Dual-in-line laser diode module for fiber-optic transmission up to 4 Gbit/s

A very high-speed laser diode (LD) module, having a "butterfly" type dual-in-line structure is developed. This LD module consists of a laser diode, a p-i-n-photodiode for monitoring the laser power, a thermoelectric cooler, and a thermistor. The power emitted from the LD is coupled into a single-mode fiber using a hemispherical tapered fiber technique. The microwave design of the LD module employing high frequency equivalent circuit and scattering (
S
) parameters is shown. Parasitic inductances and capacitances in the LD module degrade the high frequency characteristics. This is a very serious problem in gigabit fiber-optic transmission systems. The microwave impedance, small signal high frequency characteristics, and high-speed pulse response of the fabricated module with low parasitics are also shown. Electrical resonance frequency is 4.8 GHz and well opened eye patterns up to 4 Gbit/s are obtained in the experiments.