Ring resonator, light modulator, light source device, distance measuring device, and resonator device

Abstract

The main purpose of the present invention is to provide a resonator capable of increasing the group refractive index of an optical waveguide. The ring resonator (100c) according to the invention comprises a ring-shaped optical waveguide (RWG), and the optical waveguide has a photonic crystal structure (PCS). By means of the ring resonator according to the present invention, it is possible to provide a resonator capable of increasing the group refractive index of an optical waveguide.

Description

Technical Field

[0001] The technology according to the present disclosure (hereinafter also referred to as "the present technology") relates to a ring resonator, an optical modulator, a light source device, a distance measuring device, and a resonator device. Background Art

[0002] Conventionally, for example, a ring resonator used for an optical modulator or the like is known (for example, see Patent Document 1). In a ring resonator, the resonance wavelength is determined by the optical path length of an optical waveguide (a ring-shaped optical waveguide). That is, the resonance wavelength of the ring resonator depends on the refractive index of the optical waveguide of the ring resonator.

[0003] Citation List

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2019-62036 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] For example, Patent Document 1 does not mention anything about increasing the group refractive index of the optical waveguide of the ring resonator.

[0008] The main object of the present technology is to provide a ring resonator capable of increasing the group refractive index of the optical waveguide.

[0009] Solutions to the Problems

[0010] The present technology provides a ring resonator including:

[0011] A ring-shaped optical waveguide, wherein the optical waveguide has a photonic crystal structure.

[0012] The present technology also provides an optical modulator including:

[0013] An optical waveguide;

[0014] A ring resonator optically coupled to the optical waveguide; and

[0015] A phase shifter provided in the ring resonator and / or the optical waveguide, wherein

[0016] At least the ring resonator among the ring resonator and the optical waveguide has a photonic crystal structure.

[0017] In the optical modulator, the ring resonator and the optical waveguide may have a photonic crystal structure.

[0018] In the optical modulator, only the ring resonator among the ring resonator and the optical waveguide may have a photonic crystal structure.

[0019] In the optical modulator, the phase shifter may be disposed in the ring resonator.

[0020] The optical modulator may include a plurality of the ring resonators.

[0021] In the optical modulator, the phase shifter may be disposed in at least one of the plurality of ring resonators.

[0022] In the optical modulator, the phase shifter may be disposed in a part of the plurality of ring resonators, and the phase shifter may not be disposed in other parts of the ring resonators.

[0023] In the optical modulator, the phase shifter may not be disposed in at least one of the plurality of ring resonators.

[0024] The optical modulator may include a plurality of the optical waveguides.

[0025] The optical modulator may include a plurality of the ring resonators and a plurality of the optical waveguides, and each of the plurality of ring resonators may be optically coupled to at least two of the plurality of optical waveguides.

[0026] In the optical modulator, the optical waveguide may include a branching portion or a combining portion.

[0027] In the optical modulator, an end of the optical waveguide may be connected to an optical amplifier.

[0028] In the optical modulator, the phase shifter may be disposed at a position between an optical coupling portion between the optical waveguide and the ring resonator and the optical amplifier.

[0029] In the optical modulator, a mirror may be disposed at an end of the optical waveguide.

[0030] In the optical modulator, the mirror may be a Sagnac loop or a distributed Bragg reflector.

[0031] In the optical modulator, a Mach-Zehnder modulator may be disposed in the optical waveguide.

[0032] In the optical modulator, in the photonic crystal structure, the pores of the photonic crystal may include air gaps or materials having a refractive index different from that of the waveguide portion.

[0033] The present technology also provides a light source device, including

[0034] an optical amplifier; and

[0035] An optical modulator, into which light from the optical amplifier is incident, wherein

[0036] The optical modulator includes:

[0037] An optical waveguide;

[0038] An optical ring resonator optically coupled to the optical waveguide; and

[0039] A phase shifter disposed in the ring resonator and / or the optical waveguide, and

[0040] At least the ring resonator among the ring resonator and the optical waveguide has a photonic crystal structure.

[0041] The present technology also provides a ranging device, including:

[0042] An optical amplifier;

[0043] An optical modulator, into which light from the optical amplifier is incident; and

[0044] An optical receiving unit that receives light reflected by an object via the optical modulator, wherein

[0045] The optical modulator includes:

[0046] An optical waveguide;

[0047] An optical ring resonator optically coupled to the optical waveguide; and

[0048] A phase shifter disposed in the ring resonator and / or the optical waveguide, and

[0049] At least the ring resonator among the ring resonator and the optical waveguide has a photonic crystal structure.

[0050] The present technology also provides a resonator device, including:

[0051] An optical waveguide; and

[0052] An optical ring resonator optically coupled to the optical waveguide, wherein

[0053] At least the ring resonator among the ring resonator and the optical waveguide has a photonic crystal structure. Description of the Drawings

[0054] Figure 1 is a diagram schematically showing a planar configuration of an optical modulator according to Embodiment 1 of the first embodiment of the present technology.

[0055] Figure 2 is a diagram schematically showing a planar configuration of an optical modulator according to Embodiment 2 of the first embodiment of the present technology.

[0056] Figure 3 It is a diagram schematically showing the planar configuration of the optical modulator according to Embodiment 3 of the first embodiment of the present technology.

[0057] Figure 4 It is a diagram schematically showing the planar configuration of the optical modulator according to Embodiment 4 of the first embodiment of the present technology.

[0058] Figure 5 It is a diagram schematically showing the planar configuration of the optical modulator according to Embodiment 5 of the first embodiment of the present technology.

[0059] Figure 6 It is a diagram schematically showing the planar configuration of the optical modulator according to Embodiment 6 of the first embodiment of the present technology.

[0060] Figure 7 It is a diagram schematically showing the planar configuration of the optical modulator according to Embodiment 7 of the first embodiment of the present technology.

[0061] Figure 8 It is a diagram schematically showing the planar configuration of the optical modulator according to Embodiment 8 of the first embodiment of the present technology.

[0062] Figure 9 It is a diagram schematically showing the planar configuration of the optical modulator according to Embodiment 9 of the first embodiment of the present technology.

[0063] Figure 10 It is a diagram schematically showing the planar configuration of the light source device according to Embodiment 1 of the second embodiment of the present technology.

[0064] Figure 11 It is a diagram schematically showing the planar configuration of the light source device according to Embodiment 2 of the second embodiment of the present technology.

[0065] Figure 12 It is a diagram schematically showing the planar configuration of the light source device according to Embodiment 3 of the second embodiment of the present technology.

[0066] Figure 13 It is a diagram schematically showing the planar configuration of the light source device according to Embodiment 4 of the second embodiment of the present technology.

[0067] Figure 14 It is a diagram schematically showing the planar configuration of the light source device according to Embodiment 5 of the second embodiment of the present technology.

[0068] Figure 15 It is a diagram schematically showing the planar configuration of the light source device according to Embodiment 6 of the second embodiment of the present technology.

[0069] Figure 16It is a diagram schematically showing the planar configuration of the light source device according to Embodiment 7 of the second embodiment of the present technology.

[0070] Figure 17 It is a diagram schematically showing the planar configuration of the light source device according to Embodiment 8 of the second embodiment of the present technology.

[0071] Figure 18 It is a diagram schematically showing the planar configuration of the light source device according to Embodiment 9 of the second embodiment of the present technology.

[0072] Figure 19 It is a diagram schematically showing the planar configuration of the light source device according to Embodiment 10 of the second embodiment of the present technology.

[0073] Figure 20 It is a diagram schematically showing the planar configuration of the light source device according to Embodiment 11 of the second embodiment of the present technology.

[0074] Figure 21 It is a diagram schematically showing the planar configuration of the light source device according to Embodiment 12 of the second embodiment of the present technology.

[0075] Figure 22 It is a diagram showing a configuration example of a Mach-Zehnder modulator.

[0076] Figure 23 It is a diagram schematically showing the planar configuration of the light source device according to Embodiment 13 of the second embodiment of the present technology.

[0077] Figure 24 It is a diagram schematically showing the planar configuration of the light source device according to Embodiment 14 of the second embodiment of the present technology.

[0078] Figure 25 It is a diagram schematically showing the planar configuration of the light source device according to Embodiment 15 of the second embodiment of the present technology.

[0079] Figure 26 It is a diagram schematically showing the planar configuration of the light source device according to Embodiment 16 of the second embodiment of the present technology.

[0080] Figure 27 It is a diagram schematically showing the planar configuration of the light source device according to Embodiment 17 of the second embodiment of the present technology.

[0081] Figure 28 It is a block diagram showing a configuration example of the distance measuring device according to the third embodiment of the present technology.

[0082] Figure 29 It is a diagram schematically showing the planar configuration of the resonator device according to Embodiment 1 of the fourth embodiment of the present technology.

[0083] Figure 30 It is a diagram schematically showing the planar configuration of the resonator device according to Embodiment 2 of the fourth embodiment of the present technology.

[0084] Figure 31 It is a diagram schematically showing the planar configuration of the resonator device according to Embodiment 3 of the fourth embodiment of the present technology.

[0085] Figure 32 It is a diagram schematically showing the planar configuration of the resonator device according to Embodiment 4 of the fourth embodiment of the present technology.

[0086] Figure 33 It is a diagram schematically showing the planar configuration of the resonator device according to Embodiment 5 of the fourth embodiment of the present technology.

[0087] Figure 34 It is a diagram schematically showing the planar configuration of the resonator device according to Embodiment 6 of the fourth embodiment of the present technology.

[0088] Figure 35 It is a diagram schematically showing the planar configuration of the ring resonator according to the fifth embodiment of the present technology.

[0089] Figure 36 It is a diagram schematically showing an example of the cross-sectional configuration of the ring waveguide of the optical modulator according to Embodiment 1 of the first embodiment of the present technology.

[0090] Figure 37 It is a diagram schematically showing an example of the cross-sectional configuration of the linear waveguide of the optical modulator according to Embodiment 1 of the first embodiment of the present technology.

[0091] Figure 38 It is a diagram schematically showing another example of the cross-sectional configuration of the ring waveguide of the optical modulator according to Embodiment 1 of the first embodiment of the present technology. Detailed Description of the Invention

[0092] Hereinafter, preferred embodiments of the present technology will be described in detail with reference to the drawings. Note that in this specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant descriptions are omitted. The embodiments to be described below provide representative embodiments of the present technology, and the scope of the present technology should not be construed narrowly based on these embodiments. In this specification, even when it is described that the ring resonator, optical modulator, light source device, distance measuring device, and resonator device according to the present technology exhibit various effects, the ring resonator, optical modulator, light source device, distance measuring device, and resonator device according to the present technology only need to exhibit at least one effect. The effects described in this specification are merely examples and are not limited, and other effects may be applied.

[0093] In addition, the description will be given in the following order.

