Power Dependent Noise Performance of fs Supercontinuum Generation in Normal Dispersion Fibers with a Long Zero-Dispersion Wavelength

Summary form only given. One of the requirements for generating a low noise supercontinuum (SC) in a normal dispersion fiber using a femtosecond (fs) pump is to have the minimum absolute dispersion wavelength to be close to zero in order to avoid parametric Raman noise [1]. SC generation in all-normal dispersion fibers can under certain requirements provide a highly coherent spectrum [2, 3], which is of key importance to a large range of imaging and spectroscopy applications. Key requirements to avoid Raman noise and noise from polarization mode instability (PMI) is to have a sufficiently low peak power (P
₀
), short pulse length (T
₀
), short fiber length, and high fiber birefringence [4]. Silica microstructured fi bers (MSFs) pumped with 1550 nm fs lasers is an attractive platform to generate a low noise SC due to their technological maturity. We therefore fabricated a low -loss silica MSF (using 2 cladding sections with different hole sizes) with weak dispersion at 1500 nm and experimentally studied SC generation at low peak powers using a 1550 nm, 125 fs pump [5]. The group velocity dispersion (P 2 ) profile of the fi ber is shown in Fig. 1(a). Since the dispersion at the pump is weak, a low Po can be used to generate a broad SC. A further advantage of using low peak powers is the possibility of avoiding PMI. The requirement of weak dispersion at 1550 nm leads to a fi ber design with a zero dispersion wavelength (ZDW) at 1.8 p.m. The SC generated with up to Po =9 kW does not cross the ZDW and has low relative intensity noise (RIN) as was demonstrated numerically and experimentally.