A novel bit-error indicating scheme using only one judge threshold

A novel all-optical bit-error indicating scheme based on self-phase modulation and band-pass filtering is proposed. In this scheme, the amplified original bit stream propagates through a high-nonlinear fiber where self-phase modulation occurs, and then passes through a band-pass filter to be converted to a bit-error indicating signal. In the bit-error indicating signal, the error bit has the highest peak power, and the “1” and “0” bits have lower ones. At the same time, the bit-error indicating signal is synchro-nous with the delayed original bit stream. Therefore, the position of the error bit in the original bit stream can be identified by setting only one judge threshold in the bit error indicating signal. The per-formance of this scheme has been demonstrated for an 80 Gb/s bit-stream with return-to-zero format by simulation. The results show that the proposed scheme can be used for the all-optical bit-error indi-cating of the super high bit-rate systems with the return-to-zero format.