Semiconductor laser module and method for simultaneously reducing relative intensity noise and stimulated Brillouin scattering

摘要

A semiconductor laser module (50) including a semiconductor laser device (51) having an integrated diffraction grating (45) configured to output a multiple mode laser beam in the presence of a driving current, an optical fiber (55) configured to guide the multiple mode laser beam to an output of the laser module (50), and an optical attenuation device (1010) configured to attenuate the multiple mode laser beam by an amount sufficient to provide a predetermined output power from the output of the laser module (50). The optical attenuation device (1010) may be an optical coupling lens (54) offset from an optimum coupling position by an amount sufficient to provide the predetermined output power, or an optical attenuator (50b) interrupting the optical fiber (55a) and configured to attenuate the multiple mode laser beam by an amount sufficient to provide the predetermined output power. Also, a two fiber Raman amplifier having a super large area (SLA) fiber (64A) that provides amplification of the signal based primarily on the forward excitation light can also be used to suppress stimulated Brillouin Scattering.