Bistable magnetooptic switch for multimode optical fiber

A bistable nonmechanical optical switch for multimode optical fiber is presented. It is a 2-input/2-output device for the 1-microm wavelength range. The optical characteristics are independent of the polarization state of incident light. The switch consists of Faraday rotators of thin plates of yttrium-iron-garnet single crystal, electromagnets whose cores are made of semihard magnetic material, halfwave plates of crystal quartz, polarizing prisms of rutile, and lenses. Switching is performed by one-shot 3-V 20-microsec pulses with a maximum current of 500 mA. The 1.5-dB insertion losses and -32-dB cross talk were obtained at a wavelength of 1.3 microm.