Self-channeling of few-cycle laser pulses in helium at high pressure generates coherent light supercontinua spanning the range of 270-1000 nm, with the highest efficiency demonstrated to date. Our results open the door to the synthesis of powerful light waveforms shaped within the carrier field oscillation cycle and hold promise for the generation of pulses at the single-cycle limit.

We examine analytically, numerically, and experimentally the phase shift incurred by a soliton pulse when it collides with a copropagating, orthogonally polarized soliton pulse in a highly birefringent optical fiber. Use of a well-known average variational principle and a Gaussian ansatz reduces the dynamics to a set of ordinary differential equations for which an approximate analytic solution is found in the case of highly birefringent fibers. The analytic approximation is shown to be in good agreement with the full numerical model and experimental data, allowing it to be used as an evaluation tool for the design of nonlinear optical loop mirror switches.

We report photorefractive two beam coupling gain coefficients as high as Γ=19 cm−1 and net gains of Γ-α=14 cm−1 in InP:Fe at around 970 nm. This enhancement was achieved by combining band-edge resonant nonlinearities with a second resonant enhancement derived from the bipolar transport in this material. Measurements of gain as a function of pump intensity, applied field, grating spacing, wavelength, and temperature are presented. No moving gratings were required.

We have developed a technique to produce precise fiber-optic time delays with subpicosecond accuracy and <0.1-dB loss by heating and stretching optical fiber in a fusion splicer. A fiber Mach-Zehnder interferometer allows in situ measurement of these precise delays using a simple alignment process and requiring only a weak optical signal. To demonstrate this capability, we assembled a six-stage feed-forward delay line that can be used to generate 64 optical pulses with 9.5 +/- 0.8-ps pulse spacings and 4.8-dB total insertion loss.