High Optical Feedback Tolerance of a Detuned DBR Laser for 10-Gbps Isolator-Free Operation

The optical feedback tolerance (OFT) of a distributed Bragg reflector (DBR) laser was investigated experimentally. static and modulation performance the DBR under examined by evaluating its relative intensity noise (RIN) bit error rate (BER). It is shown that OFT closely related to peak wavelength detuning wavelength. A high demonstrated, both in continuous wave (CW) direct (DM) states, when red-detuned excess RIN induced well suppressed level −140 dB/Hz at −9 dB CW state. In 10 Gbps state, rates (BER) below 1 × 10−9 3 10−7 were obtained −15 dB, respectively, for case back-to-back transmission. After 20 km fiber transmission, BER still maintained with power penalty less than dB.