Characterization of a silicon Raman laser

Abstract

With a reverse biased p-i-n structure embedded in a silicon waveguide, we efficiently reduced the nonlinear loss due to two photon absorption induced free carrier absorption and achieved continuous-wave net gain and lasing in a silicon waveguide cavity on a single chip. We report here the laser characterization for different cavity lengths from 1.6 to 8 cm. With a pump wavelength at 1550 nm, the laser output at 1686 nm is single mode with over 55 dB side mode suppression and has less than 80 MHz linewidth. The lasing threshold depends on the p-i-n reverse bias voltage. With 25V bias, the threshold pump power is ~180 mW. The slope efficiency is ~4.3% for a single side output and a total output power of >10 mW can be reached at a pump power of 500 mW. The laser wavelength can be tuned by adjusting the wavelength of the pump laser. In addition to the laser line at Stokes wavelength, a narrow linewidth anti-Stokes line at 1434.3 nm is also generated in the laser cavity through parametric conversion process.