#Y2024 #光学器件 #偏振 ### Faraday rotator A Faraday rotator is a polarization rotator based on the Faraday effect, a magneto-optic effect involving transmission of light through a material when a longitudinal static magnetic field is present. The state of polarization (such as the axis of linear polarization or the orientation of elliptical polarization) is rotated as the wave traverses the device, which is explained by a slight difference in the phase velocity between the left and right circular polarizations. Thus it is an example of circular birefringence, as is optical activity, but involves a material only having this property in the presence of a magnetic field.  ### Faraday isolator  ### Faraday circulator Faraday circulators (or less specifically _optical circulators_) are a kind of non-reciprocal optical devices. They are technically related to Faraday isolator and on a broader scale similar to electronic circulators. Typically, a circulator has three or four optical ports (inputs / outputs), although there could in principle be more. These devices typically have three or four optical ports, although more can be incorporated. Light entering one port exits from the next port, or from the first port if injected into the last. For instance, in a three-port device, the light paths can be illustrated as: - 1 → 2 - 2 → 3 - 3 → 1  ### 液相外延生长（LPE）法拉第旋光片 由液相外延生长（LPE）而成的光学法拉第旋片是由铋置换稀土类铁石榴石单晶体构成的0.100-0.500mm厚的单结晶膜，通过液相外延生长（LPE）方法制成的。 ### 法拉第旋磁材料供应商 在光通信用的法拉第旋磁材料供应商中，美国的IPI（美国新泽西的集成光子Integrated Photonics，习惯称IPI，创建于2000年，是AT&T贝尔实验室的磁光材料业务剥离创建的公司，是光隔离器用工程磁光材料的领先供应商。2017年被II-VI——现在叫coherent——收购了。）和日本的GRANOPT（三菱gas化学和住友金属矿山各50%合资）是两大主力供应商。