WO2022107614A1

WO2022107614A1 - Light deflection device

Info

Publication number: WO2022107614A1
Application number: PCT/JP2021/040744
Authority: WO
Inventors: 二三夫小山; 暁冬顧; ルイシャオリ
Original assignee: 国立大学法人東京工業大学
Priority date: 2020-11-20
Filing date: 2021-11-05
Publication date: 2022-05-27
Also published as: JP2022082100A

Abstract

In a light deflection device 100, a first VCSEL structure 110 is configured to receive coherent incident light 2 at an incident end, perform slow light propagation in a horizontal first direction while performing multiple reflection of the incident light 2 in a vertical direction, and extract emitted light 6 from an emission port 122 in the upper surface thereof. A DOE 130 is provided on the upper side of the first VCSEL structure 110. The DOE 130 diffracts the emitted light 6 of the first VCSEL structure 110 in the first direction.

Description

Light deflection device

The present disclosure relates to an optical deflection device that controls the direction of an optical beam.

Laser radar (LIDAR) mounted on automobiles, drones, robots, etc., 3D scanners mounted on personal computers and smartphones to easily capture the surrounding environment, near-infrared safety monitoring systems, automatic inspection equipment at manufacturing sites, etc. A light deflection device is used.

Light deflection devices are broadly classified into mechanical and non-mechanical ones. As the former, a polygon mirror, a galvano mirror, or a machine using a mechanical drive system by a motor has been put into practical use (Non-Patent Document 1). Mechanical deflection devices have challenges in module size, deflection speed, and reliability.

Examples of the non-mechanical optical deflection device include a MEMS mirror using a micromachine (Non-Patent Document 2), a device using an electro-optical crystal (Non-Patent Document 3), and a device using a photonic crystal laser (Non-Patent Document 4). Those using a phase array antenna (Non-Patent Document 5) have been reported.

In addition, the present inventors have proposed high-resolution beam deflection by sweeping the wavelength of light by using a slow light waveguide composed of a Bragg reflector and using its huge structural dispersion (Patent Documents). 1. Non-patent documents 6, 7).

Japanese Unexamined Patent Publication No. 2013-016591

The conventional non-mechanical optical deflection device has a field of view, in other words, a deflection angle limited to about 10 °, which is not sufficient for some applications, and further expansion is desired.

The present disclosure has been made in such circumstances, and one of the exemplary purposes of that aspect is to provide an optical deflection device with increased deflection angle or increased resolution.

The light deflection device of one aspect of the present disclosure receives coherent incident light at the incident end, causes the incident light to be multiple-reflected in the vertical direction, propagates the slow light in the horizontal first direction, and exits from the outlet on the upper surface thereof. It includes a first VCSEL (vertical resonator surface emitting laser) structure configured to take out emitted light, and a diffractive optical element provided on the upper side of the first VCSEL structure.

It should be noted that an arbitrary combination of the above components or a conversion of the expression of the present invention between methods, devices and the like is also effective as an aspect of the present invention.

According to certain aspects of the present disclosure, the deflection angle can be increased.

It is a perspective view of the light deflection device which concerns on Embodiment 1. FIG. It is a figure explaining the propagation of a slow light mode wave in a light deflection device. 3 (a) and 3 (b) are diagrams illustrating the structure and operation of the DOE. It is a figure explaining the operation of a light deflection device. 5 (a) and 5 (b) are diagrams illustrating sweeping of the beam in a distant field of view with and without DOE. 6 (a) to 6 (d) are views showing a far-field image of the light deflection device. It is a figure which shows the relationship between the number of divisions of a beam by DOE, a deflection angle and a resolution point. It is a perspective view of the light deflection device which concerns on Embodiment 2. FIG. 9 (a) to 9 (d) are views showing a far-field image of the light deflection device of FIG. 7. It is a perspective view of the light deflection device which concerns on Embodiment 3. FIG. 11 (a) and 11 (b) are views showing a far-field image of the light deflection device of FIG. It is a perspective view of the modification of the light deflection device of FIG. It is a perspective view of the light deflection device which concerns on Embodiment 4. FIG. 14 (a) and 14 (b) are views showing a far-field image of the light deflection device of FIG. 13. It is a perspective view of the light deflection device which concerns on Embodiment 5. It is a figure which shows the far-field image of the light deflection device of FIG. 17 (a) to 17 (d) are diagrams showing lidar provided with a light deflection device.

