Method and apparatus for improving transmission performance over wavelength division multiplexed optical communication links using forward error correction coding

摘要

Data transmission apparatus includes first and second optical transmitters coupled to an optical link. A forward error correction (FEC) coder is coupled to the input of the second optical transmitter. A first information signal having a first information rate is provided to the first optical transmitter, and a second information signal having a second information rate is provided to the second optical transmitter. The use of the FEC coder enables the second information signal to have a higher information rate than the first information signal, while simultaneously enabling the respective output power levels of the first and second optical amplifiers to be substantially equal. The data transmission apparatus achieves higher data transmission capacity while retaining compatibility with pre-existing fiber spans and amplifier nodes. An optical transmission system incorporates an optical transmitter and an optical receiver having certain transmission characteristics, such as output power level, decision threshold level, etc., that are adjustable in response to bit error rate information. A bit error rate estimator is provided at the receiving end of the optical link. The bit error rate estimator estimates the bit error rate of the received information signal, and provides bit error rate information to the optical receiver, and/or the optical transmitter, and/or the optical link, based on the estimated bit error rate, in order to optimize the performance of the transmission system.