The semiconductor laser device and a nonlinear optical effect utilizing device

Provided is a semiconductor laser device with which it is possible to emit an extremely short optical pulse. A semiconductor laser device (6) which is disclosed herein comprises: a semiconductor laser unit (3) which emits a first pulse and a succeeding component of the first pulse by a gain switching operation in which a relaxation oscillation mechanism is used; and a filter (4) which, with respect to the output from the semiconductor laser unit (3), removes a signal of a wavelength band, which is caused to occur at least by the succeeding component, among a wavelength band which expands by chirping. The filter (4) is configured as a short-pass filter through which the short wavelength component passes. Also provided is an apparatus using non-linear optical effect in which the semiconductor laser device is used.