A fiber optic module includes a connector connected to a mother board of a
host computer, an LD semiconductor IC for converting serial data received
from the mother board to an LD electric signal for a laser diode, an LD
module for converting the LD electric signal to an LD optical signal, a
PD module for converting a photodiode optical signal to a PD electric
signal, a PD semiconductor IC for converting the PD electric signal to PD
serial data, a circuit board having the connector and carrying LD
semiconductor IC and PD semiconductor IC, an LD shielding plate and a PD
shielding plate for electrically shielding the LD module and the PD
module, respectively, a first frame and a second frame for holding the
circuit board, LD module and PD module. In the fiber optic module, the
connector is of a surface mounting type, leads of the LD and PD modules
are connected to a side of the circuit board mounted with the connector,
the circuit board has an LD variable resistor for adjusting a drive
current of the LD module, the LD variable resistor is provided to a side
of the circuit board opposite to the connector, the circuit board has a
PD variable resistor provided to the side of the circuit board opposite
to the connector for detecting a signal of the PD module, 3 signal
processing semiconductor ICs or less are provided.