Calmar Optcom is an industrial leader of ultrafast fiber lasers. One of its flagship products is the PSL-40, a 40-GHz direct fiber laser. This laser provides researchers and manufacturers with the ability to test their high-speed network and components up to a 640-GHz repetition rate with the help of Calmar's bit rate multiplier. The unique design of the PSL-40 enables users to tune the wavelengths throughout the range of 1535-1655 nm, and to vary pulse repetition rate from 0.5 to 45 GHz, pulse width from 0.8 to 5 ps. Calmar’s fiber lasers are known for their low timing jitter and low amplitude noise. It generates chirp-free and transform-limited pulse stream. Its repetition rate is continuously tunable. It is user-friendly with front panel pulse width and wavelength adjusters. It is a turnkey solution when a computer aided automatic locking function is integrated. It is self-contained and maintenance-free. The PSL-40 is polarization-maintained with an average optical output power of more than 20 mW. Our proprietary design makes the laser produce stable optical modes and thus a stable pulse-to-pulse phase relationship, which is very critical for DPSK (differential phase shift keying) transmission applications. In addition to a C-band version, Calmar also provides 780-nm and 1-µm wavelength options.