phase.
- the optical waveguides 123 and 126 have a structure called a rib waveguide having a difference in thickness, and are formed of Si, and an SiO 2 cladding layer is formed above and below.
- FIG. 2 is a cross-sectional view taken along the line II-II of the phase modulation unit 111 of the conventional MZ type optical modulator 100 shown in FIG.
- FIG. 2 is a cross-sectional view of the phase modulation unit 111 in the light guiding direction (x-axis direction) and the vertical direction (yz plane).
- the phase modulation unit 111 is formed on the Si substrate 201 and the Si substrate.
- the optical waveguide 123 is provided.
- Optical waveguide 123 includes a first SiO 2 cladding layer 202 on the Si substrate 201, a first SiO 2 and Si semiconductor layer 203 on the cladding layer 202, a second SiO on Si semiconductor layer 203 second cladding layer 204 With.
- Third clad layers 205 and 206 are formed on both sides of the Si semiconductor layer 203.
- the phase modulation unit 112 has the same configuration.
- the optical waveguide 123 has a rib waveguide structure, and a Si semiconductor layer 203 through which light is guided is sandwiched between a first SiO 2 cladding layer 202 and a second SiO 2 cladding layer 204.
- the Si semiconductor layer 203 is a rib portion A0 that is a central thick Si semiconductor layer region that becomes the core of the optical waveguide 123, and a Si semiconductor layer region that is disposed on both sides of the rib portion A0 and is thinner than the rib portion A0. 1 slab part A1 and 2nd slab part A2 are provided.
- the optical waveguide 123 confines light by utilizing the refractive index difference between the Si semiconductor layer 203 and the surrounding first SiO 2 cladding layer 202 and second SiO 2 cladding layer 204.
- the traveling wave electrode 121 is formed in the x-axis direction on the upper surface of the end portion of the first slab portion A1 of the Si semiconductor layer 203 opposite to the rib portion 0, and the traveling wave electrode 122 is formed on the Si semiconductor layer 203.
- the second slab portion A2 is formed in the x-axis direction on the upper surface of the end portion opposite to the rib portion A0.
- the Si semiconductor layer 203 has conductivity by doping atoms such as boron (B), phosphorus (P), and arsenic (As) into Si by a method such as ion implantation.
- the Si semiconductor layer 203 is composed of four regions having different doping concentrations.
- the end of the first slab portion A1 of the Si semiconductor layer 203 on the side opposite to the rib portion A0 becomes a high-concentration p-type semiconductor region 203-3, and the rib portion of the second slab portion A2 of the Si semiconductor layer 203 The end opposite to A0 is a high-concentration n-type semiconductor region 203-4.
- the rib portion A0 side of the first slab portion A1 of the Si semiconductor layer 203 and the first slab portion A1 side of the rib portion A0 form a medium concentration p-type semiconductor region 203-1. Further, the rib portion A0 side of the second slab portion A2 of the Si semiconductor layer 203 and the second slab portion A2 side of the rib portion A0 form the medium concentration n-type semiconductor region 203-2.
- the boundary between the high concentration p-type semiconductor region 203-3 and the medium concentration p-type semiconductor region 203-1 is in contact, and the boundary between the high concentration n-type semiconductor region 203-4 and the medium concentration n-type semiconductor region 203-2 is also present. It touches. These boundaries may overlap and be doped.
- the rib portion A0 has a pn junction structure in which the medium concentration p-type semiconductor region 203-1 and the medium concentration n-type semiconductor region 203-2 are in contact.
- a pin junction structure in which an i-type (intrinsic) semiconductor region is sandwiched between a medium-concentration p-type semiconductor region 203-1 and a medium-concentration n-type semiconductor region 203-2 may be employed.
- the traveling wave electrode 121 is connected to the high concentration p-type semiconductor region 203-3, and the traveling wave electrode 122 is connected to the high concentration n type semiconductor region 203-4.
- the traveling wave electrodes 121 and 122 By applying a reverse bias electric field to the pn junction or the pin junction by the traveling wave electrodes 121 and 122, the carrier density inside the rib part A0 of the Si semiconductor layer 203 is changed, and the refractive index of the Si semiconductor layer 203 is changed. (Carrier plasma effect), the phase of light can be modulated.
- the dimension of the Si semiconductor layer 203 depends on the refractive index of the material to be the core / cladding and cannot be uniquely determined.
- the core width of the optical waveguide 123 400 to 600 nm ⁇ height 150 to 300 nm ⁇ slab thickness 50 to 200 nm ⁇ length several mm.
- the optical modulator is required to have a small optical loss in order to transmit the modulated optical signal over a long distance.
- a part of light propagating by carriers such as electrons and holes is absorbed. It is necessary to set the doping conditions so as to obtain a concentration.
- the carrier density of the doped region is such that the carrier density is about 10 20 [cm ⁇ 3 ] in the high-concentration p-type semiconductor region 203-3 (p ++ ) and the carrier density in the medium-concentration p-type semiconductor region 203-1 (p + ).
- Density about 10 17-18 [cm ⁇ 3 ], medium density n-type semiconductor region 203-2 (n + ), carrier density: about 10 17-18 [cm ⁇ 3 ], high-concentration n-type semiconductor region 203-4 In (n ++ ), the carrier density is about 10 20 [cm ⁇ 3 ].
