Patent ID: 7340136

Claim:
A system, comprising an optical fiber comprising a gain medium having a Raman active material with a Raman gain spectrum, the optical fiber being configured to receive energy at a wavelength λ p ; and at least three pairs of reflectors disposed in the optical fiber, each pair of reflectors forming a resonance cavity with a resonance frequency, each resonance cavity having an index, the index of each resonance cavity being different than the index of the other resonance cavities, wherein, for a resonance cavity having an index with a value M, M being an integer having a value of at least one, the resonance cavity has a resonance frequency (c/λ sm ), where λ sm −1 =λ p −1 −Σ M λ rm −1 where (c/λ rm ) is a frequency within the Raman gain spectrum of the Raman active material contained in the gain medium and c is the speed of light, and, for a resonance cavity having an index with a value N, N being an integer having a value of at least two, the resonance cavity has a resonance frequency (c/λ sn ), the resonance cavity having the index with the value N overlapping only with a resonance cavity having a resonance frequency (c/λ s(n−1) ) and with a resonance cavity having a resonance frequency (c/λ s(n+1) ) with the caveat that the resonance cavity having the highest value for N overlaps with at most one other resonance cavity.