New technique for increasing speed of semiconductor lasers

The ultimate limit of direct modulation bandwidth of a semiconductor laser diode is the intrinsic bandwidth determined by rate equations. In this paper we show that the intrinsic bandwidth can be significantly increased through the use of injection-locking. Our analysis shows that for moderate and high injection levels, the bandwidth of a laser diode can be increased to several times the bandwidth of a free running laser diode operating at the same bias current. The required injection power depends on laser parameters but is less than the power of the free running laser. However, the injected photon number and detuning must lie within the range of values required for the dynamic injection-locked state.