Continuous-wave pumped holey fiber Raman laser

Abstract

Wavelength (om)WR5 Fig. 2. Measured optical SNRs and Q factors of optical carriers 100 nm) and is realized when nonlinear materials, such as optical fibers, are pumped bypicosecond optical pulses. It occurs due to the combined effects of self-phase modulation, cross-phase modulation, and parametric four-wave mixing. It isnoteworthythatthegeneratedSClight has high coherence and high SNR. Optical carriers are obtained by spectrally slicing individual longitudinal modes from the SC spectrum. Therefore, multiple carriers (multi-wavelength CW lights) can be generated by utilizing P wavelength demultiplexer whose channel spacing equals the repetition rate of the pump pulses. In Fig. 1, the ~omrce laser was a 1538 nm made-locked laser diode (ML-LD), generating a 4.3 ps, 12.5 GHz pulse train? It was then amplified with an EDFA and coupled into a palarilation-maintaining (PM) SC fiber? Thc output spectrum exhibited more than l00nm spectrum broadening.Thefigure shows that over 1000-channel, 12.5 GHzspaced optical carriers are generated. The spectrum around 1560 nm,which is more than 20 nm (2W ch) from the pump laser wavelength, ex^ hibits equally-spaced optical carriers.Noire characteristics (RIN and Q-factor) of each optical frequency were measured after one frequency was extracted with a 12.5-GHz-spaced AWG DEMUX? The channel crosstalk of the adjacentoprical frequencieswasgreaterthan-21 dB. The SNRs were calculated by integrating the RIN measured from 100 MHz to 2.5 GHz, and the Qfactors were measured aher externally madulating each channel in a LiNbO, modulator at 2.5 Gbit/s (2" -I PRBS). Figure 2 shows the wavelength dependencies ofthe SNRand the Q-factor. The SNR ranged from 21 dB to 35 dB for 100 nm range. The Q-factor exceeded 18.3 dB (BER S for the wavelength range of 1512-1580 nm, which is sufficient for multispan transmission.

Holey optical fibres: Fundamental properties and device applications

“…For example, poled HF devices based on second order effects should be possible with conversion efficiencies and operating bandwidth two orders of magnitude greater than can be achieved with standard fibres [47]. Similarly, it should be possible to make HF Raman and Brillouin devices with greatly reduced operating powers or device lengths and indeed first experiments in this area have been performed [46,48,49].…”

Multipump flattened-gain Raman amplifiers based on photonic-crystal fibers

“…It has been already shown that photonic-crystal fibers (PCFs), compared with conventional single mode fibers, can be designed very flexibly to enhance nonlinear effects, by proper choice of the lattice parameters, that is the center-to-center air-hole spacing, or pitch , and the ratio between hole diameter and pitch. Theoretical studies have recently been performed on highly nonlinear holey fibers [3] and germania-doped triangular PCFs [4], while experimental demonstrations include continuous-wave pumped Raman lasers [5] and -band RAs [3], showing the potential of PCFs in obtaining high Raman gain efficiency.…”