[0094] 0. Introduction

[0095] 1. Optical modulator according to Embodiment 1 of the first embodiment of the present technology

[0096] 2. Optical modulator according to Embodiment 2 of the first embodiment of the present technology

[0097] 3. Optical modulator according to Embodiment 3 of the first embodiment of the present technology

[0098] 4. Optical modulator according to Embodiment 4 of the first embodiment of the present technology

[0099] 5. Optical modulator according to Embodiment 5 of the first embodiment of the present technology

[0100] 6. Optical modulator according to Embodiment 6 of the first embodiment of the present technology

[0101] 7. Optical modulator according to Embodiment 7 of the first embodiment of the present technology

[0102] 8. Optical modulator according to Embodiment 8 of the first embodiment of the present technology

[0103] 9. Optical modulator according to Embodiment 9 of the first embodiment of the present technology

[0104] 10. Light source device according to Embodiment 1 of the second embodiment of the present technology

[0105] 11. Light source device according to Embodiment 2 of the second embodiment of the present technology

[0106] 12. Light source device according to Embodiment 3 of the second embodiment of the present technology

[0107] 13. Light source device according to Embodiment 4 of the second embodiment of the present technology

[0108] 14. Light source device according to Embodiment 5 of the second embodiment of the present technology

[0109] 15. Light source device according to Embodiment 6 of the second embodiment of the present technology

[0110] 16. Light source device according to Embodiment 7 of the second embodiment of the present technology

[0111] 17. Light source device according to Embodiment 8 of the second embodiment of the present technology

[0112] 18. Light source device according to Embodiment 9 of the second embodiment of the present technology

[0113] 19. The light source device according to Embodiment 10 of the second embodiment of the present technology

[0114] 20. The light source device according to Embodiment 11 of the second embodiment of the present technology

[0115] 21. The light source device according to Embodiment 12 of the second embodiment of the present technology

[0116] 22. The light source device according to Embodiment 13 of the second embodiment of the present technology

[0117] 23. The light source device according to Embodiment 14 of the second embodiment of the present technology

[0118] 24. The light source device according to Embodiment 15 of the second embodiment of the present technology

[0119] 25. The light source device according to Embodiment 16 of the second embodiment of the present technology

[0120] 26. The light source device according to Embodiment 17 of the second embodiment of the present technology

[0121] 27. The distance measuring device according to the third embodiment of the present technology

[0122] 28. The resonator device according to Embodiment 1 of the fourth embodiment of the present technology

[0123] 29. The resonator device according to Embodiment 2 of the fourth embodiment of the present technology

[0124] 30. The resonator device according to Embodiment 3 of the fourth embodiment of the present technology

[0125] 31. The resonator device according to Embodiment 4 of the fourth embodiment of the present technology

[0126] 32. The resonator device according to Embodiment 5 of the fourth embodiment of the present technology

[0127] 33. The resonator device according to Embodiment 6 of the fourth embodiment of the present technology

[0128] 34. The ring resonator according to the fifth embodiment of the present technology

[0129] 35. The modification of the present technology

[0130] <0. Introduction>

[0131] Traditionally, optical modulators including ring resonators and phase shifters are known. Such optical modulators are used as optical modulation units for light source devices such as tunable mode-locked lasers (hereinafter referred to as "ring lasers"). However, in such optical modulators, there is a problem that the power consumption of the phase shifter required to change the resonance wavelength of the ring resonator is large. In addition, the response speed of the phase shifter limits the speed of change of the resonance wavelength. Therefore, when the response speed of the phase shifter is slow, the speed of change of the resonance wavelength is slow, and in the case of using a ring laser as a light source for, for example, frequency-modulated continuous-wave (FMCW) optical detection and ranging (LiDAR), there is a problem of reduced distance resolution.

[0132] The wavelength of a ring laser changes according to the magnitude of the group index of the ring resonator. More specifically, as the group index of the ring resonator is higher, the resonance wavelength is more likely to change, the speed of change of the resonance wavelength increases (the response speed of the phase shifter increases), and the power consumption of the phase shifter required for the change of the resonance wavelength can be reduced.

[0133] Incidentally, in a photonic crystal waveguide (PCW) in which fine holes are regularly formed in an Si layer, by appropriately designing the shape, diameter, and pitch of each fine hole, the group index of the optical waveguide can be increased to several times or more that of an ordinary Si wire waveguide.

[0134] The present inventor has successfully significantly increased the group index of a ring resonator by introducing a photonic crystal structure into the ring resonator. In addition, for example, the present inventor has successfully reduced the power consumption and improved the distance resolution in the case where an optical modulator incorporating a ring resonator group including a photonic crystal waveguide as an optical waveguide is used as an optical modulation unit for a light source device such as a ring laser for FMCW. The present technology embodies the above novel concept.

[0135] Hereinafter, an optical modulator according to a first embodiment of the present technology will be described in detail through some examples.

[0136] <1. Optical modulator of Example 1 according to the first embodiment of the present technology>

[0137] Hereinafter, an optical modulator 10-1 of Example 1 according to the first embodiment of the present technology will be described.

[0138] <<Configuration of the optical modulator>>

[0139] Figure 1 is a diagram schematically showing the planar configuration of an optical modulator 10-1 of Example 1 according to the first embodiment of the present technology. Figure 36 is a diagram schematically showing an example of the cross-sectional configuration of the ring waveguide of the optical modulator 10-1 of Example 1 according to the first embodiment of the present technology. Figure 36is taken along Figure 1 a cross-sectional view taken along line 36-36 in Figure 37 is a diagram schematically showing an example of a cross-sectional configuration of a linear waveguide of an optical modulator 10-1 according to Example 1 of the first embodiment of the present technology. Figure 37 is taken along Figure 1 a cross-sectional view taken along line 37-37 in

[0140] As an example, the optical modulator 10-1 serves as an optical modulation unit of a light source device of a ranging device (e.g., in-vehicle LiDAR) that employs a frequency continuous modulation (FMCW) method.

[0141] As Figure 1 shown, the optical modulator 10-1 includes a first optical waveguide 100a and a second optical waveguide 100b, a ring resonator 100c optically coupled to each of the first optical waveguide 100a and the second optical waveguide 100b, and a phase shifter 200 provided in the ring resonator 100c. The resonator device 100 includes the first optical waveguide 100a and the second optical waveguide 100b and the ring resonator 100c.

[0142] As an example, the optical modulator 10-1 is formed on a silicon-on-insulator (SOI) substrate 50 (see Figure 36 and Figure 37 ). The SOI substrate 50 includes an Si substrate 51 and an Si layer 52 stacked on each other and an insulator layer 53 present between the Si substrate 51 and the Si layer 52. The Si layer 52 is a core layer of a ring-shaped optical waveguide (hereinafter also referred to as "ring waveguide RWG") included in the first optical waveguide 100a, the second optical waveguide 100b, and the ring resonator 100c. The insulator layer 53 is an SiO 2 layer (sacrificial layer) having an air layer inside, and this air layer serves as a cladding layer of the ring waveguide RWG of the first optical waveguide 100a, the second optical waveguide 100b, and the ring resonator 100c.

[0143] Returning to Figure 1 , as an example, each of the first optical waveguide 100a and the second optical waveguide 100b is a linear optical waveguide (hereinafter also referred to as "linear waveguide"). In the first optical waveguide 100a, one end 100a1 and / or the other end 100a2 may be an input / output port (input port or output port). One end 100b1 and the other end 100b2 of the second optical waveguide 100b may be used as input / output ports (input port or output port). The optical modulator 10-1 serves as a 2- to 4-port optical modulator.

[0144] Here, in a state where the first optical waveguide 100a and the second optical waveguide 100b sandwich the ring resonator 100c from the radial sides, the first optical waveguide 100a, the second optical waveguide 100b, and the ring resonator 100c are integrated. That is, each of the first optical waveguide 100a and the second optical waveguide 100b has an overlapping portion with the ring resonator 100c. Through this overlapping portion, the coupling efficiency (coupling coefficient) and the coupling length (the length of the bent portion of the ring waveguide RWG that causes the coupling phenomenon) between the ring resonator 100c and each linear waveguide are appropriately set (preferably optimized).

[0145] In the optical modulator 10-1, the ring resonator 100c and each of the first optical waveguide 100a and the second optical waveguide 100b have a photonic crystal structure PCS. That is, the ring waveguide RWG of the ring resonator 100c and each of the first optical waveguide 100a and the second optical waveguide 100b include a photonic crystal waveguide PCW having a photonic crystal structure PCS (refer to Figure 36 and Figure 37 ). In the photonic crystal waveguide PCW, the core layer (Si layer 52) is longitudinally sandwiched by air layers having a refractive index much lower than that of the core layer, thereby achieving longitudinal optical confinement.

[0146] The photonic crystal structure PCS has a plurality of fine holes P (e.g., circular holes) two-dimensionally arranged (such as a periodic arrangement like a staggered arrangement or a matrix arrangement) in the Si layer 52 of the SOI substrate 50. Each fine hole P can be an air gap or a material having a refractive index different from that of the waveguide portion (the light propagation region of each linear waveguide or the ring waveguide RWG). As shown in Figure 36 and Figure 37 , the photonic crystal waveguide PCW is an optical waveguide (also referred to as a "line defect waveguide") that includes a photonic bandgap region PBR and a light propagation region LPR (the region where light propagates) in the Si layer 52. The photonic bandgap region PBR is a region where a plurality of fine holes P are formed and prevents light in a specific wavelength band (e.g., the wavelength band including the resonance wavelength of the ring resonator 100c) from propagating in the in-plane direction. The light propagation region LPR is a region where no fine holes P are formed and is sandwiched between the photonic bandgap regions PBR in the in-plane direction. That is, in the photonic crystal waveguide PCW, transverse (in-plane direction) optical confinement is achieved by the photonic bandgap region PBR.

[0147] In the photonic crystal structure PCS, the shape, diameter, and pitch (period) of the fine holes P are set such that the group refractive index of the ring waveguide RWG and each linear waveguide is several times higher than that of a normal Si thin wire waveguide. However, the diameter and pitch (period) of the fine holes P need to be set to form the photonic bandgap region PBR.

[0148] The phase shifter 200 includes a first semiconductor region 200a provided on the inner peripheral portion of the annular waveguide RWG of the annular resonator 100c, a second semiconductor region 200b provided on the outer peripheral portion, and a third semiconductor region 200c located between the first semiconductor region 200a and the second semiconductor region 200b. Each of the first semiconductor region 200a and the second semiconductor region 200b includes a p-type or n-type semiconductor (Si). The third semiconductor region 200c includes an i-type semiconductor (Si). The first to third semiconductor regions 200a, 200b, and 200c can form a thermo-optical phase shifter having any conduction type of p-i-p, p-i-n, and n-i-n. The thermo-optical phase shifter as the phase shifter 200 has a heater for heating the annular waveguide RWG. By controlling the heating temperature of the heater, the refractive index of the annular waveguide RWG can be changed to modulate the resonance wavelength of the annular resonator 100c. The heater is provided, for example, along the annular waveguide RWG.

[0149] Note that a pn carrier plasma type phase shifter can also be formed by forming one of the first semiconductor region 200a and the second semiconductor region 200b into a p-type semiconductor region, the other into an n-type semiconductor region, and joining the first semiconductor region 200a and the second semiconductor region 200b to form a pn junction (see Figure 38 , which is a cross-sectional view corresponding to Figure 36 ). The pn carrier plasma type phase shifter as the phase shifter 200 can change the refractive index of the annular waveguide RWG and modulate the resonance wavelength of the annular resonator 100c by applying a voltage to control the carrier density of the pn junction.

