# US 11,444,428 B2 · Laser systems and related methods > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,444,428 B2 - Document ID: US11444428B2 - Status: Granted - Kind: B2 - Application number: 16/841,353 - Filed: 2020-04-06 - Published: 2020-08-06 - Granted: 2022-09-13 - Earliest claimed: 2013-11-28 - Assignees: Candela Corporation - Applicants: Candela Corporation - Inventors: Jayant D. Bhawalkar; Xiaoming Shang - Web page: https://patentgrep.com/patent/US11444428B2 ## CPC - H01S 3/1633: {BeAl2O4, i.e. Chrysoberyl} - H01S 3/0627: {the resonator being monolithic, e.g. microlaser} - H01S 3/06754: {Fibre amplifiers (H01S3/06708 takes precedence)} - H01S 3/08081: {Unstable resonators} - H01S 3/094061: {Shared pump, i.e. pump light of a single pump source is used to pump plural gain media in parallel} - H01S 3/109: Frequency multiplication, e.g. harmonic generation - H01S 3/1115: using intracavity saturable absorbers - H01S 3/1312: {by controlling the optical pumping} - H01S 3/2308: {Amplifier arrangements, e.g. MOPA} - H01S 3/005: {Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping (shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B)} - H01S 3/0071: {Beam steering, e.g. whereby a mirror outside the cavity is present to change the beam direction} - H01S 3/0092: {Nonlinear frequency conversion, e.g. second harmonic generation [SHG] or sum- or difference-frequency generation outside the laser cavity (nonlinear frequency conversion per se G02F1/35)} - H01S 3/061: {with elliptical or circular cross-section and elongated shape, e.g. rod} - H01S 3/0612: {Non-homogeneous structure (H01S3/07 takes precedence)} - H01S 3/0617: {having a varying composition or cross-section in a specific direction} - H01S 3/0625: {Coatings on surfaces other than the end-faces} - H01S 3/092: of flash lamp (H01S3/0937 takes precedence {; flash lamps per se H01J61/80; circuit arrangements for operating flash lamps in general H05B41/30}) - H01S 3/094053: {Fibre coupled pump, e.g. delivering pump light using a fibre or a fibre bundle} - H01S 3/094069: {Multi-mode pumping} - H01S 3/094076: {Pulsed or modulated pumping (H01S3/1024 takes precedence)} - H01S 3/10023: {by functional association of additional optical elements, e.g. filters, gratings, reflectors} - H01S 3/113: using intracavity saturable absorbers - H01S 3/13013: {by controlling the optical pumping} - H01S 3/1611: {neodymium} - H01S 3/1643: {YAG} - H01S 2301/02: ASE (amplified spontaneous emission), noise; Reduction thereof - H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL ## Abstract A MOPA laser system that includes a seed laser configured to output pulsed laser light, an amplifier configured to receive and amplify the pulsed laser light emitted by the seed laser; and a pump laser configured to deliver a pump laser beam to both the seed laser and the amplifier and a variable attenuator configured to eliminate missing Q-switched pulses. ## Claims ### Claim 1 A high-energy sub-nanosecond laser system comprising: a pump laser operable to generate a pump laser beam; a seed laser operable to receive the pump laser beam and to generate a seed laser beam; an optical fiber operable to receive the pump laser beam and the seed laser beam; and an amplifier coupled to the optical fiber and operable to receive the seed laser beam and the pump laser beam from the optical fiber, wherein the pump laser is operable to simultaneously deliver the pump laser beam directly to both the seed laser and the amplifier to support automatic synchronization of the seed laser and the amplifier. ### Claim 2 (depends on 1) The high-energy sub-nanosecond laser system of claim 1, wherein the pump laser is a solid-state laser pumped by at least one flash lamp, and the pump laser emits laser pulses with energies greater than 1 J and durations shorter than 0.5 msec. ### Claim 3 (depends on 1) The high-energy sub-nanosecond laser system of claim 1, wherein the pump laser is an alexandrite laser or diode laser. ### Claim 4 (depends on 1) The pump laser of claim 1, wherein the pump laser includes two portions, one of which is operable to pump the seed laser while the other portion is operable to pump the amplifier via the optical fiber. ### Claim 5 (depends on 1) The high-energy sub-nanosecond laser system of claim 1, wherein the optical fiber is a multimode fiber or a hollow core fiber. ### Claim 6 (depends on 