| Fiber Optical Parametric Amplifiers (OPA) are based on the third-order nonlinear susceptibility χ(3) in fiber. When an optical signal at ωs co-propagates with a relatively strong pump at ωp in a fiber, the signal will be amplified through this parametric process, and another wavelength component, called idler, will be generated at ωi = 2ωp − ω s. The idler contains the same modulation information as the input signal, with the spectrum inverted. OPAs may find applications as optical amplifiers in WDM transmission systems or as wavelength converters in WDM networks, depending on whether the signal or the idler is used.; OPAs can exhibit wide bandwidth, and high gain. In this work, OPAs in highly nonlinear dispersion-shifted fibers (HNLFs) are investigated and demonstrated. HNLFs are designed specifically to enhance nonlinear effects in fibers. With a 20m HNLF and a pulsed 10W pump, an OPA with a bandwidth of over 200 nm and a gain of over 10 dB has been demonstrated. The problems of cw-pumped OPAs were also investigated, and a solution to the problems has been implemented.; OPAs used as wavelength converters have the unique characteristic of providing over 100 percent conversion efficiency. That is, the converted signal (idler) is amplified. However, the quality of the idler is degraded due to pump dithering. In this work, a cancellation technique using out-of-phase dithered two-pump OPA is also demonstrated. With this technique, the idler broadening is successfully suppressed and the resulting linewidth is comparable to that of the arable to that of the amplified signal. |
