Investigation and suppression of the pump-to-Stokes relative intensity noise transfer in chalcogenide waveguide Raman laser

The characteristic of pump-to-Stokes relative intensity noise (RIN) transfer is comprehensively investigated for integrated As?Se? waveguide Raman laser (As?Se?-WRL). It is found that, compared to its silicon counterpart, the RIN transfer is 5 dB lower across all frequencies for As?Se?-WRL, mainly due to its relatively smaller Raman gain coefficient. A bidirectional pumping scheme is proposed and verified as an effective configuration to suppress RIN transfer because doubling of the inverse round trip time eliminates the RIN transfer peak at the odd multiples of the resonance frequency. The optimization of waveguide length on RIN transfer is also performed, in which two distinct regions are identified due to different dominant physical processes. In addition, we show that RIN transfer in As?Se?-WRL can be further reduced by using a high cavity for both pump and Stokes waves.