At&t Bell Laboratories

Tyco Telecommunications (us) Inc.

Donald G Duff

Howard D Kidorf

Karsten Rottwitt

Xiaobing Ma

Ricardo Mediavilla

Donald A Lane

A lightwave communication system is provided that includes first and second optical transmitters/receivers remotely located with respect to one another. First and second optical transmission paths couple the first transmitter/receiver to the second transmitter/receiver for bidirectionally transmitting optical information therebetween. First and second doped optical fibers are respectively disposed in the first and second optical transmission paths. Optical pump energy is supplied by first and second optical pump sources. The first optical pump source generates Raman gain in the first transmission path and the second optical pump source generates Raman gain in the second transmission path. A first optical coupler is provided for optically coupling pump energy from the first pump source to the second-doped optical fiber and a second optical coupler is provided for optically coupling pump energy from the second pump source to the first doped optical fiber.

Optical fiber communication system employing doped optical fiber and Raman amplification

Improved jitter performance is realized in a desynchronizer for obtaining an asynchronous digital signal, e.g., a DS3 signal, from a received synchronous digital signal, e.g., a SONET STS-1 signal. The improved jitter performance results from the use of a unique adaptive bit leaking arrangement in conjunction with a digital phase locked loop and synchronizing elastic store. An estimate of a bit leaking interval is adaptively obtained based on the intervals between a sequence of consecutive pointer adjustments in the received signal, i.e., the STS-1 signal. In one embodiment, the bit leaking interval estimate is obtained by employing a moving average of the intervals between the pointer adjustments. The desired bit leaking is effected by employing an accumulator which is responsive to the received pointer adjustments and a representation of the estimated bit leaking interval, in conjunction with a comparator. The accumulator output count is supplied to the comparator along with the current write address of the elastic store. Leak bits are supplied as an output from the comparator one at a time to the phase locked loop which, in turn, generates a smooth read clock for the elastic store.

Synchronous digital signal to asynchronous digital signal desynchronizer

Growing community of inventors

Lincroft, NJ, United States of America

Donald G Duff