Abstract: A reconfigurable multi-add/drop module for optical communications. The system includes a first network interface GRIN lens collimator connected on one end to an optical fiber of a communications network. An output of the GRIN lens is directed to a series of slidable two-section channel filters. Each filter is mechanically movable to a first position that passes all wavelengths. The second position of each filter reflects a particular wavelength to a corresponding add/drop GRIN lens collimator that receives the reflected light and outputs it into an add/drop fiber. The outputs from the add/drop collimators are directed to a single add/drop fiber through use of a power combiner. Light that passes through all of the filters is directed into a second network interface GRIN lens collimator for the purpose of coupling the light onto a second network optical fiber. A carrier wavelength can also be entered/added at the add/drop port.

Abstract: A method allowing reliable routing of individual optical carriers through an optical network is disclosed. Routing information is impressed on individual carriers by a method known as subband quadrature coding (SQC). The optical carrier is modulated at a first frequency, and at a first intensity to impress application data on the carrier. The carrier is additionally modulated at a second frequency, preferably two orders of magnitude less than the first frequency, and at a second intensity less than the first intensity to impress management data on the carrier for routing the carrier through an optical communications network, from a source to a destination. According to the method, the management data is continuously impressed upon the carrier during transmission of the application data. The optical carrier is multiplexed onto the fiber optic communications line, and upon reaching a first node, the carrier is demultiplexed and an intensity sample of the carrier is detected.

Abstract: A method for performance monitoring of data transparent communication links, including a method wherein each symbol in an incoming data symbol stream is sampled at the center of each bit period to create a main line data bit stream, and concurrently sampled at a time instant displaced from the center of each bit period to create a second line data bit stream. During each bit period, the digital value of the second line data stream is compared with the digital value for the corresponding bit period in the main line. If the main line and second line digital values are the same, no error is indicated. If they are different, i.e. if, for example, the main line is bit “1” and the second line is bit zero, an error called a pseudo error is entered on a counter. The number of errors counted per number of bits or time is indicated as a pseudo error rate for each point of time displacement in the user-defined set.