20 GHz bandwidth 1.55 mu m distributed feedback laser diode modules

This paper decribes the design and performance of distributed feedback (DFB) laser diode modules which are based on InP/InGaAsP strained multiple quantum well (MQW) DFB laser diodes. Among the many aspects of packaging the laser diodes, we would emphasize the electrical characteristics, such as frequency response and return loss of the laser diode modules considering the structure of the module. The major components of the module consist of the butterfly package with a K-connector, a thermo-electric cooler, a thermistor, and a monitor photodiode. For the electrical signal path, the components are a K-connector, a microstrip line, an impedance matching resistor, a laser diode, and a wire bonding. From the model and the measured data, the most important component affecting the electrical characteristics is wire bonding. The wire bonding is considered as an inductor at high frequency range. We calculated the inductances from various wire bonding geometries. As a result, shorter wire bonding length would. be the best Step to reduce the package induced inductance. Well-controlled package parasitics made the module achieve the modulation bandwidth of 20 GHz.