A Centrally Controlled Survivable WDM-PON Based on Optical Carrier Suppression Technique

A simple centrally controlled survivable wavelength-division-multiplexed passive optical network (WDM-PON) architecture employing an optical carrier suppression technique is proposed. Protection switching at the optical line terminal employs electrical switches to control the clock signal for the protection subcarrier generation, via optical carrier suppression. Both distribution and feeder fibers are protected simultaneously. By employing an inverse-return-to-zero format for the downstream transmission and nonreturn-to-zero for the upstream remodulated signal, the optical network units are kept colorless and simple. The 10-Gb/s transmissions under both normal working and protection modes were experimentally demonstrated and traffic restoration time was measured to be about 5 ms.