Optical isolator for transmitting light propagating forward and not transmitting light propagating backward, laser module using the optical isolator, optical amplifier using the optical isolator and polarizing filter used for a polarizer and an analyzer of the optical isolator

摘要

A laser beam is incident on a polarizer inclined by an inclined angle ranging from 50 to 60 degrees with respect to an optical axis, a polarized component of the laser beam polarized in a first polarization direction passes through the polarizer. The polarized component is rotated on the optical axis in a second polarization direction by 45 degrees in a Faraday rotator and is incident on an analyzer which is inclined by the inclined angle in a direction opposite to that of the inclination of the polarizer with respect to the optical axis to transmit only a laser beam polarized in the second polarization direction. Therefore, the polarized component passes through the analyzer almost without attenuation, and a wave front aberration of the laser beam caused by the polarizer is cancelled out in the analyzer.