# US 11,114,813 B2 · Integrated pumplight homogenizer and signal injector for high-power laser system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,114,813 B2 - Document ID: US11114813B2 - Status: Granted - Kind: B2 - Application number: 15/233,303 - Filed: 2016-08-10 - Published: 2018-09-13 - Granted: 2021-09-07 - Earliest claimed: 2015-11-25 - Assignees: Raytheon Company - Applicants: Raytheon Company - Inventors: David M. Filgas; Stephen H. McGanty; Makan Mohageg; Christopher R. Koontz - Web page: https://patentgrep.com/patent/US11114813B2 ## CPC - H01S 3/094057: {by tapered duct or homogenized light pipe, e.g. for concentrating pump light} - G02B 6/4204: {the coupling comprising intermediate optical elements, e.g. lenses, holograms (encapsulated active devices H01S5/02208)} - G02B 6/4296: {coupling with sources of high radiant energy, e.g. high power lasers, high temperature light sources} - G02B 27/0927: {Systems for changing the beam intensity distribution, e.g. Gaussian to top-hat} - G02B 27/0994: {Fibers, light pipes (optical fibers per se G02B6/02)} - H01S 3/02: Constructional details {(housings or packages of fibre lasers H01S3/06704)} - H01S 3/0405: {Conductive cooling, e.g. by heat sinks or thermo-electric elements} - H01S 3/042: for solid state lasers {(H01S3/0401 takes precedence)} - H01S 3/0632: {Thin film lasers in which light propagates in the plane of the thin film} - H01S 3/0941: of a laser diode - H01S 3/09415: {the pumping beam being parallel to the lasing mode of the pumped medium, e.g. end-pumping} - H01S 3/1103: {Cavity dumping} - H01S 3/2308: {Amplifier arrangements, e.g. MOPA} - G02B 6/4214: {the intermediate optical element having redirecting reflective means, e.g. mirrors, prisms for deflecting the radiation from horizontal to down- or upward direction toward a device (G02B6/4246 takes precedence)} - 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 - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A system includes a master oscillator configured to generate a low-power optical beam. The system also includes a planar waveguide (PWG) amplifier having one or more laser diode pump arrays, a planar waveguide, and a light pipe. The one or more laser diode pump arrays are configured to generate pumplight. The planar waveguide is configured to generate a high-power optical beam using the low-power optical beam and the pumplight. The light pipe is configured to substantially homogenize the pumplight and to inject the homogenized pumplight into the planar waveguide. The light pipe is also configured to inject the low-power optical beam into the planar waveguide. ## Claims ### Claim 1 A system comprising: a master oscillator configured to generate a first optical beam; a planar waveguide (PWG) amplifier configured to receive the first optical beam and pumplight, the PWG amplifier also configured to generate a second optical beam using the first optical beam and the pumplight; and a light pipe comprising: a first optic configured to substantially homogenize the pumplight via internal reflection and to inject the substantially homogenized pumplight into a planar waveguide of the PWG amplifier, and a cladding comprising second and third optics separated from one another by a first gap, the first gap forming a first area of reflection, the first area of reflection configured to: fold the first optical beam and thereby redirect the first optical beam into the planar waveguide, and reflect stray pumplight toward a first beam dump; wherein the second optical beam has a higher power than the first optical beam. ### Claim 2 (depends on 1) The system of claim 1, wherein the light pipe forms a pumplight aperture and an optical beam aperture that are aligned with the planar waveguide. ### Claim 3 (depends on 1) The system of claim 1, wherein the light pipe comprises: a core comprising the first optic, the first optic configured to guide the pumplight along a guiding axis, the first optic also configured to deliver the substantially homogenized pumplight into the planar waveguide. ### Claim 4 (depends on 1) The system of claim 1, wherein the cladding of the light pipe further comprises: fourth and fifth optics separated from one another by a second gap, the second gap forming a second area of reflection, the second area of reflection configured to reflect stray pumplight toward a second beam dump. ### Claim 5 (depends on 1) The system of claim 1, wherein the light pipe comprises: at least two sets of substantially parallel reflective surfaces; and a core that comprises the first optic and that is located between the sets of reflective surfaces, the core configured to guide the pumplight along a guiding axis and deliver the substantially homogenized pumplight into the planar waveguide. ### Claim 6 (depends on 5) The system of claim 5, wherein the core comprises a gas-filled space. ### Claim 7 (depends on 1) The system of claim 