Coherent Wavelength Conversion in a Quantum Dot SOA

We experimentally demonstrate wavelength conversion of coherent signals in an InAs/InGaAsP/InP columnar quantum dot semiconductor optical amplifier by using low power single pump four-wave-mixing. We report highly efficient conversion, i.e., 30 nm conversion span with a conversion efficiency larger than -10 dB and output optical signal to noise ratio larger than 20 dB. Transparency to coherent modulation formats is demonstrated in a 25 nm conversion of 10 GBaud quadrature phase shift keying (QPSK), 8-phase shift keying (PSK) and 16-quadrature amplitude modulation (QAM) signals. We found 0.9 to 1.1 dB optical signal to noise ratio penalty at forward error correction error free limit of 2 × 10^-3 bit error rate for all the signals.