210 km repeaterless 10 Gb/s transmission experiment through nondispersion-shifted fiber using partial response scheme

Narrow Filtered DPSK Implements Order-1 CAPS Optical Line Coding

“…However, with these modulation formats, the receiver cannot be a standard optically preamplified one, as a Mach-Zehnder interferometer is needed to allow for direct detection of such signal formats. Instead, such a standard receiver can be used in the case of duobinary [3], [4] or derived [5]- [7], coding, the only difference lying in this case in the generation of the coded signals. Whereas duobinary, phase-shaped binary transmission (PSBT) [6] or phased amplitude-shift signaling [7] coding can be achieved through standard Mach-Zehnder modulators, it is not so simple a matter as regards CAPS coding [5].…”

Simulation approach to the improvement of dispersion tolerance for electrical-binary-signal-based duobinary transmitters

“…This coding allows one-half narrow spectral bandwidth of binary coding [2,3] and large tolerance for the chromatic dispersion [4] thanks to two different phases of marks. It also increases the threshold for stimulated Brillouin scattering thanks to the absence of an optical carrier in the spectrum [5].…”

Receiver optimization for 40-Gb/s optical duobinary signal

“…Up to now, the spectral efficiency of 0.6 bit/s/Hz on a single polarization state has been achieved using the optical duobinary format [3]. Though an ordinary binary receiver can still be used for an optical duobinary signal, the sensitivity of an optical duobinary signal will be degraded compared to the binary singal, because of the waveform distortion caused by the electrical filter with bandwidth of a quarter of a bit rate during the duobinary generation procession [4]. An extra external modulator working under a slight modulation index can be used to improve the sensitivity of the optical duobinary signal, meanwhile, the dispersion tolerance is still high [5].…”