Reversible ring coupler for optical networks

A light coupling device for adding a first light signal having a wavelength of λ1 to a second light signal of wavelength λ2 traveling in an optical channel, said coupling comprising:

• a first optical channel port and a second optical channel port, said second light signal entering one of said first and second optical channel ports and leaving by the other of said first and second optical channel ports;
• an optical channel input port for receiving said first light signal;
• an optical circulator having first, second, and third ports and a circulation direction determined by a circulator input signal thereto;
• and
• a first reflector having first and second ports, light entering one of said ports exiting the other of said ports unless said light is reflected by said first reflector, in which case said reflected light leaves by the port through which said light entered, said first reflector having first and second reflection states, wherein said first reflector reflects light of wavelength λ1 in said first reflection state and said first reflector is transparent to light of wavelength λ1 in said second reflection state, said reflection state of said first reflector being set in response to a first reflector input signal,
• wherein said first port of said first reflector is connected to said first optical channel port, said first port of said optical circulator is connected to said optical input port, said second port of said first reflector is connected to said second port of said optical circulator.