All-optical regeneration of high bit rate lightwave systems using an all-active semiconductor optical amplifier Mach-Zehnder interferometer

Single channel optically amplified lightwave systems operating at bit rates of 10 Gb/s and above, suffer signal distortion due to dispersion and self-phase modulation in non-dispersion shifted fibers. All-optical regenerators, such as the semiconductor optical amplifier Mach-Zehnder Interferometer (SOA-MZI), present an attractive method of compensating for this distortion. Three different models of the SOA-MZI are examined and compared for a bit rate of 10 Gb/s. The detailed rate equation model proved to be the most flexible and accurate representation of the physical device. Three different types of modulators are used in order to asses the regenerative abilities of the SOA-WI and the SOA-MZI models. All three modulators perform the same basic function, however, each modulator exhibits different chirp properties as well as absorption and frequency response which greatly effect the distortion encountered by the signal. It is discovered that the regenerative abilities of the SOA-MZI depend highly upon the chirp properties of the modulator. Regeneration is shown to be only possible when the signal has been negatively chirped by the modulator.