SESAM mode-locked Nd:fiber laser at 920 nm for nonlinear optical microscopy

We report on the design, modeling, and characterization of a diode-pumped Nd-doped all-polarization-maintaining fiber laser operating at 920 nm in a passively mode-locked regime enabled by a SESAM. The laser generates pulse trains with a repetition frequency of 18.5 MHz and an average output power of 0.26 mW in an optical bandwidth of 0.6 nm. Within the broad integration bandwidth from 50 Hz to 9.25 MHz, the Nd:fiber laser exhibits ultra-low intensity noise, at a relative level of 0.04%, and timing jitter below 2 ps. Moreover, we demonstrate the ability to lock the laser's repetition frequency to that of an Yb-doped oscillator, enabling stimulated Raman scattering microscopy in the fingerprint region.