VERTICAL CAVITY SURFACE EMITTING LASER, VERTICAL-CAVITY-SURFACE-EMITTING-LASER DEVICE, OPTICAL TRANSMISSION APPARATUS, AND INFORMATION PROCESSING APPARATUS

• US 20110317540A1
• Filed: 10/18/2010
• Published: 12/29/2011
• Est. Priority Date: 06/29/2010
• Status: Active Grant

• Current Assignee: Fujifilm Business Innovation Corp. (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: KONDO, Takashi, TAKEDA, Kazutaka, MATSUSHITA, Kazuyuki
• Granted Patent: US 8,295,318 B2
• Time in Patent Office: Days
• US Class Current: 369/121
• CPC Class Codes: H01S 2301/166 Single transverse or lateral mode
• CPC Class Codes: H01S 5/02212 Can-type, e.g. TO-CAN housings with emission along or parallel to symmetry axis
• CPC Class Codes: H01S 5/02251 using optical fibres
• CPC Class Codes: H01S 5/02253 using lenses
• CPC Class Codes: H01S 5/0282 Passivation layers or treatments
• CPC Class Codes: H01S 5/18313 by oxidizing at least one of the DBR layers
• CPC Class Codes: H01S 5/18347 Mesa comprising active layer
• CPC Class Codes: H01S 5/18386 Details of the emission surface for influencing the near- or far-field, e.g. a grating on the surface
• CPC Class Codes: H01S 5/18391 Aperiodic structuring to influence the near- or far-field distribution
• CPC Class Codes: H01S 5/18394 Apertures, e.g. defined by the shape of the upper electrode
• CPC Class Codes: H01S 5/209 special etch stop layers

Abstract

A vertical cavity surface emitting laser including a substrate, a first semiconductor multilayer film reflector formed on the substrate, an active region formed on the first semiconductor multilayer film reflector, a second semiconductor multilayer film reflector formed on the active region, an electrode formed on the second semiconductor multilayer film reflector, a light absorption layer, and a light transmission layer. In the electrode, a light emitting aperture is formed. The light absorption layer is formed in a peripheral region of the light emitting aperture, and absorbs emitted light. The light transmission layer is composed of a material which the emitted light can pass through, and formed in a central region of the light emitting aperture. Thicknesses of the light absorption layer and the light transmission layer are selected so that phases of light from the light absorption layer and from the light transmission layer are adjusted.

Claims

1. A vertical cavity surface emitting laser comprising:

a substrate;

a first semiconductor multilayer film reflector of a first conductivity type, the first semiconductor multilayer film reflector being formed on the substrate;

an active region that is formed on the first semiconductor multilayer film reflector;

a second semiconductor multilayer film reflector of a second conductivity type that is a conductivity type different from the first conductivity type, the second semiconductor multilayer film reflector being formed on the active region;

an electrode which is formed on the second semiconductor multilayer film reflector, and in which a light emitting aperture from which light is emitted is formed;

a light absorption layer that is formed in at least a peripheral region of the light emitting aperture of the electrode, and that absorbs light having an emission wavelength; and

a light transmission layer that is composed of a material which the light having the emission wavelength is able to pass through, and that is formed in a central region of the light emitting aperture of the electrode,

wherein a thickness of the light absorption layer and a thickness of the light transmission layer are selected so that a phase of light which emanates from the light absorption layer and a phase of light which emanates from the light transmission layer are adjusted.

2. The vertical cavity surface emitting laser according to claim 1, wherein the thickness of the light transmission layer is in a range between about ±

10% of d1 that is obtained using an equation d1=(2a−

1)λ

/2n1 where a is an integer, λ

is an emission wavelength, and n1 is a refractive index.

3. The vertical cavity surface emitting laser according to claim 1, wherein a thickness d2 of the light absorption layer in a case in which the light absorption layer is formed in the peripheral region other than the central region satisfies a condition represented by an equation (n2−

1)×

d2+(1−

n1)×

d1=λ

×

b where b is an integer and n2 is a refractive index.

4. The vertical cavity surface emitting laser according to claim 1,

wherein the light absorption layer includes a semiconductor layer having an impurity concentration which is higher than an impurity concentration of a high-refractive-index layer and a low-refractive-index layer that are included in the second semiconductor multilayer film reflector, and

wherein the electrode is electrically connected to the light absorption layer.

5. The vertical cavity surface emitting laser according to claim 1, wherein the light absorption layer includes a layer that has a thickness smaller than a thickness of the light absorption layer in the peripheral region, and that is provided between the light transmission layer and the second semiconductor multilayer film reflector.

