Soliton self-frequency shift and spectral compression in highly nonlinear fibres for resolution improvement of all-optical analogue-to-digital conversion

A soliton self-frequency shift of ~150 nm and spectral compression in two segments of highly nonlinear fibres with 580 fs laser pulses at a wavelength of 1550 nm are demonstrated. The wavelengths of the resulting femtosecond solitons can be tuned effectively by adjusting the input power. Spectral compression of the soliton pulses is obtained from 9.5 to 2.8 nm. Experimental results indicate that a resolution of 5 bits for all-optical analogue-to-digital conversion can be achieved.