Seeded raman amplifier for applications in the 1100-1500 nm spectral region

摘要

A method of generating high-power laser output in the 1100 to 1500 um spectral region having a controllable linewidth. A Raman amplifier comprised of one or more nested pairs of fiber Bragg grating cavities tuned to the 1^st, 2^nd, . . . N−1^st order Stokes wavelengths is seeded with both the desired Nth order Stokes output wavelength and the corresponding zeroth-order Stokes pump wavelength. As the pump wavelength propagates through the apparatus, it is sequentially converted to the 1^st, 2_nd, . . . N−1^st order Stokes wavelengths in the nested fiber Bragg grating cavities. The desired Nth order Stokes output wavelength is then amplified by the N−1^st Stokes order as it propagates through the nested fiber Bragg grating cavities. The linewidths of various Stokes orders can be controlled through adjusting resonant bandwidths of the fiber Bragg grating cavities by offsetting, through heating, the reflectivity bandwidths of each pair of cavity gratings.