Amplifier assembly with semiconductor optical amplifier

Patent metadata

Field	Value
Publication number	US-10720748-B2
Application number	US-201916273736-A
Country	US
Kind code	B2
Filing date	Feb 12, 2019
Priority date	Oct 18, 2017
Publication date	Jul 21, 2020
Grant date	Jul 21, 2020

Abstract

In one embodiment, a laser system includes a seed laser diode configured to produce a free-space seed-laser beam and a seed-laser focusing lens configured to focus the seed-laser beam. The laser system also includes a semiconductor optical amplifier (SOA) that includes a front facet, a back facet, and a waveguide extending from the front facet to the back facet. The SOA is configured to: receive, at the front facet, light from the focused seed-laser beam; amplify the received light as the received light propagates along the SOA waveguide from the front facet to the back facet; and emit, from the back facet, an amplified free-space beam that includes the amplified received light. The laser system further includes a mounting platform, where one or more of the seed laser diode, the seed-laser focusing lens, and the SOA are mechanically attached to the mounting platform.

First claim

What is claimed is:

1. A laser system comprising:
a seed laser diode configured to produce a free-space seed-laser beam;
a seed-laser focusing lens configured to focus the seed-laser beam;
a semiconductor optical amplifier (SOA) comprising a front facet, a back facet, and a waveguide extending from the front facet to the back facet, wherein the SOA is configured to:
receive, at the front facet, light from the focused seed-laser beam;
amplify the received light as the received light propagates along the SOA waveguide from the front facet to the back facet; and
emit, from the back facet, an amplified free-space beam comprising the amplified received light, wherein the amplified free-space beam comprises optical pulses, the optical pulses having:
a wavelength between 1400 nm and 1600 nm;
a pulse energy between 0.01 μJ and 100 μJ;
a pulse repetition frequency between 100 kHz and 10 MHz; and
a pulse duration between 0.2 ns and 20 ns; and

a mounting platform, wherein one or more of the seed laser diode, the seed-laser focusing lens, and the SOA are mechanically attached to the mounting platform.

2. The laser system of claim 1 , wherein the seed laser diode is thermally coupled to a thermoelectric cooler configured to stabilize a temperature of the seed laser diode.

3. The laser system of claim 1 , further comprising an output lens configured to collimate the amplified free-space beam to produce a collimated free-space output beam.

4. The laser system of claim 1 , further comprising an optical filter located after the SOA and configured to remove amplified spontaneous emission (ASE) from the amplified free-space beam.

5. The laser system of claim 1 , wherein the front facet and the back facet each comprises an anti-reflection coating configured to reduce a reflectivity of the facet.

6. The laser system of claim 1 , wherein the SOA waveguide is angled with respect to the front and back facets.

7. The laser system of claim 1 , wherein the mounting platform is configured to be in thermal contact with a thermally conductive object configured to receive or dissipate heat from the platform.

8. The laser system of claim 1 , wherein the mounting platform is configured to be thermally coupled to a thermoelectric cooler configured to remove excess heat from the platform or maintain the platform at a substantially constant temperature.

9. The laser system of claim 1 , wherein the mounting platform is configured to be thermally coupled to a thermoelectric cooler (TEC), wherein when a temperature of the platform reaches or exceeds a particular maximum temperature, the TEC is configured to be activated to keep the temperature of the platform at or below the particular maximum temperature.

10. The laser system of claim 1 , wherein the mounting platform is configured to be thermally coupled to a heating element, wherein when a temperature of the platform reaches or goes below a particular minimum temperature, the heating element is configured to be activated to keep the temperature of the platform at or above the particular minimum temperature.

11. The laser system of claim 1 , wherein the mounting platform comprises a glass, ceramic, semiconductor, or metal material having a relatively low coefficient of thermal expansion or a relatively high thermal conductivity.

12. The laser system of claim 1 , wherein one or more of the seed laser diode, the seed-laser focusing lens, and the SOA are mechanically attached to the mounting platform using an active-alignment technique.

