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US 12,266,898 B2Granted
Methods and devices for laser power projection on a remote target with coherent fiber array and adaptive beam control
AssigneeII-Vi Delaware, Inc.
InventorMikhail A Vorontsov
Life of this patent
Estimating the term…
Abstract
A coherent fiber array laser power projection system scalable to large number of subapertures and includes sensors that produce signals dependent upon beam characteristics, and controllers configured to control beam characteristics to achieve either phasing of outgoing beams at transmitter plane or coherent beam combining at a remote target or both.
Claims20
A system for projecting laser power on a remotely located target, the system comprising:
- a coherent master oscillator power amplifier fiber (MOPA) system providing a plurality of laser beams on a plurality of fiber channels;
- a fiber array laser head including a plurality of subapertures positioned adjacent one another, each subaperture configured to transmit a beamlet portion of the laser beam transmitted through the subaperture from a corresponding one of the fiber channels, a peripheral portion of each subaperature configured to not transmit a beam tail portion of the laser beam through the subaperture;
- a plurality of sensors positioned to receive laser light associated with the plurality of laser beams provided by the MOPA system and configured to produce a set of sensor signals based upon the received laser light;
- and
- a control system configured to generate a set of control signals based upon the set of sensor signals, wherein the set of control signals is configured to cause the MOPA system to modulate characteristics of the plurality of laser beams, wherein the control system at least includes a phase locking controller configured to control wavefront piston phases of a plurality of the beamlet portions to converge towards a phase locking condition under which wavefront piston phases of the beamlet portions are either equal or differ by 2πn radians, where n is an integer number,
- wherein the control system further comprises one or more of:
- a polarization state controller configured to mutually co-align polarization states of the plurality of the beamlet portions in time;
- an angular co-alignment controller configured to mutually co-align the transmission angles of the plurality of beamlet portions in time;
- an optical path matching controller configured to mutually equalize optical carrier frequencies of the plurality of the beamlet portions in time;
- one or more first controllers configured to operate in a pre-defined sequential order to provide all or some characteristics of the plurality of beamlet portions in time;
- a second controller configured to provide mitigation of non-common path piston phase aberrations;
- and
- a third controller configured to provide pre-defined mutual stabilization of wavefront piston phases of the plurality of beamlets in time.
10 more elements
A system for projecting laser power on a remotely located target, the system comprising:
- a coherent master oscillator power amplifier fiber (MOPA) system providing a plurality of laser beams on a plurality of fiber channels;
- a fiber array laser head including a plurality of subapertures positioned adjacent one another, each subaperture configured to transmit a beamlet portion of the laser beam transmitted through the subaperture from a corresponding one of the fiber channels, a peripheral portion of each subaperature configured to not transmit a beam tail portion of the laser beam through the subaperture;
- a plurality of sensors positioned to receive laser light associated with the plurality of laser beams provided by the MOPA system and configured to produce a set of sensor signals based upon the received laser light;
- and
- a control system configured to generate a set of control signals based upon the set of sensor signals, wherein the set of control signals is configured to cause the MOPA system to modulate characteristics of the plurality of laser beams, wherein the control system at least includes a phase locking controller configured to control wavefront piston phases of a plurality of the beamlet portions to converge towards a phase locking condition under which wavefront piston phases of the beamlet portions are either equal or differ by 2πn radians, where n is an integer number,
- wherein at least a subset of the plurality of sensors are integrated into the fiber array laser head and are positioned to receive the laser light of a plurality of the beam tail portions of the plurality of laser beams.
3 more elements
A system for projecting laser power on a remotely located target, the system comprising:
- a coherent master oscillator power amplifier fiber (MOPA) system providing a plurality of laser beams on a plurality of fiber channels;
- a fiber array laser head including a plurality of subapertures positioned adjacent one another, each subaperture configured to transmit a beamlet portion of the laser beam transmitted through the subaperture from a corresponding one of the fiber channels, a peripheral portion of each subaperature configured to not transmit a beam tail portion of the laser beam through the subaperture;
- a plurality of sensors positioned to receive laser light associated with the plurality of laser beams provided by the MOPA system and configured to produce a set of sensor signals based upon the received laser light;
- and
- a control system configured to generate a set of control signals based upon the set of sensor signals, wherein the set of control signals is configured to cause the MOPA system to modulate characteristics of the plurality of laser beams, wherein the control system at least includes a phase locking controller configured to control wavefront piston phases of a plurality of the beamlet portions to converge towards a phase locking condition under which wavefront piston phases of the beamlet portions are either equal or differ by 2πn radians, where n is an integer number,
- wherein at least some of the plurality of sensors are positioned either inside or outside the fiber array laser head to receive the laser light of the plurality of laser beams or the beamlet portions.
