Reflective polarisation independent Mach-Zenhder modulator for FDMA/OFDMA PON

Presented is a Mach-Zehnder based subsystem allowing polarisation independent reflective carrier suppressed optical modulation for application in frequency division multiple access (FDMA) and orthogonal frequency division multiple access (OFDMA) passive optical networks (PONs). This type of shared access technique requires the use of a coherent uplink receiver in the Central Office (CO). The proposed subsystem also acts as a Faraday mirror allowing simplification of the coherent receiver by removing the need for polarisation diversity. With this setup, a data rate better than 7.5 Gbit/s is experimentally demonstrated over a class B PON budget using discrete multi-tone (DMT) modulation.