G. K. L. Wong

Scalar modulation instability in the normal dispersion regime by use of a photonic crystal fiber

Modulation instability at high frequencies has been demonstrated in the normal dispersion regime by use of a photonic crystal fiber. This fiber-optic parametric generator provides efficient conversion of red pump light into blue and near-infrared light.

Widely tunable optical parametric generation in a photonic crystal fiber

We report on the observation of widely tunable optical parametric generation in a photonic crystal fiber. The frequency shift of the generated sidebands that arise from modulational instability is strongly dependent on the detuning of the pump from the fibers zero-dispersion wavelength. We are able to demonstrate experimentally more than 450 nm of sideband tunability as we tune the pump wavelength over 10 nm. Excellent agreement has been found between the experimentally measured and theoretically predicted shifts.

Combined effect of Raman and parametric gain on single-pump parametric amplifiers.

We investigate the combined effect of Raman and parametric gain on single-pump parametric amplifiers. The phasematched parametric gain is shown to depend strongly on the real part of the complex Raman susceptibility. In fused silica fibers this results in a significant reduction in the available parametric gain for signal detunings beyond 10 THz. We are able to experimentally measure this effect for signal detunings ranging from 7 to 22 THz. Finally we discuss the implications of these results for the design of broadband optical parametric amplifiers.

Characterization of chromatic dispersion in photonic crystal fibers using scalar modulation instability

A simple and accurate method is proposed for characterizing the chromatic dispersion of high air-filling fraction photonic crystal fibers. The method is based upon scalar modulation instability generated by a strong pump wave propagating near the zero-dispersion wavelength. Measuring the modulation instability sideband frequency shifts as a function of wavelength gives a direct measurement of the fibers chromatic dispersion over a wide wavelength range. To simplify the dispersion calculation we introduce a simple analytical model of the fibers dispersion, and verify its accuracy via a full numerical simulation. Measurements of the chromatic dispersion of two different types of high air-filling fraction photonic crystal fibers are presented.

Continuous-wave tunable optical parametric generation in a photonic-crystal fiber

Continuous-wave and quasi-cw operation of tunable optical parametric generation has been demonstrated in a photonic-crystal fiber. The frequency shift of the generated sidebands, which arise from modulation instability, depends strongly on the detuning of the pump from the fiber’s zero-dispersion wavelength. Over 30 nm of sideband tunability has been demonstrated using a 300 mW cw pump, and over 185 nm of tunability using a 1.6 W quasi-cw pump. Continuous wave and quasi-cw pumps eliminate the detrimental effects of pump–sideband walk-off. In the absence of walk-off it is the fluctuations in the index profile of the photonic-crystal fiber along its length that limit the tunable sideband range.

Polarization modulation instability in photonic crystal fibers

Polarization modulation instability (PMI) in birefringent photonic crystal fibers has been observed in the normal dispersion regime with a frequency shift of 64 THz between the generated frequencies and the pump frequency. The generated sidebands are orthogonally polarized to the pump. From the observed PMI frequency shift and the measured dispersion, we determined the phase birefringence to be 5.3 x 10(-5) at a pump wavelength of 647.1 nm. This birefringence was used to estimate the PMI gain as a function of pump wavelength. Four-wave mixing experiments in both the normal and the anomalous dispersion regimes generated PMI frequency shifts that show good agreement with the predicted values over a 70 THz range. These results could lead to amplifiers and oscillators based on PMI.

Cross-phase modulation instability in photonic crystal fibers

We report on the observation of cross phase modulation instability (XPMI) in photonic crystal fiber (PCF). The rapidly varying dispersion of the fiber around its zero dispersion wavelength gives rise to a complicated phasematching curve.

An All-Fiber Widely-Tunable Photonic Crystal Fiber Optical Parametric Oscillator

We report on the performance of an all-fiber widely-tunable photonic crystal fiber optical parametric oscillator. The output is continuously tunable from 588 to 675 nm and 784 to 924 nm.

Scalar modulation instability near zero GVD using a PCF

Scalar modulation instability has been demonstrated in the normal dispersion regime using a PCF leading to efficient upconversion of a red pump to wavelengths throughout the visible.

Parametric amplification in photonic crystal fibres

Photonic crystal fibres have reinvigorated the study of parametric amplification in optical fibres through their special properties. Experimental results are presented for a range scalar and vector four wave mixing processes in photonic crystal fibres.