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Back seeding of picosecond supercontinuum generation in photonic crystal fibres

Supercontinuum generation (SCG) has been the subject of intense investigation during the last few years and its main mechanisms are now well understood. Focus has shifted towards tailoring the spectrum of the supercontinuum for specific applications. We experimentally investigate SCG with picosecond pumping in photonic crystal fibers with two closely spaced zero dispersion wavelengths. We couple parts of the output spectrum of the supercontinuum source back to the input in order to produce a gain of over 15 dB at some wavelengths. We use a variable time delay to optimize the overlap between the pump and the back seeded pulses and investigate how the delay and spectrum of the back seeded pulse affects the resulting supercontinuum spectrum.