WDM channel equalization based on subcarrier signal monitoring

Summary form only given. Several authors have proposed and demonstrated the use of acousto-optic tunable filters (AOTF) for WDM channel equalization by using these devices as wavelength-selective variable attenuators. These solutions require a system for WDM channel monitoring, which is usually realized using complex and expensive optical filtering techniques. In this paper we propose and demonstrate a simple and efficient solution to the monitoring problem, based on the use of subcarrier signals. In our system, each wavelength, besides the high bit-rate baseband signal, carries a subcarrier tone at frequency higher than the bit rate, so that the tone is spectrally separated from the baseband.