4 Gb/s soliton data transmission over 136 km using erbium dopedfiber amplifiers

The use of semiconductor-laser-pumped erbium-doped fiber amplifiers and an externally modulated mode-locked external-cavity semiconductor laser to obtain soliton data transmission at 4 Gb/s over 136 km of nondispersion shifted fiber is described. After 136 km of transmission and at low pulse powers, the ~80 ps fiber input pulse width was broadened to ~150 ps. At high pulse powers the output pulse width was maintained at 80 ps, as expected for N=1 solitons. N =3 solitons were also observed at lower data rates     

Bit-error-rate investigation of two-channel soliton propagation over more than 10000 km

Two wavelength division multiplexed soliton pulse trains (2*2 Gbit/s 0101. . .) have been propagated more than 9000 km with less than 10/sup -9/ bit error rate for both channels. Soliton collisions have no effect on the error rate for wavelength separations larger than 7 AA or for collisions centred inside the fibre.<>     

Room-temperature CW operation of 1.60 ?m GaInAsP/InP buried-heterostructure integrated laser with butt-jointed built-in distributed-Bragg-reflection waveguide

CW operation of a 1.60 ?m GaInAsP/InP buried-heterostructure integrated laser with butt-jointed built-in distributed-Bragg-reflection waveguide (BH BJB DBR integrated laser) was achieved at room temperature. Single longitudinal-mode operation at fixed mode was obtained in a temperature range of about 60 deg C, under the CW condition, and it was also maintained under rapid direct modulation of 1.6 GHz.     

SBS Suppression Using a Multichannel Tunable Laser with Data-Encoding Capability

We demonstrate stimulated Brillouin scattering (SBS) using a new laser transmitter. The device uses an integrated FM modulator for both SBS suppression and channel tuning, and an integrated AM modulator for data encoding. We measure thresholds of 25 dBm on four separate wavelength division multiplexing channels. The required modulation signal is very small, 95 mVpp, and the residual AM is only 1 %.     

Multicolor single-wavelength sources generated by a monolithic colliding pulse mode-locked quantum well laser

The authors report on the separation of single longitudinal modes from the mode-locked program spectrum of a 300-GHz monolithic colliding pulse mode-locked (CPM) semiconductor quantum-well laser. Experimentally, the selected longitudinal mode shows a 10-dB reduction of low-frequency relative intensity noise compared to that of the selected mode from the same laser in continuous-wave (CW) lasing conditions. The strong phase coherence among the passively mode-locked longitudinal modes reduces the partition noise of the unlocked CW laser.<>     

Optical gain and refractive index of a laser amplifier in the presence of pump light for cross-gain and cross-phase modulation

The wavelength dependent changes in optical gain and refractive index in a Fabry-Perot semiconductor optical amplifier are measured for various detunings of the pump wavelength from the quasi-Fermi level separation. The refractive index change is nearly constant over a very large wavelength range. We also present data for the linewidth enhancement factor due to optical injection. Estimates of the carrier densities and stimulated recombination rates are made using our optical gain model based on realistic band structure calculations for a strained quantum-well laser. Our results are very useful for ultra-broad-band wavelength conversion by cross-gain and cross-phase modulation (XGM, XPM).     

Room-temperature continuous-wave operation of long wavelength (l ?9.5 lm) MOVPE-grown quantum cascade lasers

High-power continuous-wave operation of long wavelength quantum cascade lasers grown by metal organic vapour phase epitaxy is reported. The lasers have been processed as buried heterostructures with thick gold-plated contacts. The devices emit at a wavelength of 9.5 mum with output powers of several hundreds of milliwatts at room temperature.