- the high-concentration p-type semiconductor region 203-3 and the high-concentration n-type semiconductor region 203-4 ensure electrical continuity with low contact resistance with the traveling wave electrode, and reduce the electrical resistance of the semiconductor layer itself constituting the Si semiconductor layer 203. It is provided to keep it small.
- the carrier concentration of the medium-concentration p-type semiconductor region 203-1 and medium-concentration n-type semiconductor region 203-2 constituting the rib portion A0 serving as the core is the high-concentration p-type semiconductor region 203-3 and the high-concentration n-type semiconductor. It is set lower than the area 203-4. This is because in order for the carriers generated by doping to absorb light, the doping concentration must be lowered to reduce light loss. By reducing the doping concentration, the optical loss in the optical waveguide can be suppressed to about 6 dB / cm, compared with 3 dB / cm for the passive optical waveguide without doping.
- the distance w pn between and is preferably 1600 nm or more.
- the modulation efficiency is obtained by the phase inversion voltage V ⁇ ⁇ the traveling wave (phase modulation) electrode length L. Then, if the length L of the traveling wave electrode is shortened to reduce the optical loss of the phase modulation unit without changing the modulation efficiency, the phase inversion voltage V ⁇ increases and the drive voltage increases. On the other hand, when the phase inversion voltage V ⁇ is decreased, the length L of the traveling wave electrode increases, and there is a trade-off relationship that the optical loss of the phase modulation unit increases. Therefore, in order to realize an optical modulator with low optical loss and low driving voltage, it is necessary to enable high-speed operation even when the traveling wave electrode length L is long. If the length L of the traveling wave electrode can be set long, it is not necessary to increase the phase inversion voltage V ⁇ .
- the light In order to suppress the optical loss of the optical waveguide 123 of the conventional MZ type optical modulator 100 of FIG. 1, the light must be confined in the rib portion A0 of the Si semiconductor layer 203 serving as the core of the optical waveguide 123.
- the medium-concentration p-type semiconductor region 203-1 and the medium-concentration n-type semiconductor region 203-2 are thickened so that the resistance value of the Si semiconductor layer 203 cannot be lowered, and the phase inversion voltage V ⁇ cannot be reduced. There's a problem.
- the doping concentration in the vicinity of the rib portion A0 (core of the optical waveguide) of the Si semiconductor layer 203 cannot be increased, the electrical property of the pn junction or the pin junction portion of the semiconductor constituting the Si semiconductor layer 203 is reduced. Resistance value cannot be greatly reduced. For this reason, the resistance value of the Si semiconductor layer 203 becomes a loss of a high-frequency electric signal, and the voltage applied to the pin junction or pn junction is attenuated, so that there is a problem that the phase inversion voltage V ⁇ cannot be reduced.
- the present invention has been made in view of such problems, and an object of the present invention is to provide an MZ type light that can simultaneously realize the demands of high modulation speed, low optical loss, and low driving voltage. It is to provide a modulator.
- a first aspect of the present invention is a substrate and a phase modulation unit on the substrate, which is laminated on the first cladding layer and the first cladding layer, and is higher than the first cladding layer
- An optical waveguide comprising a semiconductor layer having a refractive index, a second cladding layer laminated on the semiconductor layer and having a lower refractive index than the semiconductor layer, a first traveling wave electrode, and a second traveling wave
- the second slab part is formed thinner than the rib part and the fourth slab part.
- the optical modulator according to the present invention since the electrical resistance value of the semiconductor portion can be greatly reduced, the loss of high-frequency electrical signals is small and high-speed operation is possible.
- light leakage from the Si semiconductor layer that is the optical waveguide core is small, light absorption by carriers in the doping region can be suppressed, and highly efficient light modulation is possible. For this reason, it is possible to provide an optical modulator capable of simultaneously realizing the demands of high modulation speed, low optical loss, and low driving voltage.
- FIG. 4 is a sectional view taken along the line IV-IV of the phase modulation unit of the MZ type optical modulator of FIG.
- FIG. 5 is a diagram showing parameters of dimensions of a rib part and first to fourth slab parts in a cross section of the optical waveguide shown in FIG.
- FIG. 5 is a diagram showing an equivalent circuit when the MZ type optical modulator of FIG. 4 is viewed as a distributed constant line.
- FIG. 5 is a top perspective view showing a configuration of an MZ type optical modulator according to a second embodiment of the present invention, and particularly shows a connection portion between an input optical waveguide and an optical waveguide of a phase modulation unit.
- (A) is a sectional view of the input optical waveguide in the direction perpendicular to the light guiding direction
- (b) is a top view of the connection portion between the input optical waveguide and the optical waveguide of the phase modulation unit
- (c) is the phase modulation unit. It is sectional drawing of the orthogonal
- FIG. 3 is a top perspective view showing the configuration of the MZ type optical modulator 300 according to the first embodiment of the present invention.
- the MZ type optical modulator 300 is a silicon optical modulator, and includes an input optical waveguide 301, an optical branching device 302 that branches the light incident from the input optical waveguide 301 in a 1: 1 ratio, and light from the optical branching device 302. Incident optical waveguides 303 and 304 are provided.
- the MZ optical modulator 300 includes a phase modulation unit 311 that modulates the phase of light propagating through the optical waveguide 303, a phase modulation unit 312 that modulates the phase of light propagated through the optical waveguide 304, and a phase modulation unit 311.
