Q-switched oscillator seed-source for MOPA laser illuminator apparatus and method
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.
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 powered optical amplifier.
13. The apparatus of claim 8 , wherein the solid-state optical amplifier is an optically powered optical amplifier, the apparatus further comprising an electrically powered pump-light semiconductor-diode that is activated by an electrical pulse to supply pump light to the optically powered optical amplifier to enable the generation of the Q-switched pulsed-laser seed signal.
14. The apparatus of claim 8 , wherein the first optical-gain waveguide is a planar waveguide formed on a substrate.
15. The apparatus of claim 8 , wherein the Q-switched seed laser includes a wavelength-division multiplexer (WDM) configured to couple the amplified signal light from the first optical-gain waveguide to the solid-state optical amplifier and to couple the pump light from the first optical pump source into the first optical-gain waveguide.
16. A method comprising:
providing a lasing cavity that includes a first optical-gain waveguide and a solid-state optical amplifier;
optically pumping the first optical-gain waveguide in order to amplify signal light propagating through the first optical-gain waveguide; and
in a first mode of the solid-state optical amplifier, attenuating the amplified signal light, and in a second mode of the solid-state optical amplifier, enabling generation of a Q-switched pulsed-laser seed signal in the lasing cavity, wherein the Q-switched pulsed-laser seed signal has an energy of at least 1 milliJoule (mJ).
17. The method of claim 16 , further comprising:
configuring the first optical-gain waveguide and the solid-state optical amplifier as a Q-switched ring laser; and
forcing unidirectional light travel around the ring laser.
18. The method of claim 16 , wherein the enabling of the generation of the Q-switched pulsed-laser seed signal includes supplying electrical power to the solid-state optical amplifier.
19. The method of claim 16 , wherein the enabling generation of the Q-switched pulsed-laser seed signal includes optically powering the solid-state optical amplifier.
20. An apparatus comprising:
a lasing cavity, wherein the lasing cavity includes a first optical-gain waveguide;
an optical pump source coupled to supply pump light to the first optical-gain waveguide in order to amplify signal light propagating through the first optical-gain waveguide;
solid-state means for, in a first mode, attenuating the amplified signal light, and in a second mode, enabling generation of a Q-switched pulsed-laser seed signal in the lasing cavity, wherein the Q-switched pulsed-laser seed signal has an energy of at least 1 milliJoule (mJ).