Surface-emitting laser, surface-emitting laser array, laser device, ignitor, internal combustion engine, optical scanner, image forming apparatus, light transmission module, and light emission system

• US 10,054,870 B2
• Filed: 11/30/2016
• Issued: 08/21/2018
• Est. Priority Date: 12/11/2015
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Harada, Shinichi, Jikutani, Naoto, Izumiya, Kazuma, Okura, Yusuke
• Primary Examiner(s): Niu, Xinning
• Application Number:
  US15/364,445
• Publication Number:
  US 20170168412A1
• Time in Patent Office: 629 Days
• CPC Class Codes: F02P 23/04 Other physical ignition means, e.g. using laser rays
• CPC Class Codes: G02B 19/0057 in the form of a laser diode array, e.g. laser diode bar semiconductor laser arrays with beam combining arrangement H01S5/4012
• CPC Class Codes: G03G 15/04 for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material
• CPC Class Codes: H01S 3/0627 the resonator being monolithic, e.g. microlaser
• CPC Class Codes: H01S 3/094053 Fibre coupled pump, e.g. delivering pump light using a fibre or a fibre bundle
• CPC Class Codes: H01S 3/09415 the pumping beam being parallel to the lasing mode of the pumped medium, e.g. end-pumping
• CPC Class Codes: H01S 3/113 using intracavity saturable absorbers
• CPC Class Codes: H01S 5/02345 Wire-bonding
• CPC Class Codes: H01S 5/0237 by soldering
• CPC Class Codes: H01S 5/18311 using selective oxidation
• CPC Class Codes: H01S 5/18313 by oxidizing at least one of the DBR layers
• CPC Class Codes: H01S 5/18322 Position of the structure
• CPC Class Codes: H01S 5/18358 containing spacer layers to adjust the phase of the light wave in the cavity
• CPC Class Codes: H01S 5/18377 comprising layers of different kind of materials, e.g. combinations of semiconducting with dielectric or metallic layers
• CPC Class Codes: H01S 5/3202 grown on specifically orientated substrates, or using orientation dependent growth
• CPC Class Codes: H01S 5/34313 with a well layer having only As as V-compound, e.g. AlGaAs, InGaAs
• CPC Class Codes: H01S 5/423 having a vertical cavity
• CPC Class Codes: H04N 1/0283 in combination with a light deflecting element, e.g. a rotating mirror
• CPC Class Codes: H04N 1/0284 in combination with a light integrating, concentrating or diffusing cavity
• CPC Class Codes: H04N 1/06 using cylindrical picture-bearing surfaces , i.e. scanning a main-scanning line substantially perpendicular to the axis and lying in a curved cylindrical surface

Abstract

A surface-emitting laser includes an active layer on which a spacer layer is disposed, and a reflection mirror disposed on the spacer layer, including a current constriction layer that is a selectively-oxidized layer having been selectively oxidized. The current constriction layer is disposed at a position of a node of a standing-wave of an electric field of light oscillated at the active layer and is disposed away from an interface between the spacer layer and the reflection mirror by an optical distance of one-fourth of an oscillation wavelength at the active layer. The selectively-oxidized layer is made of AlGaAs. The reflection mirror includes at least one AlGaInP layer contacting the selectively-oxidized layer.

Claims

1. A surface-emitting laser comprising:

an active layer;

a spacer layer disposed on the active layer; and

a reflection mirror disposed on the spacer layer, the reflection mirror including a current constriction layer that is a selectively-oxidized layer made of Al(Ga)As,

the current constriction layer disposed at a position of a node of a standing-wave of an electric field of light oscillated at the active layer and disposed away from an interface between the spacer layer and the reflection mirror by an optical distance of one-fourth of an oscillation wavelength at the active layer,

the reflection mirror including at least one AlGaInP layer that is in direct contact with the selectively-oxidized layer made of Al(Ga)As.

