Patent ID: 7242516

Claim:
A Faraday rotator that uses a bismuth-substituted rare earth iron garnet single crystal and rotates the polarization plane of incident light, said single crystal necessarily containing Gd, Tb and Yb as rare earth elements and exhibiting substantially rectangular magnetic hysteresis, wherein, Faraday rotary moment in a temperature range of −40° C. to +85° C. with a wavelength of 1550 nm, is 700°/cm or more and the temperature property of the Faraday rotation angle in said temperature range with said wavelength, is 13% or less of a target value thereof, the wavelength property of the Faraday rotation angle at room temperature with a wavelength of 1500 to 1600 nm, is 8% or less of a target value thereof, and insertion loss at room temperature with a wavelength of 1550 nm, is 0.1 dB or less.