Optical amplifying element, light source device, and image pickup device

Patent metadata

Field	Value
Publication number	US-9853419-B2
Application number	US-201615345268-A
Country	US
Kind code	B2
Filing date	Nov 7, 2016
Priority date	Nov 12, 2015
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

An optical amplifying element includes: a pair of reflectors that constitutes a cavity; an active layer disposed between the pair of reflectors; and an excitation unit configured to excite the active layer, wherein the active layer excited by the excitation unit amplifies intensity of a laser beam that enters the optical amplifying element when the laser beam reflects back and forth within the cavity, and wherein the pair of reflectors is configured to change a length of the cavity according to a wavelength of the laser beam.

First claim

What is claimed is:

1. A light source device comprising:
a wavelength tunable laser; and
an optical amplifying element;
the optical amplifying element comprising:
a pair of reflectors that constitutes a cavity;
an active layer disposed between the pair of reflectors; and
an excitation unit configured to excite the active layer, wherein the active layer excited by the excitation unit amplifies the intensity of a laser beam that enters the optical amplifying element, and
an optical element configured to cause the laser beam emitted from the wavelength tunable laser to enter the optical amplifying element,
wherein the pair of reflectors is configured to change a length of the cavity according to a wavelength of the laser beam, and
wherein a light-emitting region of the optical amplifying element is larger than a light-emitting region of the wavelength tunable laser.

2. The light source device according to claim 1 , wherein the cavity length of the cavity decreases as the wavelength of the laser beam decreases.

3. The light source device according to claim 1 , wherein the cavity length of the cavity changes so that the wavelength of the laser beam is included in a full width at half maximum of a dip in a reflectivity spectrum of the optical amplifying element.

4. The light source device according to claim 1 , wherein reflectivity of each reflector among the pair of reflectors of the optical amplifying element is 99.0% or less.

5. The light source device according to claim 1 , further comprising:
a gap between at least one reflector of the pair of reflectors and the active layer; and
an electrode configured to move the at least one reflector.

6. The light source device according to claim 1 , wherein the excitation unit comprises an electrode for injecting an electric current into the active layer.

7. The light source device according to claim 1 , wherein the pair of reflectors and the active layer are laminated on a substrate in a direction perpendicular to the substrate.

8. The light source device according to claim 7 , wherein the optical amplifying element emits light in the direction in which the pair of reflectors and the active layer are laminated.

9. The light source device according to claim 7 , wherein the laser beam enters the optical amplifying element from a direction in which the pair of reflectors and the active layer are laminated.

10. The light source device according to claim 1 , further comprising a gap between at least one reflector of the pair of reflectors and the active layer,
wherein the optical amplifying element comprises a control unit configured to move the at least one reflector, and
the control unit moves the at least one reflector so that the wavelength of the light emitted from the wavelength tunable laser is included in a full width at half maximum of a dip in a reflectivity spectrum of the optical amplifying element.

11. The light source device according to claim 1 , wherein
the wavelength tunable laser comprises a pair of reflectors and an active layer disposed between the pair of reflectors,
one of the pair of reflectors of the wavelength tunable laser and one of the pair of reflectors of the optical amplifying element are common, and
the active layer of the wavelength tunable laser and the active layer of the optical amplifying element are common.

12. The light source device according to claim 1 , wherein the optical element is a lens formed on a surface of the optical amplifying element that receives the light emitted from the wavelength tunable laser.

13. The light source device according to claim 1 , wherein
the optical element comprises a circulator including a first port, a second port, and a third port,
the wavelength tunable laser is optically connected to the first port,
the optical amplifying element is optically connected to the second port, and
the light emitted from the wavelength tunable laser is emitted from the circulator through the first port, the second port, the optical amplifying element, the second port, and the third port in this order.

14. An image pickup device comprising:
the light source device according to claim 1 ;
an interference optical system configured to branch the light from the light source device into projection light to project on a measurement object and reference light, and to generate interfering light from reflected light of the light projected on the measurement object and the reference light; and
a detection unit configured to receive the interfering light.

15. An optical amplifying element comprising:
a pair of reflectors that constitutes a cavity;
an active layer disposed between the pair of reflectors; and
an excitation unit configured to excite the active layer,
wherein the active layer excited by the excitation unit amplifies the intensity of a laser beam that enters the optical amplifying element,
wherein the pair of reflectors is configured to change a length of the cavity according to a wavelength of the laser beam, and
wherein the pair of reflectors and the active layer are laminated on a substrate in a direction perpendicular to the substrate.

16. The optical amplifying element according to claim 15 , wherein the optical amplifying element emits light in the direction in which the pair of reflectors and the active layer are laminated.

17. The optical amplifying element according to claim 15 , wherein the laser beam enters the optical amplifying element from a direction in which the pair of reflectors and the active layer are laminated.

18. A light source device comprising:
an optical amplifying element,
the optical amplifying element comprising:
a pair of first reflectors that constitutes a first cavity;
a first active layer disposed between the pair of first reflectors;
a first current confinement layer that includes a first low resistance region and is disposed between either one of the pair of first reflectors and the first active layer, and
an excitation unit configured to excite the first active layer,
wherein the first active layer excited by the excitation unit amplifies the intensity of a laser beam that enters the optical amplifying element,
wherein the pair of first reflectors is configured to change a length of the first cavity according to a wavelength of the laser beam,

a wavelength tunable laser,
the wavelength tunable laser comprising:
a pair of second reflectors that constitutes a second cavity;
an second active layer disposed between the pair of second reflectors; and
a second current confinement layer that includes a second low resistance region and is disposed between either one of the pair of second reflectors and the second active layer, and
an optical element configured to cause the laser beam emitted from the wavelength tunable laser to enter the optical amplifying element,
wherein the first low resistance region in an in-plane direction perpendicular to a light-emitting direction of the optical amplifying element is larger than the second low resistance region in an in-plane direction perpendicular to a light-emitting direction of the wavelength tunable laser.

Assignees

• Canon Kk

Inventors

• Uchida Takeshi

Classifications

• H01S5/06837 Primary

  Stabilising otherwise than by an applied electric field or current, e.g. by controlling the temperature · CPC title

• H01S5/0687

  Stabilising the frequency of the laser · CPC title

• G01B9/02091

  Tomographic interferometers, e.g. based on optical coherence · CPC title

• H01S5/042

  Electrical excitation {; Circuits therefor (monolithically integrated laser drive components H01S5/0261)} · CPC title

• G01B9/02007

  Two or more frequencies or sources used for interferometric measurement (using only beat G01B9/02003) · CPC title