Study on picosecond pulse-train multi-wavelength Raman laser operating at two Raman modes without tuning

The Stokes line of multi-mode Raman laser was limited by low conversion efficiency of higher-order Stokes and the competition between pure cascaded stimulated Raman scattering (SRS) and Four-wave-mixing (FWM) process which will deplete the pump of SRS process. Through developed pulse-train synchronously pumping technique and two-Raman-mode operating, the orders of output Stokes was improved. With average power of 220mW, the developed a Raman laser providing up to 5 orders Stokes output, containing up to 16 laser lines without tuning operating and four-wave-mixing process.