High switching-speed optical RS flip-flop constructed of a TM-wave injected semiconductor laser

We have developed the high switching-speed optical RS flip-flop which is fabricated on a single chip of semiconductor laser. The optical polarization bistability, which occurs by injection of light signal into the semiconductor laser, has been developed to obtain high-speed switching performance. The bistability is caused by the interaction of the gain between the transverse electric mode and the transverse magnetic mode in the laser, and the switching speeds are higher by one order than those of the bistability caused by the saturable absorption. The injected light signal consists of the modulated TM wave, and is superposed on a dc TM wave of l.OmW. We have adopted our low threshold current InGaAsP buried heterostructure laser, for which the bias current of only 1.05 times threshold current is needed. The turn-on and turn-off times are 340psec and 430psec, respectively.