Novel multi-wavelength cascaded-Raman source based on tunable fiber Sagnac loop filter

We have experimentally demonstrated a multiwavelength fiber Raman source based on a tunable high birefringence fiber Sagnac loop filter. Using the novel scheme, we have demonstrated a generation of a broad cascaded Stokes waves with wavelength between 1.12∼1.57 μm and the generation of approximately 20 wavelength channels within the 4th order Stokes waves. By adjusting the pump power and the cavity, the multi-wavelength operation is possible within a particular Stokes waves or all the Stokes waves. Such multi-wavelength laser source is expected to be useful in many applications including the WDM and sensing area.