The present invention relates to an optical
transceiver that installs an optical transmitting
assembly and an optical receiving
assembly both are compact, inexpensive, and capable of operating at a high speed. The optical transmitting
assembly of the present invention provides the
metal bottom that installs the thermoelectric cooler thereon and the
semiconductor optical device is mounted, via the insulating substrate, on the thermoelectric cooler. The first and second multi-layered
ceramic substrates are provided to surround the thermoelectric cooler. The DC
signal or the low-frequency
signal for the thermoelectric cooler and the
semiconductor optical device is supplied through the first
ceramic substrate, while the
high frequency signal for the
semiconductor device, with the complementary signal having the opposite phase to the
high frequency signal, is provided to the
semiconductor device through the inner layer of the second
ceramic substrate and the insulating substrate. The semiconductor light-receiving device, which monitors light emitted from the semiconductor light-emitting device, is mounted on the top layer of the second
ceramic substrate. Thus, the transmission path for the
high frequency signal from the drive circuit installed outside of the transmitting assembly to the light-emitting device becomes substantially linear.