Theoretical Investigation of State Bistability Between Pure- and Mixed-Mode States in a 1550-nm VCSEL Under Parallel Optical Injection

Abstract

Based on the spin-flip model, state bistability (SB) between pureand mixed-mode states in a 1550-nm vertical-cavity surface-emitting laser under parallel optical injection is theoretically investigated. The simulated results show that two types of SB can be observed when the injection light frequency (vinj) is smaller than the dominant mode frequency of the free-running laser (ve). For type-I SB, which occurs through fixing vinj and scanning injection power (Pinj) along different routes, there exist two hysteresis loops in which the laser operates at pureor mixed-mode state, depending on the variation route of Pinj, and the hysteresis loop width increases sharply for increasing IΔνI (Δv = vinj - ve) with relatively strong Pinj whereas the loop width increases slowly for relatively weak Pinj, in agreement with our recent experimental report. Furthermore, type-II SB is also investigated through fixing Pinj and scanning vinj along different routes. There also exist two hysteresis loops in which the laser may operate at a pureor mixed-mode state. With an increase of Pinj, the hysteresis loop width located at lower IΔνI increases sharply and then decreases after reaching a maximum. However, for the hysteresis loop located at higher IΔνI, the loop width gradually increases with the increase of Pinj.

Keywords

• Vertical cavity surface emitting lasers
• parallel optical injection
• state bistability
• hysteresis loop