Q-switched oscillator seed-source for MOPA laser illuminator apparatus and method

Patent metadata

Field	Value
Publication number	US-9923329-B2
Application number	US-201514596020-A
Country	US
Kind code	B2
Filing date	Jan 13, 2015
Priority date	Nov 23, 2009
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

An apparatus, method and system that uses a Q-switched laser or a Q-seed source for a seed pulse signal having a controlled high-dynamic-range amplitude that avoids and/or compensates for pulse steepening in high-gain optical-fiber and/or optical-rod amplification of optical pulses. Optionally, the optical output is used for LIDAR or illumination purposes (e.g., for image acquisition). In some embodiments, well-controlled pulse shapes are obtained having a wide dynamic range, long duration, and not-too-narrow linewidth. In some embodiments, upon the opening of a Q-switch in an optical cavity having a gain medium, the amplification builds relatively slowly, wherein each round trip through the gain medium increases the amplitude of the optical pulse. Other embodiments use quasi-Q-switch devices or a plurality of amplitude modulators to obtain Q-seed pulses. These configurations provide optical pulses having wide dynamic ranges that ameliorate problems of pulse steepening, non-linear spectral broadening and the like in very-high-power MOPA devices.

First claim

What is claimed is:

1. An apparatus comprising:
a Q-switched seed laser, wherein the Q-switched seed laser includes:
a first optical pump source,
a first optical-gain waveguide optically coupled to receive pump light from the first optical pump source and configured to amplify signal light that propagates through the first optical-gain waveguide, and
a solid-state optical amplifier configured to receive the amplified signal light from the first optical-gain waveguide and, in a first mode, configured to attenuate the amplified signal light, and in a second mode, configured to enable generation of a Q-switched pulsed-laser seed signal;

a vehicle having an enclosure;
an electrical power supply attached to the vehicle;
a laser controller operatively coupled to receive electrical power from the electrical power supply and operably coupled to power and control the first optical pump source;
a high-power amplification system having at least a second pump source and a second optical-gain waveguide, wherein the high-power amplification system is operatively coupled to receive the Q-switched pulsed-laser seed signal and operatively configured to amplify the Q-switched pulsed-laser seed signal in the second optical-gain waveguide to obtain an output beam; and
a beam-direction controller operably coupled to receive the output beam from the second optical-gain waveguide and operable to direct the output beam in one of a plurality of different possible directions relative to the vehicle.

2. An apparatus comprising:
a Q-switched seed laser, wherein the Q-switched seed laser includes:
a first optical pump source, and
a lasing cavity, wherein the lasing cavity includes:
a first optical-gain waveguide optically coupled to receive pump light from the first optical pump source and configured to amplify signal light that propagates through the first optical-gain waveguide, and
a solid-state optical amplifier configured to receive the amplified signal light from the first optical-gain waveguide and, in a first mode, configured to attenuate the amplified signal light, and in a second mode, configured to enable generation of a Q-switched pulsed-laser seed signal in the lasing cavity,

wherein the Q-switched seed laser is implemented in a single package having a volume of no more than six (6) cm 3 .

3. An apparatus comprising:
a Q-switched seed laser, wherein the Q-switched seed laser includes:
a first optical pump source, and
a lasing cavity, wherein the lasing cavity includes:
a first optical-gain waveguide optically coupled to receive pump light from the first optical pump source and configured to amplify signal light that propagates through the first optical-gain waveguide, and
a solid-state optical amplifier configured to receive the amplified signal light from the first optical-gain waveguide and, in a first mode, configured to attenuate the amplified signal light, and in a second mode, configured to enable generation of a Q-switched pulsed-laser seed signal in the lasing cavity,

wherein the Q-switched seed laser generates an optical pulse having a full-width half-maximum (FWHM) duration of between one and five nanoseconds, inclusive.