1) The high-energy sub-nanosecond laser system of claim 1, wherein the amplifier is located within a treatment handpiece. ### Claim 7 (depends on 6) The high-energy sub-nanosecond laser system of claim 6, further comprising a pump beam shaping segment to deliver a specific spot size into an amplifier gain medium for optimizing extraction efficiency, wherein the pump beam shaping segment is located within the treatment handpiece. ### Claim 8 (depends on 7) The high-energy sub-nanosecond laser system of claim 7, further comprising a frequency multiplying segment, wherein the frequency multiplying segment is located within the treatment handpiece. ### Claim 9 (depends on 7) The high-energy sub-nanosecond laser system of claim 7, further comprising a frequency doubling device, wherein the frequency doubling device is located within the treatment handpiece. ### Claim 10 (depends on 1) The high-energy sub-nanosecond laser system of claim 1, wherein the amplifier is operable to receive and amplify a sub-nanosecond pulsed laser light emitted by the seed laser. ### Claim 11 (depends on 1) The high-energy sub-nanosecond laser system of claim 1, wherein the seed laser is operable to output a sub-nanosecond pulsed laser beam. ### Claim 12 (depends on 11) The high-energy sub-nanosecond laser system of claim 11, wherein the seed laser comprises at least a gain medium and a passive Q-switch. ### Claim 13 (depends on 1) The high-energy sub-nanosecond laser system of claim 1, further comprising a variable attenuator operable to adjust pump beam energy for the seed laser and to actively control time delay of Q-switched pulses to avoid missing Q-switched pulses. ### Claim 14 (depends on 13) The high-energy sub-nanosecond laser system of claim 13, wherein the variable attenuator is also operable to prevent generation of multiple Q-switched pulses. ### Claim 15 (depends on 1) The high-energy sub-nanosecond laser system of claim 1, further comprising a variable attenuator operable to actively control the pump energy to the amplifier to regulate the amplified laser energy. ### Claim 16 (depends on 1) The high-energy sub-nanosecond laser system of claim 1, wherein the optical fiber has a length selected to mode-scramble a pumping energy such as to provide a homogenous pumping energy distribution at an output of the multi-mode optical fiber, whereby the amplifier is insensitive to output beam quality fluctuations in the seed laser and pump laser. ### Claim 17 (depends on 1) The high-energy sub-nanosecond laser system of claim 1, wherein the optical fiber is operable to deliver both the seed laser and the pump laser. ### Claim 18 (depends on 17) The high-energy sub-nanosecond laser system of claim 17, wherein the optical fiber is operable to provide optical alignment and spatial overlap between the seed laser beam and a pumped gain region in the amplifier. ### Claim 19 A high-energy sub-nanosecond laser system comprising: an amplifier; an optical fiber coupled to the amplifier; a seed laser operable to receive a pump laser beam generated by a pump laser and generate a seed laser beam; wherein the optical fiber is operable to receive the seed laser beam and the pump laser beam and transmit the seed laser beam and the pump laser beam to the amplifier, and wherein the pump laser is operable to simultaneously deliver the pump laser beam directly to both the seed laser and the amplifier to support automatic synchronization of the seed laser and the amplifier. ### Claim 20 (depends on 19) The high-energy sub-nanosecond laser system of claim 19, wherein the amplifier is located within a treatment handpiece. ### Claim 21 A high-energy sub-nanosecond laser system comprising: a pump laser operable to generate a pump laser beam; a seed laser operable to receive the pump laser beam and to generate a seed laser beam; an optical fiber operable to receive the pump laser beam and the seed laser beam; and a treatment handpiece comprising an amplifier and a pump beam shaping element operable to receive the seed laser beam and pump energy from the optical fiber, wherein the pump laser, seed laser, and the optical fiber are located outside of the treatment handpiece, and wherein the pump laser is operable to simultaneously deliver the pump laser beam directly to both the seed laser and the amplifier to support automatic synchronization of the seed laser and the amplifier.