Broadband sagnac raman amplifiers and cascade lasers
First Claim
1. A broadband pump assembly, comprising:
- a pump laser having an output port and producing a pump beam;
a bandwidth adding mirror connected to said output port to generate a broadened pump spectrum;
a broadband Raman amplifier coupled to the pump laser.
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Accused Products
Abstract
This invention describes new developments in Sagnac Raman amplifiers and cascade lasers to improve their performance. The Raman amplifier bandwidth is broadened by using a broadband pump or by combining a cladding-pumped fiber laser with the Sagnac Raman cavity. The broader bandwidth is also obtained by eliminating the need for polarization controllers in the Sagnac cavity by using an all polarization maintaining configuration, or at least using loop mirrors that maintain polarization. The polarization maintaining cavities have the added benefit of being environmentally stable and appropriate for turn-key operation. The noise arising from sources such as double Rayleigh scattering is reduced by using the Sagnac cavity in combination with a polarization diversity pumping scheme, where the pump is split along two axes of the fiber. This also leads to gain for the signal that is independent of the signal polarization. Finally, a two-wavelength amplifier for 1310 nm and 1550 nm can be implemented by using a parallel combination of Raman amplifiers with shared pump lasers or by combining Raman amplifiers with erbium-doped fiber amplifiers. Combinations of the above improvements can be used advantageously to meet specifications for broad bandwidth, polarization independence, noise performance and multi-wavelength operation.
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Citations
17 Claims
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1. A broadband pump assembly, comprising:
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a pump laser having an output port and producing a pump beam;
a bandwidth adding mirror connected to said output port to generate a broadened pump spectrum;
a broadband Raman amplifier coupled to the pump laser. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A polarization diversity pumping system, comprising:
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a first polarization maintaining fiber;
a pump source that generates a linearly polarized pump beam in the first polarization maintaining fiber; and
a second polarization maintaining fiber coupled to the first polarization maintaining fiber, wherein a principal axis of the first polarization maintaining fiber is positioned relative to a principal axis of the second polarization maintaining fiber to produce a beam having two polarization modes. - View Dependent Claims (14, 15, 16, 17)
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Specification