[0150] <<Operation of the optical modulator>>

[0151] The operation of the optical modulator 10-1 will be described below. An optical amplifier (e.g., a laser) is optically connected to one end 100a1 (referred to as the input port) of the first optical waveguide 100a (photonic crystal waveguide). Among the light output from the optical amplifier and incident from the input port, the light having the same wavelength as the resonance wavelength of the ring resonator 100c propagates to the ring resonator 100c in the coupling region (optical coupling section) between the first optical waveguide 100a and the ring resonator 100c. The light propagating to the ring resonator 100c passes through the inside of the ring waveguide RWG while its wavelength is modulated by the phase shifter 200 provided in the ring waveguide RWG (photonic crystal waveguide). For example, the light passing through the ring waveguide RWG and propagating to the first optical waveguide 100a in the coupling region (optical coupling section) between the first optical waveguide 100a and the ring resonator 100c can be output from the other end 100a2 (referred to as the output port) of the first optical waveguide 100a. For example, the light passing through the ring waveguide RWG and propagating to the second optical waveguide 100b (photonic crystal waveguide) in the coupling region (optical coupling section) between the second optical waveguide 100b and the ring resonator 100c can be output from one end 100b1 (referred to as the output port) of the second optical waveguide 100b. In the optical modulator 10-1, the above series of operations are continuously performed, and by the action of the ring resonator 100c having a photonic crystal waveguide and the phase shifter 200 provided in the ring resonator 100c, the resonance wavelength of the ring resonator 100c can be modulated (increased or decreased) at high speed and with low power consumption. As a result, a chirp signal as an optical signal can be output from the output port in an extremely short period.

[0152] Note that in the optical modulator 10-1, even when any one of the other end 100a2 of the first optical waveguide 100a, one end 100b1 of the second optical waveguide 100b, and the other end 100b2 is used as the input port instead of the one end 100a1 of the first optical waveguide 100a, wavelength-modulated light (optical signal) can be output from at least one port.

[0153] <<Effects of the optical modulator>>

[0154] Hereinafter, the effects of the optical modulator 10-1 according to the first embodiment of the present technology will be described. The optical modulator 10-1 includes a first optical waveguide 100a and a second optical waveguide 100b, a ring resonator 100c optically coupled to each of the first optical waveguide 100a and the second optical waveguide 100b, and a phase shifter 200 provided in the ring resonator 100c, and the ring resonator 100c, the first optical waveguide 100a, and the second optical waveguide 100b have a photonic crystal structure PCS.

[0155] In this case, since the group refractive index of the optical waveguide (ring waveguide RWG) of the ring resonator 100c can be increased, the power consumption required for the change in the resonance wavelength of the phase shifter 200 can be reduced, and the speed of the change in the resonance wavelength caused by the phase shifter 200 can be increased. The fact that the speed of the wavelength change caused by the phase shifter 200 can be increased leads to, for example, an improvement in the distance resolution of the ring laser for FMCW.

[0156] Since the ring resonator 100c and the first optical waveguide 100a and the second optical waveguide 100b have a photonic crystal structure PCS, the insertion loss generated in the optical coupling part (coupling region) between the ring waveguide RWG and each linear waveguide can be reduced. This leads to, for example, an improvement in the light emission efficiency of the ring laser.

[0157] The optical modulator 10-1 has a plurality of optical waveguides (the first optical waveguide 100a and the second optical waveguide 100b) optically coupled to the ring resonator 100c. In this case, one end and the other end of each of the first optical waveguide 100a and the second optical waveguide 100b can be input ports, and at least one of the other ends can be an output port.

[0158] <Optical modulator according to Embodiment 2 of the first embodiment of the present technology>

[0159] Hereinafter, the optical modulator 10-2 according to Embodiment 2 of the first embodiment of the present technology will be described. Figure 2 is a diagram schematically showing the planar configuration of the optical modulator 10-2 according to Embodiment 2 of the first embodiment of the present technology.

[0160] As Figure 2 shown, except that phase shifters 200 are provided at each end of the first optical waveguide 100a and the second optical waveguide 100b (the part of each linear waveguide different from the repeating part of the linear waveguide and the ring waveguide), the optical modulator 10-2 has a configuration similar to that of the optical modulator 10-1 according to Embodiment 1. Note that the phase shifter provided in the linear waveguide is different in shape from, for example, the phase shifter provided in the ring resonator of the optical modulator 10-1, but has the same configuration and function, and is therefore denoted by the same reference numeral 200 (this also applies hereinafter).

[0161] In the optical modulator 10-2, for example, when one end 100a1 of the first optical waveguide 100a is set as the input port, by means of the phase shifter 200 provided at the end including the one end 100a1, the central wavelength of the input light can be shifted within the wavelength band including the resonance wavelength of the ring resonator 100c (e.g., coincide with the resonance wavelength). For example, when the other end 100a2 of the first optical waveguide 100a and one end 100b1 of the second optical waveguide 100b are set as the output ports, the phase shifters 200 provided at the end including the other end 100a2 and the end including the one end 100b1 can modulate the wavelength of the light having the same wavelength as the resonance wavelength via the ring resonator 100c. Therefore, the optical modulator 10-2 can basically modulate the resonance wavelength at high speed and with low power consumption. At least two phase shifters 200 can be synchronously controlled in the optical modulator 10-2.

[0162] Note that in the optical modulator 10-2, the phase shifters 200 are provided at two ends (a total of four ends) of each of the first optical waveguide 100a and the second optical waveguide 100b, but it is not limited thereto, and preferably at least provided at the end including the output port. With the increase of the phase shifters 200, the degree of freedom and stability of modulation can be improved, but on the other hand, the power and optical loss increase. Considering this, it is desirable to select the input port and the output port and determine the number and configuration of the phase shifters 200.

[0163] <Optical Modulator according to Embodiment 3 of the First Embodiment of the Present Technology>

[0164] Hereinafter, the optical modulator 10-3 according to Embodiment 3 of the first embodiment of the present technology will be described. Figure 3 is a diagram schematically showing the planar configuration of the optical modulator 10-3 according to Embodiment 3 of the first embodiment of the present technology.

[0165] As Figure 3 shown, except that the phase shifters 200 are provided at the overlapping portions between each of the first optical waveguide 100a and the second optical waveguide 100b and the ring resonator 100c, the optical modulator 10-3 has a similar configuration to the optical modulator 10-1 according to Embodiment 1.

[0166] The optical modulator 10-3 can also basically modulate the resonance wavelength at high speed and with low power consumption.

[0167] Note that in the optical modulator 10-3, the phase shifters 200 are provided at the overlapping portions between each of the first optical waveguide 100a and the second optical waveguide 100b and the ring resonator 100c, but can also be provided only at the overlapping portions between one of the first optical waveguide 100a and the second optical waveguide 100b and the ring resonator 100c.

[0168] <4. Optical Modulator According to Embodiment 4 of the First Embodiment of the Present Technology>

[0169] Hereinafter, the optical modulator 10-4 according to Embodiment 4 of the first embodiment of the present technology will be described. Figure 4 is a diagram schematically showing the planar configuration of the optical modulator 10-4 according to Embodiment 4 of the first embodiment of the present technology.

[0170] As Figure 4 shown, except that each of the first optical waveguide 100a and the second optical waveguide 100b does not have a photonic crystal structure PCS, the optical modulator 10-4 has a configuration similar to that of the optical modulator 10-1 according to Embodiment 1.

[0171] In the optical modulator 10-4, the first optical waveguide 100a and the second optical waveguide 100b achieve lateral and longitudinal optical confinement through the refractive index difference between the Si layer as the core layer and the air surrounding the Si layer.

[0172] Note that in the optical modulator 10-4, the ring resonator 100c and one of the first optical waveguide 100a and the second optical waveguide 100b may have a photonic crystal structure PCS.

[0173] <5. Optical Modulator According to Embodiment 5 of the First Embodiment of the Present Technology>

[0174] Hereinafter, the optical modulator 10-5 according to Embodiment 5 of the first embodiment of the present technology will be described. Figure 5 is a diagram schematically showing the planar configuration of the optical modulator 10-5 according to Embodiment 5 of the first embodiment of the present technology.

[0175] As Figure 5 shown, except that the second optical waveguide 100b is not included, the optical modulator 10-5 has a configuration similar to that of the optical modulator 10-4 according to Embodiment 4.

[0176] In the optical modulator 10-5, the first optical waveguide 100a achieves lateral and longitudinal optical confinement through the refractive index difference between the Si layer as the core layer and the air surrounding the Si layer.

[0177] In the optical modulator 10-5, for example, light having the same wavelength as the resonance wavelength of the ring resonator 100c among the light input from one end 100a1 (referred to as the input port) of the first optical waveguide 100a propagates to the ring resonator 100c at the optical coupling portion between the first optical waveguide 100a and the ring resonator 100c. The light that has propagated to the ring resonator 100c passes through the inside of the ring resonator 100c while being wavelength-modulated by the phase shifter 200 provided in the ring resonator 100c, and propagates to the first optical waveguide 100a at the optical coupling portion between the ring resonator 100c and the first optical waveguide 100a. The light that has propagated to the first optical waveguide 100a is output from the other end 100a2 (referred to as the output port) of the first optical waveguide 100a.

[0178] Note that in the optical modulator 10-5, the first optical waveguide 100a may have a photonic crystal structure PCS.

[0179] <Optical modulator according to Embodiment 6 of the first embodiment of the present technology>

[0180] Hereinafter, the optical modulator 10-6 according to Embodiment 6 of the first embodiment of the present technology will be described. Figure 6 is a diagram schematically showing the planar configuration of the optical modulator 10-6 according to Embodiment 6 of the first embodiment of the present technology.

[0181] As Figure 6 shown, the optical modulator 10-6 has a configuration substantially similar to that of the optical modulator 10-1 according to Embodiment 1, except that each of the first optical waveguide 100a and the second optical waveguide 100b is optically coupled to the ring resonator 100c separately from each other (without overlapping portions).

[0182] In the optical modulator 10-6, each linear waveguide includes a Si thin wire waveguide, and the linear waveguide achieves lateral and longitudinal optical confinement by the refractive index difference between the Si layer as the core layer and the air around the Si layer. The distance between each linear waveguide and the ring waveguide is set such that the coupling efficiency and the coupling length (the length of the bent portion of the ring waveguide that causes the coupling phenomenon) between the linear waveguide and the ring resonator 100c are appropriately set (preferably optimized).

[0183] Since each of the first optical waveguide 100a and the second optical waveguide 100b is separated from the ring resonator 100c, it is relatively easy to manufacture the optical modulator 10-6.

[0184] <Optical modulator according to Embodiment 7 of the first embodiment of the present technology>

[0185] Hereinafter, the optical modulator 10-7 according to Embodiment 7 of the first embodiment of the present technology will be described.Figure 7 FIG. is a plan view schematically showing the planar configuration of the optical modulator 10-7 according to Embodiment 7 of the first embodiment of the present technology.

[0186] The optical modulator 10-7 has a configuration substantially similar to that of the optical modulator 10-6 according to Embodiment 6, except that a phase shifter 200 is not provided in the ring resonator 100c and a phase shifter 200 is provided in each of the first optical waveguide 100a and the second optical waveguide 100b.

[0187] In the optical modulator 10-7, in each linear waveguide, transverse and longitudinal optical confinement is achieved by the refractive index difference between the Si layer as the core layer and the air surrounding the Si layer. The distance between each linear waveguide and the ring waveguide is set such that the coupling efficiency and coupling length (the length of the bent portion of the ring waveguide that causes the coupling phenomenon) between the linear waveguide and the ring resonator 100c are appropriately set (preferably optimized).

[0188] Note that in the optical modulator 10-7, the phase shifter 200 may be provided only near the output port of at least one of the first optical waveguide 100a and the second optical waveguide 100b.

[0189] <8. Optical Modulator According to Embodiment 8 of the First Embodiment of the Present Technology>

[0190] Hereinafter, the optical modulator 10-8 according to Embodiment 8 of the first embodiment of the present technology will be described. Figure 8 FIG. is a plan view schematically showing the planar configuration of the optical modulator 10-8 according to Embodiment 8 of the first embodiment of the present technology.

[0191] The optical modulator 10-8 has a configuration similar to that of the optical modulator 10-6 according to Embodiment 6, except that it does not include the second optical waveguide 100b.

[0192] In the optical modulator 10-8, the Si fine wire waveguide serving as the linear waveguide achieves transverse and longitudinal optical confinement by the refractive index difference between the Si layer as the core layer and the air surrounding the Si layer. The distance between the linear waveguide and the ring waveguide is set such that the coupling efficiency and coupling length (the length of the bent portion of the ring waveguide that causes the coupling phenomenon) between the linear waveguide and the ring resonator 100c are appropriately set (preferably optimized).

[0193] <9. Optical Modulator According to Embodiment 9 of the First Embodiment of the Present Technology>

[0194] Hereinafter, the optical modulator 10-9 according to Embodiment 9 of the first embodiment of the present technology will be described. Figure 9 FIG. is a plan view schematically showing the planar configuration of the optical modulator 10-9 according to Embodiment 9 of the first embodiment of the present technology.

[0195] The optical modulator 10-9 has a configuration that is substantially similar to that of the optical modulator 10-7 according to Embodiment 7, except that the second optical waveguide 100b is not included.

[0196] In the optical modulator 10-9, the linear waveguide achieves transverse and longitudinal optical confinement through the refractive index difference between the Si layer serving as the core layer and the air surrounding the Si layer. The distance between the linear waveguide and the ring waveguide is set such that the coupling efficiency and coupling length (the length of the bent portion of the ring waveguide that causes the coupling phenomenon) between the linear waveguide and the ring resonator 100c are appropriately set (preferably optimized).

[0197] Note that in the optical modulator 10-9, the phase shifter 200 is provided only at the end portion including the other end 100a2 of the first optical waveguide 100a. However, in addition to this or as an alternative, the phase shifter 200 may be provided at the end portion including the one end 100a1 of the first waveguide 100a and / or at the intermediate portion of the first optical waveguide 100a.

[0198] <10. Light source device according to Embodiment 1 of the second implementation of the present technology>

[0199] Hereinafter, the light source device according to Embodiment 1 of the second implementation of the present technology will be described. Figure 10 is a diagram schematically showing the planar configuration of the light source device 5-1 according to Embodiment 1 of the second implementation of the present technology.

[0200] The light source device 5-1 includes an optical amplifier 300 and an optical modulator 20-1, and the light from the optical amplifier 300 is incident on the optical modulator.

[0201] The optical modulator 20-1 includes first to third optical waveguides 100a, 100b, and 100d and first and second ring resonators 100c1 and 100c2. The first to third optical waveguides 100a, 100b, and 100d are linear waveguides (e.g., Si fine wire waveguides). Here, at least one linear waveguide and / or at least one ring waveguide is a photonic crystal waveguide PCW having a photonic crystal structure PCS (refer to Figures 36 - 38 ).

[0202] The first ring resonator 100c1 is optically coupled to the first optical waveguide 100a and the second optical waveguide 100b. Here, the first optical waveguide 100a and the second optical waveguide 100b arranged in parallel sandwich the first ring resonator 100c1 in the in-plane direction (e.g., the radial direction). The first resonator device 100A includes the first optical waveguide 100a, the second optical waveguide 100b, and the first ring resonator 100c1. Note that at least one of the first optical waveguide 100a and the second optical waveguide 100b can be separated from the first ring resonator 100c1 in an optically couplable manner.

[0203] The second ring resonator 100c2 is optically coupled to the second optical waveguide 100b and the third optical waveguide 100d. Here, the second optical waveguide 100b and the third optical waveguide 100d arranged in parallel sandwich the second ring resonator 100c2 in the in-plane direction (e.g., the radial direction). The second resonator device 100B includes the second optical waveguide 100b, the third optical waveguide 100d, and the second ring resonator 100c2. The second ring resonator 100c2 is disposed at a position offset from the first ring resonator 100c1 in the direction in which each linear waveguide extends. Note that at least one of the second optical waveguide 100b and the third optical waveguide 100d can be separated from the second ring resonator 100c2 in an optically couplable manner.

[0204] The first ring resonator 100c1 and the second ring resonator 100c2 can have the same resonance wavelength or different resonance wavelengths. Phase shifters 200 are provided in each of the first ring resonator 100c1 and the second ring resonator 100c2.

[0205] In the optical modulator 20-1, a Sagnac loop (the part enclosed by the dashed line in Figure 10 is provided as a mirror at the end portion including the other end 100a2 of the first optical waveguide 100a. Note that as the mirror, other mirror elements such as a distributed Bragg reflector can be provided instead of the Sagnac loop.

[0206] As the optical amplifier 300, for example, a reflective semiconductor optical amplifier (RSOA), a distributed feedback (DFB) laser, a surface-emitting laser, an end-face-emitting laser, etc. can be used.

[0207] The end portion including one end 100d1 of the third optical waveguide 100d is connected to the optical amplifier 300.

[0208] The second ring resonator 100c2 is optically coupled to a portion between one end 100d1 and the other end 100d2 of the third optical waveguide 100d. The phase shifter 200 is disposed at a position between the optical amplifier 300 in the third optical waveguide 100d and the optical coupling portion between the third optical waveguide 100d and the second ring resonator 100c2.

[0209] In the light source device 5-1, the light output from the optical amplifier 300 to the third optical waveguide 100d can be wavelength-modulated and output from at least one of one end 100a1 of the first optical waveguide 100a, one end 100b1 and the other end 100b2 of the second optical waveguide 100b, and the other end 100d2 of the third optical waveguide 100d via at least the second ring resonator 100c2 among the first ring resonator 100c1 and the second ring resonator 100c2. At this time, it is preferable to synchronously control the phase shifter 200 provided in the third optical waveguide 100d and the phase shifters provided in each of the first ring resonator 100c1 and the second ring resonator 100c2. Thereby, continuous wavelength modulation without mode hopping can be performed.

[0210] In the light source device 5-1, a reduction effect of the spectral line width can be obtained by the vernier effect of the first ring resonator 100c1 and the second ring resonator 100c2.

[0211] <11. Light source device according to Embodiment 2 of the second embodiment of the present technology>

[0212] Hereinafter, the light source device according to Embodiment 2 of the second embodiment of the present technology will be described. Figure 11 is a diagram schematically showing a planar configuration of a light source device 5-2 according to Embodiment 2 of the second embodiment of the present technology.

[0213] The light source device 5-2 has a configuration similar to that of the light source device 5-1 according to Embodiment 1, except that the phase shifter 200 is not provided in the first ring resonator 100c1 of the optical modulator 20-2.

[0214] <12. Light source device according to Embodiment 3 of the second embodiment of the present technology>

[0215] Hereinafter, the light source device according to Embodiment 3 of the second embodiment of the present technology will be described. Figure 12 is a diagram schematically showing a planar configuration of a light source device 5-3 according to Embodiment 3 of the second embodiment of the present technology.

[0216] The light source device 5-3 has a configuration similar to that of the light source device 5-2 according to Embodiment 2, except that the phase shifter 200 is not provided in the third optical waveguide 100d of the optical modulator 20-3.

[0217] <13. Light source device according to Embodiment 4 of the second embodiment of the present technology>

[0218] Hereinafter, a light source device according to Embodiment 4 of the second embodiment of the present technology will be described. Figure 13 is a diagram schematically showing a planar configuration of a light source device 5-4 according to Embodiment 5 of the second embodiment of the present technology.

[0219] The light source device 5-4 includes an optical amplifier 300 and an optical modulator 20-4, and light from the optical amplifier 300 is incident on the optical modulator.

[0220] The optical modulator 20-4 includes a first optical waveguide 100a and a second optical waveguide 100b, and a first ring resonator 100c1 and a second ring resonator 100c2.

[0221] The first optical waveguide 100a includes a connection portion J and three waveguide portions WG1, WG2, and WG3 connected via the connection portion J (branch portion or combining portion). In the waveguide portion WG3, one end (end portion 100a3 of the first optical waveguide 100a) is connected to the optical amplifier 300, and the other end is connected to the two waveguide portions WG1 and WG2 at the connection portion J, and a phase shifter 200 is provided in a portion between the one end and the other end. One end of the waveguide portion WG1 is connected to the waveguide portion WG3 at the connection portion J. One end of the waveguide portion WG2 is connected to the waveguide portion WG3 at the connection portion J. Each waveguide portion is a linear waveguide portion (e.g., Si fine wire waveguide). Here, the connection portion J serves as a branch portion that branches the light output from the optical amplifier 300 and guides it into the two waveguide portions WG1 and WG2 by the waveguide portion WG3.

[0222] In the optical modulator 20-4, the second optical waveguide 100b is a linear waveguide (e.g., Si fine wire waveguide).

[0223] In the optical modulator 20-4, at least one linear waveguide and / or at least one ring waveguide is a photonic crystal waveguide PCW having a photonic crystal structure PCS (see Figures 36 - 38 ).

[0224] The first ring resonator 100c1 is sandwiched in the in-plane direction between the waveguide portion WG1 and the second optical waveguide 100b. The first resonator device 100A includes the waveguide portion WG1, the second optical waveguide 100b, and the first ring resonator 100c1. At least one of the waveguide portion WG1 and the second optical waveguide 100b can be optically coupled to and separated from the first ring resonator 100c1.

[0225] The second ring resonator 100c2 is sandwiched between the waveguide section WG2 and the second optical waveguide 100b in the in-plane direction. The second resonator device 100B includes the waveguide section WG2, the second optical waveguide 100b, and the second ring resonator 100c2. At least one of the waveguide section WG2 and the second optical waveguide 100b can be optically coupled and separated from the second ring resonator 100c2.

[0226] In the optical modulator 20-4, the resonance wavelengths of the first ring resonator 100c1 and the second ring resonator 100c2 can be the same or different.

[0227] As the optical amplifier 300, for example, a reflective semiconductor optical amplifier (RSOA), a distributed feedback (DFB) laser, a vertical cavity surface emitting laser (VCSEL), an edge emitting laser, etc. can be used.

