Add-drop optical spectrum-division multiplexer

An add-drop optical spectrum-division multiplexer for dropping a drop multiplex from an incoming multiplex, and for adding an add multiplex to an outgoing multiplex, the multiplexer comprising:

• spectrum-division demultiplexing means for separating N number of carriers from the incoming multiplex, said incoming multiplex having no more than N number of carriers;
• spectrum-division multiplexing means for multiplexing N number of carriers, thereby constituting an outgoing multiplex;
• and
• coupling means for coupling the demultiplexing means to the multiplexing means;
• the spectrum-division demultiplexing means and the coupling means comprise:
• an optical broadcaster which receives the incoming multiplex and reproducing the incoming multiplex on at least N number of outlets;
• a first set of N tunable filters coupled to respective ones of the N number of outlets from the broadcaster to select, in the incoming multiplex, E number of drop carriers and T number of through carriers where the numbers T and E are variable and not greater than N;
• a second set of N number of tunable filters for selecting, for the carriers constituting the add multiplex, I number of add carriers, the number I being variable and not greater than N;
• N number of wavelength converters for providing the multiplexing means with T number of new carriers respectively modulated by the signals modulating the T number of through carriers, and I number of new optical carriers modulated by the signals modulating the I number of add carriers, said N number of new carriers having N number of different wavelengths;
• and
• N number of optical switches each having two inlets and two outlets, and each having:
• a first inlet connected to an outlet of a respective filter of the first set;
• a second inlet connected to an outlet of a respective filter of the second set;
• a first outlet connected to the inlet of a respective one of the wavelength converters;
• and
• a second outlet providing a drop carrier to the drop multiplex;
• and in that the multiplexing means includes an N-inlet optical combiner having its inlets connected to the outlets of respective ones of the N number of wavelength converters.

An add-drop optical spectrum-division multiplexer for dropping a drop multiplex from an incoming multiplex, and for adding an add multiplex to an outgoing multiplex, the multiplexer comprising:

• spectrum-division demultiplexing means for separating N number of carriers from the incoming multiplex, said incoming multiplex having no more than N number of carriers;
• spectrum-division multiplexing means for multiplexing N number of carriers, thereby constituting an outgoing multiplex;
• and
• coupling means for coupling the demultiplexing means to the multiplexing means;
• the spectrum-division demultiplexing means and the coupling means comprise:
• an optical broadcaster for receiving the incoming multiplex and reproducing said incoming multiplex on N number of outlets;
• a first set of N number of tunable filters coupled to the N number of respective outlets of the broadcaster to select, from the incoming multiplex, E number of drop carriers;
• a second set of N number of tunable filters coupled to the N number of respective outlets of the broadcaster to select from the incoming multiplex T number of through carriers;
• a third set of N number of tunable filter for selecting, from the carriers constituting the add multiplex I number of add carriers, the number I being variable and not greater than N;
• N number of passive couplers each having two inlets and one outlet, the two inlets being respectively connected to the outlet of a filter in the second set and to the outlet in the of a filter in the third set;
• and
• N number of wavelength converters for providing the multiplexing means with T+I number of new carriers respectively modulated by the signals modulating the T number of through carriers and the I number of add carriers, where the sum T+1 is not greater than N;
• and
• the multiplexing means include an N inlet optical combiner whose N number of inlets are connected to respective outlets from the N number of wavelength converters.

An add-drop optical spectrum-division multiplexer for dropping a drop multiplex from an incoming multiplex, and for adding an add multiplex to an outgoing multiplex, the multiplexer comprising:

• spectrum-division demultiplexing means for separating N number of carriers from the incoming multiplex, said incoming multiplex having no more than N number of carriers;
• spectrum-division multiplexing means for multiplexing N number of carriers, thereby constituting an outgoing multiplex;
• and
• coupling means for coupling the demultiplexing means to the multiplexing means;
• the spectrum-division demultiplexing means and the coupling means comprise:
• an optical broadcaster for receiving the incoming multiplex and reproducing said incoming multiplex on N number of outlets;
• a first set of N number of tunable filters coupled to respective ones of the N number of outlets of the broadcaster to select E number of drop carriers from the incoming multiplex, and for selecting T number of through carriers therefrom, the numbers T and E being variable and not greater than N;
• a second set of N number of tunable filters coupled to respective ones of the N number of outlets of the broadcaster to select T number of through carriers from the incoming multiplex;
• a third set of N number of tunable filters for selecting, from the carriers constituting the add multiplex, I number of add carriers, where the number I is variable and not greater than N;
• N number of wavelength converters each having one inlet connected to an outlet from a respective filter of the first set, to provide the multiplexing means with T number of new carriers respectively modulated by the signals modulating the N number of through carriers;
• and
• N number of wavelength converters for providing the multiplexing means with I number of new carriers respectively modulated by the signals modulating the I number of carriers to be inserted;
• and
• the multiplexing means comprise an optical combiner having 2N number of inlets connected to respective outlets of the 2N number of wavelength converters.