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 achievable in a hybrid-cavity surface-emitting laser (HCSEL), where the active region of the surface-emitting laser is pumped by an integrated edge-emitting laser. The pumping scheme of the HCSEL is very similar to that in a conventional multi-segment edge-emitting laser, where optical bistability has been widely demonstrated. We use the two-mode rate equations to show that if the edge-emitter on and off output levels lie, respectively, above and below 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 absorption characteristics of the vertical-cavity region, with the upper limit influenced by the relative sizes of the vertical cavity and edge-emitting segments. 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