AN649 Datasheet, PDF (1/11 Pages) Maxim Integrated Products – HFTA-04.0: Optical/Electrical Conversion in SDH/SONET Fiber Optic Systems

FIBER OPTIC CIRCUITS
Application Note 649: Jun 28, 2000
HFTA-04.0: Optical/Electrical Conversion in SDH/SONET Fiber Optic Systems
This article explains the basic functions and design challenges of the optical to
electrical and electrical to optical signal conversion in SDH/SONET fiber optic
receivers and transmitters. A complete chip set solution to develop the electronic part
of OC 12/STM 4 receivers and transmitters is presented.
The advent of cheaper and more powerful personal computers has not only expanded the user
base; it is also creating a demand for greater transmission capacity among the telecom
networks by adding an increasing volume of internet and videophone connections to the
traditional phone and fax services. The following discussion of an OC 12/STM 4
receiver/transmitter chipset supports these developments and includes a description of the
electronic components required for optic/electric (O/E) conversion in SDH/SONET fiber optic
transmission systems.
Competition among network providers enables the multimedia market to grow, and the
introduction of new and improved products and services in the near future should strengthen
the demand for increased transmission capacity. This need for more data throughput can be
satisfied economically with fiber optic (FO) cables because the transmission capacity is
potentially very high (versus that of copper wires). The physical nature of the fiber cable lets
providers expand capacity by increasing the transmission bit rate or by introducing alternative
transmission techniques, without the need for further upgrades or additional cable installations.
These advantages have led many countries to build extensive fiber networks, and further
expansion of these networks can be expected.
To transmit optical data via fiber cables, signals must be converted from electrical to optical at
the transmit end, and then converted back to electrical at the receive end. These necessary
conversions are handled by receiver/transmitter units that contain electronic devices along with
the optical components.
FO transceivers
The widely used Time Division Multiplex (TDM) transmission technique now enables bit rates
up to 10Gbps and is well established in modern transport systems. Today's high-speed fiber
optic transmission systems offer the following standard bit rates:
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