Improved Switching for Magneto-Optic Fiber-Based Technologies

A new method for magnetic field generation is presented that enhances the reliability of fiber-based interferometric switches. Suitable switching technologies have been proposed and implemented, but magneto-optic (MO) materials have shown promise in realizing all-optical switching with reasonable power, loss, and switching speed. However, bottlenecks in field generation drivers have limited the performance of MO devices in fiber-based switches. Improving the design of the field generation system will enhance this technology, ultimately realizing practical and reliable solutions. Conventional drivers in MO switching devices utilize one coil with a low number of turns to quickly magnetize the MO material. This, in effect, leads to a fast optical rise time. However, the optical fall time is determined by the response of the MO material and the decay rate of any trapped magnetic energy in the coil, which can be sluggish. The proposed design achieves fast optical fall time by better controlling the demagnetization of the MO material. In this paper, the design of the magnetic field generation system is presented and compared to other recently proposed systems, the electrical system is characterized, and the reliability of the optical output is investigated.