Automated Bit-Error-Rate (BER) Measurement System

In the last few decades the use of optical communications has proliferated, permitting significantly faster data-rates than conventional electrical links, and enabling such advanced technologies as the internet. In the optical communications community, it is critical to assess the quality of an optical link, which is most commonly done using bit-error-rate (BER) measurements. Currently, in the Lightwave Research Laboratory, as well as many other research laboratories, BER measurements are done by manually adjusting the parameters of several independent instruments.

In its most succinct description, a BER measurement consists of an optical signal being variably attenuated, and then received on a photoreceiver, converting the signal to an electrical form that can be assessed by a BER tester. The variable attenuation, which is performed manually, allows one to measure the BER of the signal at several different power levels; a characterization that the researcher can use to gauge the quality of the optical signal.

The purpose of this project was to utilize the software environment LabView, a common laboratory tool, to orchestrate the actions of these discrete instruments into an automated process. This system can thereby introduce substantial improvements in the time, accuracy, and number of BER measurements that the researcher can perform.

To validate the system, the automated measurement we developed was compared to a BER measurement performed using the traditional manual technique.