Abstract:
This thesis describes the studies performed for the implementation and characterisation of various nonlinear optical wavelength conversion techniques. The experimental work presented within this thesis is accompanied by discussion of the practical considerations necessary for the successful implementation of the nonlinear wavelength conversion techniques described. The primary focus of this thesis and the largest body of experimental research is on the experimental characterisation of the four wave mixing effect of Bragg Scattering in optical fibers. Experimental and numerical characterisations of this process have been performed. The studies have enabled the phase matching condition, conversion efficiencies and bandwidth to be measured for this effect in a highly nonlinear fiber. The phase matching curve has been measured for two fibers with opposite sign β4 dispersion coefficients and an experimental implementation of a transparent high-speed optical switch based on this effect has also been demonstrated for the first time. The interfering effects of competing nonlinear processes have been investigated and the impact of zero dispersion wavelength fluctuations have been studied. Additionally this process has been used to recover the dispersion parameters for two highly nonlinear fibers and the error free transmission of a 10Gb/s data signal over 33nm has demonstrated. The four wave mixing effect of Bragg Scattering has also been investigated in the active medium of nonlinear semiconductor optical amplifiers. Several experimental procedures are outlined for the use of this effect for wavelength conversion applications. A direct experimental comparison has been performed between Bragg Scattering and Modulation Instability for wavelength conversion of data signals in these devices with Bragg Scattering demonstrating an improved performance over the single pump process. Bragg Scattering has been used to effect the wavelength conversion of both multiple data channels and high speed data signals. Two 10Gb/s data channels spaced at both 50 and 100GHz were successfully converted and single channel conversion was demonstrated at speeds as high as 80Gb/s. The third topic investigated concerns wavelength conversion in nonlinear crystals. The construction of two 10Gb/s sources has been demonstrated for the characterisation of novel micro-structured plastic fibers. Sum frequency and second harmonic generation were both used for the generation of a 10Gb/s source in the visible. This source was used to demonstrate the first successful transmission of a 10Gb/s data signal through a micro-structured polymer optical fiber.