IdealPhotonics' extinction ratio meter is a precision instrument specifically designed to quantify the polarization purity of optical signals or the performance of digital optical switches. Its core function is to measure the extinction ratio (ER), the logarithmic ratio of high-level to low-level optical power, to evaluate the polarization selectivity or switching contrast of optical devices (such as polarizers, modulators, and lasers).Through high dynamic range optical power comparison technology (>30dB), it achieves μs-level high-precision measurement of the polarization/switching extinction ratio (0.01dB resolution), while also featuring automatic calibration and multi-scene adaptability.