Optical add-drop multiplexer

A method of extracting a selected channel from a multiplexed signal stream containing a plurality of channels, the method comprising the steps of:

• providing an optical device comprising a plurality of different output ports for directing the multiplexed signal stream to a selected output port corresponding to the selected channel;
• providing a concave mirror reflector which receives and reflects the multiplexed signal stream emitted from the selected output port of the optical device;
• providing a thin film filter which receives the multiplexed signal stream reflected from the reflector and divides the signal stream into the selected channel and remaining channels;
• and
• directing the remaining channels of the signal stream onto the reflector.

An optical device comprising:

• an optical switch for switching to a channel to be extracted, the switch having an input port for inputting a multiplexed signal stream and a plurality of output ports, with one output port corresponding to the channel to be extracted and remaining output ports corresponding to other channels;
• a first channel assembly optically connected with the output ports of the optical switch and emitting the multiplexed signal stream received from said one output port;
• a reflector reflecting the multiplexed signal stream emitted from the first channel assembly;
• and
• an optical thin film filter receiving the multiplexed signal stream from the reflector and dividing the multiplexed signal stream into a signal corresponding to the channel to be extracted and remaining signals corresponding to the other channels, the remaining signals being directed to the reflector from the optical thin film filter.

A switchable add-drop multiplexer system comprising:

• an optical switch adapted to transmit a light from a same source to different positions;
• a first channel assembly connected to said optical switch to provide a plurality of parallel light paths corresponding to said different positions;
• an optical device configured to converge said parallel light paths into a focal point;
• and
• an optical extractor positioned at said focal point for dropping a signal of a desired wavelength, the extractor having a filter formed thereon.

A method of switchably dropping different signals with different center wavelengths, comprising the steps of:

• providing an optical switch defining a plurality of different output positions;
• providing a first channel assembly defining a plurality of different light paths corresponding to said different output positions, respectively;
• providing an extractor with a filter;
• and
• providing means for guiding the different light paths toward said extractor at different incident angles for dropping the signals with the different center wavelengths exclusively according to the different incident angles, respectively.