Direct-detection optical differential 8-level phase-shift keying (OD8PSK) for spectrally efficient transmission

An implementation of optical differential 8-level phase-shift keying (OD8PSK) is proposed for spectrally efficient high capacity long-haul optical fiber transmission systems. Interferometric demodulation and direct detection at the receiver yield three output binary sequences identical to the three input binary sequences. This is accomplished by proper design of electrical encoding and optical encoding at the transmitter. Three optical encoding schemes are proposed with corresponding differential electrical encoding schemes. Numerical simulations are performed for a single channel transmission to evaluate the transmission performances of OD8PSK systems

Phase-and-amplitude regeneration of differential phase-shift keyed signals using a phase-sensitive amplifier

DPSK phase- and- amplitude regeneration with a NOLM- based phase- sensitive amplifier is demonstrated experimentally. For a highly degraded input signal, maximum differential phase errors were reduced from 82 degrees to 41 degrees, while the SNR was improved by more than 5- dB. Differential phase Q- factor improvement was better than 6- dB. The PSA was operated free of excess noise due to stimulated Brillouin scattering by using a binary phase modulated pulse train as the pump. The impact of pump fluctuations on regeneration performance is clarified. The regenerated signal was characterized by measurement of the constellation diagram by linear optical sampling, giving the first directly measured evidence of DPSK phase regeneration

Wavelength-insensitive all-optical clock extraction and enhancement of nonreturn-to-zero data using a semiconductor optical amplifier and fiber Bragg grating

A scheme for wavelength and polarization insensitive all-optical clock extraction and enhancement of nonreturn-to-zero (NRZ) data is proposed and demonstrated. At 10 Gbit/s, more than 7-dB clock enhancement and 19-dB clock-to-data suppression ratio (CDSR) enhancement have been realized using a semiconductor optical amplifier (SOA) and a reflective fiber Bragg grating (FBG) over a 30-nm input wavelength range

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 2.3 x 10(-5)

180-Gb/S Clock Recovery Using A Multi-Section Gain-Coupled Distributed Feedback Laser

180-Gb/s all-optical clock recovery has been demonstrated by using a self-pulsing multi-section gain-coupled distributed feedback laser. This clock recovery scheme has a jitter less than 0.4 ps over a dynamic range of 7dB. © 2005 Optical Society of America