Optical oscillation device and recording apparatus

Patent metadata

Field	Value
Publication number	US-2015131425-A9
Application number	US-201213545688-A
Country	US
Kind code	A9
Filing date	Jul 10, 2012
Priority date	Jul 19, 2011
Publication date	May 14, 2015
Grant date	—

Abstract

Provided is a recording apparatus including a self-excited oscillation semiconductor laser that has a double quantum well separate confinement heterostructure and includes a saturable absorber section to which a negative bias voltage is applied and a gain section into which a gain current is injected, an optical separation unit, an objective lens, a light reception element, a pulse detection unit, a reference signal generation unit, a phase comparison unit, a recording signal generation unit, and a control unit.

First claim

The invention is claimed as follows:

1 . A recording apparatus comprising:
a self-excited oscillation semiconductor laser that has a double quantum well separate confinement heterostructure and includes a saturable absorber section to which a negative bias voltage is applied and a gain section into which a gain current is injected; an optical separation unit that separates an oscillated light beam from the self-excited oscillation semiconductor laser into two oscillated light beams; an objective lens that condenses one of the separated oscillated light beams on an optical recording medium; a light reception element that receives the other of the oscillated light beams separated by the optical separation unit; a pulse detection unit that detects a pulse of the oscillated light beam received by the light reception element; a reference signal generation unit that generates a master clock signal; a phase comparison unit that calculates a phase difference between the master clock signal and the pulse; a recording signal generation unit that generates a recording signal using a negative voltage at a timing of the master clock signal and applies the recording signal as the negative bias voltage to the saturable absorber unit of the self-excited oscillation semiconductor laser; and a control unit that controls an oscillation frequency of the self-excited oscillation semiconductor laser by changing the gain current to be injected into the gain section of the self-excited oscillation semiconductor laser or the negative bias voltage to be applied to the saturable absorber unit based on the phase difference.

2 . The recording apparatus according to claim 1 , wherein the control unit controls the negative bias voltage during an oscillation period of the self-excited oscillation semiconductor laser.

3 . The recording apparatus according to claim 2 , wherein the negative bias voltage during the oscillation period is a constant direct current voltage.

4 . The recording apparatus according to claim 1 , wherein the control unit controls the gain current during an oscillation period of the self-excited oscillation semiconductor laser.

5 . The recording apparatus according to claim 4 , wherein the gain current during the oscillation period is a constant direct current.

6 . The recording apparatus according to claim 3 , wherein the control unit controls power of the oscillated light beam by controlling the gain current or the negative bias voltage during the oscillation period.

7 . The recording apparatus according to claim 6 , wherein the self-excited oscillation semiconductor laser includes a GaInN guide layer, a p-type AlGaN barrier layer, a p-type GaN/AlGaN superlattice first-clad layer, and a p-type GaN/AlGaN superlattice second-clad layer that are sequentially formed on one surface of an active layer.

8 . The recording apparatus according to claim 7 , wherein the self-excited oscillation semiconductor laser includes an n-type GaN guide layer, an n-type AlGaN clad layer, and an n-type GaN layer that are sequentially formed on the other surface of the active layer.

9 . An optical oscillation device comprising:
a self-excited oscillation semiconductor laser that has a double quantum well separate confinement heterostructure and includes a saturable absorber section to which a negative bias voltage is applied and a gain section into which a gain current is injected; an optical separation unit that separates an oscillated light beam from the self-excited oscillation semiconductor laser; a light reception element that receives one of the oscillated light beams separated by the optical separation unit; a pulse detection unit that detects a pulse of the oscillated light beam received by the light reception element; a reference signal generation unit that generates a master clock signal; a phase comparison unit that calculates a phase difference between the master clock signal and the pulse; a signal generation unit that generates a predetermined signal using a negative voltage at a timing of the master clock signal and applies the predetermined signal as the negative bias voltage to the saturable absorber unit of the self-excited oscillation semiconductor laser; and a control unit that controls the gain current to be injected into the gain section of the self-excited oscillation semiconductor laser or the negative bias voltage to be applied to the saturable absorber unit based on the phase difference.

Assignees

• Fujita Goro
• Maruyama Tsutomu
• Kuramoto Masaru
• Watanabe Hideki
• Sony Corp

Inventors

• Fujita Goro
• Maruyama Tsutomu
• Kuramoto Masaru
• Watanabe Hideki

Classifications

• G11B7/1275

  Two or more lasers having different wavelengths · CPC title

• H01S5/34333

  with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser · CPC title

• H01S5/06253

  Pulse modulation · CPC title

• H01S5/0658

  Self-pulsating · CPC title

• G11B7/126 Primary

  Circuits, methods or arrangements for laser control or stabilisation · CPC title