A lumped Raman amplifier for all-Raman long-haul and ultra-long haul optical communications systems based on highly non-linear Photonic Crystal Fiber (HNL-PCF) is proposed and demonstrated. Applications for such an amplifier are discussed, focusing on discrete loss compensation for L-Band all-Raman reconfigurable systems. The main specifications required for this and similar applications have been analyzed, and include Power Conversion Efficiency above 30%, Net gain of about 15dB, and output power in the range of 20-23 dBm. Additional specifications such as Noise Figure, Multi-Path Interference (MPI), and transient suppression are also considered. In order to achieve the required specifications, the HNL-PCF should exhibit high Raman efficiency and low attenuation at pump wavelengths of 1470-1500nm, resulting in a Figure of Merit (FOM) above 8 dB(-1)W(-1). The splice loss of the HNL-PCF to conventional Single Mode Fiber is also shown to be critical, and should not exceed 0.5 dB. Initial samples of HNL-PCF have been characterized, and it has been demonstrated that high Raman efficiency and. low splice loss are achievable, while further work is being carried out to increase the FOM. Finally, an experimental demonstration of 10Gb/s WDM transmission using a prototype Lumped Raman Fiber Amplifier based on HNL-PCF is presented.

A multi-service optical packet ring for the metro area are presented in this paper. Cascadability issues through theoretical analysis and experimental investigations indicate that an optical packet technology could be a competitive solution for the next generation of metro networks.

Pump-to-signal relative intensity noise (RIN) transfer in copumped Raman amplifiers is analyzed. By means of simulations and experiments, the authors call attention to the impact of the polarized nature of stimulated Raman scattering on RIN transfer. Although depolarizing the Raman pump enables polarization-independent signal gain, the authors demonstrate that proper modeling of RIN transfer requires including the polarization dependence of the Raman effect and the polarization mode dispersion of the fiber. A second key phenomenon is emphasized. Besides the RIN transfer induced by Raman gain, pump RIN is also transferred to the signal via nonlinear gain. This phenomenon can be addressed as pump-signal cross-phase modulation since it essentially generates phase noise on the signal. For the first time, in this paper, a model of pump-to-signal RIN transfer that includes polarization and nonlinear gain is presented. The authors reveal the key influence of these factors that had been uncared for so far. Their analysis is supported by experimental data. Signal noise characteristics (RIN spectrum and high-resolution optical power spectrum) measured at the output of a copumped Raman amplifier were presented. The Raman pump is a pair of semiconductor diodes in the first two experiments and then a Raman fiber laser. For these two kinds of depolarized or unpolarized Raman pumps that are commonly used in the field, the authors emphasize the necessity of considering polarization for the good assessment of RIN transfer.

We demonstrate the transmission of 256 polarization-division and wavelength-division multiplexed channels at 42.7Gbit/s rate over 100km of TeraLight™ fiber. An overall capacity of 10Tbit/s is achieved in C and L bands at a record 1.28bit/s/Hz spectral efficiency.