- the optical waveguide 305 which propagates the light from the light and the optical waveguide 306 which propagates the light from the phase modulation unit 312 are provided. Further, the MZ type optical modulator 300 includes an optical multiplexer 307 that combines the light whose phases are modulated from the optical waveguides 305 and 306, and an output optical waveguide 308 that emits the light combined by the optical multiplexer 307. With.
- the phase modulation unit 311 includes traveling wave electrodes 321 and 322 extending in the x-axis direction and an optical waveguide 323, and a phase of light guided through the optical waveguide 323 by applying a voltage to the traveling wave electrodes 321 and 322.
- the phase modulation unit 312 includes traveling wave electrodes 324 and 325 extending in the x-axis direction and an optical waveguide 326. By applying a voltage to the traveling wave electrodes 324 and 325, the phase modulation unit 312 transmits light guided through the optical waveguide 326. Change the phase.
- the optical waveguides 323 and 326 have Si semiconductor layers composed of a rib portion serving as a core of the optical waveguide formed in the optical axis direction and slab portions formed on both sides and thinner than the rib portions. It has a structure called a rib waveguide in which a SiO 2 cladding layer is formed.
- the phase modulation unit 311 includes a Si substrate 401 and an optical waveguide 323 on the Si substrate.
- the optical waveguide 323 includes a first SiO 2 cladding layer 402 on the substrate 401, a Si semiconductor layer 403 on the first cladding layer 402, and a second SiO 2 cladding layer 404 on the Si semiconductor layer 403. .
- third SiO 2 cladding layers 405 or 406 are formed on both sides of the Si semiconductor layer 403.
- this region may be formed of a Si semiconductor layer having the same thickness as the rib portion C0 that is an optical waveguide layer.
- the phase modulator 312 has the same configuration.
- the optical waveguide 323 has a structure obtained by further deforming the rib waveguide, and a Si semiconductor layer 403 through which light is guided is sandwiched between the first SiO 2 cladding layer 402 and the second SiO 2 cladding layer 404. ing.
- the Si semiconductor layer 403 includes a rib portion C0 that is a central thick Si semiconductor layer region serving as a core.
- the Si semiconductor layer 403 includes a first slab portion C1 and a second slab portion C2 that are disposed on both sides of the rib portion C0 and are Si semiconductor layer regions thinner than the rib portion C0.
- the Si semiconductor layer 403 is disposed at the end of the first slab portion C1 opposite to the rib portion C0, and is thinner than the rib portion C0 and thicker than the adjacent first slab portion C1.
- the third slab part C3 and the second slab part C2, which are regions, are disposed at the opposite ends of the rib part C0 and are thinner than the rib part C0 and thicker than the adjacent second slab part C2.
- a fourth slab portion C4 which is a Si semiconductor layer region.
- the first slab portion C1 is inserted between the rib portion C0 serving as the core of the optical waveguide 323 and the third slab portion C3 formed on one side of the rib portion C0. It can be said that the second slab part C2 is inserted between the second slab part C4 formed on the other side of the rib part C0.
- the optical waveguide 323 confines light by utilizing the refractive index difference between the Si semiconductor layer 403 and the surrounding first SiO 2 cladding layer 402 and the second SiO 2 cladding layer 404.
- the traveling wave electrode 321 is formed in the x-axis direction on the upper surface of the end portion of the third slab portion C3 of the Si semiconductor layer 403 opposite to the first slab portion C1, and the traveling wave electrode 322 is formed of the Si semiconductor.
- the fourth slab portion C4 of the layer 403 is formed in the x-axis direction on the upper surface of the end portion opposite to the second slab portion C2.
- the Si semiconductor layer 403 has conductivity by doping atoms such as boron (B), phosphorus (P), and arsenic (As) into Si by a method such as ion implantation.
- the Si semiconductor layer 403 is composed of five regions having different doping concentrations.
- An end portion of the third slab portion C3 of the Si semiconductor layer 403 opposite to the first slab portion C1 is a high-concentration p-type semiconductor region 403-3, and the fourth slab portion C4 of the Si semiconductor layer 403 has a fourth slab portion C4.
- the end opposite to the second slab portion C2 becomes a high-concentration n-type semiconductor region 403-4.
- first slab part C1 side of the third slab part C3 of the Si semiconductor layer 403, the first slab part C1, and the first slab part C1 side of the rib part C0 are medium-concentration p-type semiconductors. It becomes area 403-1.
- second slab portion C2 side of the fourth slab portion C4 of the Si semiconductor layer 403, the second slab portion C2, and the second slab portion C2 side of the rib portion C0 are medium-concentration n-type semiconductors. It becomes area 403-2.
- the boundary between the high concentration p-type semiconductor region 403-3 and the medium concentration p-type semiconductor region 403-1 is in contact, and the boundary between the high concentration n-type semiconductor region 403-4 and the medium concentration n-type semiconductor region 403-2 is also present. It touches. These boundaries may overlap and be doped.
- the rib portion C0 has a pn junction structure in which the medium concentration p-type semiconductor region 403-1 and the medium concentration n-type semiconductor region 403-2 are in contact with each other.
- a pin junction structure in which an i-type (intrinsic) semiconductor region is sandwiched between a medium-concentration p-type semiconductor region 403-1 and a medium-concentration n-type semiconductor region 403-2 may be used.
- the carrier density inside the core of the optical waveguide 323 (the rib C0 of the Si semiconductor layer 403) changes, and the refractive index of the optical waveguide Changes (carrier plasma effect), the phase of light is modulated.
