The id300 laser source from id Quantique SA generates short laser pulses at wavelengths of 780, 850, 1310 or 1550 nm. It is designed to work with the id200 single-photon-detection and -counting modules at telecommunications wavelengths. Based on a VCSEL (for 850 nm) or a Fabry-Perot laser diode (for the other wavelengths), the source is triggered externally to produce subnanosecond pulses with a repetition rate ranging from DC to 500 MHz. It has a pulse duration of 300 ps, a peak power of 1 mW and a typical spectral width (FWHM) of 7 nm. Polarization-maintaining fiber is optional. The device has applications in such areas as spectroscopy and optical measurements.