A laser diode module with a built-in high-frequency modulation IC used to
remove the reflected noise generated as the laser beam reads the signal
to be played back and directly packaged within a metal cap. The
high-frequency modulation IC creates an electrical connection through
wire bonding with several connection legs and the laser diode module. The
packaged laser diode module has four connection legs. Two of these
connection legs act as a positive and a negative terminal for supplying
power to the built-in high-frequency modulation IC. The other two
connection legs are electrically connected to an external automatic power
control (APC) circuit and act as the positive terminal of the laser diode
and the photo diode, respectively. In this way, the inconvenience of
externally attaching a high-frequency current producing circuit board can
be avoided, the productivity can be enhanced and the radiation of
electromagnetic interference (EMI) can be reduced.