Multiple emitter side pumping method and apparatus for fiber lasers
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
H01S-003/30
H01S-003/09
G02B-006/26
출원번호
US-0449934
(2003-05-30)
발명자
/ 주소
Snell, Kevin J.
Setzler, Scott D.
출원인 / 주소
BAE Systems Information and Electronic Systems Integration Inc.
대리인 / 주소
Tendler Robert K.
인용정보
피인용 횟수 :
35인용 특허 :
5
초록▼
A modified V-groove structure in a double clad laser system permits multiple emitter side pumping of a fiber laser. In one embodiment, a stack of at least five emitters have individual outputs coupled into the inner cladding, with as many sources as desired coupled to the fiber to raise the cumulati
A modified V-groove structure in a double clad laser system permits multiple emitter side pumping of a fiber laser. In one embodiment, a stack of at least five emitters have individual outputs coupled into the inner cladding, with as many sources as desired coupled to the fiber to raise the cumulative pumping power to in excess of 2-KW, thus to achieve a 1-KW fiber laser.
대표청구항▼
1. Apparatus for pumping a high power fiber laser having a fiber with a doped core, comprising:a number of pumping sources;optics for focusing the light from said pumping sources to points within said fiber; and,a series of closely spaced V-grooves in the side of said fiber pointing towards respecti
1. Apparatus for pumping a high power fiber laser having a fiber with a doped core, comprising:a number of pumping sources;optics for focusing the light from said pumping sources to points within said fiber; and,a series of closely spaced V-grooves in the side of said fiber pointing towards respective pumping sources, said grooves spaced by less than an absorption length, each of said grooves having an alpha facet angled to reflect pumping light down said fiber in a predetermined direction, said V-grooves being positioned such that the point to which a pumping source is focused lies on an alpha facet of an associated V-groove, such that light from a number of pumping sources is reflected down said fiber around subsequent V-grooves and is combined to pump the core of said fiber. 2. The apparatus of claim 1, wherein selected V-grooves downstream of a first V-groove have beta facets which are sloped to assure total internal reflection of any light reflected by an upstream alpha facet onto a downstream beta facet, whereby downstream V-grooves do not interfere with upstream V-grooves, thus to permit pumping from multiple pumping sources. 3. The apparatus of claim 2, wherein said fiber includes a double clad fiber having an inner cladding surrounding said core and an outer cladding, said grooves being formed in the outer surface of said inner cladding. 4. The apparatus of claim 2, wherein said core is doped with a rare earth element. 5. The apparatus of claim 4, wherein said rare earth element is Thulium. 6. The apparatus of claim 1, wherein the V-grooves are made by etching said fiber with CO 2 laser radiation. 7. The apparatus of claim 3, wherein the angle that said beta facet makes with the center line of said fiber is less than 3°. 8. A method of pumping a high power fiber laser made from a double clad fiber having a core, an inner cladding layer and an outer cladding layer, comprising the steps of:providing a number of closely spaced modified V-grooves in a surface of the inner cladding so as to define a first V-groove and subsequent downstream V-grooves, the downstream V-grooves having a beta facets which are sloped so as not to reflect light from an upstream facet so that light reflected by the beta facet impinges on the outer surface of the inner core at an angle less than the critical angle such that upstream pumping light introduced at one V-groove moves by a subsequent V-groove, whereby there is total internal reflection of pumping light introduced into the inner cladding, each V-groove having an alpha facet for reflecting pumping light in the downstream direction; and,focusing pumping light from a number of independent pumping sources onto the alpha facets of the V-grooves, whereby a number of independent pumping sources may be used to pump the core, thus to combine the pumping energy from a number of independent pumping sources sufficient to provide for a high power fiber laser output. 9. The method of claim 8, wherein the pumping sources are direct coupled to the fiber. 10. The method of claim 8, wherein the pumping sources are remote from the fiber and have the outputs thereof coupled to the fiber through the use of optical filters. 11. The method of claim 10, wherein the optical fiber are multimode fibers. 12. The method of claim 8, wherein the double clad fiber core is doped with a rare earth element. 13. The method of claim 8, wherein the laser output exceeds 1-KW. 14. The method of claim 13, wherein the combined pumping power from the pumping source exceeds 2-KW. 15. A high powered fiber laser, comprising:a double clad fiber having a core, an inner cladding for said fiber and an outer cladding for said fiber;a plurality of modified V-grooves closely spaced along a surface of said inner cladding, each of said modified V-grooves having an alpha facet, modified V-grooves downstream of a first modified V-groove having beta facets sloped to assure total internal reflection of pumping light reflected from an upst ream alpha facet onto a downstream beta facet such that light introduced at one modified V-groove goes by a subsequent modified V-groove;a substantially identical plurality of pumping sources having pumping light focused on alpha facets of respective modified V-grooves;an HR Bragg grating in the fiber upstream of said first modified V-groove; and,an output coupler Bragg grating downstream of the last of said modified V-grooves, said pumping sources collectively providing sufficient pumping power. 16. The laser of claim 15, wherein said fiber is spooled and wherein said modified V-grooves on successive turns are positioned adjacent each other. 17. The laser of claim 15, wherein said plurality of pumping sources are spaced along a bar, said bar being located adjacent said fiber such that each of said pumping sources overlies a different V-groove. 18. The laser of claim 15, wherein said fiber is divided into sections, the output of one of said sections being coupled by a coupler to the input of a succeeding section. 19. The laser of claim 18, wherein said coupler includes an optical limiter. 20. The laser of claim 19, wherein said optical limiter includes a germanium window and optics for focusing said output onto said window, thus to quench Q-switched pulses so as to act as a noise suppressor.
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이 특허에 인용된 특허 (5)
Goldberg, Lew; LeFlohic, Marc; Kulcsar, Gabor, Hermetic pump module for double cladding fiber amplifiers and method for making same.
Gates, James Christopher; Gawith, Corin Barry Edmund; Smith, Peter George Robin, Method of fabricating waveguide devices which use evanescent coupling between waveguides and grooves.
Lee, Seihyoung; Yoon, Shin Young; Kang, Hyun Seo, Optical fiber for out-coupling optical signal and apparatus for detecting optical signal using the same optical fiber.
Stadler, Andrew D.; Goldman, David; Farley, Mark; Mielke, Michael M.; Kim, Kyungbum; Vaissié, Laurent; Waarts, Robert G.; Cumbo, Michael J., Systems and methods for control of ultra short pulse amplification.
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