6. The vertical cavity surface emitting laser according to claim 1, wherein the vertical cavity surface emitting laser further comprises an etching stopper layer that is provided between the light absorption layer and an additional light absorption layer, or between the light absorption layer and the second semiconductor multilayer film reflector, and that has an etching selection ratio with respect to the light absorption layer.

7. The vertical cavity surface emitting laser according to claim 1, wherein the light absorption layer is covered with a protective film.

8. The vertical cavity surface emitting laser according to claim 1,

wherein a columnar structure extending from the second semiconductor multilayer film reflector to the first semiconductor multilayer film reflector is formed,

wherein, in the columnar structure, a current confinement layer that includes an oxidized region which is oxidized from a side wall of the columnar structure, and an electrically conductive region the periphery of which is defined by the periphery of the oxidized region is formed, and

wherein the light absorption layer is formed so that an inside diameter of the light absorption layer is smaller than a diameter of the electrically conductive region.

9. The vertical cavity surface emitting laser according to claim 8, wherein a diameter of the electrically conductive region is about five micrometers or larger.

10. A vertical-cavity-surface-emitting-laser device comprising:

the vertical cavity surface emitting laser according to claim 1; and

an optical member that light emitted from the vertical cavity surface emitting laser enters.

11. An optical transmission apparatus comprising:

the vertical-cavity-surface-emitting-laser device according to claim 10; and

a transmission unit that transmits, via an optical medium, laser light emitted from the vertical-cavity-surface-emitting-laser device.

12. An information processing apparatus comprising:

the vertical cavity surface emitting laser according to claim 1;

a light gathering unit that gathers, onto a recording medium, laser light which is emitted from the vertical cavity surface emitting laser; and

a mechanism that scans the laser light, which has been gathered by the light gathering unit, on the recording medium.

13. A method for producing a vertical cavity surface emitting laser, the method comprising:

stacking, on a substrate, a first semiconductor multilayer film reflector of a first conductivity type, an active region, and a second semiconductor multilayer film reflector of a second conductivity type that is a conductivity type different from the first conductivity type;

forming, on the second semiconductor multilayer film reflector, a light absorption layer that is capable of absorbing light having an emission wavelength and that has an opening;

forming, on the second semiconductor multilayer film reflector, an electrode that has a light emitting aperture the periphery of which is defined by the periphery of the light absorption layer; and

forming, on the second semiconductor multilayer film reflector that is exposed through the opening of the light absorption layer, a light transmission layer that the light having the emission wavelength is able to pass through,

wherein a thickness of the light transmission layer is in a range between about ±

10% of d1 that is obtained using an equation d1=(2a−

1)λ

/2n1 where a is an integer, λ

is an emission wavelength, and n1 is a refractive index, and

wherein a thickness d2 of the light absorption layer satisfies a condition represented by an equation (n2−

1)×

d2+(1−

n1)×

d1=λ

×

b where b is an integer and n2 is a refractive index.

14. A method for producing a vertical cavity surface emitting laser, the method comprising:

stacking, on a substrate, a first semiconductor multilayer film reflector of a first conductivity type, an active region, and a second semiconductor multilayer film reflector of a second conductivity type that is a conductivity type different from the first conductivity type, the second semiconductor multilayer film reflector including a high-concentration semiconductor layer having a relatively high impurity concentration as a top layer;

forming, on the second semiconductor multilayer film reflector, an electrode that is electrically connected to the high-concentration semiconductor layer and that has a light emitting aperture; and

etching one portion of the high-concentration semiconductor layer that is exposed through the light emitting aperture of the electrode, and forming, in a region corresponding to the etched portion, a light transmission layer that light having an emission wavelength is able to pass through,

wherein a thickness of the light transmission layer is in a range between about ±

10% of d1 that is obtained using an equation d1=(2a−

1)λ

/2n1 where a is an integer, λ

is an emission wavelength, and n1 is a refractive index, and

wherein a thickness d2 of the high-concentration semiconductor layer satisfies a condition represented by an equation (n2−

1)×

d2+(1−

n1)×

d1=λ

×

b where b is an integer and n2 is a refractive index.

15. The method for producing a vertical cavity surface emitting laser according to claim 14,

wherein an etching stopper layer having an etch selection ratio is included between the high-concentration semiconductor layer and an additional high-concentration semiconductor layer, or between the high-concentration semiconductor layer and a semiconductor layer that is included in the second semiconductor multilayer film reflector and that has a relatively low impurity concentration, and

wherein etching of the high-concentration semiconductor layer is stopped by the etching stopper layer.