Stability and dynamic range of a Mach-Zehnder wavelength shifter

In future wavelength-division multiplexed (WDM) reconfigurable networks, the ability to shift a signal from one wavelength to another may be an essential function due to a limited number of available wavelengths. The Mach-Zehnder interferometer (MZI) has sparked the interest of the WDM community because ofits ability to wavelength convert signals at high speed, in both inverting and noninverting configurations with a high output extinction ratio, and with low chirp. In this paper, we assess the stability of the extinction ratio of the MZI with variations in the SOA bias currents, as well as with the wavelength and the power of the pump and probe. We characterize the operating point stability of the MZI and find ranges for the bias currents and for the input parameters, in order to minimize the sensitivity of the extinction ratio (ER)