Laser device, and laser waveform control method

Patent metadata

Field	Value
Publication number	US-12362539-B2
Application number	US-201917274672-A
Country	US
Kind code	B2
Filing date	Jul 2, 2019
Priority date	Sep 21, 2018
Publication date	Jul 15, 2025
Grant date	Jul 15, 2025

Abstract

A laser apparatus includes a semiconductor laser element, a waveform calculation unit for calculating input waveform data, a driver circuit for supplying a drive current having a temporal waveform according to the input waveform data to the semiconductor laser element, an optical amplifier for amplifying laser light output from the semiconductor laser element, and a light waveform detection unit for detecting a waveform of laser light after the amplification output from the optical amplifier. The waveform calculation unit compares the waveform of the laser light after the amplification detected by the light waveform detection unit with a target waveform, adjusts a temporal waveform of the input waveform data, and brings the waveform of the laser light after the amplification close to the target waveform.

First claim

The invention claimed is:

1. A laser apparatus comprising:
a semiconductor laser element being a single laser diode;
a waveform calculation unit configured to calculate input waveform data;
a driver circuit electrically connected to the waveform calculation unit and the semiconductor laser element, and configured to generate a drive current having a temporal waveform according to the input waveform data, and supply the drive current to the single laser diode of the semiconductor laser element;
an optical amplifier optically coupled to the semiconductor laser element, and configured to amplify light output from the semiconductor laser element; and
a light waveform detection unit configured to detect a light waveform after the amplification output from the optical amplifier, wherein
the waveform calculation unit is configured to compare the light waveform after the amplification detected by the light waveform detection unit with a target waveform to generate difference data, adjust the temporal waveform of the drive current by adjusting a temporal waveform of the input waveform data based on the target waveform and the difference data, and adjust a light waveform output from the semiconductor laser element only by the drive current having the temporal waveform adjusted by the input waveform data to bring the light waveform after the amplification close to the target waveform, and
the waveform calculation unit is configured to adjust the temporal waveform of the input waveform data so that a difference between the light waveform after the amplification detected by the light waveform detection unit and the target waveform approaches 0.

2. The laser apparatus according to claim 1 , wherein the waveform calculation unit includes a storage unit configured to store data representing the target waveform in advance.

3. The laser apparatus according to claim 1 , wherein the driver circuit includes:
a D/A conversion unit configured to convert the digital input waveform data into an analog drive signal; and
a current conversion unit configured to convert the drive signal into the drive current, wherein
the D/A conversion unit is configured to sequentially convert a plurality of continuous section waveform data formed by dividing the temporal waveform of the input waveform data into the drive signal while giving a time difference.

4. A laser waveform control method comprising:
a current supply step of generating a drive current having a temporal waveform according to input waveform data prepared for a semiconductor laser element being a single laser diode, and supplying the drive current to the single laser diode of the semiconductor laser element;
an optical amplification step of amplifying light output from the semiconductor laser element;
a light waveform detection step of detecting a light waveform after the amplification; and
a waveform adjustment step of comparing the light waveform after the amplification detected by the light waveform detection step with a target waveform to generate difference data, adjusting the temporal waveform of the drive current by adjusting a temporal waveform of the input waveform data based on the target waveform and the difference data, and adjusting a light waveform output from the semiconductor laser element only by the drive current having the temporal waveform adjusted by the input waveform data to bring the light waveform after the amplification close to the target waveform,
wherein the waveform adjustment step adjusts the temporal waveform of the input waveform data so that a difference between the light waveform after the amplification detected by the light waveform detection step and the target waveform approaches 0.

5. The laser waveform control method according to claim 4 , wherein the current supply step includes:
a D/A conversion step of converting the digital input waveform data into an analog drive signal; and
a current conversion step of converting the drive signal into the drive current, wherein
the D/A conversion step sequentially converts a plurality of continuous section waveform data formed by dividing the temporal waveform of the input waveform data into the drive signal while giving a time difference.

Assignees

• Hamamatsu Photonics Kk

Inventors

• Kurita Takashi
• Kato Yoshinori
• Kawashima Toshiyuki

Classifications

• H01S2301/08

  Generation of pulses with special temporal shape or frequency spectrum · CPC title

• H01S5/0064

  Anti-reflection components, e.g. optical isolators · CPC title

• H01S5/06835

  Stabilising during pulse modulation or generation · CPC title

• H01S3/1301

  in optical amplifiers · CPC title

• H01S3/10015

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