[0228] In the light source device 5-4, the light output from the optical amplifier 300 and guided through the waveguide section WG3 can be wavelength-modulated and output from at least one of the other end of the waveguide section WG1 (one end 100a1 of the first optical waveguide 100a), the other end of the waveguide section WG2 (the other end 100a2 of the first optical waveguide 100a), and one end 100b1 and the other end 100b2 of the second optical waveguide 100b. At this time, it is preferable to synchronously control the phase shifter 200 provided in the waveguide section WG3 and the phase shifters provided in each of the first ring resonator 100c1 and the second ring resonator 100c2. Thereby, continuous wavelength modulation without mode hopping can be performed.

[0229] In the light source device 5-4, a reduction effect of the spectral linewidth can be obtained by the Vernier effect of the first ring resonator 100c1 and the second ring resonator 100c2.

[0230] <14. Light source device according to Embodiment 5 of the second embodiment of the present technology>

[0231] Hereinafter, a light source device according to Embodiment 5 of the second embodiment of the present technology will be described. Figure 14 is a diagram schematically showing the planar configuration of the light source device 5-5 according to Embodiment 5 of the second embodiment of the present technology.

[0232] The light source device 5-5 has a configuration similar to that of the light source device 5-4 according to Embodiment 4, except that the phase shifter 200 is not provided in the second ring resonator 100c2 of the optical modulator 20-5.

[0233] <15. Light source device according to Embodiment 6 of the second embodiment of the present technology>

[0234] In the following, a light source device according to Embodiment 6 of the second embodiment of the present technology will be described. Figure 15 FIG. is a plan view schematically showing the planar configuration of a light source device 5-6 according to Embodiment 6 of the second embodiment of the present technology.

[0235] The light source device 5-6 has a configuration similar to that of the light source device 5-4 according to Embodiment 4, except that the phase shifter 200 is not provided in the waveguide portion WG3 of the optical modulator 20-6 and the second ring resonator 100c2.

[0236] <16. Light source device according to Embodiment 7 of the second embodiment of the present technology>

[0237] In the following, a light source device according to Embodiment 7 of the second embodiment of the present technology will be described. Figure 16 FIG. is a plan view schematically showing the planar configuration of a light source device 5-7 according to Embodiment 7 of the second embodiment of the present technology.

[0238] The light source device 5-7 includes an optical amplifier 300 and an optical modulator 20-7, and the light from the optical amplifier 300 is incident on the optical modulator.

[0239] The optical modulator 20-7 includes first to third optical waveguides 100a, 100b, and 100c and first to third ring resonators 100c1, 100c2, and 100c3.

[0240] The first optical waveguide 100a includes three waveguide portions WG1, WG2, and WG3 connected via a connection portion J (branch portion or synthesis portion). In the waveguide portion WG3, one end (the end portion 100a3 of the first optical waveguide 100a) is connected to the optical amplifier 300, and the other end is connected to the waveguide portions WG1 and WG2 at the connection portion J, and the phase shifter 200 is provided in a portion between the one end and the other end. One end of the waveguide portion WG1 is connected to the waveguide portion WG3 at the connection portion J. One end of the waveguide portion WG2 is connected to the waveguide portion WG3 at the connection portion J. Each waveguide portion is a linear waveguide portion (e.g., Si thin wire waveguide). Here, the connection portion J serves as a branch portion that branches the light output from the optical amplifier 300 and guides it into the two waveguide portions WG1 and WG2 by the waveguide portion WG3.

[0241] Each of the second optical waveguide 100b and the third optical waveguide 100d is a linear waveguide (e.g., Si thin wire waveguide).

[0242] In the optical modulator 20-7, at least one linear waveguide and / or at least one ring waveguide is a photonic crystal waveguide PCW having a photonic crystal structure PCS (refer to Figures 36 - 38 ).

[0243] For example, the first ring resonator 100c1 is sandwiched in the in-plane direction between a waveguide section WG1 configured to form an acute angle and a second optical waveguide 100b. The first resonator device 100A includes the waveguide section WG1, the second optical waveguide 100b, and the first ring resonator 100c1. At least one of the waveguide section WG1 and the second optical waveguide 100b can be optically coupled and separated from the first ring resonator 100c1.

[0244] For example, the second ring resonator 100c2 is sandwiched in the in-plane direction between a waveguide section WG2 configured to form an acute angle and a third optical waveguide 100d. The second resonator device 100B includes the waveguide section WG2, the third optical waveguide 100d, and the second ring resonator 100c2. At least one of the waveguide section WG2 and the third optical waveguide 100d can be optically coupled and separated from the second ring resonator 100c2.

[0245] For example, the third ring resonator 100c3 is sandwiched in the in-plane direction between the second optical waveguide 100b and the third optical waveguide 100d configured to form an acute angle. The third resonator device 100C includes the second optical waveguide 100b, the third optical waveguide 100d, and the third ring resonator 100c3. At least one of the second optical waveguide 100b and the third optical waveguide 100d can be optically coupled and separated from the third ring resonator 100c3.

[0246] In the optical modulator 20-7, the resonance wavelengths of at least two of the first to third ring resonators 100c1, 100c2, and 100c3 can be the same or different.

[0247] As the optical amplifier 300, for example, a reflective semiconductor optical amplifier (RSOA), a distributed feedback (DFB) laser, a vertical cavity surface emitting laser (VCSEL), an edge emitting laser, etc. can be used.

[0248] In the light source device 5-7, the light output from the optical amplifier 300 and guided through the waveguide section WG3 can be wavelength-modulated and output from at least one of the first to third ring resonators 100c1, 100c2, and 100c3 and at least one of the first ring resonator 100c1 and the second ring resonator 100c2 from at least one of the other end of the waveguide section WG1 (one end 100a1 of the first optical waveguide 100a), the other end of the waveguide section WG2 (the other end 100a2 of the first optical waveguide 100a), one end 100b1 and the other end 100b2 of the second optical waveguide 100b, and one end 100d1 and the other end 1000d2 of the third optical waveguide 100d. At this time, it is preferable to synchronously control the phase shifter 200 provided in the waveguide section WG3 and the phase shifters provided in each of the first to third ring resonators 100c1, 100c2, and 100c3. Thereby, continuous wavelength modulation without mode hopping can be performed.

[0249] In the light source device 5-7, the reduction effect of the spectral line width can be obtained by the Vernier effect of the first to third ring resonators 100c1, 100c2, and 100c3.

[0250] <17. Light source device according to Embodiment 8 of the second embodiment of the present technology>

[0251] Hereinafter, the light source device according to Embodiment 8 of the second embodiment of the present technology will be described. Figure 17 is a diagram schematically showing the planar configuration of the light source device 5-8 according to Embodiment 8 of the second embodiment of the present technology.

[0252] The light source device 5-8 has a configuration similar to that of the light source device 5-7 according to Embodiment 7, except that the phase shifter 200 is not provided in the third ring resonator 100c3 of the optical modulator 20-8.

[0253] <18. Light source device according to Embodiment 9 of the second embodiment of the present technology>

[0254] Hereinafter, the light source device according to Embodiment 9 of the second embodiment of the present technology will be described. Figure 18 is a diagram schematically showing the planar configuration of the light source device 5-9 according to Embodiment 9 of the second embodiment of the present technology.

[0255] The light source device 5-9 has a configuration similar to that of the light source device 5-7 according to Embodiment 7, except that the phase shifters 200 are not provided in the first ring resonator 100c1 and the second ring resonator 100c2 of the optical modulator 20-9.

[0256] <19. Light source device according to Embodiment 10 of the second embodiment of the present technology>

[0257] In the following, a light source device according to Embodiment 10 of the second embodiment of the present technology will be described. Figure 19 FIG. is a diagram schematically showing a planar configuration of a light source device 5-10 according to Embodiment 10 of the second embodiment of the present technology.

[0258] The light source device 5-10 includes an optical amplifier 400 and an optical modulator 20-10, and light from the optical amplifier 400 is incident on the optical modulator.

[0259] As the optical amplifier 400, for example, a transmissive semiconductor optical amplifier (SOA), an end-face emitting laser, or the like can be used.

[0260] The optical modulator 20-10 includes first to third optical waveguides 100a, 100b, and 100d, and first and second ring resonators 100c1 and 100c2. The first to third optical waveguides 100a, 100b, and 100d are linear waveguides (e.g., Si fine wire waveguides). Here, at least one linear waveguide and / or at least one ring waveguide is a photonic crystal waveguide PCW having a photonic crystal structure PCS (see Figures 36 - 38 ).

[0261] One end 100a1 of the first optical waveguide 100a is connected to the output port of the optical amplifier 400. One end 100b1 of the second optical waveguide 100b is connected to another output port of the optical amplifier 400. A phase shifter 200 is provided in the third optical waveguide 100d.

[0262] The first ring resonator 100c1 is optically coupled to the first optical waveguide 100a and the third optical waveguide 100d. Here, the first optical waveguide 100a and the third optical waveguide 100d sandwich the first ring resonator 100c1 in the in-plane direction. The first resonator device 100A includes the first optical waveguide 100a, the third optical waveguide 100d, and the first ring resonator 100c1. Note that at least one of the first optical waveguide 100a and the third optical waveguide 100d can be optically coupled to the first ring resonator 100c1 and separated from each other.

[0263] The second ring resonator 100c2 is optically coupled to the second optical waveguide 100b and the third optical waveguide 100d. Here, the second optical waveguide 100b and the third optical waveguide 100d sandwich the second ring resonator 100c2 in the in-plane direction. The second resonator device 100B includes the second optical waveguide 100b, the third optical waveguide 100d, and the second ring resonator 100c2. Note that at least one of the second optical waveguide 100b and the third optical waveguide 100d can be optically coupled to the second ring resonator 100c2 and separated from each other.

[0264] The first ring resonator 100c1 and the second ring resonator 100c2 may have the same resonance wavelength or different resonance wavelengths. The phase shifter 200 is disposed in each of the first ring resonator 100c1 and the second ring resonator 100c2.

[0265] In the light source device 5-10, the light output from the optical amplifier 400 to each of the first optical waveguide 100a and the second optical waveguide 100b can be wavelength-modulated and output from at least one of the other end 100a2 of the first optical waveguide 100a, the other end 100b2 of the second optical waveguide 100b, and at least one of the one end 100d1 and the other end 100d2 of the third optical waveguide 100d via at least one of the first ring resonator 100c1 and the second ring resonator 100c2. At this time, it is preferable to synchronously control the phase shifter 200 disposed in each of the first ring resonator 100c1 and the second ring resonator 100c2 and the phase shifter 200 disposed in the third optical waveguide 100d. Thereby, continuous wavelength modulation without mode hopping can be performed.

[0266] In the light source device 5-10, the reduction effect of the spectral linewidth can be obtained by the Vernier effect of the first ring resonator 100c1 and the second ring resonator 100c2.

[0267] <20. Light source device according to Embodiment 11 of the second embodiment of the present technology>

[0268] Hereinafter, the light source device according to Embodiment 11 of the second embodiment of the present technology will be described. Figure 20 is a diagram schematically showing the planar configuration of the light source device 5-11 according to Embodiment 11 of the second embodiment of the present technology.

[0269] The light source device 5-11 includes a first optical amplifier 400A and a second optical amplifier 400B and an optical modulator 20-11, and the light from each of the first optical amplifier 400A and the second optical amplifier 400B is incident on the optical modulator.

