Abstract: An optical pulse generator comprises a signal source, an excitation light source, a first optical fibre, a first lens, a diffraction grating, a second lens, a second optical fibre and an optical switch. Herein, signal beams produced form the signal source are transmitted through the first optical fibre, first lens, diffraction grating and second lens in turn, so that a signal beam having a desired wavelength is selectively outputted. This signal beam is converged onto and is incident to a terminal portion of the second optical fibre which is excited by an excitation beam produced from the excitation light source. Under an operation of the optical switch, the terminal portion of the second optical fibre is vibrated, resulting that an optical path to be formed between the first optical fibre and the second optical fibre is periodically opened or closed. Thus, an optical pulse of which amplitude is controlled and of which pulse width is also desirably controlled is outputted form the second optical fibre.