Abstract
On/off extinction ratio and receiving power penalties of a 10-Gb/s all-optical on-off-keying pulse data generated from a multiwavelength dark-optical-comb injected semiconductor optical amplifier (SOA) is analyzed. Such an SOA with a temporally constricted gain window is employed to offer an on-off-keying (OOK)-generated data stream with on/off extinction ratio of 17 dB and bit error rate (BER) of 10 <sup>-13</sup> at a receiving optical power of - 1.8 dBm. With an input nonreturn-to-zero (NRZ) power as low as - 15 dBm and an injected dark-optical-comb power of 16.5 dBm, the generated OOK pulse data reaches a BER 10 <sup>-13</sup> at receiving power as low as - 18.5 dBm. The OOK operation in the SOA also exhibits a decision-gate function with improved negative power penalty of 1.5 dB as compared with the back-to-back NRZ transmission condition. The injection via a multiwavelength dark-optical-comb source further benefits from a lower noise level as compared with single-wavelength laser or broadband spontaneous emission source. Such a system exhibits a tolerance for detuning timing of >65% period with power penalties on the on/off extinction ratio and the receiving power of 3 and 1 dB, respectively. Even after 25-km propagation in a single-mode fiber spool, there is only a power penalty of 0.5 dB at a BER of 10 <sup>-13</sup> obtained for the generated pulse data stream. © 2009 IEEE.