Polarization Extinction Ratio (PER) refers to the ratio of the transmitted or reflected light intensity of a device in different polarization directions. It is also commonly called the polarization splitting ratio and is commonly found in optical components such as polarizing fibers and polarizing beam splitters. Specifically, when a beam of light passes through these devices, only the light that conforms to a specific polarization direction can be completely transmitted or reflected, while the light perpendicular to this direction will be mostly blocked, which forms the so-called extinction phenomenon. . Therefore, the polarization extinction ratio refers to the ratio between the maximum transmittance and the minimum transmittance of light in the extinction state, usually expressed in decibels (dB).
Polarisationsgrad (PD) bezeichnet den Polarisationsgrad einer Lichtwelle. Es kann verwendet werden, um die Richtung und Amplitude des elektrischen Feldvektors im Raum zu quantifizieren, normalerweise ausgedrückt als Dezimal zwischen 0 und 1. Bei linear polarisiertem Licht bezieht sich der Polarisationsgrad auf den Anteil der Komponente des elektrischen Feldvektors in einer bestimmten Richtung zum gesamten elektrischen Feldvektor. Bei zirkulär polarisiertem Licht bezieht sich der Polarisationsgrad auf den Anteil der Polarisationsintensität in Rotationsrichtung zur Gesamtintensität.
characteristics of light, but the polarization extinction ratio is more used to describe the device‘s ability to process different polarized light, such as polarization splitting, filtering, etc., while the degree of polarization It is more commonly used to describe the polarization state of a light source or transmission system. In addition, the polarization extinction ratio is usually a finite value that depends on the characteristics of the device itself, while the polarization degree can be measured in any light field and represents the polarization state of the optical element with low accuracy requirements.