LED source for determining optical detector time response at 1.06 microm

A gallium indium arsenide light emitting diode (LED) is investigated as a source for determining optical detector time response at 1.06 microm. To obtain either impulse or step-shaped waveforms, the diode is driven by a charged transmission line switched by a transistor operating in the avalanche mode. A pulse with a 2.5-ns full width at half-maximum and a step with a 3-4-ns transition time are produced at repetition rates to 1 kHz. The effects of wavelength change during the pulse (chirping) are discussed and evaluated.