1, wherein the light pipe comprises one or more evanescent wave coatings applied to one or more surfaces of the light pipe. ### Claim 8 An apparatus comprising: a light pipe comprising: a first optic configured to substantially homogenize pumplight via internal reflection and to inject the substantially homogenized pumplight into a planar waveguide of a planar waveguide (PWG) amplifier; and a cladding comprising second and third optics separated from one another by a first gap, the first gap forming a first area of reflection, the first area of reflection configured to: fold an optical beam and thereby redirect the optical beam into the planar waveguide, and reflect stray pumplight toward a first beam dump. ### Claim 9 (depends on 8) The apparatus of claim 8, wherein the light pipe forms a pumplight aperture and an optical beam aperture that are configured to align with the planar waveguide. ### Claim 10 (depends on 8) The apparatus of claim 8, wherein the light pipe comprises: a core comprising the first optic, the first optic configured to guide the pumplight along a guiding axis, the first optic also configured to deliver the substantially homogenized pumplight into the planar waveguide. ### Claim 11 (depends on 8) The apparatus of claim 8, wherein the cladding of the light pipe further comprises: fourth and fifth optics separated from one another by a second gap, the second gap forming a second area of reflection, the second area of reflection configured to reflect stray pumplight toward a second beam dump. ### Claim 12 (depends on 8) The apparatus of claim 8, wherein the light pipe comprises: at least two sets of substantially parallel reflective surfaces; and a core that comprises the first optic and that is located between the sets of reflective surfaces, the core configured to guide the pumplight along a guiding axis and deliver the substantially homogenized pumplight into the planar waveguide. ### Claim 13 (depends on 8) The apparatus of claim 8, wherein the light pipe comprises one or more evanescent wave coatings applied to one or more surfaces of the light pipe. ### Claim 14 A method comprising: generating a first optical beam using a master oscillator; generating pumplight using one or more laser diode pump arrays; generating a second optical beam based on the first optical beam and the pumplight using a planar waveguide (PWG) amplifier; using a first optic of a light pipe to substantially homogenize the pumplight via internal reflection and to inject the substantially homogenized pumplight into a planar waveguide of the PWG amplifier; and using a first area of reflection to fold the first optical beam and thereby redirect the first optical beam into the planar waveguide and to reflect stray pumplight toward a first beam dump, the first area of reflection formed by a first gap separating second and third optics in a cladding of the light pipe; wherein the second optical beam has a higher power than the first optical beam. ### Claim 15 (depends on 14) The method of claim 14, wherein the light pipe comprises: a core comprising the first optic, the first optic configured to guide the pumplight along a guiding axis, the first optic configured to deliver the substantially homogenized pumplight into the planar waveguide. ### Claim 16 (depends on 14) The method of claim 14, wherein the cladding of the light pipe further comprises: fourth and fifth optics separated from one another by a second gap, the second gap forming a second area of reflection, the second area of reflection configured to reflect stray pumplight toward a second beam dump. ### Claim 17 (depends on 14) The method of claim 14, wherein the light pipe comprises: at least two sets of substantially parallel reflective surfaces; and a core that comprises the first optic and that is located between the sets of reflective surfaces, the core configured to guide the pumplight along a guiding axis and deliver the substantially homogenized pumplight into the planar waveguide. ### Claim 18 An apparatus comprising: a light pipe comprising a first optic configured to pass pumplight and to inject the pumplight into a planar waveguide of a planar waveguide (PWG) amplifier; and the light pipe also comprising a cladding that comprises second and third optics separated from one another by a first gap, the first gap forming a first area of reflection, the first area of reflection configured to: fold an optical beam and thereby redirect the optical beam into the planar waveguide, and reflect stray pumplight toward a first beam dump. ### Claim 19 (depends on 18) The apparatus of claim 18, wherein the light pipe comprises: a core comprising the first optic configured to guide the pumplight along a guiding axis, the first optic configured to deliver the pumplight into the planar waveguide. ### Claim 20 An apparatus comprising: a light pipe configured to pass pumplight from one or more laser diode pump