Low hysteresis threshold current (39 mA) active multimode-interferometer (MMI) bistable laser diodes using lateral-modes bistability

We demonstrate low hysteresis threshold current (39mA) bistable laser diodes (BLDs), with maintaining sufficient hysteresis window (7 mA, 18% of the hysteresis threshold), in active multimode-interferometer (MMI) using lateral-modes bistability. The sufficient cross-gain saturation effect, due to the lateral-modes bistability principle, enables wide hysteresis window. By using this principle, we could design the active-MMI BLDs with relatively short saturable-absorber length that has been one of the main causes of high hysteresis threshold current. In the actual design, we reduce the saturable-absorber region length to 25 μm, and thus, we could achieve a low hysteresis current of 39 mA in the active-MMI BLDs with maintaining sufficient hysteresis window for the first time. © 2011 IEEE.