Fiber-optic tapping via induced scattering

A noninvasive and potentially inexpensive method for fabricating a passive linear tapped optical waveguide bus is described. In the method, a small flame or a CO/sub 2/ laser is used as a heat source to induce devitrification within the alumina-doped cores of multimode waveguide fibers having numerical apertures in the range of 0.25-0.29. The discrete crystal sites created by careful localized heating can be used to scatter controlled fractions of propagating light onto a detector.<
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