Tip of the Week – High Optical Power Levels in Fiber
When operating DWDM, CWDM or long haul optical amplifier systems one should be aware of the total optical power in the fiber. The fiber’s total optical power is the sum of all individual channel powers. For example, if you are operating a 16 channel DWDM or CWDM system, and each channel optical transmit power is 0 dBm, then the total fiber power is 12 dBm at the transmit end. It is not unusual to measure total fiber power levels of over +17 dBm (50mW) in fiber systems.
There are a number of concerns with high optical power. One is safety of course. All personnel working with high power systems need to be aware of and practice all safety precautions including eye safety.
Another concern is the effect of the high power level on fiber connectors. During one study, it was found that selected LC and SC type connectors performed well up to an optical power level of +30 dBm (1 Watt). Other connector types may not perform this well.
It was also noted that caution should be exercised when cleaning fiber connectors that are connected to high power sources. At power levels over +15 dBm there is a chance that the cleaning material may ignite damaging the connector and possibly harming the individual. It is suggested that total fiber power be reduced significantly below +15dBm or be powered down completely before cleaning connectors.
Effects of High Power Levels on Optical Connectors, Splices and Related Components, D.N. Ridgway, National Fiber Optic Engineers Conference 2001 Technical Proceedings