Self-phase modulation enabled, wavelength-tunable ultrafast fiber laser sources: an energy scalable approach

• DOI: 10.1364/oe.24.015328
• Publication Date: 2016-06-28T16:50:54Z
• Authors: Wei Liu; Chen Li; Zhigang Zhang; Franz X. Kärtner; Guoqing Chang
• Keywords: Modulation (music); Self-phase modulation; Cross-phase modulation

We propose and demonstrate a new approach to implement wavelength-tunable ultrafast fiber laser source suitable for multiphoton microscopy. employ fiber-optic nonlinearities broaden narrowband optical spectrum generated by an Yb-fiber system then use bandpass filters select the leftmost or rightmost spectral lobes from broadened spectrum. Detailed numerical modeling shows that self-phase modulation dominates broadening, self-steepening tends blue shift spectrum, stimulated Raman scattering is minimal. also find wave breaking caused dispersion slows down of leftmost/rightmost therefore limits wavelength tuning range filtered spectra. show both numerically experimentally shortening used broadening while increasing input pulse energy can overcome this dispersion-induced limitation; as result, have higher power, constituting powerful practical scaling resulting femtosecond sources. two commercially available photonic crystal fibers verify simulation results. More specific, 20-mm NL-1050-ZERO-2 enables us based source, delivering (70-120 fs) pulses tunable 825 nm 1210 with >1 nJ energy.