ABSTRACT

Wavelength conversion is important for photonic networks, when the optical signal is transferred from one node to another by assigning optical wavelength to each optical path and changing it in accordance with the destination of the optical signal. Wavelength conversion has been proposed and verified experimentally by several methods. From the device point of view, it is categorized as: semiconductor optical amplifier (SOA) and lasers (LD), electroabsorption modulator, electro-optic crystal, and optical fiber. Wavelength conversion can be achieved by: cross gain modulation, cross phase modulation, four wave mixing, cross absorption modulation, self-phase modulation, and quasi-phase matching. A SOA is a semiconductor optical device in which optical signal intensity is amplified 10 to 100 times greater than the input signal by stimulated emission. A LD is also a gain medium with large optical gain and nonlinearity. The cross phase modulation is a wavelength conversion technique using the optical phase change, or in other words, refractive index change by signal light injection.