3 more elements
A system for projecting laser power on a remotely located target, the system comprising:
- a coherent master oscillator power amplifier fiber (MOPA) system providing a plurality of laser beams on a plurality of fiber channels;
- a fiber array laser head including a plurality of subapertures positioned adjacent one another, each subaperture configured to transmit a beamlet portion of the laser beam transmitted through the subaperture from a corresponding one of the fiber channels, a peripheral portion of each subaperature configured to not transmit a beam tail portion of the laser beam through the subaperture;
- a plurality of sensors positioned to receive laser light associated with the plurality of laser beams provided by the MOPA system and configured to produce a set of sensor signals based upon the received laser light;
- and
- a control system configured to generate a set of control signals based upon the set of sensor signals, wherein the set of control signals is configured to cause the MOPA system to modulate characteristics of the plurality of laser beams, wherein the control system at least includes a phase locking controller configured to control wavefront piston phases of a plurality of the beamlet portions to converge towards a phase locking condition under which wavefront piston phases of the beamlet portions are either equal or differ by 2πn radians, where n is an integer number,
- wherein the plurality of sensors includes a beam tail interference sensor positioned proximate to a center of an overlap region of a pair of the beam tail portions corresponding to first and second adjacent ones of the subapertures, wherein the beam tail interference sensor comprises:
- a transmissive amplitude grating configured to transmit a variable light power therethrough dependent on mutual piston phases of the corresponding laser beams;
- and
- a photodetector configured to receive the variable light power and produce a signal based on the variable light power;
- wherein the control system is further configured to:
- (i) correlate the signal to a piston phase difference between the corresponding laser beams;
- and
- (ii) generate the set of control signals, based on the signal correlated to the piston phase difference, to mitigate the piston phase difference.
10 more elements
A system for projecting laser power on a remotely located target, the system comprising:
- a coherent master oscillator power amplifier fiber (MOPA) system providing a plurality of laser beams on a plurality of fiber channels;
- a fiber array laser head including a plurality of subapertures positioned adjacent one another, each subaperture configured to transmit a beamlet portion of the laser beam transmitted through the subaperture from a corresponding one of the fiber channels, a peripheral portion of each subaperature configured to not transmit a beam tail portion of the laser beam through the subaperture;
- a plurality of sensors positioned to receive laser light associated with the plurality of laser beams provided by the MOPA system and configured to produce a set of sensor signals based upon the received laser light;
- and
- a control system configured to generate a set of control signals based upon the set of sensor signals, wherein the set of control signals is configured to cause the MOPA system to modulate characteristics of the plurality of laser beams, wherein the control system at least includes a phase locking controller configured to control wavefront piston phases of a plurality of the beamlet portions to converge towards a phase locking condition under which wavefront piston phases of the beamlet portions are either equal or differ by 2πn radians, where n is an integer number,
- wherein the plurality of sensors includes a beam tail interference sensor comprising:
- a reflective diffractive grating positioned proximate to a center of an overlap region of a pair of the beam tail portions corresponding to first and second adjacent ones of the subaperture, wherein the reflective diffractive grating is configured to reflect a diffracted pair of the beam tail portions across a distance towards a location;
- an optical system disposed at the location and configured to receive the diffracted pair of the beam tail portions, the optical system configured to transmit a variable light power dependent on one or more of piston phases, or polarization states of the corresponding laser beams;
- a photo-detector configured to receive the variable light power and produce a signal based on the variable light power;
- wherein the control system is further configured to:
- (i) correlate the signal to one or more of a piston phase difference, a polarization state difference, or an optical carrier frequency difference between the corresponding laser beams;
- and
- (ii) generate the set of control signals, based on the signal correlated to one or more of the piston phase difference, the polarization state difference, or the optical carrier frequency difference, to mitigate one or more of the piston phase difference, the polarization state difference, or the optical carrier frequency difference.
10 more elements
A coherent laser power projection system, comprising:
- a fiber array laser head including a plurality of subapertures, wherein the plurality of subapertures includes at least a first subaperture and a second subaperture positioned adjacent to the first subaperture;
- a laser power system configured to provide laser power to the fiber array laser head and configured to produce a set of laser beams, wherein each laser beam of the set of laser beams includes a beamlet portion that is transmitted from a corresponding one of the subapertures and includes a beam tail portion that is not transmitted from the corresponding one of the subapertures;
- a sensing system coupled with the fiber array laser head and designed to measure one or more characteristics of the set of beamlet portions;
- a laser power system controller configured to produce control signals based on signals received from the sensing system to operate the laser power system, the laser power system controller configured to produce the set of laser beams that cause a set of coherently combined beamlet portions to be transmitted from the fiber array laser head;
- and
- a beam tail interference sensor positioned at a center of an overlap region of a pair of the beam tail portions from a pair of the laser beams corresponding to the first subaperture and the second subaperture, the beam tail interference sensor including an amplitude grating and a photodetector, wherein:
- (i) the amplitude grating is configured to transmit a variable light to the photodetector based on piston phases of the pair of laser beams;
- and
- (ii) the photo-detector is configured to produce a signal based on the variable light;
- and
- wherein the laser power system controller is configured to:
- (i) provide a first set of control signals to the laser power system;
- (ii) use the signal as a periodic function of a piston phase difference between the pair of laser beams while providing the first set of control signals;
- (iii) create a second set of controls signals, based on the signal as the periodic function of the piston phase difference, to mitigate the piston phase difference;
- and
- (iv) provide the second set of control signals to the laser power system.
13 more elements
Dependencies are inferred from the claim text.