Embedded modulable self-tuning cavity for WDM-PON transmitter

A network-embedded self-tuning cavity based on a self-seeded RSOA is analysed with particular regards to the impact of some parameters that characterize the transmitter. The cavity is defined by the SOA reflective mirror and a Faraday rotator mirror at the remote node, which allows polarization independent operation with low PDG RSOAs. The majority of the cavity is formed by the distribution fibre, while the arrayed waveguide grating (AWG) at the RN operates as the frequency selective element. The experimental analysis is carried out by varying fundamental cavity parameters such as the distribution fibre length, the cavity losses, the bandwidth of the AWG filter and its spectral location with respect to the RSOA gain peak. Performance is experimentally evaluated at 1.25 Gb/s. Transmitter output power is determined by cavity losses independently of the AWG bandwidth. On the other hand AWG bandwidth strongly influence BER performance: for lower FWHMs error floors appear associated to intensity noise.