Highly stable ultrabroadband mid-IR optical parametric chirped-pulse amplifier optimized for superfluorescence suppression.

We present a 9 GW peak power, three-cycle, 2.2 microm optical parametric chirped-pulse amplification source with 1.5% rms energy and 150 mrad carrier envelope phase fluctuations. These characteristics, in addition to excellent beam, wavefront, and pulse quality, make the source suitable for long-wavelength-driven high-harmonic generation. High stability is achieved by careful optimization of superfluorescence suppression, enabling energy scaling.

Tunable enhancement of a soliton spectrum using an acoustic long-period grating.

We demonstrate a scheme for tunable shaping of a soliton spectrum. Specifically, we show a local enhancement of 6 dB in the pulse spectrum by propagating the pulse through a fiber containing micro-bends generated by a flexural acoustic wave - an acoustic long-period grating (LPG) - followed by nonlinear propagation through uniform fiber. The location of the enhancement peak can be tuned by external control of the acoustic frequency of the LPG. We discuss the potential application of this scheme to tunable supercontinuum sources.

Nonlinear propagation effects in antiresonant high-index inclusion photonic crystal fibers.

We experimentally and numerically investigate femtosecond-pulse propagation in a microstructured optical fiber consisting of a silica core surrounded by airholes that are filled with a high-index fluid. This fiber combines the resonant properties of hollow-core bandgap fibers and the high nonlinearity of index-guiding waveguides. A range of nonlinear optical effects can be observed, including soliton propagation, dispersive wave generation, and a Raman self-frequency shift. Tuning the center wavelength of the laser and varying the refractive index of the fluid lead to different propagation effects, mediated by the strongly wavelength-dependent group-velocity dispersion in these photonic bandgap confining structures.

In-band OSNR and chromatic dispersion monitoring using a fibre optical parametric amplifier.

This paper presents an all-optical, in-band optical signal-to-noise ratio (OSNR) and chromatic dispersion monitor. We demonstrate monitoring over the 1 nm bandwidth of our signal, which is a 10 GHz pulse train of 8.8 ps pulses. The monitor output power, as measured on a slow detector, has a 1.9 dB dynamic range when the signal OSNR is varied by 20 dB, and a 1.6 dB dynamic range when +/- 150 ps/nm of chromatic dispersion is applied. Cascaded four-wave mixing occurring in the optical parametric amplifier provides the nonlinear power transfer function responsible for the monitoring. An analysis using the signals' probability density functions show that the nonlinear power transfer function provides preferential gain to clean undispersed pulses when compared to noisy and/or dispersed pulses. Our analysis includes a consideration of the applicability of the device to high duty cycle systems, and simulations on monitoring of a 40 Gb/s pulse train with a 50% duty cycle.