(Outline of Embodiment)
Some exemplary embodiments of the present disclosure will be outlined. This overview simplifies and describes some concepts of one or more embodiments for the purpose of basic understanding of embodiments, as a prelude to the detailed description described below, and is an invention or disclosure. It does not limit the size. Also, this overview is not a comprehensive overview of all possible embodiments and does not limit the essential components of the embodiment. For convenience, "one embodiment" may be used to refer to one embodiment (examples or modifications) or a plurality of embodiments (examples or modifications) disclosed herein.

The light deflection device according to one embodiment receives coherent incident light at the incident end, propagates the incident light in the horizontal first direction while multiple-reflecting the incident light in the vertical direction, and emits light from the outlet on the upper surface thereof. It is provided with a first VCSEL (vertical resonator surface emitting laser) structure configured to take out the light, and a diffractive optical element provided on the upper side of the first VCSEL structure.

From the outlet of the first VCSEL structure, a beam is emitted at an emission angle θ _r based on the relative relationship between the wavelength λ _S of the incident light (seed light) and the resonance wavelength λ _C of the first VCSEL structure, and λ _S. By changing λ C and λ _C relatively, the emission angle θ _r can be changed and the beam can be swept. This beam is diffracted by a diffractive optical element and split into a plurality of beams to be emitted. This makes it possible to increase the deflection angle or increase the resolution.

The two wavelengths preferably satisfy λ _S <λ _C. The return light from the first VCSEL structure through the incident end can be suppressed, and the quality of the beam emitted from the first VCSEL structure can be improved.

In one embodiment, the diffractive optical element may diffract the emitted light of the first VCSEL structure in the first direction. In this case, the emission angle of each of the plurality of beams emitted from the diffractive optical element is represented by θ _r + m · θ _sep (m is 0, -1, +1, -2, +2 ...).

When the sweep range of θ _r is Δθ _r , it is preferable to satisfy 2θ _sep ≦ Δθ _r . In this case, adjacent beams can be continuously swept.

In one embodiment, the diffractive optical element may diffract the emitted light of the first VCSEL structure in a second direction perpendicular to the first direction. In this case, a plurality of beams can be branched and radiated in the second direction, and they can be swept in the first direction, so that the resolution can be increased.

In one embodiment, the diffractive optical element may diffract the emitted light of the first VCSEL structure in the first direction and the second direction perpendicular to the first direction. As a result, the deflection angle can be increased and the resolution can be increased.

In one embodiment, the light deflection device may further comprise a light source comprising a second VCSEL structure coupled in a first direction to the incident end of the first VCSEL structure. The light source may be configured so that the oscillation wavelength can be controlled. The emission angle of the beam can be controlled according to the oscillation wavelength of the light source.

In one embodiment, the first VCSEL structure and the second VCSEL structure may be continuously formed with DBRs (Distributed Bragg Reflectors) and active layers. By integrating the first VCSEL structure and the second VCSEL structure, the optical deflection device can be further reduced in size and cost.

In one embodiment, the light source may be configured with a variable drive current to be injected into the second VCSEL structure. The oscillation wavelength of the light source can be changed according to the drive current, and the emission angle _θr can be controlled.

In one embodiment, a drive current exceeding the oscillation threshold value may be injected into the first VCSEL structure (active operation). As a result, light can be amplified with high efficiency in the first VCSEL structure. The emitted light becomes coherent light with a uniform wavefront, can be imaged in a minute spot, and can be made longer to achieve higher output at the same time.

In one embodiment, the first VCSEL structure may be injected with a drive current equal to or less than the oscillation threshold value (passive operation). Even in this case, the beam can be swept.

At least one of the first VCSEL structure and the second VCSEL structure has an air gap layer, and the thickness of the air gap layer may be variably configured by the micromachine structure. Thereby, the cavity length of the first VCSEL structure or the second VCSEL structure can be changed, λ _C or λ _S can be controlled, and the emission angle θ _r can be controlled.

(Embodiment)
Hereinafter, the present invention will be described with reference to the drawings based on the preferred embodiments. The same or equivalent components, members, and processes shown in the drawings shall be designated by the same reference numerals, and duplicate description thereof will be omitted as appropriate. Further, the embodiment is not limited to the invention, but is an example, and all the features and combinations thereof described in the embodiment are not necessarily essential to the invention.