13. The laser system of claim 1 , wherein one or more of the seed laser diode, the seed-laser focusing lens, and the SOA are mechanically attached to the mounting platform by epoxy, solder, or one or more mechanical fasteners.

14. The laser system of claim 1 , wherein:
the free-space seed-laser beam comprises optical pulses having a particular pulse repetition frequency; and
the SOA is configured to receive pulsed electrical current having a pulse frequency that matches the pulse repetition frequency of the seed-laser optical pulses, wherein the SOA is configured to provide optical gain when a seed-laser optical pulse is present.

15. The laser system of claim 1 , wherein:
the free-space seed-laser beam comprises continuous-wave (CW) light; and
the SOA is configured to receive pulsed electrical current, wherein the SOA is configured to amplify the CW seed-laser light when electrical current is supplied to the SOA and absorb the CW seed-laser light when little or no electrical current is supplied to the SOA.

16. The laser system of claim 1 , wherein the laser system is part of a lidar system comprising a scanner and a receiver, wherein:
the laser system provides the amplified free-space beam to the scanner as a collimated free-space output beam;
the scanner is configured to scan at least a portion of the output beam across a field of regard of the lidar system; and
the receiver is configured to detect at least a portion of the output beam scattered by a target located a distance from the lidar system.

17. The laser system of claim 16 , wherein the lidar system is part of a vehicle comprising an advanced driver assistance system (ADAS) configured to assist a driver of the vehicle in driving the vehicle.

18. The laser system of claim 16 , wherein the lidar system is part of an autonomous vehicle comprising an autonomous-vehicle driving system, wherein the lidar system is configured to provide information about a surrounding environment of the vehicle to the autonomous-vehicle driving system.

19. A laser system comprising:
a seed laser diode configured to produce a free-space seed-laser beam;
a seed-laser focusing lens configured to focus the seed-laser beam;
a semiconductor optical amplifier (SOA) comprising a front facet, a back facet, and a waveguide extending from the front facet to the back facet, wherein the SOA is configured to:
receive, at the front facet, light from the focused seed-laser beam;
amplify the received light as the received light propagates along the SOA waveguide from the front facet to the back facet; and
emit, from the back facet, an amplified free-space beam comprising the amplified received light; and

a mounting platform, wherein:
one or more of the seed laser diode, the seed-laser focusing lens, and the SOA are mechanically attached to the mounting platform; and
the mounting platform comprises one or more mechanical registration features configured to define a fixed position on the platform for each of one or more of the seed laser diode, the seed-laser focusing lens, and the SOA.

20. The laser system of claim 19 , wherein:
the mounting platform comprises silicon or a silicon-based material; and
the mechanical registration features are produced through a microfabrication process applied to the platform.

21. The laser system of claim 19 , wherein one or more of the seed laser diode, the seed-laser focusing lens, and the SOA are mechanically attached to the mounting platform using a passive-alignment technique based on the mechanical registration features.

22. A laser system comprising:
a seed laser diode configured to produce a free-space seed-laser beam;
a seed-laser focusing lens configured to focus the seed-laser beam;
a semiconductor optical amplifier (SOA) comprising a front facet, a back facet, and a waveguide extending from the front facet to the back facet, wherein the SOA is configured to:
receive, at the front facet, light from the focused seed-laser beam;

Assignees

• Luminar Tech Inc

Inventors

• Villeneuve Alain
• Eichenholz Jason M
• Lingvay Laurance S

Classifications

• G01S17/10 Primary

  using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32) · CPC title

• H01S3/0078

  Frequency filtering · CPC title

• G01S17/42

  Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S17/46) · CPC title

• H01S5/0057

  for temporal shaping, e.g. pulse compression, frequency chirping · CPC title

• G02B27/10

  Beam splitting or combining systems (polarising systems G02B27/28; mixing and splitting light signals using optical waveguides G02B6/28; {beam shaping, e.g. changing the cross-sectional area, by dividing or superposing multiple light beams G02B27/0905}) · CPC title