Patent ID: 6934474
Filing Date: 2005-08-23
Classification: H04J

Abstract:
1. A bidirectional add/drop multiplexer for transmitting a wavelength division multiplexed signal and adding/dropping a signal in both forward and reverse directions, comprising; a first circulator having an input for receiving a forward optical signal and an output; a second circulator having an input for receiving a reverse optical signal and an output; a forward waveguide grating having first and second ends, said forward optical signal traversing the forward waveguide grating once to travel from the first end to the second end, said forward waveguide grating being coupled to said first circulator at said first end, and being coupled at said second end to said second circulator to transmit said forward optical signal to said second circulator, said forward waveguide grating for demultiplexing said forward optical signal received from said first circulator, for at least one of adding a channel to and dropping a channel from the demultiplexed channels of said forward optical signal, and for multiplexing both the forward channels added and the forward channels not dropped; and a reverse waveguide grating having two ends, said reverse waveguide grating being coupled to said first circulator at one of said two ends and to said second circulator at the other of said two ends, said reverse waveguide grating for demultiplexing said reverse optical signal received from said second circulator, for at least one of adding a channel to and dropping a channel from the demultiplexed channels of said reverse optical signal, and for multiplexing both the reverse channels added and the reverse channels not dropped.