A calorimeter for μW level optical power transfer standard

A calorimeter than can measure μW-level optical power has been developed for an optical power transfer standard. It can measure the 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% to 0.4% in 20-mW to 10-μW optical power measurements. An error evaluation for an optical power level of 10 μW yielded a two-sigma (two standard deviation) total uncertainty of 0.9%