A. Willinger

Large tunable delay with low distortion of 10 Gbit/s data in a slow light system based on narrow band fiber parametric amplification

We describe slow light propagation of a 10 Gbit/s data stream in a narrow band fiber parametric amplifier. A large tunable delay of 10 to 60 ps with very low signal distortion has been demonstrated in a 1 km long dispersion shifted fiber. The longitudinal variation of the fiber propagation parameters was extracted from measured amplified spontaneous emission and these parameters serve to accurately predict the delayed temporal pulse shape. Simulated results suggest that the system exhibits large delays with low distortions in a wide spectral range within the OPA gain spectrum.

Fiber parametric oscillator for the 2 μm wavelength range based on narrowband optical parametric amplification.

We describe a widely tunable synchronously pumped coherent source based on the process of narrowband parametric amplification in a dispersion-shifted fiber. Using an experimental fiber with a zero-dispersion wavelength of 1590 nm and pump wavelengths of 1530 to 1570 nm yields oscillations at 1970 to 2140 nm-the longest reported wavelength for a fiber parametric oscillator. The long-wavelength oscillations are accompanied by simultaneous short-wavelength oscillations at 1200 to 1290 nm. The parametric gain is coupled to stimulated Raman scattering. For parametric oscillations close to the Raman gain peak, the two gain processes must be discriminated from each other. We devised two configurations that achieve this discrimination: one is based on the exploitation of the difference in group delay between the wavelengths where Raman and parametric gain peak, and the other uses intracavity polarization tuning.

Observation of parametric gain due to four-wave mixing in dispersion engineered GaInP photonic crystal waveguides

We investigate four-wave mixing (FWM) in GaInP 1.5 mm long dispersion engineered photonic crystal waveguides. We demonstrate an 11 nm FWM bandwidth in the CW mode and a conversion efficiency of -24 dB in the quasi-CW mode. For picosecond pump and probe pulses, we report a 3 dB parametric gain and nearly a -5 dB conversion efficiency at watt-level peak pump powers.

On the Roles of Polarization and Raman-Assisted Phase Matching in Narrowband Fiber Parametric Amplifiers

This paper presents a comprehensive framework for the analysis of narrowband optical fiber parametric amplifiers. The novel vector model comprises virtually every significant nonlinear contribution, including a full stimulated Raman interaction model. We employ the model to calculate the influence of fiber random birefringence, as well as of longitudinal variations of linear and nonlinear propagation parameters on both gain and phase spectra.

Narrowband optical parametric gain in slow mode engineered GaInP photonic crystal waveguides.

We predict narrowband parametric amplification in dispersion-tailored photonic crystal waveguides made of gallium indium phosphide. We use a full-vectorial model including the dispersive nature both of the nonlinear response and of the propagation losses. An analytical formula for the gain is also derived.

Efficient parametric interactions in a low loss GaInP photonic crystal waveguide

We describe time domain characterizations of dynamic four-wave mixing in a low loss modified W1 GaInP photonic crystal waveguide. Using 32 ps wide pump pulses with peak powers of up to 1.1 W we achieved a very large conversion efficiency of -6.8 dB as well as a 1.3 dB parametric gain experienced by a weak CW probe signal. Time domain simulations confirm quantitatively all the measured results.

Parametric Gain and Conversion Efficiency in Nanophotonic Waveguides With Dispersive Propagation Coefficients and Loss

Nanophotonic waveguides can be engineered in order to exhibit slow mode propagation thereby enhancing the nonlinear responses. In such waveguides, loss and nonlinear coefficients are strongly wavelength dependent, a property that must be considered when the signal to pump detuning is large. Exact formulas for the parametric gain and conversion efficiency, accounting for the dispersion of losses and nonlinearity, are derived here. They can be applied to any waveguide presenting such features; in particular they have been calculated for a III-V semiconductor photonic crystal waveguide, where narrow- and broad-band amplification are predicted. The asymmetry of losses causes major asymmetries in the gain and conversion efficiency, which are no longer simply related as in the case of waveguides in which loss do not depend on the wavelength.

High resolution extraction of fiber propagation parameters for accurate modeling of slow light systems based on narrow band optical parametric amplification

The spatial distributions of fiber propagation parameters are estimated with a high spatial resolution using measured ASE spectra of narrow parametric gain. This allows accurate modeling of slow light propagation of high bit rate data.

Large Delay and Low Distortion of a 40 Gb/s Signal Propagating in a Slow Light System Based on Parametric Amplification in Optical Fibers

We determine the distribution of fiber dispersion parameters with extremely high resolutions and use the results to accurately predict large delays and low distortions of 40-Gb/s signals propagating in fiber parametric amplification slow light systems.

Split Step Fourier Transform: A Comparison Between Single and Multiple Envelope Formalisms

We describe a modified version of the split step Fourier transform algorithm used to analyze the propagation of multi-channel optical pulses. The modified algorithm divides the signal spectrum into separate envelopes, one for each channel, and computes the evolution of a set of nonlinear Schrödinger equations which accounts for the dispersion of both linear and nonlinear propagating parameters. We choose four exemplary cases for which the performances of the modified and standard split-step methods are compared in terms of computation cost versus global error of the solutions. We show that the modified technique is inferior when the spectrum is dense but it has a significant advantage for sparsely occupied spectra and for cases when the linear and nonlinear propagation parameters are dispersive.