arrays and to inject the pumplight into a planar waveguide of a planar waveguide (PWG) amplifier; the light pipe also configured to fold an optical beam and thereby redirect the optical beam from a master oscillator into the planar waveguide; the light pipe further configured to scrape stray pumplight so that the stray pumplight is redirected away from the planar waveguide; wherein the light pipe comprises: a core comprising a first optic configured to guide the pumplight along a guiding axis, the first optic configured to deliver the pumplight into the planar waveguide; and a cladding comprising second and third optics separated from one another by a first gap, the first gap forming a first area of reflection, the first area of reflection configured to: fold the optical beam into the planar waveguide; and reflect the stray pumplight away from the planar waveguide. ### Claim 21 (depends on 1) The system of claim 1, wherein the planar waveguide comprises a core and one or more cladding layers, the core configured to receive the first optical beam, at least one of the core and the one or more cladding layers configured to receive the substantially homogenized pumplight. ### Claim 22 (depends on 1) The system of claim 1, wherein the light pipe comprises one or more anti-reflection coatings applied to one or more input or output faces of the light pipe. ### Claim 23 (depends on 1) The system of claim 1, wherein the light pipe comprises one or more heat rejection surfaces extending laterally near one or more input or output ends of the light pipe. ### Claim 24 (depends on 8) The apparatus of claim 8, wherein the light pipe comprises one or more anti-reflection coatings applied to one or more input or output faces of the light pipe. ### Claim 25 (depends on 8) The apparatus of claim 8, wherein the light pipe comprises one or more heat rejection surfaces extending laterally near one or more input or output ends of the light pipe. ### Claim 26 (depends on 18) The apparatus of claim 18, wherein the cladding of the light pipe further comprises: fourth and fifth optics separated from one another by a second gap, the second gap forming a second area of reflection, the second area of reflection configured to reflect stray pumplight toward a second beam dump. ### Claim 27 (depends on 18) The apparatus of claim 18, wherein the light pipe comprises: at least two sets of substantially parallel reflective surfaces; and a core that comprises the first optic and that is located between the sets of reflective surfaces, the core configured to guide the pumplight along a guiding axis and deliver the pumplight into the planar waveguide. ### Claim 28 (depends on 18) The apparatus of claim 18, wherein the light pipe forms a pumplight aperture and an optical beam aperture that are aligned with the planar waveguide. ### Claim 29 (depends on 1) The system of claim 1, wherein: the light pipe comprises (i) a core comprising the first optic and (ii) the cladding positioned along a side of the core; the light pipe is configured to receive the pumplight at an end of the light pipe; the light pipe is configured to receive the first optical beam along the side of the light pipe, the side of the light pipe larger than the end of the light pipe; and the first area of reflection is at an oblique angle with respect to the side of the core in order to fold the first optical beam by approximately 90° into the planar waveguide. ### Claim 30 (depends on 12) The apparatus of claim 12, wherein the core comprises a gas-filled space. ### Claim 31 (depends on 17) The method of claim 17, wherein the core comprises a gas-filled space. ### Claim 32 (depends on 27) The apparatus of claim 27, wherein the core comprises a gas-filled space. ### Claim 33 (depends on 20) The apparatus of claim 20, wherein the light pipe forms a pumplight aperture and an optical beam aperture that are aligned with the planar waveguide. ### Claim 34 (depends on 20) The apparatus of claim 20, wherein the first optic is configured to substantially homogenize the pumplight via internal reflection. ### Claim 35 (depends on 20) The apparatus of claim 20, wherein the cladding of the light pipe further comprises: fourth and fifth optics separated from one another by a second gap, the second gap forming a second area of reflection, the second area of reflection configured to reflect stray pumplight toward a second beam dump. ### Claim 36 (depends on 20) The apparatus of claim 20, wherein: the light pipe comprises at least two sets of substantially parallel reflective surfaces; and the first optic in the core is located between the sets of reflective surfaces. ### Claim 37 (depends on 36) The apparatus of claim 36, wherein the core comprises a gas-filled space. ### Claim 38 (depends on 20) The apparatus of claim 20, wherein the light pipe comprises one or more evanescent wave coatings applied to one or more surfaces of the light pipe.