Raman-induced frequency shift in CS2-filled integrated liquid-core optical fiber

We demonstrate an optically tunable frequency shift in an all-fiber based system using a carbon disulfide (CS2) filled integrated liquid-core optical fiber (i-LCOF) and co-propagating pulses of comparable temporal lengths. In 1 m of i-LCOF we were able to shift 18 ps pulses, a full spectral bandwidth at low pump peak powers, using the Raman-induced frequency shift and slow light effects. Numerical simulations of the pulse-propagation equations agree well with the observed shifts. We also analyze the contributions of both the Raman cross-frequency shift and slow light effects to the overall frequency shift. The system is all-fiber based and compact, making it suitable for applications such as a low power wavelength converter.