[0270] As each of the first optical amplifier 400A and the second optical amplifier 400B, for example, a transmissive semiconductor optical amplifier (SOA), a surface-emitting laser, etc. can be used.

[0271] The optical modulator 20-11 includes first to fifth optical waveguides 100a, 100b, 100d, 100e, and 100f, and first to second ring resonators 100c1, 100c2, and 100c. The first to fifth optical waveguides 100a, 100b, 100d, 100e, and 100f are linear waveguides (e.g., Si fine wire waveguides). Here, at least one linear waveguide and / or at least one ring waveguide is a photonic crystal waveguide PCW having a photonic crystal structure PCS (refer to Figures 36 - 38 ).

[0272] One end 100a1 of the first optical waveguide 100a is connected to the output port of the first optical amplifier 400A. One end 100b1 of the second optical waveguide 100b is connected to another output port of the first optical amplifier 400A. One end 100d1 of the third optical waveguide 100d is connected to the output port of the second optical amplifier 400B. One end 100e1 of the fourth optical waveguide 100e is connected to another output port of the second optical amplifier 400B. The phase shifter 200 is disposed in the fifth optical waveguide 100f.

[0273] The first ring resonator 100c1 is optically coupled to the first optical waveguide 100a and the fifth optical waveguide 100f. Here, for example, the first optical waveguide 100a and the fifth optical waveguide 100f configured to form an acute angle sandwich the first ring resonator 100c1 in the in-plane direction. The first resonator device 100A includes the first optical waveguide 100a, the fifth optical waveguide 100f, and the first ring resonator 100c1. Note that at least one of the first optical waveguide 100a and the fifth optical waveguide 100f may be optically coupled to the first ring resonator 100c1 and separable from each other.

[0274] The second ring resonator 100c2 is optically coupled to the second optical waveguide 100b and the third optical waveguide 100d. Here, for example, the second optical waveguide 100b and the third optical waveguide 100d configured to form an acute angle sandwich the second ring resonator 100c2 in the in-plane direction. The second resonator device 100B includes the second optical waveguide 100b, the third optical waveguide 100d, and the second ring resonator 100c2. Note that at least one of the second optical waveguide 100b and the third optical waveguide 100d may be optically coupled to the second ring resonator 100c2 and separable from each other.

[0275] The third ring resonator 100c3 is optically coupled to the fourth optical waveguide 100e and the fifth optical waveguide 100f. Here, for example, the fourth optical waveguide 100e and the fifth optical waveguide 100f configured to form an acute angle sandwich the third ring resonator 100c3 in the in-plane direction. The third resonator device 100C includes the fourth optical waveguide 100e, the fifth optical waveguide 100f, and the third ring resonator 100c3. Note that at least one of the fourth optical waveguide 100e and the fifth optical waveguide 100f can be optically coupled to the third ring resonator 100c3 and separated from each other.

[0276] At least two of the first to third ring resonators 100c1, 100c2, and 100c3 may have the same resonance wavelength or different resonance wavelengths. The phase shifter 200 is provided in the second ring resonator 100c2.

[0277] In the light source device 5-10, the light output from the first optical amplifier 400A to each of the first optical waveguide 100a and the second optical waveguide 100b and the light output from the second optical amplifier 400B to each of the third optical waveguide 100d and the fourth optical waveguide 100e can be wavelength-modulated and output from at least one of the other end 100a2 of the first optical waveguide 100a, the other end 100b2 of the second optical waveguide 100b, the other end 1000d2 of the third optical waveguide 100d, the other end 100e2 of the fourth optical waveguide 100e, and the one end 100f1 and the other end 100f2 of the fifth optical waveguide 100f via at least one of the first to third ring resonators 100c1, 100c2, and 100c3. At this time, it is preferable to synchronously control the phase shifter 200 provided in the second ring resonator 100c2 and the phase shifter 200 provided in the fifth optical waveguide 100f. Thereby, continuous wavelength modulation without mode hopping can be performed.

[0278] In the light source device 5-11, a reduction effect of the spectral linewidth can be obtained by the Vernier effect of the first to third ring resonators 100c1, 100c2, and 100c3.

[0279] <21. Light source device according to Embodiment 12 of the second embodiment of the present technology>

[0280] Hereinafter, a light source device according to Embodiment 12 of the second embodiment of the present technology will be described. Figure 21 is a diagram schematically showing the planar configuration of the light source device 5-12 according to Embodiment 12 of the second embodiment of the present technology. Figure 22 is a diagram showing a configuration example of a Mach-Zehnder modulator.

[0281] In addition to providing a Mach-Zehnder modulator 500 (MZM) in the first optical waveguide 100a of the optical modulator 20-12, the light source device 5-12 has a configuration similar to that of the light source device 5-1 according to Embodiment 1 (see Figure 10 ).

[0282] Here, the Mach-Zehnder modulator 500 is provided at a position between the optical coupling portion between the first ring resonator 100c1 in the first optical waveguide 100a and the first optical waveguide 100a and the Sagnac loop.

[0283] By applying a predetermined RF signal to the phase shifter included in the Mach-Zehnder modulator 500, continuous wavelength modulation without mode hopping can be performed at a higher speed and stably.

[0284] Note that instead of or in addition to the first optical waveguide 100a, the Mach-Zehnder modulator 500 may be provided in at least one of the second optical waveguide 100b and the third optical waveguide 100d.

[0285] Configuration examples of the Mach-Zehnder modulator 500 include Figure 22 the configurations (i) to (iii) shown.

[0286] (i) A configuration in which incident light is branched into two optical waveguides LWG provided with phase shifters PS (pn junctions), and after a phase difference is imparted, the light is combined (incidentally, by applying a bias voltage to the pn junction of the phase shifter PS provided in each optical waveguide LWG, the refractive index of the optical waveguide LWG is changed to change the phase of the light).

[0287] (ii) A configuration obtained by connecting in parallel the configuration in which the optical waveguide LWG provided with the phase shifter PS and the configuration of (i) are connected in series with the configuration of (i).

[0288] (iii) A configuration obtained by directly connecting the configuration in which the optical waveguide LWG provided with the phase shifter PS and the configuration of (i) are connected in parallel with the configuration in which the phase shifter PS is provided only in one optical waveguide LWG in the configuration of (i).

[0289] <Light source device according to Embodiment 13 of the second implementation of the present technology>

[0290] Hereinafter, the light source device according to Embodiment 13 of the second implementation of the present technology will be described. Figure 23 is a diagram schematically showing the planar configuration of the light source device 5-13 according to Embodiment 13 of the second implementation of the present technology.

[0291] In addition to providing the Mach-Zehnder modulator 500 (MZM) in the waveguide section WG3 of the optical modulator 20-13, the light source device 5-13 has a configuration similar to that of the light source device 5-5 according to Embodiment 5 (refer to Figure 14 ).

[0292] In the light source device 5-13, by applying a predetermined RF signal to the phase shifter included in the Mach-Zehnder modulator 500, continuous wavelength modulation without mode hopping can be performed at a higher speed and stably.

[0293] Note that instead of or in addition to the waveguide section WG3, the Mach-Zehnder modulator 500 may be provided in at least one of the waveguide sections WG1 and WG2.

[0294] <23. Light source device according to Embodiment 14 of the second implementation of the present technology>

[0295] Hereinafter, the light source device according to Embodiment 14 of the second implementation of the present technology will be described. Figure 24 is a diagram schematically showing the planar configuration of the light source device 5-14 according to Embodiment 14 of the second implementation of the present technology.

[0296] In addition to providing the Mach-Zehnder modulator 500 (MZM) in the second optical waveguide 100b of the optical modulator 20-14, the light source device 5-14 has a configuration similar to that of the light source device 5-5 according to Embodiment 5 (refer to Figure 14 ).

[0297] Here, the Mach-Zehnder modulator 500 is provided at a position between the optical coupling portion between the first ring resonator 100c1 in the second optical waveguide 100b and the second optical waveguide 100b and the optical coupling portion between the second ring resonator 100c2 and the second optical waveguide 100b.

[0298] In the light source device 5-14, by applying a predetermined RF signal to the phase shifter included in the Mach-Zehnder modulator 500, continuous wavelength modulation without mode hopping can be performed at a higher speed and stably.

[0299] <24. Light source device according to Embodiment 15 of the second implementation of the present technology>

[0300] Hereinafter, the light source device according to Embodiment 15 of the second implementation of the present technology will be described. Figure 25 is a diagram schematically showing the planar configuration of the light source device 5-15 according to Embodiment 15 of the second implementation of the present technology.

[0301] In addition to providing a Mach-Zehnder modulator 500 (MZM) in the third optical waveguide 100d of the optical modulator 20-15, the light source device 5-15 has a configuration similar to that of the light source device 5-10 according to Embodiment 10 (refer to Figure 19 ).

[0302] Here, the Mach-Zehnder modulator 500 is provided at a position between the optical coupling portion between the first ring resonator 100c1 and the third optical waveguide 100d in the third optical waveguide 100d and the optical coupling portion between the second ring resonator 100c2 and the third optical waveguide 100d.

[0303] In the light source device 5-15, by applying a predetermined RF signal to the phase shifter included in the Mach-Zehnder modulator 500, continuous wavelength modulation without mode hopping can be performed at a higher speed and stably.

[0304] Note that instead of or in addition to the third optical waveguide 100d, the Mach-Zehnder modulator 500 may be provided in at least one of the first optical waveguide 100a and the second optical waveguide 100b.

[0305] <Light source device according to Embodiment 16 of the second implementation of the present technology>

[0306] Hereinafter, the light source device according to Embodiment 16 of the second implementation of the present technology will be described. Figure 26 is a diagram schematically showing a planar configuration of a light source device 5-16 according to Embodiment 16 of the second implementation of the present technology.

[0307] In addition to providing a Mach-Zehnder modulator 500 (MZM) in the fifth optical waveguide 100b of the optical modulator 20-16, the light source device 5-16 has a configuration similar to that of the light source device 5-11 according to Embodiment 11 (refer to Figure 20 ).

[0308] Here, the Mach-Zehnder modulator 500 is provided at a position between the optical coupling portion between the first ring resonator 100c1 and the fifth optical waveguide 100f in the fifth optical waveguide 100f and the optical coupling portion between the third ring resonator 100c3 and the fifth optical waveguide 100f.

[0309] In the light source device 5-16, by applying a predetermined RF signal to the phase shifter included in the Mach-Zehnder modulator 500, continuous wavelength modulation without mode hopping can be performed at a higher speed and stably.

[0310] Note that, instead of or in addition to the fifth optical waveguide 100f, the Mach-Zehnder modulator 500 may be provided in at least one of the first to fourth optical waveguides 100a, 100b, 100d, and 100e.

[0311] <26. Light source device according to Embodiment 17 of the second embodiment of the present technology>

[0312] Hereinafter, a light source device according to Embodiment 17 of the second embodiment of the present technology will be described. Figure 27 is a diagram schematically showing a planar configuration of a light source device 5-17 according to Embodiment 17 of the second embodiment of the present technology.

