Patent ID: 7035302

Claim:
An optical transmission module comprising: a laser diode which generates a laser beam; and a differential type current switch having a first switch and a second switch for the purpose of supplying a modulating current to said laser diode, each of the first switch and second switch being a bipolar transistor, a collector terminal of said first switch being connected to a DC power supply voltage through a first resistor, a collector terminal of said second switch being connected to a DC power supply voltage through a second resistor, an emitter terminal of said first switch and an emitter terminal of said second switch being connected together and being connected to ground potential via a single common modulation current supply; wherein an anode of said laser diode is connected to a collector terminal of said first switch and a cathode of said laser diode is connected to a collector terminal of said second switch, thereby modulating said laser diode bidirectionally using the anode and the cathode.