Delay-tunable gap-soliton-based slow-light system.

We numerically and analytically evaluate the delay of solitons propagating slowly, and without broadening, in an apodized Bragg grating. Simulations indicate that a 100 mm Bragg grating with Deltan = 10-3 can delay sub-nanosecond pulses by nearly 20 pulse widths without any change in the output pulse width. Delay tunability is achieved by simultaneously adjusting the launch power and detuning. A simple analytic model is developed to describe the monotonic dependence of delay on Deltan and compared with simulations. As the intensity may be greatly enhanced due to a reduced velocity, a procedure for improving the delay while avoiding material damage is outlined.

Soliton compression and pulse-train generation by use of microchip Q-switched pulses in Bragg gratings.

Pulse compression and pulse-train generation are demonstrated by use of kilowatt 580 ps pulses generated by a compact (15 cm x 3 cm x 3 cm) microchip Q-switched laser followed by a fiber Bragg grating. A 12-fold pulse compression to 45 ps with five times peak power enhancement is achieved at 1.4 kW through soliton effect compression in the fiber grating. At 2.5 kW, modulational instability leads to a train of high-contrast sub-100 ps pulses. These demonstrations take advantage of the ultrastrong dispersion at frequencies close to the edge of the photonic bandgap. Experimental results are discussed in the context of the nonlinear Schrödinger equation and are compared with simulations of the nonlinear coupled-mode equations.