FIG. 1 is a perspective view of the optical deflection device 100A according to the first embodiment. The light deflection device 100A emits a light beam (emitted light) 6 in the vertical direction, and sweeps the emitted light 6 in the first horizontal direction (x direction in the figure).

The optical deflection device 100A includes a first VCSEL structure 110 and a diffractive optical element (DOE) 130.

The first VCSEL structure 110 is laminated on the substrate 102 in the vertical direction (z direction in the drawing), and includes an upper DBR layer 112, an active layer 114, and a lower DBR layer 116. The first VCSEL structure 110 is configured with the horizontal first direction (x direction in the figure), which is the scanning direction of the beam, as the longitudinal direction. The first VCSEL structure 110 has a unique resonance wavelength λ _C determined by the length of the resonator in the vertical direction. The first VCSEL structure 110 can be characterized by comprising an oxidative stenosis layer 118, the size of the active region being determined according to the width of the oxidative stenosis.

The first VCSEL structure 110 receives coherent incident light (laser light) 2 at an incident port (also referred to as a coupling region) 120 provided on one end side in the first direction (x direction). Inside the first VCSEL structure 110, the laser beam 3 propagates slowly in the first direction while being multiple-reflected in the vertical direction (z direction). Light from the external light source 200 may be coupled to the incident port 120 by using an optical fiber.

An electrode 124 is formed on the surface of the first VCSEL structure 110, and a region surrounded by the electrode 124 serves as an exit port (emission aperture) 122. A part of the slow light mode wave 4 propagating inside the first VCSEL structure 110 is emitted as emitted light 6 from the exit port 122 on the upper surface of the first VCSEL structure 110.

The first VCSEL structure 110 may be inactive and operated as a mere waveguide without supplying a current to the electrode 124 (passive mode). However, in this case, since the laser beam 3 propagates in the x direction while being partially emitted inside the first VCSEL structure 110, the intensity of the emitted light 6 becomes weaker as the distance from the incident port 120 increases.

Preferably, a current exceeding the threshold value may be injected into the electrode 124 to operate the first VCSEL structure 110 in an activated state (active mode). As a result, the intensity distribution of the emitted light 6 becomes substantially constant with respect to the first direction, and the intensity thereof becomes extremely large. Further, the emitted light 6 becomes coherent light having a uniform wavefront, can be imaged in a minute spot, and can be made long to achieve high output at the same time.

The light deflection device 100A emits the emitted light 6 at an emission angle θ _r determined according to the relative relationship between the wavelength λ _S of the incident light 2 and the resonance wavelength λ _C of the first VCSEL structure 110.

FIG. 2 is a diagram illustrating the propagation of the slow light mode wave 4 in the light deflection device 100A. Consider the slow light mode wave 4 pointing to the right. The incident light 2 having the wavelength λ _S propagates in the slow light to the right while being multiple-reflected in the vertical direction in the first VCSEL structure 110. The wave vector k of the light 3 that is multiple-reflected in the vertical direction is represented by the equation (1). n is the refractive index.
k = 2πn / λ _S ... (1)

Further, when the resonance wavelength (also referred to as cutoff wavelength) stable in the vertical direction (z direction) of the first VCSEL structure 110 is λ _C , the wave vector kc with respect to the resonance wavelength λ _C is expressed by the equation (2). Will be done.
kc = 2πn / λ _C ... (2)

For the slow light mode wave 4, the slow light propagation constant β _SL corresponding to the wave vector can be conceived, and it is expressed by the equation (3) using the effective refractive index n _eff .
β _SL = 2πn _eff / λ _S … (3)

Further, the equation (4) holds for the three wave vectors.
k ² = kc ² + β _SL ² … (4)

By substituting the equations (1) to (3) into the equation (4) and rearranging them, the equation (5) is obtained.
n _eff = n × √ (1- (λ _S / λ _C ) ² )… (5)
This is the effective refractive index for the slow light mode wave 4.

Assuming that the incident angle of the laser beam 2 is θ _i and the emission angle is θ _r , the equation (6) holds.
sinθ _r = nsinθ _i … (6)

Further, the equation (7) holds.
sinθ _i = β _SL / k… (7)

From the equations (5) to (7), the emission angle θ _r satisfies the equation (8), and the emitted light 6 is emitted at an angle corresponding to the ratio of the two wavelengths λ _S and λ _C.
sinθ _r = n√ (1- (λ _S / λ _C ) ² )… (8)

Return to FIG. A transmissive DOE 130 is provided on the upper side of the first VCSEL structure 110. In the present embodiment, the DOE 130 is one-dimensional, and a diffracted beam that receives the emitted light 6 of the first VCSEL structure 110 on the lower surface, diffracts in the first direction (x direction), and splits into a plurality of (three in this example). It emits BM _0th , BM _-1st , and BM _{+ 1st} .

