Qijie Xie

Raman-Assisted Phase-Sensitive Amplification Enabled Optical Add-Drop Filter

We present a novel reconfigurable optical add-drop filter based on phase-sensitive amplifiers (PSAs). By manipulating the relative phase among an optical pump, signals, and idlers, spectral selectivity can be achieved along with low noise amplification. The use of backward Raman amplification enhances the phase-sensitive operation of the parametric process, enabling higher stopband isolation and lower intra-band crosstalk. A Raman-assisted phase-sensitive amplifier (RA-PSA) is characterized in detail, showing a 7.8-dB combined gain extinction ratio enhancement and 10.85-dB gain improvement. For the first time, we demonstrate an RA-PSA enabled optical add-drop filter with less than 0.4-dB penalty using three-channel QPSK signals. The novel scheme provides a simple way to enhance the extinction ratio of the PSA enabled add-drop filter, which can be an essential subsystem in optical links based on phase-sensitive amplification.

Binary Pattern Controlled Optical Pulse-Rate Multiplication Based on Fractional Temporal Self-Imaging Effect

We demonstrate electrically adjustable multiplication of 9.72 GHz pedestal-free picosecond pulses using fractional temporal self-imaging effect. Various multiplication factors of 2, 4 and 8 are achieved and up to ∼80 GHz pulse train is generated.

Uniformity Improvement in Serial-to-Parallel Data Conversion via Time Lens Processing with Raman Amplification

We apply Raman amplification in a nonlinear fiber to compensate the roll-off in conversion efficiency due to phase mismatch between the signal and chirped pump in time-lens processing. A 3.5-dB improved uniformity is observed.

Relaxation dynamics of optically generated carriers in graphene-on-silicon nitride waveguide devices

We studied the carrier relaxation dynamics in graphene-on-silicon nitride waveguides. Optically generated carriers from a quasi-continuous wave pump laser show a microsecond response time while those generated from mode-locked laser pulses exhibit accelerated relaxation dynamics.