Optical scanning device that includes waveguides

Patent metadata

Field	Value
Publication number	US-10877215-B2
Application number	US-201816116499-A
Country	US
Kind code	B2
Filing date	Aug 29, 2018
Priority date	Sep 29, 2016
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

An optical scanning device includes a waveguide array including a plurality of waveguides arranged in a first direction. Each waveguide includes: an optical waveguide layer that propagates light supplied to the waveguide in a second direction intersecting the first direction; a first mirror having a first reflecting surface intersecting a third direction; and a second mirror having a second reflecting surface that faces the first reflecting surface. The optical waveguide layer is located between the first and second mirrors and has a variable thickness and/or a variable refractive index for the light. The width of the first mirror and the width of the second mirror are each larger than the width of the optical waveguide layer. The first mirror has a higher light transmittance than the second mirror and allows part of the light propagating through the optical waveguide layer to be emitted in the third direction.

First claim

What is claimed is:

1. An optical scanning device comprising a waveguide array including a plurality of waveguides arranged in a first direction,
wherein each of the plurality of waveguides includes:
an optical waveguide layer that propagates light supplied to the waveguide, in a second direction intersecting the first direction;
a first mirror extending in the second direction and having a first reflecting surface that intersects a third direction; and
a second mirror extending in the second direction and having a second reflecting surface that faces the first reflecting surface of the first mirror,

wherein the third direction intersects a virtual plane parallel to the first and second directions,
wherein, in each of the plurality of waveguides, the optical waveguide layer is located between the first mirror and the second mirror and has a variable thickness and/or a variable refractive index for the light,
wherein the width of the first mirror in the first direction and the width of the second mirror in the first direction are each larger than the width of the optical waveguide layer in the first direction,
wherein the first mirror has a higher light transmittance than the second mirror and allows part of the light propagating through the optical waveguide layer to pass through and be emitted in the third direction, and
wherein the refractive index of the optical waveguide layer and/or the thickness of the optical waveguide layer is changed to change the third direction that is an emission direction of the part of the light.

2. The optical scanning device according to claim 1 ,
wherein, in each of the plurality of waveguides, the first and second mirrors each have a protruding portion that protrudes in the first direction from an edge surface of the optical waveguide layer as viewed in a direction perpendicular to the virtual plane parallel to the first and second directions;
evanescent light leaks from the edge surface of the optical waveguide layer; and
y 1 and y d satisfy y 1 ≥7y d ,
where y 1 is the size of the protruding portion in the first direction, and
y d is the distance in the first direction between the edge surface and a position at which the light intensity of the evanescent light is 1/e of the light intensity of the evanescent light at the edge surface,
where e is the base of natural logarithm.

3. The optical scanning device according to claim 2 ,
wherein y 1 and y d satisfy y 1 ≥11 yd .

4. The optical scanning device according to claim 1 , further comprising
an integrally formed third mirror,
wherein the first mirror of each of the plurality of waveguides is part of the third mirror.

5. The optical scanning device according to claim 1 , further comprising
an integrally formed fourth mirror,
wherein the second mirror of each of the plurality of waveguides is part of the fourth mirror.

6. The optical scanning device according to claim 1 , further comprising
a first adjusting element that changes the refractive index of each optical waveguide layer and/or the thickness of each optical waveguide layer to change the third direction that is the emission direction of the part of the light.

7. The optical scanning device according to claim 6 ,
wherein each optical waveguide layer of the waveguides contains a first material whose refractive index for the light is changed when a voltage is applied, and
the first adjusting element includes a pair of electrodes sandwiching one or more optical waveguide layers and changes the refractive index of each of the one or more optical waveguide layers by applying a voltage to the pair of electrodes.

8. The optical scanning device according to claim 7 ,
wherein the first material contains an electrooptical material, and
wherein the first adjusting element changes the refractive index of the electrooptical material by applying a voltage to the pair of electrodes.

9. The optical scanning device according to claim 7 ,
wherein the first material contains a liquid crystal material, and
wherein the first adjusting element changes the refractive index anisotropy of the liquid crystal material by applying a voltage to the pair of electrodes to change the refractive index of each of the one or more optical waveguide layers.

10. The optical scanning device according to claim 1 , further comprising
a second material that is disposed between the optical waveguide layers of each two adjacent waveguides of the plurality of waveguides and has a lower refractive index than the optical waveguide layers.

11. The optical scanning device according to claim 10 ,
wherein the second material contains at least one selected from the group consisting of SiO 2 , TiO 2 , Ta 2 O 5 , SiN, and AlN.

12. The optical scanning device according to claim 10 ,
wherein the second material contains SiO 2 .

13. The optical scanning device according to claim 10 ,
wherein the second material is in direct contact with the optical waveguide layers of the each two adjacent waveguides.

14. The optical scanning device according to claim 1 ,
wherein, when a second direction component of the wave vector of the light emitted in the third direction is denoted as an X component and a first direction component of the wave vector is denoted as a Y component,
the X component of the wave vector is changed by changing the refractive index of the optical waveguide layer of each of the waveguides and/or the thickness of the optical waveguide layer of each of the waveguides, and
the Y component of the wave vector is changed when the difference in phase between light beams to be supplied to each two adjacent waveguides of the plurality of waveguides is changed.

15. The optical scanning device according to claim 1 ,
wherein the first direction is orthogonal to the second direction.

16. The optical scanning device according to claim 1 ,
wherein the plurality of waveguides are arranged in the first direction at regular intervals.

17. The optical scanning device according to claim 1 ,
wherein, in each of the plurality of waveguides, at least one of the first and second mirrors includes a dielectric multilayer film.

18. The optical scanning device according to claim 1 , further comprising
a plurality of phase shifters,
wherein each of the plurality of phase shifters includes a waveguide connected to a corresponding one of the plurality of waveguides directly or indirectly through another waveguide and supplies a light beam to the corresponding one of the plurality of waveguides, and
wherein the phases of the light beams to be supplied from the waveguides of the phase shifters to the respective optical waveguide layers are changed such that the difference in phase between light beams to be supplied to the optical waveguide layers of each two adjacent waveguides of the plurality of waveguides is changed to change the third direction.

19. The optical scanning device according to claim 18 , further comprising
a second adjusting element that changes the phases of the light beams to be supplied from the waveguides of the phase shifters to the respective optical waveguide layers to change the difference in phase between light beams to be supplied to each two adjacent waveguides of the plurality of waveguides, so that the third direction is changed.

20. The optical scanning device according to claim 19 ,
wherein the waveguide of each of the phase shifters contains a third material whose refractive index is changed when a voltage is applied or temperature is change

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Hashiya Akira
• Inada Yasuhisa
• Hirasawa Taku
• Yamaoka Yoshikazu
• Nagao Nobuaki

Classifications

• G02F1/29 Primary

  for the control of the position or the direction of light beams, i.e. deflection · CPC title

• G01S17/89

  for mapping or imaging · CPC title

• G02B6/122 Primary

  Basic optical elements, e.g. light-guiding paths · CPC title

• G01S7/4817

  relating to scanning · CPC title

• G02B26/08

  for controlling the direction of light (in light guides G02B6/35) · CPC title