Liam Jones

FWM-based wavelength conversion of 40 Gbaud PSK signals in a silicon germanium waveguide

We demonstrate four wave mixing (FWM) based wavelength conversion of 40 Gbaud differential phase shift keyed (DPSK) and quadrature phase shift keyed (QPSK) signals in a 2.5 cm long silicon germanium waveguide. For a 290 mW pump power, bit error ratio (BER) measurements show approximately a 2-dB power penalty in both cases of DPSK (measured at a BER of 10(-9)) and QPSK (at a BER of 10(-3)) signals that we examined.

Phase sensitive amplification in a highly nonlinear lead-silicate fibre

We experimentally demonstrate phase-sensitive amplification in a highly nonlinear lead-silicate W-type fibre. A phase-sensitive gain swing of 6dB was observed in a 1.56m sample of the fibre for a total launched power of 33dBm.

Phase regeneration of DPSK signals in a highly nonlinear lead-silicate W-type fiber

We experimentally demonstrate phase regeneration of a 40-Gb/s differential phase shift keying (DPSK) signal in a 1.7-m long highly nonlinear lead silicate W-type fiber using a degenerate two-pump phase-sensitive amplifier (PSA). Results show an improvement in the Error Vector Magnitude (EVM) and a reduction of almost a factor of 2 in the phase noise of the signal after regeneration for various noise levels at the input.

Modulation format conversion employing coherent optical superposition

We propose and experimentally study the passive coherent optical addition of complex modulation format signals through the use of a delay line interferometer followed by a temporal gate to increase the encoded bits per symbol and consequently, the spectral efficiency of an incident signal. Modulation format conversion and packet compression are demonstrated as two possible application examples. A variety of modulation formats can be accommodated, whereas higher compression factors can be achieved through the use of a cascade of delay line interferometers.

Full quadrature regeneration of QPSK signals using sequential phase sensitive amplification and parametric saturation

We demonstrate all-optical regeneration of both the phase and the amplitude of a 10 GBaud quadrature phase shift keying (QPSK) signal using two nonlinear stages. First we regenerate the phase using a wavelength converting phase sensitive amplifier and then we regenerate the amplitude using a saturated single-pump parametric amplifier, returning the signal to its original wavelength at the same time. We exploit the conjugating nature of the two processing stages to eliminate the intrinsic SPM distortion of the system, further improving performance.

FWM-based, idler-free phase quantiser with flexible operating power

Coherently adding a signals conjugate and third harmonic at the latters wavelength enables phase quantisation across a large operating power range. With broadband phase noise, a 5.6dB QPSK receiver sensitivity improvement is achieved with BER= 10-4.

Phase and amplitude regeneration through sequential PSA and FWM saturation in HNLF

All-optical phase and amplitude regeneration of a QPSK signal using only two nonlinear stages is achieved by combining a PSA with a saturated pump-degenerate FWM based amplitude squeezer. EVM, phase noise and magnitude noise are all reduced by 50%.

All-Optical broadband phase noise emulation

We demonstrate and characterize a technique to emulate broadband phase noise. This is achieved by exploiting cross-phase modulation induced spectral broadening, in a highly nonlinear fiber, of a signal from an intense incoherent light source.

Transmission performance of phase-preserving amplitude regenerator based on optical injection locking

We experimentally investigate the phase-to-amplitude noise redistribution of a 10Gbit/s BPSK signal in a phase-preserving amplitude regenerator based on optical injection locking and demonstrate its performance in a transmission experiment over an installed fiber link.

Packet compression of complex modulation formats based on coherent optical superposition

We propose and numerically demonstrate a packet compression scheme based on re-coding of complex modulation formats through the use of a delay line interferometer (DLI) followed by a temporal gate. A variety of modulation formats can be accommodated and high compression factors can be obtained by using multiple DLIs to achieve higher order modulation formats.