title: Experimental investigation of phase-sensitive amplification of data signals in a four-mode fiber-based PSA.
abstract: In this Letter, we investigate the influence of the phase and power of pump and signal waves on the gain of a four-mode phase-sensitive amplifier (PSA) built with a highly nonlinear fiber (HNLF), using a copier + PSA scheme to generate phase- and frequency-correlated idler waves. Using such an amplifier, low-noise amplification of a 10 Gsymbol/s quadrature phase-shift keying (QPSK) signal, with net gain of ∼20  dB and less than 1 dB optical signal-to-noise ratio (OSNR) penalty at a bit error ratio (BER) of 10(-3), was achieved. We also verified an additional net gain of 11.6 dB when switching from phase-insensitive to phase-sensitive operation, which is in good agreement with theoretical predictions of 12 dB.
authors: André A C
authors: AA
authors: Albuquerque
authors: Benjamin J
authors: BJ
authors: Puttnam
authors: José M D
authors: JM
authors: Mendinueta
authors: Miguel V
authors: MV
authors: Drummond
authors: Satoshi
authors: S
authors: Shinada
authors: Rogério N
authors: RN
authors: Nogueira
authors: Naoya
authors: N
authors: Wada