Reconfigurable wavelength division multiplex add/drop device using micromirrors

A WDM add/drop device for adding wavelengths to and dropping wavelengths from a multiple-wavelength optical signal in an optical communication system, comprising:

• an input port for receiving a WDM multiple-wavelength input optical signal from at least one first optic fiber;
• an output port for outputting a WDM multiple-wavelength output optical signal to at least one second optic fiber;
• a WDM add port for receiving as an input an add wavelength to be added to the multiple-wavelength optical signal;
• a WDM transmit/reflect unit having a first port and a second port for transmitting one of the multiple wavelengths of the multiple-wavelength signal from the first port to the second port in a first direction, for transmitting the added wavelength from the second port to the first port in a second direction, and for reflecting one of the multiple wavelengths of the multiple-wavelength signal from the first port back to the first port;
• a first multiport circulator disposed between said WDM input port, said WDM output port and said first port of said WDM transmit/reflect unit, said circulator being operable for receiving the WDM multiple-wavelength input signal from said input port and providing the WDM input signal to said first port of said WDM transmit/reflect unit and for receiving the WDM multiple-wavelength signal reflected by said WDM transmit/reflect unit and the added wavelength transmitted by said WDM transmit/reflect unit and providing the received reflected WDM multiple-wavelength signal and added wavelength to said output port;
• a WDM drop port for outputting from the WDM input signal, one of the multiple wavelengths dropped from the WDM multiple-wavelength optical signal transmitted by said WDM transmit/reflect unit;
• and
• a second circulator disposed between said WDM add port, said WDM drop port and said second port of said WDM transmit/reflect unit for forwarding one of the multiple transmitted wavelengths from the WDM transmit/reflect unit to said WDM drop port and for forwarding the WDM added wavelength from said WDM add port to said second port of said WDM transmit/reflect unit.

A WDM transmit/reflect unit for selectively transmitting a select wavelength of a multiple-wavelength optical signal from a first optic fiber to a second optic fiber and reflecting the select wavelength from the first optic fiber back to the first optic fiber, said unit comprising:

• a first port for receiving the multiple-wavelength optical signal from the first fiber;
• means for angularly displacing from each other individual ones of the multiple wavelengths in the multiple-wavelength optical signal when the multiple-wavelength optical signal is travelling in a first direction, and for angularly combining the individual wavelengths of the multiple-wavelength optical signal when the multiple-wavelength optical signal is travelling in a second direction;
• first means for imaging the angularly displaced multiple-wavelength optical signal to form an image;
• a micromirror array for receiving the image from said first imaging means, said micromirror array being selectively switchable between a transmission mode for transmitting the select wavelength to the second fiber and a reflection mode for reflecting the select wavelength to the first fiber;
• said first imaging means operatively imaging the reflected select wavelength at said first port for receipt by the first optic fiber when said micromirror array is in said reflection mode;
• second imaging means for imaging the transmitted select wavelength when said micromirror array is in said transmission mode;
• and
• a second port connected to the second fiber for receiving the image of the transmitted select wavelength from said second imaging means.