FIGS. 3A and 3B are diagrams illustrating the structure and operation of the DOE130. As shown in FIG. 3 (a), the DOE 130 has a groove periodic in the x direction.

As shown in FIG. 3B, the beam emitted from the single spot light source 10 is diffracted in the DOE 130, the 0th-order light is transmitted as it is, and the +1st-order light is -1 at an angle separated by + θ _sep in the x direction. The secondary light is emitted at an angle separated by −θ _sep in the x direction. FIG. 3 (b) shows the intensity distribution on the virtual screen 12.

The above is the configuration of the optical deflection device 100A. Next, the operation will be described.

FIG. 4 is a diagram illustrating the operation of the light deflection device 100A. It is assumed that the wavelength λ _S of the incident light 2 of the light deflection device 100 is changed from λ ₁ to λ ₂ by the external light source 200. The solid line shows the light beam when λ _S = λ ₁ , and the broken line shows the light ray when λ _S = λ ₂ .

The radiation angle θ _r when light of wavelength λ ₁ is incident is
θ ₁ = arcsin (n√ (1- (λ ₁ / λ _C ) ² ))
The radiation angle θ _r when light of wavelength λ ₂ is incident is
θ ₂ = arcsin (n√ (1- (λ ₂ / λ _C ) ² ))
Will be.

When the wavelength λ _S of the incident light 2 is λ ₁ , the DOE 130 emits beams BM _0th , BM _-1st , and BM _{+ 1st} in the three directions of θ ₁ , θ ₁ + θ _sep , and θ ₁ − θ _sep . When the wavelength λ _S of the incident light 2 is λ ₂ , the DOE 130 emits beams BM _0th , BM _-1st , and BM _{+ 1st} in the three directions of θ ₂ , θ ₂ + θ _sep , and θ ₂ -θ _sep . ..

Since the irradiation positions of the three beams can be controlled according to the wavelength λ _S of the incident light, the three beams can be scanned in the x direction by sweeping the wavelength λ _S.

5 (a) and 5 (b) are diagrams illustrating sweeping of the beam in a distant field of view with and without DOE. As shown in FIG. 5A, in the absence of DOE, the beam is scanned in the range θ ₁ to θ ₂ , and the deflection angle is θ ₂ − θ ₁ .

On the other hand, by providing DOE, as shown in FIG. 5 (b), the scanning range is expanded to (θ ₁ − θ _sep ) to (θ ₂ + θ _sep ), and the deflection angle is (θ ₂ −. θ ₁ ) + 2θ _sep , which increases by 2θ _sep .

The sweep angle Δθ = θ ₂ − θ ₁ of one beam should be about the same as θ _sep , and the sweep width of the wavelength λ _S is determined so as to satisfy the condition. As a result, the gap between the scanning range of the beam BM _0th and the scanning range of the beam BM _-1st can be eliminated in the x direction, and the gap between the scanning range of the beam BM _0th and the scanning range of the beam BM _{+ 1st} can be eliminated. In this case, the total deflection angle is 3θ _sep . In other words, the deflection angle can be magnified three times. This means that the deflection angle, which was conventionally about 10 °, can be expanded to 30 °.

In this example, the DOE130 diffracts the beam in three directions of 0th order, + 1st order, and -1st order, but the order of DOE130 is the number of diffraction beams arbitrarily according to the period and depth of the groove of DOE130. It is possible to design to increase. The polarization angle and the number of resolution points can be increased in proportion to the number of diffraction beams.

Next, the evaluation results of the actually created device will be explained.

6 (a) to 6 (d) are views showing a far-field image of the light deflection device 100A. FIG. 6A shows a far-field image when the wavelength of the incident light 2 is fixed, when there is no DOE, and FIG. 6B shows a case where the DOE is present. The spread angle of the beam in the x direction is 0.02 ° to 0.024 °.

FIG. 6 (c) shows a far-field image when the wavelength of the incident light 2 is swept in the absence of DOE. The deflection angle in the absence of DOE is about 10 °.

FIG. 6D shows a far-field image when the wavelength of the incident light 2 is swept when DOE is added. The deflection angle when the DOE is provided is expanded to about 40 °.

