Patent ID: 6721508
Filing Date: 2004-04-13
Classification: H04J

Abstract:
A wavelength division multiplexed (WDM) optical communication system comprising:a first optical line terminal comprising: a line interface to receive from external to the system a first WDM optical signal having multiplexed therein at least one optical wavelength to be locally dropped by the system and at least one pass-through optical wavelength that is not to be locally dropped by the system; a first demultiplexer to demultiplex from the received first WDM optical signal the at least one optical wavelength to be locally dropped by the system; a first all-optical pass-through port to which the at least one pass-through wavelength of the received first WDM optical signal is provided optically to the exclusion of the at least one optical wavelength to be locally dropped from the first WDM optical signal, the first all-optical pass-through port residing on a modular card of the system; a first multiplexer to provide a second WDM optical signal for transmission external to the system; and a second all-optical pass-through port being optically connected to provide optical pass-through signals received at the second all-optical pass-through port to the first multiplexer for multiplexing, the second all-optical pass-through port residing on a modular card of the system; a second optical line terminal comprising: a line interface to receive from external to the system a third WDM optical signal having multiplexed therein at least one optical wavelength to be locally dropped by the system and at least one pass-through optical wavelength that is not to be locally dropped by the system; a second demultiplexer to demultiplex from the received third WDM optical signal the at least one optical wavelength to be locally dropped by the system; a third all-optical pass-through port to which the at least one pass-through wavelength of the received third WDM optical signal is provided optically to the exclusion of the at least one optical wavelength to be locally dropped from the third WDM optical signal, the third all-optical pass-through port residing on a modular card of the system that is physically distinct from the modular card on which resides the second all-optical pass through port of the first optical line terminal; a second multiplexer to provide a fourth WDM optical signal for transmission external to the system; and a fourth all-optical pass-through port being optically connected to provide optical pass-through signals received at the fourth all-optical pass-through port to the second multiplexer for multiplexing, the fourth all-optical pass-through port residing on a modular card of the system that is physically distinct from the modular card on which resides the first all-optical pass through port of the first optical line terminal; optical fiber optically connecting the first all-optical pass-through port to the fourth all-optical pass-through port, whereby the system permits the at least one pass-through optical wavelength from the received first WDM optical signal to be further transmitted by the system without any intervening electro-optical conversion by the system of the at least one pass-through optical wavelength; and optical fiber optically connecting the third all-optical pass-through port to the second all-optical pass-through port, whereby the system permits the at least one pass-through optical wavelength from the received third WDM optical signal to be further transmitted by the system without any intervening electro-optical conversion by the system of the at least one pass-through optical wavelength.