Locate Calibration and Repair Services providers in Austria. The invention relates to an extinction ratio tester calibrating device with an adjustable extinction ratio in a large range, which comprises a first light source with adjustable power, a second light source with adjustable power, a first polarizer, a second polarizer and a beam combining device. Fiber-optic transceivers used in high-speed digital communications systems must comply with a stringent set of performance criteria. One important parameter that is typically measured with an oscilloscope is extinction ratio (ER), which describes how efficiently laser transmitter power is converted. One parameter, extinction ratio, is used to describe optimal biasing conditions and how efficiently available laser transmitter power is converted to modulation power. Although specifications are defined by industry standards and test method-ologies loosely described, historically it has been. The Thorlabs ERM100 Extinction Ratio Meter Benchtop is a powerful instrument designed for accurately measuring the extinction ratio of optical signals.