Specialty Optical Fibers Handbook

Applications of fibers with electrodes include active control of the refractive

index through the electro-optical effect, control of the fiber birefringence

through the passage of current in the electrode, and ‘‘poling,’’ a process after

which the fiber gains an effective second order nonlinearity. Lithography

of electrodes in D-shaped and twin-hole fibers has also been reported to produce

a periodic structure for quasi-phase matching. The sections to follow review

these devices.

6.3.1 Electrode Incorporation

In the early 1980s the PANDA fiber was invented [16], where a pair of stress

elements were inserted in the cladding on opposite sides of the core introducing

birefringence, which results in polarization maintenance. Soon after, a similar

fiber was ...