Turn-on Time Delay of Uncooled Semiconductor Laser Diode Subject to External Optical Feedback: Theoretical Analysis

In this paper, the effect of external optical feedback (EOF) on the turn-on time delay (t_on) of uncooled semiconductor laser diode (SLD) is investigated theoretically. The effects temperature of operation (T) and EOF on t_on are calculated according to their effect on threshold carrier density (N_th). The temperature dependence (TD) of N_th is calculated according to the TD of laser cavity parameters and not by the well-known Parkove relationship. Simulation results show that t_on increases as T increases due to increasing of N_th. In addition, t_on decreases as external reflectivity (rext) increases when the phase of reflected light is coherent. While at incoherent reflected light, ton increases sharply around specified value of r_ext where this leads to inoperable case for SLD.