A calorimeter for mu W level optical power transfer standard

A calorimeter which can measure microwatt-level optical power has been developed for an optical power transfer standard. It can measure the optical power of a light beam and can be used with optical fiber simply by attaching an adapter. This calorimeter sensor uses a compensative absorber to reduce the influence of pressure fluctuation and temperature variation in the measurement room and an ultra-low-noise preamplifier. With this calorimeter, the standard deviation of the measured value is in the range of 0.02-0.4% in 20-mW to 10- mu W optical power measurements. An error evaluation for an optical power level of 10 mu W yielded a two-sigma (two standard deviation) total uncertainty of 0.9%.<
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