Efficient backward-propagation using wavelet-based filtering for fiber backward-propagation.

With the goal of reducing the number of operations required for digital backward-propagation used for fiber impairment compensation, wavelet-based filtering is presented. The wavelet-based design relies on signal decomposition using time-limited basis functions and hence is more compatible with the dispersion operator, which is also time-limited. This is in comparison with inverse-Fourier filter design which by definition is not time-limited due to the use of harmonic basis functions for signal decomposition.

BER estimation of QPSK homodyne detection with carrier phase estimation using digital signal processing.

An approximate analytical expression for the bit error rate of a QPSK homodyne receiver employing digital signal processing for carrier recovery is derived. BER estimated using the analytical expression is in excellent agreement with Monte-Carlo simulations. The analytical approximation leads to an intuitive understanding of the trade off in such systems and allows optimization of system parameters without resorting to Monte-Carlo simulations.

WDM Transmission over 320 km EDFA-Amplified SSMF Using 30 Gb/s Return-to-Zero Optical Differential 8-Level Phase-Shift Keying (OD8PSK).

Fiber transmission of optical differential 8-level phase-shift keying (OD8PSK) signals is demonstrated for the first time. Co-polarized 8 WDM channels of 10 Giga-symbol/s or 30 Gb/s return-to-zero (RZ) OD8PSK signals with a channel spacing of 50 GHz were transmitted over 320 km of standard single mode fiber (SSMF) with an EDFA spacing of 80 km. The BER of the worst WDM channel after transmission of 320 km was 2.