Steven R. Wilkinson

Demonstration of optical multicasting using Kerr frequency comb lines

We experimentally demonstrate optical multicasting using Kerr frequency combs generated from a Si3N4 microresonator. We obtain Kerr combs in two states with different noise properties by varying the pump wavelength in the resonator and investigate the effect of Kerr combs on multicasting. Seven-fold multicasting of 20 Gbaud quadrature phase-shift-keyed signals and four-fold multicasting of 16-quadrature amplitude modulation signals have been achieved when low-phase-noise combs are input into a periodically poled lithium niobate waveguide. In addition, we find that the wavelength conversion efficiency in the PPLN waveguide for chaotic combs with high noise is similar to that for low-noise combs, while the signal quality of the multicast copy is significantly degraded.

Dependence of a microresonator Kerr frequency comb on the pump linewidth

We experimentally investigate the dependence of Kerr comb generation, comb linewidth, and coherent system performance on the pump linewidth in a microresonator. We find that the generation of the primary comb can have a larger tolerance to the pump linewidth compared with that of the low-phase-noise comb. In addition, the linewidths of the generated combs are almost linearly dependent on the pump linewidth in the primary and low-phase-noise states. Furthermore, the optical signal-to-noise ratio penalty between the pump and generated Kerr combs in a coherent communication system is less than 0.2 dB in both the primary and low-phase-noise states, showing that Kerr frequency combs in these two states can have similar coherent system performance to the pump.

Experimental demonstration of phase-sensitive regeneration of a binary phase-shift keying channel without a phase-locked loop using Brillouin amplification

All-optical phase regeneration of a binary phase-shift keying signal is demonstrated at 10-30 Gb/s without a phase-locked loop in a phase-sensitive amplification-based system using Brillouin amplification of the idler. The system achieves phase noise reduction of up to 56% and up to 11 dB OSNR gain at 10-5 bit error rate for the 10 Gb/s signal. The systems sensitivity to different parameters and stability is also evaluated.

Dual-pump generation of high-coherence primary Kerr combs with multiple sub-lines

We experimentally generate high-coherence primary Kerr combs with multiple sub-lines by using dual pumps and demonstrate the application of a primary comb state in multichannel communications. We find that more than 10 primary comb lines can be generated within the spectrum of modulation instability gain in our microring resonator. The generation is also verified by numerical simulations and the measured linewidth confirms the high coherence of the generated primary comb lines. We also demonstrate the high-coherence characteristics in a coherent communication experiment, in which each comb line is encoded with 20 Gbaud quadrature phase-shift-keyed signals.

Pilot-tone-based self-homodyne detection using optical nonlinear wave mixing

An all-optical pilot-tone-based self-homodyne detection scheme using nonlinear wave mixing is experimentally demonstrated. Two scenarios are investigated using (1) multiple wavelength-division-multiplexed channels with sufficient power of the pilot tones and (2) a single channel with a low-power pilot tone. The eye diagram and bit error rate of the system are studied by tuning various parameters such as pump power, relative phase, and pilot-to-signal ratio.

Experimental demonstration of phase-sensitive regeneration of a 10–20 Gb/s BPSK channel without a phase-locked loop using Brillouin amplification

We experimentally demonstrate all-optical phase-sensitive regeneration of a 10-20Gb/s BPSK signal without a phase-locked loop by amplifying the idler using Brillouin amplification. Phase noise reduction of up to 56% along with 11dB gain at BER of 10-5 were observed.

Wavelength and pump power characterization of low-phase-noise Kerr frequency comb lines

We characterize a low-phase-noise Kerr frequency comb for carrying data channels. Results show pump wavelength detuning region grows slightly at higher pump power and the phase noise stays relatively unchanged over pump wavelength detuning region.

Demonstration of automatically phase-locked self-homodyne detection with a low-power pilot tone based on brillouin amplification and optical frequency combs

A scheme of automatically phase-locked self-homodyne detection with a low-power pilot-tone is proposed. The performance is experimentally demonstrated by back-to-back 10/20-Gbaud BPSK, 10-Gbaud QPSK and 100km-transmission of 10-Gbaud BPSK with pilot-to-signal power ratio of -30dB.

Tunable ROADM with crosstalk reduction for overlapped 20–25 Gbaud QPSK WDM channels using wave mixing

We experimentally demonstrate a tunable simultaneous ROADM with crosstalk reduction using optical nonlinear elements in spectrally overlapped 20–25 Gbaud QPSK WDM channels. OSNR gain of 5 dB shows the effectiveness of the approach.

Experimental demonstration of 7-fold Multicasting of a 20-Gbaud QPSK signal using Kerr frequency combs

We experimentally demonstrate 7-fold multicasting of 20-Gbaud QPSK signals based on Kerr frequency combs generated in a silicon nitride microresonator. The effect of high phase-noise comb state on the multicasting performance has also been studied.