4. The apparatus of claim 3 , further comprising:
a high-power amplification system that includes at least a second optical pump source and a second optical-gain waveguide, wherein the high-power amplification system is operatively coupled to receive the Q-switched pulsed-laser seed signal and is operatively configured to amplify the Q-switched pulsed-laser seed signal in the second optical-gain waveguide to obtain an output beam,
wherein the Q-switched seed laser includes an output coupler beam splitter configured to transmit a first portion of the Q-switched pulsed-laser seed signal to the high-power amplification system and configured to transmit a second portion of the Q-switched pulsed-laser seed signal as feedback into the first optical-gain waveguide.

5. The apparatus of claim 3 , further comprising:
a high-power amplification system that includes at least a second optical pump source and a second optical-gain waveguide, wherein the high-power amplification system is operatively coupled to receive the Q-switched pulsed-laser seed signal and is operatively configured to amplify the Q-switched pulsed-laser seed signal in the second optical-gain waveguide to obtain an output beam,
wherein the second optical-gain waveguide includes a first high-gain optical fiber amplifier and a second high-gain optical fiber amplifier optically coupled in a chain configuration.

6. The apparatus of claim 3 , further comprising:
a high-power amplification system that includes at least a second optical pump source and a second optical-gain waveguide, wherein the high-power amplification system is operatively coupled to receive the Q-switched pulsed-laser seed signal and is operatively configured to amplify the Q-switched pulsed-laser seed signal in the second optical-gain waveguide to obtain an output beam,
wherein the high-power amplification system further includes a hollow-core delivery fiber having a fiber endcap.

7. The apparatus of claim 3 further comprising:
a vehicle having an enclosure;
an electrical power supply attached to the vehicle;
a laser controller operatively coupled to receive electrical power from the electrical power supply and operably coupled to power and control the first optical pump source;
a high-power amplification system having at least a second pump source and a second optical-gain waveguide, wherein the high-power amplification system is operatively coupled to receive the Q-switched pulsed-laser seed signal and operatively configured to amplify the Q-switched pulsed-laser seed signal in the second optical-gain waveguide to obtain an output beam; and
a beam-direction controller operably coupled to receive the output beam from the second optical-gain waveguide and operable to direct the output beam in one of a plurality of different possible directions relative to the vehicle.

8. An apparatus comprising:
a Q-switched seed laser, wherein the Q-switched seed laser includes:
a first optical pump source, and
a lasing cavity, wherein the lasing cavity includes:
a first optical-gain waveguide optically coupled to receive pump light from the first optical pump source and configured to amplify signal light that propagates through the first optical-gain waveguide, and
a solid-state optical amplifier configured to receive the amplified signal light from the first optical-gain waveguide and, in a first mode, configured to attenuate the amplified signal light, and in a second mode, configured to enable generation of a Q-switched pulsed-laser seed signal in the lasing cavity,

wherein the Q-switched seed laser generates an optical pulse having an energy of at least 4 milliJoules (mJ).

9. The apparatus of claim 8 , wherein the first optical-gain waveguide and the solid-state optical amplifier are configured as a Q-switched ring laser, the ring laser further comprising an optical isolator configured to force unidirectional light travel around the ring laser.

10. The apparatus of claim 8 , wherein the solid-state optical amplifier is an electrically powered semiconductor-diode optical amplifier.

11. The apparatus of claim 8 , wherein the solid-state optical amplifier is an electrically powered semiconductor-diode optical amplifier, the apparatus further comprising:
an electrical driver that supplies electrical power to the semiconductor-diode optical amplifier to enable generation of the Q-switched pulsed-laser seed signal.

12. The apparatus of claim 8 , wherein the solid-state optical amplifier is an optically

Assignees

• Lockheed Corp

Inventors

• Savage-Leuchs Matthias P
• Dilley Christian E
• Lemaire Charles A

Classifications

• H01S3/115

  using intracavity electro-optic devices · CPC title

• H01S3/1022

  by controlling the optical pumping · CPC title

• H01S3/094003

  the pumped medium being a fibre · CPC title

• H01S3/2316

  Cascaded amplifiers · CPC title

• H01S2301/03

  Suppression of nonlinear conversion, e.g. specific design to suppress for example stimulated brillouin scattering [SBS], mainly in optical fibres in combination with multimode pumping · CPC title