  We demonstrate how the presence of gain-loss contrast between two coupled
identical resonators can be used as a new degree of freedom to enhance the
modulation frequency response of laser diodes. An electrically pumped microring
laser system with a bending radius of 50 {\mu}m is fabricated on an
InAlGaAs/InP MQW p-i-n structure. The room temperature continuous wave (CW)
laser threshold current of the device is 27 mA. By adjusting the ratio between
the injection current levels in the two coupled microrings, our experimental
results clearly show a bandwidth improvement by up to 1.63 times the
fundamental resonant frequency of the individual device. This matches well with
our rate equation simulation model.