- FIG. 5 is a diagram showing parameters of each dimension of the rib portion and the first to fourth slab portions in the cross section of the Si semiconductor layer 403 shown in FIG.
- the thickness of the rib portion C0 is t0
- the thickness of the first slab portion C1 is t1
- the thickness of the second slab portion C2 is t2
- the thickness of the third slab portion C3 is t3
- the fourth slab The thickness of the part C4 is t4.
- the width of the rib C0 is w0
- the width of the first slab C1 is w1
- the width of the second slab C2 is w2
- the width of the third slab C3 is w3
- the width is w4.
- the thickness t0 of the rib part C0, the thickness t1 of the first slab part C1, the thickness t2 of the second slab part C2, the thickness t3 of the third slab part C3, and the fourth The thickness t4 of the slab part C4 will be described.
- the light is confined in the rib portion C 0 of the Si semiconductor layer 403 that becomes the core of the optical waveguide 323.
- the third slab part C3 and the fourth slab part C4 which are Si semiconductor layers having the same effective refractive index or higher effective refractive index in the vicinity of the rib part C0, mode coupling occurs, and constant
- the third slab part C3 and the fourth slab part C4 that are close to the rib part C0 are transferred.
- the light transferred to the third slab part 3 and the fourth slab part C4 close to the rib part C0 causes optical loss of the modulator.
- the first method is to prevent the third slab part C3 and the fourth slab part C4 from coming close to the rib part C0.
- the second method is to keep the lengths of the third slab part C3 and the fourth slab part C4 close to the rib part C0 short.
- the third method is to make the effective refractive index of the third slab part C3 and the fourth slab part C4 close to the rib part C0 smaller than the effective refractive index of the rib part C0 through which light propagates. is there. In the following, three methods will be examined.
- the third slab part C3 and the fourth slab part C4 are not brought close to the rib part C0 of the first method.
- W1 increases, the cross-sectional area of the medium-concentration p-type semiconductor region 403-1 decreases, and as w2 increases, the cross-sectional area of the medium-concentration n-type semiconductor region 403-2 decreases, and the resistance of the Si semiconductor layer 403 decreases. Get higher. Therefore, the structure of the conventional MZ type optical modulator 100 shown in FIG. 1 is not changed, and operation at a high frequency becomes difficult. Therefore, this method cannot be adopted in the present invention.
- the lengths of the third slab part C3 and the fourth slab part C4 of the second method that are close to the rib part C0 are kept short.
- the third slab part C3 and the fourth slab part C4 It is necessary to shorten the length, that is, to shorten the entire length of the phase modulation unit 311.
- mode coupling can be suppressed. In this case, however, the length L of the traveling wave electrode must be shortened.
- the modulation efficiency is determined by V ⁇ L, it is necessary to increase the phase inversion voltage V ⁇ in order to make the modulation efficiency constant.
- the MZ type optical modulator 300 cannot be driven with low power consumption, and it is difficult to adopt in this embodiment.
- the relationship between t0, t1, and t3 satisfies the inequality t0> t3> t1.
- the effective refractive index of light propagating through the third slab part C3 can be made smaller than the effective refractive index of light propagating through the rib part C0.
- the relationship between t0, t2, and t4 is made to satisfy the inequality t0> t4> t2.
- the effective refractive index of light propagating through the fourth slab part C4 can be made smaller than the effective refractive index of light propagating through the rib part C0.
- t1 and t2 may be the same value or different values, and t3 and t4 may be the same value or different values.
- w1 and w2 may be the same value or different values, and w3 and w4 may be the same value or different values.
- the traveling wave electrode 321 is provided on the high concentration p-type semiconductor region 403-3, and the high concentration n type semiconductor region 403-4.
- a traveling wave electrode 322 is connected to the top, and a reverse bias electric field is applied to the pn junction or the pin junction by the traveling wave electrodes 321 and 322.
- the carrier density inside the rib C0 of the Si semiconductor layer 403 that becomes the core of the optical waveguide 323 is changed (carrier plasma effect), and the refractive index of the Si semiconductor layer 403 is changed to modulate the phase of light. To do.
- FIG. 6 is a diagram showing an equivalent circuit when the MZ type optical modulator 300 of FIG. 4 is viewed as a distributed constant line.
- the pn junction (or pin junction) is a capacitance C, the resistance R1 from the traveling wave electrode 321 to the pn junction (or pin junction), and the traveling wave electrode 322 to the pn junction (or pin junction).
- the resistor R2 can be described as a series circuit of R1-C-R2.
- the resistance value depends on the medium concentration p-type semiconductor region 403-1 and the medium concentration n-type semiconductor region 403-2 having a low carrier concentration.
- the following two methods are conceivable for reducing the resistance values of the resistors R1 and R2.
- the first method Increasing the doping concentration of the medium concentration p-type semiconductor region 403-1 and the medium concentration n-type semiconductor region 403-2 increases the doping concentration of the rib portion C0 of the Si semiconductor layer 403 serving as the core of the optical waveguide 323. .
- light absorption by the carriers increases in the doping region of the rib portion C0 of the Si semiconductor layer 403, so that the optical loss of the optical waveguide 323 cannot be suppressed. Therefore, the first method is not appropriate in this embodiment.
- the third slab part C3 and the fourth slab part that are thicker than the first slab part C1 and the second slab part C2 further outside the first slab part C1 and the second slab part C2.
- C4 is provided.
