Time-Multiplexed Signals and Parallel Signal Analysis/Switch Optimization for MEMS-Mirror OXC System Training

The calibration, or "training," of the numerous mirror-pairs, or switches, in MEMS-mirror OXC systems is a critical process in their manufacture. Because the number of switch connections for these systems scales quadratically to the number of inputs/outputs this places great demands on the equipment used to perform training. This equipment must be fairly compact, fast, as low in cost as possible, and be scalable to OXC systems where I/Os can vary from 40x40, on up to 1296x1296, and larger, systems. Present training equipment technology has relied heavily upon the use of numerous and costly OEM optical switch boxes and also on as many optical sources and detectors as there are I/Os. This paper reports on the use of time-multiplexed optical signals created by fiber delay coils, and also the system that was developed to demonstrate this technology, for improved OXC system training. Data from the tests conducted on a 40x40 Agere Corp. OXC system is presented as well as a comparison of current training system technologies with a proposed 256x256 training system based on time-multiplexed signal technology. It appears that OXC training systems based on the use of fiber delay coils and time-multiplexed optical signal technology has clear advantages when compared with currently used training system technologies. These advantages are in the areas of cost and size reduction. A cost reduction of at least 6x and the possibility of a portable training system look feasible. While a speed advantage may also be possible additional work still remains in sourcing or developing a more appropriate optical source and detector as well as fast data acquisition electronics. Some equipment possibilities have been suggested.