Patent ID: 6891616

Claim:
A polarization analyzer comprising: a plurality of Faraday rotators which are serially disposed on an optical axis onto which light to be measured is incident, and each have a Faraday element which rotates the light to be measured and a magnetic field generator which applies a magnetic field to the Faraday element; a wavelength plate which is disposed between said plurality of Faraday rotators, and retards the light to be measured; a polarizer which transmits, of the light to be measured, light having a predetermined plane of polarization, which has been rotated by said plurality of Faraday rotators, and retarded by the wavelength plate; an optical receiver which receives the light transmitted by the polarizer and outputs a light receiving electric signal in accordance with the amount of light received; a signal generator which outputs a control signal for polarizing the light to be measured into at least four polarization states to the magnetic field generator; and a signal processor which determines Stokes parameters which indicate the polarization state of the light to be measured based on the four polarization states, and the light receiving electric signal from the optical receiver corresponding to each of the four polarization states.