The authors demonstrate the generation of transform limited short optical pulses, which display excellent spectral and temporal qualities by employing a novel technology, based on an externally injected gain-switched laser in conjunction with a non-linearly chirped grating. Using this technique, 3.5 ps optical pulses, exhibiting a time bandwidth product of 0.45, are generated, which are suitable for use in high-speed 80 Gb/s OTDM communications systems.