Spontaneous cascaded Raman amplification is demonstrated as a practical and efficient means of power transfer from telecommunications wavelengths to mid-IR wavelength bands through use of conventional silica fibers and amplifiers. We show that silica fibers possessing normal dispersion over all near-IR and mid-IR wavelengths can facilitate 37% and 16% efficient Raman power conversion from 1.53 ...

We report on the first (to our knowledge) demonstration of nonlinear dual-frequency-comb spectroscopy. In multi-heterodyne femtosecond Raman-induced Kerr-effect spectroscopy, the Raman gain resulting from the coherent excitation of molecular vibrations by a spectrally narrow pump is imprinted onto the femtosecond laser frequency comb probe spectrum. The birefringence signal induced by the nonli...

High-resolution stimulated Raman gain spectroscopy of the Q1(0) transition of para-H2 crystals with varying ortho-H2 concentrations is reported. A crystal containing 0.06% of ortho-H2 showed a single sharp Raman transition with the width of less than 7MHz. The Raman signal became broader with increasing concentration of ortho-H2 . At the concentration of 2%, the spectrum splits into a doublet. ...

Raman laser generation at the long wavelength transmission edge of silica fiber is explored. Numerical simulation reveals that high efficiency 2nd Stokes Raman laser operation around 2.5 μm is feasible with highly Ge-doped silica fiber as the gain medium and pulsed 2-μm fiber laser as the pump source. Based on the spontaneous cascaded Raman amplification process, 0.30-W laser at 2.43 μm is obta...

Raman amplification in plasma has been proposed to be a promising method of amplifying short radiation pulses. Here, we investigate chirped pulse Raman amplification (CPRA) where the pump pulse is chirped and leads to spatiotemporal distributed gain, which exhibits superradiant scaling in the linear regime, usually associated with the nonlinear pump depletion and Compton amplification regimes. ...

In this paper, we address Raman amplification properties of photonic crystal fibers (PCFs), by incorporating an efficient full-vectorial finite element method combined with Runge-Kutta equations. The effect of the structural parameter’s variations on the performance of the PCF based Raman amplifier (PCFRA) is extensively studied. Maximum gain of 9 dB and the lowest double Rayleigh backscatterin...

We report the demonstration of 11 dB fiber-to-fiber optical gain in a silicon Raman amplifier. Pulsed pumping is employed to reduce the TPA induced free carrier losses resulting in net signal amplification. The influence of free carriers is elucidated by observing the dependence of gain on pulse energy.

A technique of Raman compensation for a two-channel soliton-based fiber communication system is introduced. By fixing the wavelength spacing between two channels, one can calculate the pumping wavelength and intensity in such a way that balance between loss and gain is reached for each channel. In this computation the Raman conversion between two channels plays an important role in simultaneous...

A FBG-based pump-phase-shifter is used in the Raman-assisted PSA. By actively tuning the FBG central-wavelength to enable pump phase optimization, up-to-5.6dB signal gain is observed. An improvement of ~6% EVM and ~4dB system sensitivity is observed by 20/25-Gbaud QPSK signals. Introduction Capacity upgrade utilizing higher level modulation formats such as 64QAM and 256QAM has been studied aggr...