[0313] Except that the optical modulator 20-17 does not have the second optical waveguide 100b and the first ring resonator 100c1 and the second ring resonator 100c2 form a dual-ring resonator (composite resonator), the light source device 5-17 has a configuration similar to that of the light source device 5-2 according to Embodiment 2 (refer to Figure 11 )

[0314] In the optical modulator 20-17, the first ring resonator 100c1 and the second ring resonator 100c2 are directly or connected in parallel. In the optical modulator 20-17, the resonator device 100 includes a dual-ring resonator (the first ring resonator 100c1 and the second ring resonator 100c2) and the first optical waveguide 100a and the third optical waveguide 100d.

[0315] Note that three or more ring resonators may be connected in series or in parallel to form a composite resonator.

[0316] <27. Distance measuring device according to the third embodiment of the present technology>

[0317] Hereinafter, a distance measuring device according to the third embodiment of the present technology will be described. Figure 28 is a block diagram showing a configuration example of a distance measuring device 30 according to the third embodiment of the present technology.

[0318] The distance measuring device 30 is a frequency modulated continuous wave (FMCW) type lidar (LiDAR). In the FMCW LiDAR, a laser (transmission signal) modulated so that the frequency linearly increases with time is continuously emitted, and the distance is obtained from the frequency difference between the transmission signal and the reflected light (return signal).

[0319] For example, as Figure 28 shown, the distance measuring device 30 includes an upper die 2000 and a lower die 3000. The upper die 2000 and the lower die 3000 are actually stacked on top of each other and electrically connected to each other.

[0320] (Upper die 2000)

[0321] The upper die 2000 includes a laser 210, a modulator 220 (optical modulator), a splitter 230, a circulator 240, an antenna 250, a coupler 260, and a detector 270. In the upper die 2000, the modulator 220, the splitter 230, the circulator 240, the antenna 250, the coupler 260, and the detector 270 are formed within a photonic integrated circuit (PIC) substrate.

[0322] The laser 210 is a light source chip that generates an optical signal. The laser 210 is, for example, a chip-shaped edge-emitting semiconductor laser (edge-emitting laser), and emits a laser beam L having a predetermined fixed wavelength (e.g., 1550 nm) from the end face of the active layer under the control of the controller 310.

[0323] The laser beam L emitted from the laser 210 enters the optical waveguide LWG1. The laser beam L propagating in the optical waveguide LWG1 is input to the modulator 220.

[0324] As the modulator 220, for example, the optical modulators 10-1 to 10-9 according to Examples 1 to 9 of the first embodiment and the optical modulators 20-1 to 20-17 of the light source devices 5-1 to 5-17 according to Examples 1 to 17 of the second embodiment can be used.

[0325] The modulator 220 frequency-modulates the laser beam L under the control of the controller 310. For example, the modulator 220 modulates the laser beam L such that the frequency linearly increases over time, and then modulates the laser beam L such that the frequency linearly decreases over time. For example, the modulator 220 periodically repeats this linear increase and decrease in frequency, and outputs the resulting transmission signal Stx to the splitter 230 via the optical waveguide LWG1. The transmission signal Stx is a chirp signal obtained by frequency-modulating the laser beam L by the modulator 220.

[0326] The splitter 230 separates the transmission signal Stx into a transmission signal Stx for irradiating the target TG (transmission signal Stx1) and a transmission signal Stx for causing the coupler 260 to interfere with the return signal Srx (transmission signal Stx2). The transmission signal Stx1 has most of the energy of the transmission signal Stx. The transmission signal Stx2 is a reference signal, the amount of whose energy is much smaller than the energy of the transmission signal Stx1, but is sufficient to cause the coupler 260 to interfere with the return signal Srx. The return signal Srx corresponds to a signal whose phase is delayed due to its relationship with the transmission signal Stx1. The return signal Srx is generated by the transmission signal Stx reflected by the target TG.

[0327] The separator 230 is a component with three ports. In the separator 230, the first port and the third port are present in the optical waveguide LWG1. The second port is present in the optical waveguide LWG2. The optical waveguide LWG2 is configured near a portion between the first port and the third port of the optical waveguide LWG1. As a result, the optical signal propagating through the optical waveguide LWG1 leaks into the optical waveguide LWG2. The optical signal leaking from the optical waveguide LWG1 into the optical waveguide LWG2 propagates in the optical waveguide LWG2 as the transmission signal Stx2.

[0328] The circulator 240 is a component with three ports that transmits the transmission signal Stx1 incident from the first port to the third port and transmits the return signal Srx incident from the third port to the second port. In the circulator 240, the optical waveguide LWG1 is connected to the first port, and the optical waveguide LWG2 is connected to the second port. The optical waveguide extending from the antenna 250 is connected to the third port. The function of the circulator 240 is to rectify, for example, the optical signal to be transmitted and the optical signal received from the antenna 250. In the circulator 240, due to the structure of the optical waveguide branches containing Si, in each branch, the signal intensities of the transmission signal and the reception signal are divided by 50% and 50%. By processing this half of the signal, the transmitted light and the received light can be separated.

[0329] The antenna 250 is a non-mechanical scanner without a driving unit. The antenna 250 transmits the transmission signal Stx1 to the target TG via a lens and receives the return signal Srx via the lens.

[0330] The coupler 260 is a component that generates a beat signal Sbt through the interference between the transmission signal Stx2 and the return signal Srx. The frequency of the beat signal Sbt varies according to the frequency difference between the transmission signal Stx2 and the return signal Srx. The frequency difference varies according to the distance from the antenna 250 to the target TG. Therefore, the distance from the antenna 250 to the target TG can be estimated based on the frequency of the beat signal Sbt.

[0331] The detector 270 is a component that extracts the beat signal Sbt from the signal propagated by the coupler 260. The detector 270 includes two GePDs connected in series with each other and a transimpedance amplifier connected to the connection node of the two GePDs. The transimpedance amplifier performs impedance conversion and amplification on the current signal photoelectrically converted by each GePD and outputs the beat signal Sbt as a voltage signal.

[0332] (Lower die 3000)

[0333] For example, as Figure 28 shown, the lower die 3000 includes a controller 310, a DAC 320, an ADC 330, and a fast Fourier transform (FFT) 340.

[0334] For example, the controller 310 generates control signals for controlling the laser 210, the modulator 220, the antenna 250, and the detector 270, and outputs the control signals to the DAC 320. For example, the controller 310 also generates a control signal for controlling the ADC 330 and outputs the control signal to the ADC 330. The DAC 320 performs DA conversion on the control signals input from the controller 310 and outputs the analog control signals to the laser 210, the modulator 220, the antenna 250, and the detector 270. The ADC 330 performs AD conversion on the beat signal Sbt input from the detector 270 and outputs the converted signal to the FFT 340. The FFT 340 performs FFT on the digital beat signal Sbt input from the ADC 330 and derives the frequency of the beat signal Sb based on the power spectral density obtained by the FFT. The FFT 340 outputs information (frequency information) about the derived frequency to the controller 310. The controller 310 outputs the frequency information input from the FFT 340 to the outside according to control from the outside.

[0335] The lower die 3000 has a Si substrate. For example, on the Si substrate, signal processing circuits such as the controller 310, the DAC 320, the ADC 330, and the FFT 340 are formed.

[0336] Note that in the ranging device 30, instead of the light source device including the laser 210 and the modulator 220, a light source device according to each embodiment of the second embodiment can be used.

[0337] On the other hand, a resonator device having an optical waveguide and a ring resonator, and the ring resonator can be applied to, for example, an optical filter incorporated in an optical network because the ring resonator has a function of a filter that allows only light of a specific wavelength to pass through. In addition, a resonator device having an optical waveguide and a ring resonator, and the ring resonator can be expected to be applied to an external resonator of a laser, a biosensor, an optical switch, etc.

[0338] <28. Resonator device according to Embodiment 1 of the fourth embodiment of the present technology>

[0339] Hereinafter, a resonator device according to Embodiment 1 of the fourth embodiment of the present technology will be described. Figure 29 is a diagram schematically showing a planar configuration of a resonator device 40-1 according to Embodiment 1 of the fourth embodiment of the present technology.

[0340] The resonator device 40-1 has a configuration in which the phase shifter 200 is removed from the ring resonator 100c of the optical modulator 10-1 (refer to Figure 1 ) according to Embodiment 1 of the first embodiment. Since the linear waveguide and the ring waveguide are photonic crystal waveguides PCW (refer toFigure 37 ), so that the resonator device 40-1 can implement a 2- to 4-port resonator device with high efficiency (low loss).

[0341] <Resonator device according to Embodiment 2 of the fourth embodiment of the present technology>

[0342] Hereinafter, the resonator device according to Embodiment 2 of the fourth embodiment of the present technology will be described. Figure 30 is a diagram schematically showing the planar configuration of the resonator device 40-2 according to Embodiment 2 of the fourth embodiment of the present technology.

[0343] Except for not including the second optical waveguide 100b, the resonator device 40-2 has a configuration similar to that of the resonator device 40-1 according to Embodiment 1. Since the linear waveguide and the ring waveguide are photonic crystal waveguides PCW (refer to Figure 37 ), so that the resonator device 40-2 can implement a 2-port resonator device with high efficiency (low loss).

[0344] <Resonator device according to Embodiment 3 of the fourth embodiment of the present technology>

[0345] Hereinafter, the resonator device according to Embodiment 3 of the fourth embodiment of the present technology will be described. Figure 31 is a diagram schematically showing the planar configuration of the resonator device 40-3 according to Embodiment 3 of the fourth embodiment of the present technology.

[0346] Except that both the first optical waveguide 100a and the second optical waveguide 100b are linear waveguides that are not photonic crystal waveguides, the resonator device 40-3 has a configuration similar to that of the resonator device 40-1 according to Embodiment 1. In the resonator device 40-3, since the ring waveguide is a photonic crystal waveguide PCW (refer to Figure 37 ), so that a 2- to 4-port resonator device with high efficiency (low loss) can be implemented.

[0347] <Resonator device according to Embodiment 4 of the fourth embodiment of the present technology>

[0348] Hereinafter, the resonator device according to Embodiment 4 of the fourth embodiment of the present technology will be described. Figure 32 is a diagram schematically showing the planar configuration of the resonator device 40-4 according to Embodiment 4 of the fourth embodiment of the present technology.

[0349] Except that the first optical waveguide 100a is a linear waveguide that is not a photonic crystal waveguide, the resonator device 40-4 has a configuration similar to that of the resonator device 40-2 according to Embodiment 2. In the resonator device 40-2, since the ring waveguide is a photonic crystal waveguide PCW (refer to Figure 37), and thus an efficient (low-loss) two-port resonator device can be realized.

[0350] <32. Resonator device according to Embodiment 5 of the fourth embodiment of the present technology>

[0351] Hereinafter, the resonator device according to Embodiment 5 of the fourth embodiment of the present technology will be described. Figure 33 is a diagram schematically showing the planar configuration of the resonator device 40-5 according to Embodiment 5 of the fourth embodiment of the present technology.

[0352] The resonator device 40-5 has a configuration in which the phase shifter 200 is removed from the ring resonator 100c of the optical modulator 10-6 according to Embodiment 6 of the first embodiment (refer to Figure 6 ). In the resonator device 40-5, since the ring waveguide is a photonic crystal waveguide PCW (refer to Figure 37 ), an efficient (low-loss) two- to four-port resonator device can be realized.