FIG. 7 is a diagram showing the relationship between the number of beam divisions by DOE, the deflection angle, and the resolution point. As the number of divisions by DOE130 is increased, the deflection angle and the resolution point can be increased.

(Embodiment 2)
In the first embodiment, the light from the external light source 200 is coupled to the light deflection device 100A, but in the second embodiment, the light deflection device 100B is integrated together with the light source.

FIG. 8 is a perspective view of the optical deflection device 100B according to the second embodiment. The light deflection device 100B includes a second VCSEL structure 140. The second VCSEL structure 140 is coupled in the first direction at the incident end 126 of the first VCSEL structure 110.

The second VCSEL structure 140 is a light source that replaces the external light source 200, and includes an upper DBR layer 142, an active layer 144, a lower DBR layer 146, and an oxidation narrowing layer 148.

The first VCSEL structure 110 and the second VCSEL structure 140 can be formed in such a manner that the DBR layers 116 and 146, 112 and 142, and the

active layers

114 and 144, respectively, are continuous. That is, the first VCSEL structure 110 and the second VCSEL structure 140 can be simultaneously created on the same substrate 102 by the same semiconductor process.

The first VCSEL structure 110 and the second VCSEL structure 140 are electrically insulated from each other. For example, by injecting an ion into the region 128 at the boundary between the first VCSEL structure 110 and the second VCSEL structure 140, electrical insulation can be achieved without disturbing the optical bond.

The first VCSEL structure 110 and the second VCSEL structure 140 may be individually configured and the end faces may be joined to each other.

The drive circuit 210 injects a current _IDRV into the electrode 154 of the second VCSEL structure 140 to oscillate the second VCSEL structure 140. Unlike a general VCSEL, the second VCSEL structure 140 does not need to take out emitted light from its upper surface, so that the reflectance of the upper surface may be increased to around 100%. Therefore, the electrode 154 may be formed over the entire upper surface of the second VCSEL structure 140 and used as a metal reflective film.

When the second VCSEL structure 140 oscillates, the laser beam exudes into the first VCSEL structure 110. The exuded laser beam is coupled to the first VCSEL structure 110 as incident light 2. The configuration and operation of the first VCSEL structure 110 side are the same as those in the first embodiment.

The oscillation wavelength λ _S of the second VCSEL structure 140 can be controlled according to the drive current _IDRV injected by the drive circuit 210. That is, the temperature of the second VCSEL structure 140 changes due to self-heating corresponding to the drive current _IDRV , and the second VCSEL structure oscillates at the wavelength λ _S corresponding to the temperature. By changing the current amount of the drive current I _DRV from I ₁ to I ₂ , the wavelength λ _S of the incident light 2 can be changed in the range λ ₁ to λ ₂ according to the current amount.

The method for controlling the oscillation wavelength λ _S of the second VCSEL structure 140 is not limited to this. The current _IDRV injected from the drive circuit 210 may be constant, the temperature of the second VCSEL structure 140 may be controlled by a heater, and the oscillation wavelength λ _S may be changed. It can be said that the wavelength control by the drive current _IDRV described above is simple and low cost because it does not require a heater.

9 (a) to 9 (d) are views showing a far-field image of the light deflection device 100B of FIG. 7. 9 (a) shows a far-field image of the injected current _IDRV , that is, a fixed wavelength λs of the incident light 2 in the absence of DOE and FIG. 9 (b). The spread angle of the beam in the x direction is 0.11 ° to 0.12 °, which is larger than that of the light deflection device 100A of the first embodiment.

FIG. 9 (c) shows a far-field image when the current amount of the drive current I _DRV is swept in the absence of DOE. The deflection angle in the absence of DOE is about 10 °.

FIG. 9 (d) shows a far-field image when the drive current I _DRV is swept when DOE is added. The deflection angle when the DOE is provided is expanded to about 40 °.

(Embodiment 3)
FIG. 10 is a perspective view of the light deflection device 100C according to the third embodiment. The optical deflection device 100C includes two optical deflection devices 100_1 and 100_2 adjacent to each other in the second horizontal direction (y direction) perpendicular to the horizontal first direction (x direction). The two light deflection devices 100_1 and 100_2 are configured so that the propagation directions of the slow light mode waves are opposite to each other.

