부산대학교 도서관

Error-free (bit-error ratio < 10 −9 ) generation and amplification of phase-coded signals are presented with a symbol rate up to 40 GBd using quantum-dot (QD) based semiconductor optical amplifiers (SOA) emitting at a wavelength of 1.3 µm. Phase-coded signal generation is demonstrated via direct modulation of a QD SOA exhibiting a linear fiber-to-fiber gain of 8 dB. In comparison to gain modulation, the phase modulation of the QD SOAs via the current is found to be much faster. Various symbol rates from 10 to 25 GBd and input power levels from −11 dBm to 3 dBm are investigated. The amplification of a 40 GBd differential (quadrature) phase-shift keying (D(Q)PSK) signal is investigated using QD SOAs exhibiting a linear fiber-to-fiber gain of 26 dB. The input-power dynamic range is determined and discussed, based on bit-error ratio and error-vector magnitude measurements using differential detection and coherent detection receivers. Finally, investigations of the influence of a 40 GBd OOK neighboring channel (5 nm grid) on a 40 GBd DQPSK channel in dependence of the input power levels of both signals are presented.