Patent ID: 7603039

Claim:
A bidirectional transmitting/receiving circuit in which a transmitter and receiver are integrated together by sharing common parts between the transmitter and receiver, and which connects to a laser diode and a photo diode, comprising: a main amplifier including a main amplifier input and a main amplifier output; a first switch including an electric signal input for receiving an electrical signal from a semiconductor, an optical signal input for receiving a optical signal from the photo diode, and a first switch output in communication with said main amplifier input for selectively sending the electrical signal and the optical signal to the main amplifier; and a second switch including a second switch input in communication with said main amplifier output for receiving the electrical signal and the optical signal from the main amplifier, an electric signal output for outputting the optical signal to the semiconductor, and an optical signal output for outputting the electrical signal to the laser diode, whereby said first switch receives an electrical signal from the semiconductor, said first switch selectively outputs the electrical signal to said main amplifier, said main amplifier outputs the electrical signal to said second switch, and said second switch selectively outputs the electrical signal to the laser diode, and said first switch receives a optical signal from the photo diode, said first switch selectively outputs the optical signal to said main amplifier, said main amplifier outputs the optical signal to said second switch, and said second switch selectively outputs the optical signal to the laser diode.