Patent ID: 8078052

Claim:
In an optical network having a link carrying optical signals in one direction and carrying optical signals in an opposite direction with 1 +1 protection in each direction, each node for said link comprising: an optical splitter having an input terminal configured to receive optical signals to transmit across said link, a first output terminal and a second output terminal; a first optical modulator connected between said first optical splitter output terminal and a first terminal for connection to a first transmission optical fiber configured to carry said optical signals across said link in said one direction; a second optical modulator connected between said second optical splitter output terminal and a second terminal for connection to a second transmission optical fiber configured to carry said optical signals across said link in said one direction; a receiving optical switch having an output terminal for transmitting optical signals, a first input terminal for receiving said optical signals from a first receiving optical fiber for carrying across said link in said opposite direction, and a second input terminal configured to receive said optical signals from a second receiving optical fiber across said link in said opposite direction; a first photo diode coupled to said first input terminal of said receiving optical switch; and a second photo diode coupled to said second input terminal of said receiving optical switch; wherein said first and second optical modulators are configured to continuously toggle between an optical signal and a partially attenuated optical signal for transmission across said first and second transmission optical fibers.