Comparison of amplitude noise of a fiber-optical parametric oscillator and a supercontinuum source

Abstract

Fiber-based optical parametric oscillators (FOPOs) are an alternative to supercontinuum light sources for nonlinear optical microscopy. In nonlinear microscopy implementations such as stimulated Raman scattering and coherent anti-Stokes Raman scattering, the signal noise is proportional to the second or third order of the input intensity noise. It is not yet known how FOPO intensity noise levels compare with supercontinuum sources. We measure excess noise for a FOPO and a supercontinuum source as a function of input power and wavelength. We find that the FOPO sideband excess noise can be as low as 5 dB above the shot noise limit of −150  dBc [Hz]−1. This FOPO can reach excess noise levels 50 dB below that of spectral slices of supercontinuum output in a comparable spectral range.