Q-switched operation of a coupled-resonator vertical-cavity laser diode

We report Q-switched operation from an electrically injected monolithic cou pled-resonator structure which consists of an active cavity with InGaAs qua ntum wells optically coupled to a passive cavity. The passive cavity contai ns a bulk GaAs region which is reverse biased to provide variable absorptio n at the lasing wavelength of 990 nm. Cavity coupling is utilized to effect large changes in output intensity with only very small changes in passive cavity absorption. The device is shown to produce pulses as short as 150 ps at repetition rates as high as 4 GHz. A rate equation approach is used to model the Q-switched operation yielding good agreement between the experime ntal and theoretical pulse shape. Small-signal frequency response measureme nts also show a transition from a slower (similar to 300 MHz) forward-biase d modulation regime to a faster (similar to 2 GHz) modulation regime under reverse-bias operation. (C) 2000 American Institute of Physics. [S0003-6951 (00)01215-8].