New Metric Offers More Accurate Estimate of Optical Transmitter's Impact on Multimode Fiber-optic Links

摘要

Reliable metrics to define and quantify performance of transmitters used in high-speed optical communications have been historically difficult to achieve. The classic eye-mask test provides a coarse method to screen out bad devices, but is not an accurate predictor of system level performance in terms of bit error ratio (BER). Transmitter and dispersion penalty (TDP) analysis yields a BER-based metric, but is complicated and expensive to perform. A recent IEEE Ethernet project (802.3bm) has developed a new signal quality metric, TDEC (transmitter and dispersion eye closure), for multimode optical transmitters that seeks to provide a simple and low cost test method that reliably predicts operation when deployed with standards-compliant channels and receivers. In this paper we discuss the limitations of the existing metrics and present the new TDEC metric and its expected advantages. Methods to implement the new measurement in standard instrumentation and actual measurement results will be reviewed.