All-optical tunable delay line based on nonlinearities in a chalcogenide microfiber coil resonator

Abstract

We propose an all-optical tunable delay line based on nonlinear effects in a two-turn chalcogenide microfiber coil resonator (MCR). Continuous rotation of light due to coupling between the two uniform MCR turns at the resonance induces a time delay. Using numerical simulation, we show the possibility of designing a continuously tunable all-optical and real-time delay line, taking advantage of the high Kerr nonlinear effect in a chalcogenide glass-based MCR. The threshold power for making the Kerr nonlinearity in the chalcogenide sulfide glass (Ge20Ga5Sb10S65, also known as 2S2G) MCR is less than 0.1 W. By selecting an appropriate pump power, one can adjust the time delay in the proposed MCR delay line as desired. Results of numerical simulations show that the time delay in an appropriately designed two-turn MCR can be tuned in the range of 24–147 ps with a bandwidth of ∼4.1 GHz. Pulse broadening and distortion related to group velocity dispersion (GVD) and the self-phase modulation (SPM) effect of the proposed microfiber coil delay line (MCDL) are also studied.