Fiber coupling enhancement via external feedback
First Claim
1. An apparatus for coupling a multi-mode diode laser to a double-clad fiber, comprising:
- a. a multi-mode diode laser having an output of electromagnetic radiation wherein the output has brightness, wavelength, and lower order and higher order spatial modes;
b. a double-clad fiber comprising an outer cladding, an inner cladding with a dopant that is substantially photoexcited by the output from the multi-mode diode laser, and an inner core substantially transparent to the output of the multi-mode diode laser, and further comprising an end whereby electromagnetic radiation can be directed into the core and cladding, and;
c. a focusing objective, wherein;
i. the multi-mode diode laser, focusing objective and double-clad fiber are aligned, such that the output from the multi-mode laser is substantially directed through the focusing objective to the end of the double-clad fiber; and
, ii. a Bragg grating having a reflectivity is fabricated within the core of the double-clad fiber at the wavelength of the multi-mode diode laser so that output from the multi-mode diode laser is reflected back to the multi-mode diode laser such that the lower order spatial modes of the diode laser are enhanced and, thereby, the brightness of the multi-mode diode laser output that is coupled back into the core and inner cladding of the double-clad fiber is also enhanced.
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Accused Products
Abstract
The present invention provides for the coupling of laser diodes into electromagnetic radiation transmitting fibers wherein coupling efficiency is improved by improving the spatial brightness of multi-mode diode lasers as they are coupled into double-clad fibers. A Bragg grating 100 is fabricated into the core 102 of a double-clad fiber 104 coupled to a multi-mode diode laser 106. The output 108 from the multi-mode diode laser 106 is coupled into the core 102 and inner cladding 110 of the double-clad fiber by proximity or by one or more focusing objectives 112. The Bragg grating 100 in the core 102 of the double-clad fiber 104 is written at the wavelength of the multi-mode diode laser 106. The original output 108 from the multi-mode diode laser 106 strikes the Bragg grating 100 which reflects feedback 114 back to the diode laser 106.
16 Citations
16 Claims
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1. An apparatus for coupling a multi-mode diode laser to a double-clad fiber, comprising:
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a. a multi-mode diode laser having an output of electromagnetic radiation wherein the output has brightness, wavelength, and lower order and higher order spatial modes;
b. a double-clad fiber comprising an outer cladding, an inner cladding with a dopant that is substantially photoexcited by the output from the multi-mode diode laser, and an inner core substantially transparent to the output of the multi-mode diode laser, and further comprising an end whereby electromagnetic radiation can be directed into the core and cladding, and;
c. a focusing objective, wherein;
i. the multi-mode diode laser, focusing objective and double-clad fiber are aligned, such that the output from the multi-mode laser is substantially directed through the focusing objective to the end of the double-clad fiber; and
,ii. a Bragg grating having a reflectivity is fabricated within the core of the double-clad fiber at the wavelength of the multi-mode diode laser so that output from the multi-mode diode laser is reflected back to the multi-mode diode laser such that the lower order spatial modes of the diode laser are enhanced and, thereby, the brightness of the multi-mode diode laser output that is coupled back into the core and inner cladding of the double-clad fiber is also enhanced. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for coupling a multi-mode diode laser to a double-clad fiber, wherein:
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a. the multi-mode diode laser has an output of electromagnetic radiation wherein the output has brightness, wavelength, and lower order and higher order spatial modes;
b. the double-clad fiber comprises an outer cladding, an inner core that guides the output from the multi-mode diode laser, and is substantially transparent to the output of the multi-mode diode laser, and further comprises an end whereby electromagnetic radiation can be directed into the core and cladding;
said method comprising;
i. aligning the multi-mode diode laser, any focusing objectives, and the double-clad fiber such that the output from the multi-mode laser is substantially directed into the end of the double-clad fiber; and
,ii. fabricating a Bragg grating having a reflectivity within the core of the double-clad fiber at the wavelength of the multi-mode diode laser so that output from the multi-mode diode laser is reflected back to the multi-mode diode laser such that the lower order spatial modes of the diode laser are enhanced and, thereby, the brightness of the multi-mode diode laser output that is coupled back into the core and inner cladding of the double-clad fiber is also enhanced. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification