The ability to process optical signals without passing into the electrical domain has always
attracted the attention of the research community. Processing photons by photons unfolds …

The capacity and reach of long-haul fiber optical communication systems is limited by in-line
amplifier noise and fiber nonlinearities. Phase-sensitive amplifiers add 6 dB less noise than …

This tutorial reviews the recent research on fiber-based phase-sensitive amplifiers (PSAs),
and describes how they can be used in transmission systems. We describe the …

The optical parametric amplifier (OPA) has attractive features for optical communications,
such as a wideband, high gain, and fast transient response. In addition, by using idler light …

We demonstrate fiber nonlinearity mitigation by using multiple optical phase conjugations
(OPCs) in the WDM transmission systems of both 8× 32-Gbaud PDM QPSK channels and 8× …

We present nonlinear impairment mitigation of wavelength division multiplexed signals,
through optical phase conjugation (OPC). We conduct our experiments on a 400-km-long …

We report on the design, fabrication, and experimental characterization of germanium-
doped graded-index multi-mode fibers that are tailored to achieve broadband operation for …

We experimentally investigate a wavelength-division multiplexing (WDM) system with a
single span of 80 km standard single-mode fiber (SSMF) and a phase-sensitive amplifier …

A phase-sensitive amplifier (PSA) has the potential of low-noise optical amplification and
nonlinear phase noise mitigation. For PSA operation, the chromatic dispersion (CD) that …

We investigate the impact of in-line amplifier noise in transmission systems amplified by two-
mode phase-sensitive amplifiers (PSAs) and present the first experimental demonstration of …