[0353] <33. Resonator device according to Embodiment 6 of the fourth embodiment of the present technology>

[0354] Hereinafter, the resonator device according to Embodiment 6 of the fourth embodiment of the present technology will be described. Figure 34 is a diagram schematically showing the planar configuration of the resonator device 40-6 according to Embodiment 6 of the fourth embodiment of the present technology.

[0355] The resonator device 40-6 has a configuration similar to that of the resonator device 40-5 according to Embodiment 5, except that the second optical waveguide 100b is not included. In the resonator device 40-6, since the ring waveguide is a photonic crystal waveguide PCW (refer to Figure 37 ), an efficient (low-loss) two-port resonator device can be realized.

[0356] <34. Ring resonator according to the fifth embodiment of the present technology>

[0357] Hereinafter, the ring resonator according to the fifth embodiment of the present technology will be described. Figure 35 is a diagram schematically showing the planar configuration of the ring resonator 100c according to the fifth embodiment of the present technology.

[0358] The ring resonator 100c according to the fifth embodiment has a configuration in which the first optical waveguide 100a is removed from the resonator device 40-6 according to Embodiment 6 of the fourth embodiment. The ring resonator 100c can realize an efficient (low-loss) ring resonator because the ring waveguide RWG (ring-shaped optical waveguide) is a photonic crystal waveguide PCW having a photonic crystal structure PCS (refer to Figure 37 ).

[0359] <35. Variations of the present technology>

[0360] The present technology is not limited to the above-described embodiments and can be variously modified.

[0361] For example, the optical modulators according to the embodiments of the first embodiment can be provided inside or outside the resonator of a Fabry - Perot laser. As a result, automatic integration with the laser frequency occurs, enabling high - speed and low - power modulation.

[0362] For example, in the light source device according to the embodiments of the second embodiment, the phase shifter 200 can be provided only in the linear waveguide.

[0363] For example, each of the resonator device, optical modulator, light source device, and distance measuring device according to the present technology can include four or more ring resonators.

[0364] For example, each of the light source device and distance measuring device according to the present technology can include three or more optical amplifiers.

[0365] At least two of the configuration of the optical modulator according to the embodiments of the first embodiment, the configuration of the light source device according to the embodiments of the second embodiment, and the configuration of the resonator device according to the embodiments of the fourth embodiment can be combined within a non - conflicting range.

[0366] The materials, conductivity types, thicknesses, widths, lengths, shapes, sizes, arrangements, etc. of the constituent elements of the ring resonator, optical modulator, resonator device, light source device, and distance measuring device can be appropriately changed within the scope of their functions as the ring resonator, optical modulator, resonator device, light source device, and distance measuring device.

[0367] In addition, the present technology can also adopt the following configurations.

[0368] (1) A ring resonator, comprising:

[0369] A ring - shaped optical waveguide, wherein

[0370] The optical waveguide has a photonic crystal structure.

[0371] (2) An optical modulator, comprising:

[0372] An optical waveguide;

[0373] A ring resonator optically coupled to the optical waveguide; and

[0374] A phase shifter provided in the ring resonator and / or the optical waveguide, wherein

[0375] At least the ring resonator among the ring resonator and the optical waveguide has a photonic crystal structure.

[0376] (3) The optical modulator according to (2), wherein the ring resonator and the optical waveguide have a photonic crystal structure.

[0377] (4) The optical modulator according to (2) or (3), wherein only the ring resonator among the ring resonator and the optical waveguide has a photonic crystal structure.

[0378] (5) The optical modulator according to (2) or (3), wherein the phase shifter is disposed in the ring resonator.

[0379] (6) The optical modulator according to any one of (2) to (4), including a plurality of the ring resonators.

[0380] (7) The optical modulator according to (6), wherein the phase shifter is disposed in at least one of the plurality of ring resonators.

[0381] (8) The optical modulator according to (6) or (7), wherein the phase shifter is disposed in a part of the plurality of ring resonators, and the phase shifter is not disposed in other parts of the ring resonators.

[0382] (9) The optical modulator according to any one of (6) to (8), wherein the phase shifter is not disposed in at least one of the plurality of ring resonators.

[0383] (10) The optical modulator according to any one of (2) to (9), including a plurality of the optical waveguides.

[0384] (11) The optical modulation device according to any one of (2) to (10), including a plurality of the ring resonators and a plurality of the optical waveguides, wherein

[0385] each of the plurality of ring resonators is optically coupled to at least two of the plurality of optical waveguides.

[0386] (12) The optical modulator according to any one of (2) to (11), wherein the optical waveguide includes a branching portion or a combining portion.

[0387] (13) The optical modulator according to any one of (2) to (12), wherein an end of the optical waveguide is connected to an optical amplifier.

[0388] (14) The optical modulator according to (13), wherein the phase shifter is disposed at a position between an optical coupling portion between the optical waveguide and the ring resonator of the optical waveguide and the optical amplifier.

[0389] (15) The optical modulator according to any one of (2) to (14), wherein a mirror is disposed at an end of the optical waveguide.

[0390] (16) The optical modulator according to (15), wherein the mirror is a Sagnac loop or a distributed Bragg reflector.

[0391] (17) The optical modulator according to any one of (2) to (16), wherein a Mach-Zehnder modulator is disposed in the optical waveguide.

[0392] (18) The optical modulator according to any one of (2) to (17), wherein in the photonic crystal structure, the pores of the photonic crystal include air gaps or materials having a refractive index different from that of the waveguide portion.

[0393] (19) A light source device, comprising

[0394] an optical amplifier; and

[0395] an optical modulator, light from the optical amplifier is incident on the optical modulator, wherein

[0396] the optical modulator includes:

[0397] an optical waveguide;

[0398] a ring resonator optically coupled to the optical waveguide; and

[0399] a phase shifter disposed in the ring resonator and / or the optical waveguide, and

[0400] at least the ring resonator among the ring resonator and the optical waveguide has a photonic crystal structure.

[0401] (20) A ranging device, comprising:

[0402] an optical amplifier;

[0403] an optical modulator, light from the optical amplifier is incident on the optical modulator; and

[0404] a light receiving unit that receives light reflected by an object via the optical modulator, wherein

[0405] the optical modulator includes:

[0406] an optical waveguide;

[0407] An optical ring resonator coupled to the optical waveguide; and

[0408] A phase shifter disposed in the ring resonator and / or the optical waveguide, and

[0409] At least the ring resonator among the ring resonator and the optical waveguide has a photonic crystal structure.

[0410] (21) A resonator device, comprising:

[0411] An optical waveguide; and

[0412] An optical ring resonator coupled to the optical waveguide, wherein

[0413] At least the ring resonator among the ring resonator and the optical waveguide has a photonic crystal structure.

[0414] List of reference numerals

[0415] 10-1 to 10-9, 20-1 to 20-17 Optical modulators

[0416] 5-1 to 5-17 Light source devices

[0417] 30 Ranging devices

[0418] 40-1 to 40-4 Resonator devices

[0419] 100 Resonator device

[0420] 100A First resonator device (resonator device)

[0421] 100B Second resonator device (resonator device)

[0422] 100C Third resonator device (resonator device)

[0423] 100a First optical waveguide (optical waveguide)

[0424] 100b Second optical waveguide (optical waveguide)

[0425] 100c Ring resonator

[0426] 100c1 First ring resonator (ring resonator)

[0427] 100c2 Second ring resonator (ring resonator)

[0428] 100c3 Third ring resonator (ring resonator)

[0429] 100d Third optical waveguide (optical waveguide)

[0430] 100e Fourth optical waveguide (optical waveguide)

[0431] 100f Fifth optical waveguide (optical waveguide

[0432] 200 Phase shifter

[0433] 300 Optical amplifier

[0434] 400 Optical amplifier

[0435] 400A First optical amplifier (optical amplifier)

[0436] 400B Second optical amplifier (optical amplifier)

[0437] 500 Mach-Zehnder modulator

[0438] RWG Ring waveguide (annular optical waveguide)

[0439] PCS Photonic crystal structure

[0440] P Pores of the photonic crystal

Claims

1. A ring resonator, comprising: a ring-shaped optical waveguide, wherein the optical waveguide has a photonic crystal structure.

2. An optical modulator, comprising: an optical waveguide; a ring resonator optically coupled to the optical waveguide; and a phase shifter disposed in the ring resonator and / or the optical waveguide, wherein at least the ring resonator among the ring resonator and the optical waveguide has a photonic crystal structure.

3. The optical modulator according to claim 2, wherein the ring resonator and the optical waveguide have a photonic crystal structure.

4. The optical modulator according to claim 2, wherein only the ring resonator among the ring resonator and the optical waveguide has a photonic crystal structure.

5. The optical modulator according to claim 2, wherein the phase shifter is disposed in the ring resonator.

6. The optical modulator according to claim 2, comprising a plurality of the ring resonators.

7. The optical modulator according to claim 6, wherein the phase shifter is disposed in at least one of the plurality of ring resonators.

8. The optical modulator according to claim 6, wherein the phase shifter is disposed in a part of the plurality of ring resonators, and the phase shifter is not disposed in other parts of the ring resonators.

9. The optical modulator according to claim 6, wherein the phase shifter is not disposed in at least one of the plurality of ring resonators.

10. The optical modulator according to claim 2, comprising a plurality of the optical waveguides.

11. The optical modulation device according to claim 2, comprising a plurality of the ring resonators and a plurality of the optical waveguides, wherein each of the plurality of ring resonators is optically coupled to at least two of the plurality of optical waveguides.

12. The optical modulator according to claim 2, wherein the optical waveguide includes a branch portion or a combining portion.

13. The optical modulator according to claim 2, wherein an end of the optical waveguide is connected to an optical amplifier.

14. The optical modulator according to claim 13, wherein the phase shifter is disposed at a position between an optical coupling portion between the optical waveguide and the ring resonator and the optical amplifier.

15. The optical modulator according to claim 2, wherein a mirror is disposed at an end of the optical waveguide.

16. The optical modulator according to claim 15, wherein the mirror is a Sagnac loop or a distributed Bragg reflector.

17. The optical modulator according to claim 2, wherein a Mach-Zehnder modulator is disposed in the optical waveguide.

18. The optical modulator according to claim 2, wherein in the photonic crystal structure, the pores of the photonic crystal include air gaps or materials having a refractive index different from that of the waveguide portion.

19. A light source device, comprising an optical amplifier ； and an optical modulator, light from the optical amplifier is incident on the optical modulator, wherein the optical modulator comprises: an optical waveguide; a ring resonator optically coupled to the optical waveguide; and a phase shifter disposed in the ring resonator and / or the optical waveguide, and At least the ring resonator among the ring resonator and the optical waveguide has a photonic crystal structure.

20. A ranging device, comprising: an optical amplifier; an optical modulator into which light from the optical amplifier is incident; and an optical receiving unit that receives light reflected by an object via the optical modulator, wherein the optical modulator includes: an optical waveguide; a ring resonator optically coupled to the optical waveguide; and a phase shifter provided in the ring resonator and / or the optical waveguide, and at least the ring resonator among the ring resonator and the optical waveguide has a photonic crystal structure.

21. A resonator device, comprising: an optical waveguide; and a ring resonator optically coupled to the optical waveguide, wherein at least the ring resonator among the ring resonator and the optical waveguide has a photonic crystal structure.

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