Laser module

Patent metadata

Field	Value
Publication number	US-2016204568-A1
Application number	US-201514886447-A
Country	US
Kind code	A1
Filing date	Oct 19, 2015
Priority date	Jan 9, 2015
Publication date	Jul 14, 2016
Grant date	—

Abstract

A laser module includes a light source device having a first amplifier that outputs first output light, and a second amplifier that outputs second output light, a first drive circuit that supplies the first amplifier with a first drive current, a second drive circuit that supplies the second amplifier with a second drive current. A dither signal is superimposed on one of two drive currents to respectively grasp the characteristics of the two amplifiers.

First claim

What is claimed is:

1 . A laser module comprising:
a light source device having a first amplifier that outputs first output light, and a second amplifier that outputs second output light; a first drive circuit that supplies the first amplifier with a first drive current on which a dither signal is superimposed; a first monitoring circuit that detects the current supplied to the first amplifier; a second drive circuit that supplies the second amplifier with a second drive current; a second monitoring circuit that detects the second drive current; a light receiving element that receives part of the first output light and the second output light; an optical output monitoring circuit that detects the intensity of the light received by the light receiving element; and a processing circuit that controls the first drive circuit and the second drive circuit, wherein the processing circuit obtains a correlation between the first drive current and the intensity of the first output light from the output from the first monitoring circuit and the output from the optical output monitoring circuit, computes from the correlation the first drive current by which the average of the first output light is made equal to a predetermined value, causes the computed first drive current to be supplied to the first drive circuit, and causes the second drive current to be supplied to the second drive circuit so that the average of the output from the optical output monitoring circuit is constant.

2 . The laser module according to claim 1 , wherein the correlation is a gradient when the abscissa represents the current supplied to the first amplifier and the ordinate represents the first output light.

3 . A laser module comprising:
a light source device having a first amplifier that outputs first output light, and a second amplifier that outputs second output light; a first drive circuit that supplies the first amplifier with a first drive current; a first monitoring circuit that detects the current supplied to the first amplifier; a second drive circuit that supplies the second amplifier with a second drive current; a second monitoring circuit that detects the current supplied to the second amplifier; a light receiving element that receives part of the first output light and the second output light; an optical output monitoring circuit that detects the intensity of the light received by the light receiving element; and a processing circuit that controls the first drive circuit and the second drive circuit, wherein the processing circuit causes a dither signal to be alternately superimposed on the first drive current and the second drive current; obtains a first correlation as a correlation between the first drive current and the intensity of the first output light from the output from the first monitoring circuit and the output from the optical output monitoring circuit when the dither signal is superimposed on the first drive current; obtains a second correlation as a correlation between the second drive current and the intensity of the second output light from the output from the second monitoring circuit and the output from the optical output monitoring circuit when the dither signal is superimposed on the second drive current; computes from the first correlation the first drive current by which the average of the first output light is made equal to a predetermined value, and causes the computed first drive current to be supplied to the first drive circuit, and computes from the second correlation the second drive current by which the average of the second output light is made equal to a predetermined value, and causes the computed second drive current to be supplied to the second drive circuit.

4 . The laser module according to claim 1 , wherein the frequency of the dither signal is set equal to or lower than 100 kHz.

5 . The laser module according to claim 1 , wherein the amplitude of the dither signal is set equal to or smaller than 0.2 dB with respect to the amplitude of the first drive current.

6 . The laser module according to claim 1 , wherein the processing circuit increases the first drive current and the second drive current with passage of time.

7 . The laser module according to claim 1 , further comprising a D/A converter that generates the dither signal.

8 . The laser module according to claim 1 , wherein the optical output monitoring circuit comprises an A/D converter that detects vibration of the light intensity due to the dither signal.

9 . The laser module according to claim 1 , wherein the first output light is transmission light, the second output light is local light to be used for detection on the receiving side, and the laser module performs coherent optical communication.

10 . The laser module according to claim 1 , wherein the second output light is transmission light, the first output light is local light to be used for detection on the receiving side, and the laser module performs coherent optical communication.

Assignees

• Mitsubishi Electric Corp

Inventors

• Kajiya Satoshi
• Fukao Tetsuhiro

Classifications

• H01S5/4087 Primary

  emitting more than one wavelength · CPC title

• H01S3/10015 Primary

  by monitoring or controlling, e.g. attenuating, the input signal · CPC title

• H01S5/0683

  by monitoring the optical output parameters · CPC title

• H01S5/06251

  Amplitude modulation · CPC title

• H01S5/50

  Amplifier structures not provided for in groups H01S5/02 - H01S5/30 · CPC title