Prediction of a large optical bistability in hybrid-cavity surface-emitting lasers

We propose that optical bistability with a large on/off ratio should be ach ievable in a hybrid-cavity surface-emitting laser (RCSEL), where the active region of the surface-emitting laser is pumped by an integrated edge-emitt ing laser. The pumping scheme of the HCSEL is very similar to that in a con ventional multi-segment edge-emitting laser, where optical bistability has been widely demonstrated. We use the two-mode rate equations to show that i f the edge-emitter on and off output levels lie, respectively, above and be low the vertical-cavity threshold condition, then a very large on/off ratio can be obtained from the HCSEL. Calculations show that the lower limit of the bistable current range is determined primarily by the effective absorpt ion characteristics of the vertical-cavity region, with the upper limit inf luenced by the relative sizes of the vertical cavity and edge-emitting segm ents. The enhanced on/off ratio makes the HCSEL a very attractive candidate for such applications as efficient optical pickup heads, optical triggers or memory cells.