- the optical waveguide within the distance w pn of the region between the high-concentration p-type semiconductor region 403-3 and the high-concentration n-type semiconductor region 403-4 is widened and thickened as much as possible, the effect can be obtained.
- the optical field is applied to the high-concentration p-type semiconductor region 403-3 or the high-concentration n-type semiconductor region 403-4, resulting in an increase in optical waveguide loss. Furthermore, since the field of light existing in the region where the refractive index changes due to the carrier plasma effect is reduced, the modulation efficiency is deteriorated.
- the thickness t1 of the first slab part C1 and the thickness t2 of the second slab part C2 are equal to or less than half the thickness t0 of the rib part C0, that is, the inequality t0 / 2> t1 and the inequality t0 / 2>. It is desirable to satisfy t2.
- the high-concentration p-type doping region 403-3 and the high-concentration n-type doping region 403-4 have sufficient carrier concentration and low resistivity, even if t1 and t2 have a thickness satisfying the above inequality.
- the increase in the resistance value hardly affects the characteristics of the modulator. Therefore, the boundary between the high concentration p-type semiconductor region 403-3 and the medium concentration p-type semiconductor region 403-1 and the boundary between the high concentration n-type semiconductor region 403-4 and the medium concentration n-type semiconductor region 403-2 are The third slab part C3 having a thickness t3 and the fourth slab part C4 having a thickness t4 that are formed outside the first slab part C1 and the second slab part C2, respectively.
- the effects of the invention are most desirable and desirable.
- the width w0 of the rib part C0, the width w1 of the first slab part C1, the width w2 of the second slab part C2, the width w3 of the third slab part C3, and the width w4 of the fourth slab part C4 explain.
- it is more effective to reduce the width w1 of the first slab part C1 and the width w2 of the second slab part C2 as much as possible.
- the alignment accuracy of the photomask at the time of manufacturing the MZ type optical modulator 300 is about ⁇ 60 nm, if the width of w1 and w2 is 60 nm or less, w1 and w2 may not be formed due to variations in manufacturing. Conceivable.
- the rib portion C0 is adjacent to the third slab portion C3 and the second slab portion C4, which are the next thicker than the rib portion C0, so that the light field greatly protrudes from the rib portion C0, and an increase or modulation of optical loss occurs. A decrease in efficiency occurs.
- Table 1 compares the electric field strength of the phase modulation unit when the values of w1 and w2 of the MZ type optical modulator 300 of FIG. 5 are changed, and the conventional MZ type optical modulator 100 (FIG. 1).
- the increase rate of the electric field strength of the MZ type optical modulator 300 and the calculated value of the attenuation constant ⁇ of the high frequency signal of the MZ type optical modulator 300 are shown.
- the example in Table 1 shows the calculated value when the modulation frequency is 10 GHz.
- the electric field strength is increased by 25.6% when w1 (w2) is 200 nm and 16.2% when w1 (w2) is 400 nm as compared with the conventional MZ type optical modulator 100.
- w2 is 1000 nm, it increases only by 1.1% and almost no effect is obtained. Therefore, it is desirable that the value of w1 is a value satisfying the inequality 60nm ⁇ w1 (w2) ⁇ 600nm because the effects of the invention are most obtained.
- the outer sides of the third slab part C3 and the fourth slab part C4 can be Si semiconductor layers having the same thickness as the rib part C0 which is an optical waveguide layer.
- the width w3 of the third slab part C3 and the width w4 of the fourth slab part C4 need to be 200 nm or more so that the rib part C0 does not approach the outer Si semiconductor layer.
- the thickness t0 of the rib part C0 calculated as described above, the thickness t1 of the first slab part C1, the thickness t2 of the second slab part C2, the thickness t3 of the third slab part C3, and the fourth Thickness t4 of slab part C4, width w0 of rib part C0, width w1 of first slab part C1, width w2 of second slab part C2, width w3 of third slab part C3, fourth slab part
- the size of the cross-sectional structure of the Si semiconductor layer 403 of the MZ type optical modulator 300 was created from the C4 width w4 as follows.
- the doping concentration is as follows.
- the extinction characteristic of the conventional MZ type optical modulator 100 is shown by a curve 701
- a voltage is applied to the phase modulation section of the MZ type optical modulator, the phase of the light propagating through the two optical waveguides in the MZ interference system changes, and after the light intensity is reduced, the light whose phase is inverted is output. The characteristics to be seen are seen.
- the modulation efficiency deteriorates because the field of light existing in the region where the refractive index changes due to the carrier plasma effect is reduced.
- the relationship between the thicknesses t0, t1, and t3 preferably satisfies the relationship of inequality t0>t3> t1 and the relationship of t0 / 2> t1 as in this embodiment.
- FIG. 8 shows a comparison of calculated values of the electrical frequency characteristics (S-parameter) of the modulator between the conventional MZ type optical modulator 100 and the MZ type optical modulator 300 produced as in the present embodiment.
- FIG. FIG. 8A shows the frequency characteristic of the reflected signal (S11)
- FIG. 8B shows the frequency characteristic of the transmitted signal (S21).
- the frequency characteristic of the reflected signal (S11) of the conventional MZ type optical modulator 100 is a curve 801
- the frequency characteristic of the reflected signal (S11) of the MZ type optical modulator 300 of this embodiment is a curved line. This is indicated by 802.