2. The surface-emitting laser according to claim 1,

wherein the at least one AlGaInP layer includes two AlGaInP layers,

wherein the selectively-oxidized layer is disposed between the two AlGaInP layers, and

wherein an optical thickness of the selectively-oxidized layer and the two AlGaInP layers is (2n+1)λ

/4, where n is a natural number and λ

is the oscillation wavelength at the active layer.

3. The surface-emitting laser according to claim 1,

wherein the at least one AlGaInP layer is disposed on only one side of the selectively-oxidized layer that faces the active layer.

4. The surface-emitting laser according to claim 1,

wherein the selectively-oxidized layer is made of Al_x1Ga₁₋

x1As,

wherein Al content x1 satisfies a relation of 0.95≤

x1≤

1,

wherein the at least one AlGaInP layer is made of (Al_x2Ga<sub>1−

x2</sub>As)_0.5In_0.5P, and

wherein Al content x2 satisfies a relation of 0.04≤

x2≤

2.80x1−

1.92.

5. The surface-emitting laser according to claim 1,

wherein the spacer layer is made of (Al_x3Ga₁₋

x3)_0.5In_0.5P,

wherein Al content x3 satisfies a relation of 0≤

x3≤

0.55, and

wherein a difference in band gap energy between the at least one AlGaInP layer and the spacer layer is greater than or equal to 102 meV.

6. The surface-emitting laser according to claim 1,

wherein a valence band discontinuity between the spacer layer and the AlGaInP layer is less than or equal to 134 meV.

7. The surface-emitting laser according to claim 1,

wherein a plurality of semiconductor layers is disposed between the active layer and a substrate, and

wherein the substrate is an inclined substrate that is inclined toward any one of a crystal orientation [1 1 1], a crystal orientation [1 −

1 −

1], a crystal orientation [1 1 −

1], and a crystal orientation [1 −

1 1] relative to a crystal orientation [1 0 0].

8. A surface-emitting laser array comprising a plurality of surface-emitting lasers, each being the surface-emitting laser according to claim 1.

9. A laser device comprising:

the surface-emitting laser array according to claim 8; and

an optical system to guide a laser beam emitted from the surface-emitting laser array to a target.

10. A laser device comprising:

the surface-emitting laser array according to claim 8; and

a condensing optical system to collect and condense a laser beam emitted from the surface-emitting laser array.

11. The laser device according to claim 10, further comprising a microlens array disposed between the surface-emitting laser array and the condensing optical system.

12. The laser device according to claim 10, further comprising a light transmission member to transmit light having passed through the condensing optical system.

13. A laser device comprising:

the surface-emitting laser array according to claim 8; and

a laser resonator to which a laser beam emitted from the surface-emitting laser array enters.

14. An ignitor comprising:

the laser device according to claim 13; and

an optical system to collect and condense a laser beam emitted from the laser device.

15. An internal combustion engine comprising the ignitor according to claim 14 to ignite fuel to generate inflammable gas.

16. An optical scanner comprising:

a scanning light source including the surface-emitting laser according to claim 1;

a light deflector to deflect light emitted from the scanning light source; and

a scanning optical system to collect and condense the light deflected by the light deflector.

17. The optical scanner comprising:

a scanning light source including the surface-emitting laser according to claim 8;

a light deflector to deflect light emitted from the scanning light source; and

a scanning optical system to collect and condense the light deflected by the light deflector.

18. An image forming apparatus comprising:

an image bearer to bear an image; and

the optical scanner according to claim 16 to scan the image bearer with light modulated according to data of the image.

19. An optical transmitter module comprising:

the surface-emitting laser array according to claim 8;

a drive device to drive the surface-emitting laser array to generate a light signal according to an input electrical signal.

20. A light transmission system comprising:

the optical transmitter module according to claim 19;

a light transmission medium to transmit a light signal generated by the optical transmitter module; and

a converter to convert the light signal transmitted from the light transmission medium into an electrical signal.