The thrust of our research effort addresses questions regarding the physical nature of nonlinear noise processes in optical fibers. Experimentally, we exploit nonlinear optical processes to achieve quantum noise reduction for applications toward sensitivity enhancement in photon number and phase measurements. Using our new scheme for generating amplitude-squeezed solitons in an asymmetric fiber Sagnac loop interferometer, we measured a record reduction in photon number fluctuations by direct detection. The same scheme was also shown to generate a significant classical noise reduction and is fundamentally limited by Raman effects in fiber. We have shown the first numerical and experimental evidence demonstrating explicitly this break-up phenomenon.
Solitons are also critical to the design of short-pulse lasers.
We can obtain soliton formation in a specially designed laser cavity with minimal perturbations where the pulse is essentially a soliton of the average group-velocity dispersion and Kerr nonlinearity. In our extremely compact cavity the perturbations to the pulse with each round trip are small enough that fundamental solitons propagate in the cavity. We demonstrate the presence and influence of solitons by showing that the output pulses remain transform-limited despite changes in average cavity dispersion, pulse width, spectral bandwidth, and pulse energy. We pursue the applications of solitons in fiber optic networks. In particular, we are studying a novel optical packet switched network architecture that enables scalable data communications at ultrahigh throughput bandwidths with minimal latency.