- the frequency characteristic of the transmission signal (S21) of the conventional MZ type optical modulator 100 is indicated by a curve 803, and the frequency characteristic of the transmission signal (S21) of the MZ type optical modulator 300 of this embodiment is indicated by a curve 804. .
- the MZ type optical modulator 300 of this embodiment since the loss of the high frequency electrical signal at the traveling wave electrode is small, the attenuation of the transmission signal (S21) is small, and the frequency band defined by 6 dB is 18 GHz, which is the conventional MZ. It can be seen that it is larger than 16 GHz of the type optical modulator 100.
- FIG. 9 is a diagram showing a comparison of the electric field intensity distribution at the pn junction between the conventional MZ type optical modulator 100 and the MZ type optical modulator 300 of the present embodiment.
- FIG. 9A shows the electric field intensity distribution at the pn junction in the Si semiconductor layer 203 of the conventional MZ type optical modulator 100
- FIG. 9B shows the inside of the Si semiconductor layer 403 of the MZ type optical modulator 300 of this example.
- the electric field strength distribution in a pn junction part is shown.
- the modulation frequency is 10 GHz
- the electric field strength at the pn junction in the Si semiconductor layer 403 of this example is 25.6% larger than the electric field strength at the pn junction in the conventional Si semiconductor layer 203.
- the attenuation constant ⁇ of the high-frequency signal is also 67.1 Np / m, which is smaller than that of the conventional structure of 85.5 Np / m. From the results shown in FIGS. 8 and 9, it can be seen that a good Si optical modulator with low loss of high-frequency signals can be realized in the present invention.
- FIG. 10 is a top perspective view showing a configuration of the MZ type optical modulator 1000 according to the second embodiment of the present invention, and particularly shows a connection portion between the optical waveguide 1003 and the optical waveguide 1023 of the phase modulation unit 1011.
- . 10A is a cross-sectional view perpendicular to the light guiding direction (x-axis direction) of the optical waveguide 1003
- FIG. 10B is a connection portion between the optical waveguide 1003 and the optical waveguide 1023 of the phase modulation unit 1011.
- FIG. 10C is a cross-sectional view in the direction perpendicular to the light guiding direction (x-axis direction) of the optical waveguide 1023 of the phase modulation unit 1011.
- the MZ type optical modulator 1000 according to the second embodiment is similar to the MZ type optical modulator 300 of the first embodiment in that the connection portion between the optical waveguide 303 and the optical waveguide 323 of the phase modulation unit 311 is shown in FIG. b).
- the connection portion the incident-side optical waveguide 1003 and the optical waveguide 1023 of the phase modulation unit 1011 are connected.
- the incident-side optical waveguide 1003 is connected to the waveguide 303 of the first embodiment, and the phase modulation unit 1011 is In the phase modulation unit 311, the optical waveguide 1023 corresponds to the optical waveguide 323.
- the optical waveguide 1003 includes a rib part C0, a first slab part C1, and a second slab part C2.
- the width of the region of the first slab portion C1 gradually becomes narrower and becomes the width w1 in accordance with the light guiding direction.
- the width of the region of the second slab portion C2 is gradually narrowed to become the width w2.
