S.A.E. Lewis

Characterization of double Rayleigh scatter noise in Raman amplifiers

Optical measurements of double Rayleigh scatter noise from fiber Raman amplifiers have been made using a modified time-domain extension method. A uniform gain approximation for calculating the double Rayleigh scatter (DRS) noise is shown to agree closely with the experiment. Comparison is also made with the DRS noise from a dual-stage amplifier.

Temperature-dependent gain and noise in fiber Raman amplifiers

An experimental investigation of the temperature dependence of the gain and noise performance of a silica-fiber Raman amplifier is described. A decrease in the Raman scattering cross section in a fiber amplifier cooled from a temperature of 300 K to 77 K was measured and found to be in agreement with theoretical values. No difference between the Raman gain coefficients at these two temperatures was observed.

Broadband Raman amplifiers in the spectral range of 1480-1620 nm

Raman amplifiers using germano-silica fibers are demonstrated with a continuous operation bandwidth from 20 nm to more than 100 nm, 20-40 dB net gain and 4.5-7 dB noise figure. Single-, dual-, and triple-wavelength pumping are implemented in the configuration incorporating circulators for pump/signal multiplexing.

Low-noise high gain dispersion compensating broadband Raman amplifier

Raman gain module compensating for both loss and dispersion of a 40 km standard telecommunication fiber span over the 1510-1565 nm band is reported. The optimized configuration ensures a low signal-spontaneous noise figure and negligible double Rayleigh scattering noise. The high gain margin of the amplifier makes it applicable for compensation of an 80 km span.

Fibre-optic tunable CW Raman laser operating around 1.3 μm

We describe an integrated fibre-optic, CW, broadly tunable Raman laser operating around 1.3 μm. This laser was pumped by a cascaded-Raman fibre laser at a wavelength of 1.24 μm, which was pumped at a fundamental wavelength of 1.06 μm derived from a multi-clad, high-power Yb-fibre laser. Tunability from 1.29 μm to 1.33 μm was achieved with a maximum output power of 140 mW.

Broadband silica fibre Raman amplifiers at 1.3 /spl mu/m and 1.5 /spl mu/m

High power fibre lasers operating at 1.24 /spl mu/m and 1.42 /spl mu/m respectively have been used to provide broad band Raman gain around 1.3 /spl mu/m and 1.5 /spl mu/m in compact, efficient, silica fibre-amplifier configurations. The gain and noise performance of these broad band amplifiers are described as well the mechanism to further increase and flatten the operational bandwidths.

1.4 W saturated output power from a fibre Raman amplifier

Fiber Raman amplifiers with high output power and a 50% net pump to signal conversion efficiency are reported. A 100-nm supercontinuum based upon a 10-GHz, 8-ps pulse source was generated strong nonlinear interaction in the amplifier.

Simultaneous modulation of several WDM channels using a single electro-absorption modulator

A characterisation has been undertaken of the simultaneous modulation of several fibre optical WDM channels employing a single electro-absorption modulator operating at 10 GHz. This experimental investigation has demonstrated that sub 8 ps pulses can be generated over a 19 nm wavelength range under fixed operating conditions.

Picosecond pulse-duration-selectable soliton source based upon adiabatic compression in a Raman amplifier

Raman amplification of 10 ps soliton pulses generated directly from an electroabsorption modulator based source have been adiabatically compressed in a Raman fibre amplifier, giving a pulse duration tunable source, 1-10 ps at 10 GHz and average powers up to 650 mW dependent on the magnitude of the amplification.

Fibre mopfa source of femtosecond pulses with wavelength tunability from 790 to 830 nm

A fibre-optic of sub-150 fs pulse with wavelength tunability from 790 to 830 nm is demonstrated. The output from a gain-switched DFB laser diode at 1552 nm is amplified and compressed in an EDFA generating a soliton-Raman continuum which was then frequency doubled. The output wavelength was tuned over a 40 nm range with very little variation in the pulse duration and output power.