The Infineon module for bidirectional optical transmission has been designed for
different optical networks structures.
In the last few years the structure has changed from point to point planned for Broad
band ISDN to a point to multipoint passive optical network (PON) architecture for the
optical network in the subscriber loop.
A transceiver can be realized with discrete elements (Figure 3). Transmitter and
receiver with pigtails are connected with a fiber-coupler (2:1 or 2:2, wavelength
independent or WDM).
2:1 or 2:2
3 dB wavelength independent
or wavelength division multiplexing
Figure 3 Realization with Discrete Elements
Infineon has realized this transceiver configuration in a compact module called a BIDI®
This module is especially suitable for separating the opposing signals at the ends of a
link. It replaces a discrete solution with a transmitter, receiver and coupler.
The basic devices are a laser diode and a photodiode, each in a TO package, plus the
filter in the beam path. A lens in the TO laser concentrates the light and enables it to be
launched into the single-mode fiber of the module. In the same way the light from the
fiber is focused onto the small, light-sensitive area of the photodiode to produce a high
photo current. The mirror for coupling out the received signal is arranged in the beam so
that the transmitter and receiver are at right angles to each other. This means the
greatest possible degree of freedom in the layout of the electric circuit.
Data Sheet 3 2002-05-01