Zohreh Lali-Dastjerdi

Parametric amplification and phase preserving amplitude regeneration of a 640 Gbit/s RZ-DPSK signal

We report the first experimental demonstration of parametric amplification and all-optical phase-preserving amplitude regeneration for a 640 Gbit/s return-to-zero (RZ) differential phase-shift keying (DPSK) optical time division multiplexed (OTDM) signal. In the designed gain-flattened single-pump fiber optical parametric amplifier (FOPA), 620 fs short optical pulses are successfully amplified with 15 dB gain with error-free performance and less than 1 dB power penalty. Phase-preserving amplitude regeneration based on gain saturation in the FOPA is carried out for optical signals with degraded optical signal-to-noise ratio. An improvement of 2.2 dB in receiver sensitivity at a bit-error-ratio of 10(-9) has been successfully achieved after regeneration, together with 13.3 dB net gain.

Asymmetric gain-saturated spectrum in fiber optical parametric amplifiers

We demonstrate experimentally and numerically an unexpected spectral asymmetry in the saturated-gain spectrum of single-pump fiber optical parametric amplifiers. The interaction between higher-order four-wave mixing products and dispersive waves radiated as an effect of third-order dispersion influences the energy transfer to the signal, depending on its detuning with respect to the pump, and breaks the symmetry of the gain expected from phase-matching considerations in unsaturated amplifiers. The asymmetry feature of the saturated spectrum is shown to particularly depend on the dispersion characteristics of the amplifier and shows local maxima for specific dispersion values.

Dynamic characterization and amplification of sub-picosecond pulses in fiber optical parametric chirped pulse amplifiers

We show a first-time demonstration of amplification of 400 fs pulses in a fiber optical parametric amplifier. The 400 fs signal is stretched in time, amplified by 26 dB and compressed back to 500 fs. A significant broadening of the pulses is experimentally shown due to dispersion and limited gain bandwidth both in saturated and unsaturated gain regimes.

Pump-To-Signal Intensity Modulation Transfer Characteristics in FOPAs: Modulation Frequency and Saturation Effect

This paper reports a comprehensive study of pump-to-signal intensity modulation transfer (IMT) in single-pump fiber optic parametric amplifiers (FOPAs). In particular, the IMT is studied for the first time for high-frequency fluctuations of the pump as well as in the saturated gain regime. The IMT cut-off frequency in typical single-pump FOPAs is around 100-200 GHz. The possibilities to shift this frequency based on dispersion and nonlinearities involved in the parametric gain are discussed. The severe IMT to the signal at low modulation frequencies can be suppressed by more than 50% in the gain saturation regime with respect to the linear gain operation. Experimental results confirm the validity of the numerical study.

Parametric amplification of a 640 Gbit/s RZ-DPSK signal

We report the first demonstration and characterization of parametric amplification of a 640Gbit/s RZ-DPSK OTDM signal. With proper design of the fiber parametric amplifier, error-free amplification with less than 1 dB penalty has been achieved.

Cascadability of silicon microring resonators for 40-Gbit/s OOK and DPSK optical signals

The cascadability of a single silicon micro-ring resonator for CSRZ-OOK and CSRZ-DPSK signals is experimentally demonstrated at 40 Gbit/s for the first time. Error-free performance is obtained for both modulation formats after 5 cascaded resonators.

Fiber-Optical Parametric Amplification of Sub-Picosecond Pulses for High-Speed Optical Communications

Abstract This article reviews recent results of amplification of short optical pulses using fiber-optical parametric amplifiers. This includes chirped-pulse amplification of 400 fs pulses, error-free amplification of a 640-Gbit/s optical time-division multiplexed signal with less than a 1-dB power penalty, and all-optical phase-preserving amplitude regeneration of a 640-Gbit/s return-to-zero differential phase-shift keying optical time-division multiplexed signal.

Dynamic Characterization of Fiber Optical Chirped Pulse Amplification for Sub-ps Pulses

We investigate experimentally the propagation of sub-picosecond pulses in fiber optical parametric chirped pulse amplifiers, showing a significant broadening of the pulses from 450 fs up to 720 fs due to dispersion and self-phase modulation.

Pulse distortion in saturated fiber optical parametric chirped pulse amplification

Fiber optical parametric chirped pulse amplification is experimentally compared for different chirped pulses in the picosecond regime. The amplified chirped pulses show distortion appearing as pedestals after recompression when the amplifier is operated in saturation.

Asymmetric gain-saturated spectrum in one-pump fiber optical parametric amplifiers

The effect of third-order dispersion on the saturated-gain in fiber optical parametric amplifiers is experimentally demonstrated. A possible interpretation in terms of dispersive waves, which change the power transfer to the signal, is presented.