The D1861A direct-modulated laser (DML) module is a cost-effective solution for 10 Gbits/s digital transmission up to 50 km using traditional intracity SMF28 single-mode fiber links. The 1310 nm wavelength eliminates the need for concern about dispersion control over most installed intracity fiber plants. The package contains a high-speed DFB laser chip, thermoelectric cooler, thermistor, optical isolator, and a rear-facet monitor photodiode, which allows for external optical power control.