Methods and apparatus for optical switching

A method of processing an optical signal in a manner that can be used to perform optical time slot switching, the method comprising:

• optically demultiplexing a first time division multiplexed signal to produce a first plurality of demultipled signals;
• supplying each of said first plurality of demultiplexed signals to a separate input of an optical switching device having a plurality of inputs and outputs;
• using a plurality of optical time delay elements to couple at least some of the outputs of said optical switching device to a first optical time division multiplexer;
• operating the first optical time division multiplexer to generate a second optical time division multiplexed signal by performing an optical time division multiplexing operation;
• optically demultiplexing a third time division multiplexed signal to produce a second plurality of demultiplexed signals;
• supplying at least some of said second plurality of demultiplexed signals to separate inputs of said optical switching device;
• using an additional plurality of optical time delay elements to couple at least some of the outputs of said optical switching device corresponding to a second optical time division multiplexer;
• and
• operating the second optical time division multiplexer to generate a fourth optical time division multiplexed signal.

An apparatus for performing switching operations on optical signals, the apparatus comprising:

• an optical switching device having a plurality of inputs and outputs;
• a first time division demultiplexer for demultiplexing a first time division multiplexed signal into a first plurality of optical signals corresponding to different communications channels, the first time division demulitiplexer having an output for each of said plurality of optical signals, each output being coupled to a corresponding input of the optical switching device;
• a first time division multiplexer for multiplexing optical signals supplied to said first multiplexer to produce at an output of the first multiplexer a second optical time division multiplexed signal;
• a first plurality of variable optical time delay elements for coupling at least some outputs of said optical switching device to said first time division multiplexer;
• and
• means for synchronizing said variable optical time delay elements as a function of a feedback signal generated from one of the switched optical signals supplied to an input of said first time division multiplexer.

An apparatus for performing switching operations on optical signals, the apparatus comprising:

• an optical switching device having a plurality of inputs and outputs;
• a first time division demultiplexer for demultiplexing a first time division multiplexed signal into a first plurality of optical signals corresponding to different communications channels, the first time division demulitiplexer having an output for each of said plurality of optical signals, each output being coupled to a corresponding input of the optical switching device;
• a first time division multiplexer for multiplexing optical signals supplied to said first multiplexer to produce at an output of the first multiplexer a second optical time division multiplexed signal;
• a first plurality of variable optical time delay elements for coupling at least some outputs of said optical switching device to said first time division multiplexer;
• a second time division demultiplexer for demultiplexing a third time division multiplexed signal into a second plurality of optical signals corresponding to different communications channels, the second time division demulitiplexer having an output for each of said plurality of optical signals, each output being coupled to a corresponding input of the optical switching device;
• a second time division multiplexer for multiplexing optical signals supplied to said second multiplexer to produce at an output of the second multiplexer a fourth optical time division multiplexed signal;
• and
• a second plurality of variable optical time delay elements for coupling at least some outputs of said optical switching device to said second time division multiplexer.

An apparatus for performing switching operations on optical signals, the apparatus comprising:

• an optical switching device having a plurality of inputs and outputs;
• a first time division demultiplexer for demultiplexing a first time division multiplexed signal into a first plurality of optical signals corresponding to different communications channels, the first time division demulitiplexer having an output for each of said plurality of optical signals, each output being coupled to a corresponding input of the optical switching device;
• a first plurality of variable optical time delay elements for coupling at least some inputs of said optical switching device to said first time division demultiplexer;
• a first time division multiplexer having inputs coupled to outputs of said optical switching device for producing at an output of the first multiplexer a second optical time division multiplexed signal;
• and
• means for synchronizing said variable optical time delay elements as a function of a feedback signal generated from one of the switched optical signals supplied to an input of said first time division multiplexer.

An apparatus for performing switching operations on optical signals, the apparatus comprising:

• an optical switching device having a plurality of inputs and outputs;
• a first time division demultiplexer for demultiplexing a first time division multiplexed signal into a first plurality of optical signals corresponding to different communications channels, the first time division demulitiplexer having an output for each of said plurality of optical signals, each output being coupled to a corresponding input of the optical switching device;
• a first plurality of variable optical time delay elements for coupling at least some inputs of said optical switching device to said first time division demultiplexer;
• a first time division multiplexer having inputs coupled to outputs of said optical switching device for producing at an output of the first multiplexer a second optical time division multiplexed signal;
• a second time division demultiplexer for demultiplexing a third time division multiplexed signal into a second plurality of optical signals corresponding to different communications channels, the second time division demulitiplexer having an output for each of said plurality of optical signals;
• a second plurality of variable optical time delay elements for coupling at least some outputs of said second time division demultiplexer to optical switching device;
• and
• a second time division multiplexer for multiplexing optical signals supplied to said second multiplexer to produce at an output of the second multiplexer a fourth optical time division multiplexed signal.