THEORETICAL PERFORMANCE OF MULTIGIGABIT-PER-SECOND LIGHTWAVE SYSTEMS USING INJECTION-LOCKED SEMICONDUCTOR-LASERS

Injection locking can be used to reduce the transient frequency chirp and pulse distortion in directly modulated semiconductor lasers; hence, it is potentially useful for systems operating in a high-dispersion regime, such as the 1.55-μm wavelength region with conventional single-mode fiber. In this study, the locking conditions for multigigabit-per-second modulation are examined and the dependence of the receiver sensitivity on the fiber dispersion coefficient × length product is investigated. With 4.8-Gb/s NRZ modulation, a 1-dB penalty in receiver sensitivity occurs for a transmission distance of 68 km. The injected power is 0.4 mW and the frequency detuning is -35 GHz. With 10-Gb/s NRZ modulation, the allowable transmission distance is 12.5 km for an injected power of 1.0 mW and a frequency detuning of -35 GHz. These results represent increases in the transmission distances obtained with a solitary laser by factors of 3.7 at 4.8 Gb/s and 2.7 at 10 Gb/s. © 1990 IEEE