Abstract: Recently,the "butterfly" high speed laser diode(LD)module of the order of GHz has been developed.The LD module consists of a DC-PBH laser diode,a pin photodiode for monitoring the laser power,a thermoelectric cooler,and a thermis-ter.In designing the LD module,the high frequency equivalent circuits are employed and reported in this paper.The small signal high frequency characteristics of the module are measured,and the 3 dB bandwidth of electrical response of the module is more than 1.5 GHz,the modulation freqtiency is high up to 2.7 GHz.