- the effective refractive index of the light propagating through the optical waveguide is also affected by the refractive indexes of the third slab part C3 and the fourth slab part C4 located away from the rib part C0.
- the approach of the third slab part C3 and the fourth slab part C4 is 10% or less with respect to the length L that is sufficiently long with respect to the wavelength of light, for example, the propagation length L is close to 1 ⁇ m with respect to 10 ⁇ m. It is desirable to approximate the length ratio.
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Abstract
Description
図3は、本発明の第1の実施形態に係るMZ型光変調器300の構成を示す上面透視図である。MZ型光変調器300は、シリコン光変調器であり、入力光導波路301と、入力光導波路301から入射した光を1:1に分岐する光分岐器302と、光分岐器302からの光が入射される光導波路303及び304とを備える。また、MZ型光変調器300は、光導波路303を伝搬する光の位相を変調する位相変調部311と、光導波路304を伝搬する光の位相を変調する位相変調部312と、位相変調部311からの光を伝搬する光導波路305と、位相変調部312からの光を伝搬する光導波路306とを備える。また、MZ型光変調器300は、光導波路305及び306からの位相が変調された光を合波する光合波器307と、光合波器307により合波された光を出射する出力光導波路308とを備える。
上述の通り算出したリブ部C0の厚さt0、第1のスラブ部C1の厚さt1、第2のスラブ部C2の厚さt2、第3のスラブ部C3の厚さt3、及び第4のスラブ部C4の厚さt4、リブ部C0の幅w0、第1のスラブ部C1の幅w1、第2のスラブ部C2の幅w2、第3のスラブ部C3の幅w3、第4のスラブ部C4幅w4から、一例として、以下の通りMZ型光変調器300のSi半導体層403の断面構造のサイズを作成した。また、ドーピング濃度については以下の通りとしている。
t0=220nm w0=500nm
第1のスラブ部C1
t1=80nm w1=100nm
第2のスラブ部C2
t2=80nm w2=100nm
第3のスラブ部C3
t3=150nm w3>200nm
第4のスラブ部C4
t4=150nm w4>200nm
高濃度p型半導体領域403-3
p++:1×1020 cm-3
高濃度n型半導体領域403-4
n++:1×1020 cm-3
中濃度p型半導体領域403-1
p+ :2.7×1017 cm-3
中濃度n型半導体領域403-2
n+ : 3.0×1017 cm-3
図7は、従来のMZ型光変調器100(図1)の消光特性、本実施例の通りの寸法により作成したMZ型光変調器300の消光特性、及びt1=t2=t3=t4=150nmとして作成したMZ型光変調器の消光特性の関係を示す図である。図7において、従来のMZ型光変調器100の消光特性は、曲線701により、本実施例の通りの寸法により作成したMZ型光変調器300の消光特性は、曲線702により、及びt1=t2=t3=t4=150nmとして作成したMZ型光変調器の消光特性は、曲線703により示している。MZ型光変調器の位相変調部に電圧を印加すると、MZ干渉系内の2本の光導波路を伝播する光の位相が変化し、一旦光強度が減少した後、位相が反転した光が出力される特性が見られる。t1=t2=t3=t4=150nmとして作成したMZ型光変調器の消光特性(曲線701)は、光のフィールドがコアとなるリブ部からはみ出しているため、光損失が大きい。また、キャリアプラズマ効果を受け屈折率が変わる領域に存在する光のフィールドが少なくなるため、変調効率が劣化していることもわかる。このため、厚さt0、t1及びt3の関係は、本実施例のように不等式t0>t3>t1を満たすとともに、t0/2>t1の関係を満たすことが望ましいことがわかる。また、厚さt0、t2及びt4の関係についても、本実施例のように不等式t0>t4>t2を満たすとともに、t0/2>t4の関係を満たすことが望ましいことがわかる。
図10は、本発明の第2の実施形態に係るMZ型光変調器1000の構成を示す上面透視図で、特に光導波路1003と位相変調部1011の光導波路1023との接続部分を示している。図10(a)は光導波路1003の光の導波方向(x軸方向)と垂直方向の断面図、図10(b)は光導波路1003と位相変調部1011の光導波路1023との接続部分の上面透視図、図10(c)は位相変調部1011の光導波路1023の光の導波方向(x軸方向)と垂直方向の断面図である。第2の実施形態に係るMZ型光変調器1000は、第1の実施形態のMZ型光変調器300において、光導波路303と位相変調部311の光導波路323との接続部分を、図10(b)の構成にしたものである。接続部分において、入射側の光導波路1003と位相変調部1011の光導波路1023とが接続されており、入射側の光導波路1003は、第1の実施形態の導波路303に、位相変調部1011は位相変調部311に、光導波路1023は光導波路323に対応する。なお、光導波路1003は、リブ部C0と、第1のスラブ部C1及び第2のスラブ部C2とから構成されている。
101、103、104、105、106、108、123、301、303、304、305、306、308、323 光導波路
102、302 光分岐器
107、307 光合波器
111、112、311、312 位相変調部
121、122、124、125、321、322、324、325 進行波電極
201、401 Si基板
202、204、205、206、402、404、405、406 SiO2クラッド層
203、403 Si半導体層
203-3、403-3 高濃度p型半導体領域
203-4、403-4 高濃度n型半導体領域
203-1、403-1 中濃度p型半導体領域
203-2、403-2 中濃度n型半導体領域
A0、C0 リブ部
A1~A2、C1~C4 スラブ部
C 容量
R1、R2 抵抗
Claims (9)
- 基板(401)と、
前記基板上の位相変調部(311)であって、第1のクラッド層(402)と、前記第1のクラッド層(402)上に積層され、前記第1のクラッド層(402)よりも高い屈折率を有する半導体層(403)と、前記半導体層(403)上に積層され、前記半導体層(403)よりも低い屈折率を有する第2のクラッド層(404)とからなる光導波路(323)と、第1の進行波電極(321)と、第2の進行波電極(322)とを含む、位相変調部(311)とを含む光変調器(300)であって、
前記半導体層(403)は、
前記光導波路(323)の光軸方向に形成され、前記光導波路(323)のコアとなるリブ部(C0)と、
前記リブ部(C0)の一方の脇に前記光軸方向に形成される第1のスラブ部(C1)と、
前記リブ部(C0)の他方の脇に前記光軸方向に形成される、第2のスラブ部(C2)と、
前記第1のスラブ部(C1)の前記リブ部(C0)の反対側に前記光軸方向に形成される、第3のスラブ部(C3)と、
前記第2のスラブ部(C2)の前記リブ部(C0)の反対側に前記光軸方向に形成される、第4のスラブ部(C4)と
を備え、
前記第1のスラブ部(C1)は、前記リブ部(C0)及び前記第3のスラブ部(C3)よりも薄く形成され、
