Contents I. Introduction
As A TYPE of active absorption bistability device, the two-segment bistable semiconductor laser diode (TBLD) has attracted considerable attention because of its potential applications for optical switching, optical memory, optical gate operations, optical time-division demultiplexing, signal reshape and regeneration, etc., and many theoretical and experimental investigations on TBLD have been reported [1]–[18]. The reported results have shown that self-pulsation and chaos may happen in the upper branch of the hysteresis of TBLD under certain conditions [3], [4], [13]–[18]. These unstable behaviors are harmful for bistable switching, but sometimes usable such as for clock recovery [19] and all-optical subcarrier multiplexing (SCM) optical communication system [15]–[18]. In order to make the dual functions of bistability and self-pulsation employed effectively, the crucial problem is to find adjustable system parameters to control its behaviors flexibly. In 1978, Smith et al. have realized the control of passive bistable device with electrooptic modulation by means of delayed optoelectronic feedback [20], which has been paid special attention [21]–[23]. In 1990, Sharaf and Ibrahim adopted the same method for Fabry–Pérot optical amplifier and semiconductor lasers with optical injection, and investigated in detail the influences of feedback gain on bistable performances such as the switching-ON threshold, switching time, ON–OFF switching ratio, etc. [24]. In fact, the optoelectronic-induced self-pulsation of semiconductor laser diodes has been studied experimentally earlier by Li et al., where it has been observed that optoelectronic feedback can reduce the line width of self-pulsation [25], and the dependence of frequency response on bias current displays a staircase-like feature at low feedback levels and bistable loop at high feedback levels [26]. Based on previous works, in this paper, the delayed optoelectronic feedback is introduced to the absorption region of TBLD to control its bistability and self-pulsation characteristics, and the rate equations have been used to explore the effects of system parameters on the stability region and degree of hysteresis. The numerical simulations show that the stable region of TBLD varies periodically with delayed time, the bistable region shrinks with the increased delayed time, stability can be enhanced for certain values of delayed time, and instability can be reached easily for negative optoelectronic delayed feedback. Due to the merits of easier realization and the wideband frequency noise reduction for lasers with delayed optoelectronic feedback [27], [28], this paper provides an instructive insight for device design and control of the TBLD.
