Pump to signal RIN transfer in Raman fibre amplifiers

An analytical model and measurements of the pump to signal relative intensity noise transfer characteristics of co- and counter-pumped Raman amplifiers is presented. Quantitative analysis of noise averaging from chromatic dispersion in co-pumped systems, and from different propagation directions in counter-pumped systems is given     

Electrical measurements of multipath interference in distributedRaman amplifiers

Measurements of multipath interference (MPI) using an electrical technique have shown that the use of distributed Raman amplification can significantly increase the amount of MPI in a system. The MPI is primarily attributed to double-Rayleigh scattering along the length of the transmission fiber. Analytical expressions for MPI have been developed that give good agreement with measurements and numerical simulations. These can be used to predict the buildup of MPI in a lightwave transmission system. Poor connectors will cause a further increase in MPI by causing back-reflections into the Raman gain cavity     

Pump to signal RIN transfer in Raman fiber amplifiers

We present an analytical model and measurements of the pump to signal relative intensity noise (RIN) transfer characteristics of copumped and counterpumped Raman amplifiers. We give a quantitative analysis of noise averaging from chromatic dispersion in copumped systems and from different propagation directions in counterpumped systems. It is shown that nondispersion-shifted fibers and other fibers with high dispersion between the signal and pump wavelengths give a greater potential for use in copumped Raman amplified systems     

Polarisation-channel-interleaved CS-RZ transmission at 40Gbit/swith 0.8bit/s/Hz spectral efficiency

Experimental results are reported of polarisation-channel-interleaved carrier-suppressed RZ (PCI CS-RZ) ETDM/DWDM transmission of 8 × 40 Gbit/s over 320 km (2 × 160 kin) NDSF, with 0.8 bit/s/Hz spectral efficiency. An average system linear Q of 6.5 at a PRBS pattern length of 2³¹ - 1 and tolerance to at least 50% degradation in orthogonality are demonstrated     

2.56 Tbit/s (32×80 Gbit/s) polarisation-bit-interleavedtransmission over 120 km NDSF with 0.8 bit/s/Hz spectral efficiency

Experimental results of 32×80 Gbit/s polarisation-bit-interleaved carrier-suppressed RZ transmission over 120 km of NDSF with 0.8 bit/s/Hz spectral efficiency are reported. System Q values between 6.1 and 8 (2³¹-1 pattern) were achieved with the use of distributed Raman amplification and polarisation demultiplexing     

Channel Parameter Estimation for Polarization Diverse Coherent Receivers

A robust in-service estimation of fiber channel parameters from equalizer parameters of a polarization diverse coherent receiver is presented. The equations used for estimation are evolved from a theoretical fiber channel model. The theory is validated based on simulations and data from transmission experiments.     

Coherent Equalization and POLMUX-RZ-DQPSK for Robust 100-GE Transmission

We discuss the use of a coherent digital receiver for the compensation of linear transmission impairments and polarization demultiplexing in a transmission system compatible with a future 100-Gb/s Ethernet standard. We present experimental results on the transmission performance of 111 Gbit/s POLMUX-RZ-DQPSK. For a dense WDM setup with channels carrying 111 Gbit/s with a 50 GHz channel spacing (2.0 bits/s/Hz), we show the feasibility of 2375 km transmission. This is enabled through coherent detection which results in excellent noise performance, and subsequent electronic equalization which provides the high tolerance to polarization mode dispersion and chromatic dispersion (CD). Furthermore, we discuss the impact of sampling and digital signal processing with either 1 or 2 samples/bit. We show that when combined with low-pass electrical filtering, 1 sample/bit signal processing is sufficient to obtain a large tolerance towards CD. The proposed modulation and detection techniques enable 111 Gbit/s transmission that is directly compatible with the existing 10 Gbit/s infrastructure.