Wavelength division multiplexed optical communication system having a reconfigurable optical switch and a tunable backup laser transmitter

Abstract

In a WDM optical communication system that includes a plurality of nodes interconnected by communication links, a node is provided that includes a reconfigurable optical switch having a plurality of input ports and at least one output port. The node also includes a plurality of transmitters that are each coupled to one of the input ports of the optical switch. Each of the transmitters generate an information-bearing optical signal at a different channel wavelength from one another. The reconfigurable optical switch is adaptable to receive at any of the input ports any of the channel wavelengths at which the plurality of transmitters operate and direct the channel wavelengths to the output port. At least one backup transmitter is coupled to one of the input ports of the optical switch. The backup transmitter includes a tunable laser tunable to any of the channel wavelengths at which the plurality of transmitters operate. The reconfigurable optical switch includes at least one wavelength selective element that selects at least one channel wavelength from among any of the channel wavelengths received at any of the input ports. The switch also includes a plurality of optical elements associated with the wavelength selective elements, Each of the optical elements direct one of the selected channel wavelengths selected by the associated wavelength selective element to the output port independently from every other channel wavelength. The selected channel wavelengths directed to the output port are combined on the output port.