The two optical deflection devices 100_1 and 100_2 have the configurations described in the first embodiment or the second embodiment. The region 150 corresponds to the incident port 120 that receives the light from the external light source in the first embodiment, or corresponds to the second VCSEL structure 140 in the second embodiment. The light deflection device 100_1 has a first VCSEL structure 110_1, and the light deflection device 100_1 has a third VCSEL structure 110_2. In the present embodiment, the optical deflection devices 100_1 and 100_2 are integrated on the same substrate, and the corresponding layers of the respective VCSEL structures are continuous. Further, one DOE 130 is arranged so as to cover both the light deflection devices 100_1 and 100_1.

It should be noted that two individually configured optical deflection devices 100_1 and 100_2 may be arranged adjacent to each other in the second direction.

The above is the configuration of the optical deflection device 100C. Next, the operation will be described. 11 (a) and 11 (b) are views showing a far-field image of the light deflection device 100C of FIG.

FIG. 11A shows a far-field image in the absence of DOE130. When the emission beam BM1 of the light deflection device 100_1 changes in the range of angles θ ₁ to θ ₂ , the emission beam BM ₂ of the light deflection device 100_1 changes in the range of angles −θ ₁ to −θ2.

FIG. 11B shows a far-field image of a plurality of beams split by the DOE 130. The emitted beam BM1 of the light deflection device 100_1 is split and emitted at an angle separated by ± θ _sep . Similarly, the emitted beam BM2 of the light deflection device 100_2 is also split and emitted at an angle separated by ± θ _sep . This allows the beam to be scanned over a wide range of positive and negative angles.

FIG. 12 is a perspective view of a modified example of the light deflection device of FIG. The ends of the two opposing optical deflection devices 100_1 and 100_2 may be coupled to each other by the folded structure 152 to form one optical deflection device.

(Embodiment 4)
FIG. 13 is a perspective view of the light deflection device 100D according to the fourth embodiment. In the fourth embodiment, the DOE130D is a two-dimensional diffractive element and has a periodic structure in both the X direction and the Y direction.

The DOE130D splits the emitted beam of the first VCSEL structure 110 in both the X direction and the Y direction, and emits a plurality of beams. In the X direction, it is radiated at a distance of ± θsepx, and in the Y direction, it is radiated at a distance of ± θsepy.

The light source may be provided outside the first VCSEL structure 110 as described in the first embodiment, or may be integrated together with the first VCSEL structure 110 as described in the second embodiment.

14 (a) and 14 (b) are views showing a far-field image of the light deflection device 100D of FIG. FIG. 14 (a) shows a far-field image in the absence of DOE130D. The emission beam of the light deflection device 100D has a relatively large spread angle in the y direction, while the spread angle of the beam in the x direction is very small.

FIG. 14B shows a far-field image when the DOE130D is present, and the irradiation area can be expanded by splitting the beam in the x-direction and the y-direction, respectively.

(Embodiment 5)
FIG. 15 is a perspective view of the light deflection device 100E according to the fifth embodiment. In the fifth embodiment, the DOE130E is a one-dimensional diffractive element and has a structure periodic in the Y direction.

FIG. 16 is a diagram showing a far-field image of the light deflection device 100E of FIG. According to the fifth embodiment, the irradiation area can be expanded by splitting the beam in the y direction.

Next, an example of the use of the light deflection device 100 will be described.

FIGS. 17 (a) to 17 (d) are diagrams showing LIDAR (Light Detection and Ringing, Laser Imaging Detection and Ringing) including the light deflection device 100. The LIDAR 300a of FIG. 17A includes a device chip 302 and an optical system 304. The optical deflection device 100 is integrated on the device chip 302. The light deflection device 100 scans the signal light 21. The return light reflected by the object 400 is detected by a detector connected to the device chip 302 via the device chip 302. The detector may be integrated on the same surface as the device chip 302.

In the LIDAR 300b of FIG. 17B, the optical deflection device 100 and the detector are separately configured. The LIDAR 300b includes two

device chips

306, 308 and

optical systems

310, 312. One of the above-mentioned optical deflection devices 100 is integrated on the device chip 306. The light deflection device 100 scans the signal light 21. The return light 22 reflected by the object 400 is detected by a detector connected to the device chip 308 via the device chip 308.