前記第2のスラブ部(C2)は、前記リブ部(C0)及び前記第4のスラブ部(C4)よりも薄く形成されることを特徴とする光変調器(300)。 - 前記リブ部(C0)の厚さをt0、前記第1のスラブ部(C1)の厚さをt1、前記第3のスラブ部(C3)の厚さをt3としたときに、厚さの関係が不等式t0>t3>t1を満たし、前記第2のスラブ部(C2)の厚さをt2、前記第4のスラブ部(C4)の厚さをt4としたときに、厚さの関係が不等式t0>t4>t2を満たすことを特徴とする請求項1に記載の光変調器(300)。
- 前記厚さの関係が、更に不等式t0/2>t1及び不等式t0/2>t2を満たすことを特徴とする請求項2に記載の光変調器(300)。
- 前記第1の進行波電極(321)は、前記第3のスラブ部(C3)の、前記リブ部(C0)とは反対側の端部の上面に前記光軸方向に形成され、
前記第2の進行波電極(322)は、前記第4のスラブ部(C4)の、前記リブ部(C0)とは反対側の端部の上面に、前記光軸方向に形成される
ことを特徴とする請求項3に記載の光変調器(300)。 - 前記第3のスラブ部(C3)の前記第1のスラブ部(C1)と反対側の端部は、高濃度p型半導体領域(403-3)であり、前記第4のスラブ部(C4)の前記第2のスラブ部(C2)と反対側の端部は、高濃度n型半導体領域(403-4)であり、
前記第3のスラブ部(C3)の前記第1のスラブ部(C1)側、前記第1のスラブ部(C1)及び前記リブ部(C0)の前記第1のスラブ部(C1)側は、中濃度p型半導体領域(403-1)であり、前記第4のスラブ部(C4)の前記第2のスラブ部(C2)側、前記第2のスラブ部(C2)及び前記リブ部(C0)の前記第2のスラブ部(C2)側は、中濃度n型半導体領域(403-2)であることを特徴とする請求項4に記載の光変調器(300)。 - 前記中濃度p型半導体領域(403-1)と、前記中濃度n型半導体領域(403-2)との接合部は、pn接合構造であることを特徴とする請求項5に記載の光変調器。
- 前記中濃度p型半導体領域(403-1)と、前記中濃度n型半導体領域(403-2)との接合部は、前記中濃度p型半導体領域(403-1)と、前記中濃度n型半導体領域(403-2)との間に、ドーピングされていないi型(真性)半導体領域をさらに挟んだpin接合構造であることを特徴とする請求項5に記載の光変調器(300)。
- 前記第1のスラブ部(C1)をw1とし、前記第2のスラブ部(C2)の幅をw2としたときに、前記w1の関係が、不等式60nm<w1<600nmを満たし、前記w2の関係が、不等式60nm<w2<600nmを満たすことを特徴とする請求項3に記載の光変調器(300)。
- 前記位相変調部(311)と前記光変調器に形成されたリブ導波路との接続部において、前記位相変調部(311)の前記第1のスラブ部(C1)及び前記第2のスラブ部(C2)の領域の幅が前記位相変調器側に向かって徐々に狭くなることを特徴とする請求項2に記載の光変調器(300)。
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EP15866773.3A EP3232255B1 (en) | 2014-12-09 | 2015-12-08 | Optical modulator |
SG11201704080YA SG11201704080YA (en) | 2014-12-09 | 2015-12-08 | Optical modulator |
CN201580067277.9A CN107003549B (zh) | 2014-12-09 | 2015-12-08 | 光调制器 |
CA2969504A CA2969504C (en) | 2014-12-09 | 2015-12-08 | Optical modulator |
US15/528,874 US10146099B2 (en) | 2014-12-09 | 2015-12-08 | Optical modulator |
JP2016563506A JP6434991B2 (ja) | 2014-12-09 | 2015-12-08 | 光変調器 |
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CN108931859A (zh) * | 2017-05-24 | 2018-12-04 | 瑞萨电子株式会社 | 半导体器件 |
WO2019202894A1 (ja) * | 2018-04-19 | 2019-10-24 | 日本電信電話株式会社 | 光変調器 |
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CN110320596A (zh) * | 2018-03-28 | 2019-10-11 | 华为技术有限公司 | 光波导器件及其制备方法 |
US11982919B2 (en) * | 2018-12-06 | 2024-05-14 | Mitsubishi Electric Corporation | Mach-Zehnder type optical modulator |
JP2020095131A (ja) * | 2018-12-12 | 2020-06-18 | 住友電気工業株式会社 | 光変調器 |
CN109683354B (zh) * | 2019-01-15 | 2020-09-15 | 中国科学院半导体研究所 | 一种中红外波段调制器及其制备方法 |
JP7131425B2 (ja) * | 2019-02-19 | 2022-09-06 | 日本電信電話株式会社 | 光変調器 |
US10866440B1 (en) * | 2019-07-17 | 2020-12-15 | Taiwan Semiconductor Manufacturing Company, Ltd. | Optical modulator and package |
JP2021167851A (ja) * | 2020-04-08 | 2021-10-21 | 富士通オプティカルコンポーネンツ株式会社 | 光変調器 |
US11415820B2 (en) * | 2020-05-04 | 2022-08-16 | Taiwan Semiconductor Manufacturing Company, Ltd. | Waveguide structure |
CN212341627U (zh) * | 2020-06-29 | 2021-01-12 | 苏州旭创科技有限公司 | 一种硅基行波电极调制器 |
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CN112162446A (zh) * | 2020-10-15 | 2021-01-01 | 中国科学院上海微系统与信息技术研究所 | Mz电光调制器及其制备方法 |
CN113284964B (zh) * | 2021-04-22 | 2022-06-24 | 北京邮电大学 | 一种导模光电探测器 |
JP2023028947A (ja) * | 2021-08-20 | 2023-03-03 | 富士通オプティカルコンポーネンツ株式会社 | 光導波路素子、光通信装置及びスラブモード除去方法 |
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CN107003549A (zh) | 2017-08-01 |
CA2969504C (en) | 2019-02-26 |
US20170336696A1 (en) | 2017-11-23 |
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EP3232255A4 (en) | 2018-07-25 |
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JP6434991B2 (ja) | 2018-12-05 |
US10146099B2 (en) | 2018-12-04 |
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