An apparatus and method for processing a supervisory signal for optical network applications. The apparatus includes a subcarrier transmission system configured to receive a first supervisory signal and output a second supervisory signal, and an electrical-to-optical conversion system configured to receive...http://www.google.com/patents/US20050201752?utm_source=gb-gplus-sharePatent US20050201752 - System and method for subcarrier modulation as supervisory channel