In the LIDAR 300c shown in FIG. 17 (c), a CMOS (Complementary Metal Oxide Semiconductor) sensor is arranged as a detector. The LIDAR 300c includes a device chip 314 in which the optical deflection device 100 is integrated and an optical system 316 on the beam deflector side thereof. The light receiving side is provided with an optical system 320 and an array-shaped detector 318. The array detector 318 may be a CMOS sensor or a CCD. The light deflection device 100 scans the signal light 21. The return light 22 reflected by the object 400 is detected by the array detector 318 via the optical system 320.

The LIDAR 300d of FIG. 17 (d) is provided with an optical deflection device 100 on the beam deflector side. The light receiving side is provided with an optical system 322 and a detector array 324. The detector array 324 may be a CMOS sensor or a CCD. The light deflection device 100 can split the beam in the Y direction as described in the fourth and fifth embodiments. The light deflection device 100 scans the signal light 21 in a one-dimensional direction. Since the beam itself splits in the direction orthogonal to it, a plurality of target objects 402 are simultaneously irradiated. The return light 22 reflected by the target object here is detected by the detector array 324 via the optical system 322. The individual positions of the plurality of target objects 402 can be detected simultaneously by using the detector array 324.

As described above, according to the light deflection device 100 according to the embodiment, a wide range of beam scans can be realized. Therefore, by using it for LIDAR, it is possible to detect a wider range of three-dimensional position information of the object 400.

In some of the above-described embodiments, the emission angle θ _r of the emitted light 6 is controlled by fixing the resonance wavelength λ _C of the first VCSEL structure 110 and controlling the wavelength λ _S of the incident light 2. The invention is not limited to that. Since the emission angle θ _r is determined based on the relative relationship between the two wavelengths λ _S and λ _C , the resonance wavelength λ _C may be controlled in place of or in addition to the wavelength λ _S. In this case, the first VCSEL structure 110 may be configured with a variable resonance wavelength λ _C. Specifically, the first VCSEL structure 110 is provided with a MEMS structure and an air gap layer to control the thickness of the air gap layer. You may.

The present invention has been described using specific terms and phrases based on the embodiments, but the embodiments merely indicate the principles and applications of the present invention, and the embodiments are defined in the claims. Many modifications and arrangement changes are permitted within the scope of the above-mentioned idea of the present invention.

100 ... light deflection device, 110 ... first VCSEL structure, 112 ... upper DBR, 114 ... active layer, 116 ... lower DBR, 118 ... oxidative stenosis layer, 120 ... incident port, 122 ... exit port, 124 ... electrode, 130 ... DOE, 140 ... 2nd VCSEL structure, 142 ... upper DBR, 144 ... active layer, 146 ... lower DBR, 148 ... oxidative constriction layer, 2 ... incident light, 4 ... slow light mode wave, 6 ... emitted light, 200 ... external Light source, 210 ... Drive circuit.

Claims

A first VCSEL configured to receive coherent incident light at the incident end, propagate the incident light in a horizontal first direction while multiple-reflecting the incident light in the vertical direction, and extract the emitted light from the outlet on the upper surface thereof. Vertical resonator surface emitting laser) structure and
The diffractive optical element provided on the upper side of the first VCSEL structure and
A light deflection device characterized by comprising.
The light deflection device according to claim 1, wherein the diffractive optical element diffracts the emitted light of the first VCSEL structure in the first direction.
The light deflection device according to claim 1, wherein the diffractive optical element diffracts the emitted light of the first VCSEL structure in the first direction and the second direction perpendicular to the first direction.
The light deflection device according to claim 1, wherein the diffractive optical element diffracts the emitted light of the first VCSEL structure in a second direction perpendicular to the first direction.
Further provided at the incident end of the first VCSEL structure is a light source comprising the second VCSEL structure coupled in the first direction.
The light deflection device according to any one of claims 1 to 4, wherein the light source is configured so that the oscillation wavelength can be controlled.
The light deflection device according to claim 5, wherein the first VCSEL structure and the second VCSEL structure are continuously formed with DBRs (Distributed Bragg Reflectors) and active layers.
The light deflection device according to claim 5 or 6, wherein the light source has a variable drive current to be injected into the second VCSEL structure.
The first VCSEL structure is arranged in a second direction perpendicular to the first direction, receives coherent incident light at its incident end, and multiple-reflects the incident light in the vertical direction. It further comprises a third VCSEL structure configured to propagate slow light in the opposite direction of one direction and extract the emitted light from the exit port on its upper surface.
The light deflection device according to any one of claims 1 to 7, wherein the diffractive optical element is provided above the first VCSEL structure and the third VCSEL structure.