INNOVATIVE IMPROVEMENTS IN BISMUTH-DOPED RARE-EARTH IRON-GARNET FARADAY ROTATORS

Performance of magneto-optic isolators is often limited by the propert ies of the Faraday rotator, which can be improved. 1) A compensation p oint layer can be used to control the temperature dependence of the ma terial and consequently improve the extinction ratio to greater than o r equal to 30 dB from -10 degrees C to 85 degrees C without significan t increase in device size or complexity. 2) Variation of composition a nd lattice parameter can decrease the material absorption and therefor e the device insertion loss at specific wavelengths. 3) Development of a ''latching'' Faraday rotator material with an effective coercivity above 1 kOe allows the design of devices with no bias magnet and conse quently lower cost and size.