Specialty Optical Fibers Handbook

therefore, loss-index, curve is well fitted using Sharma’s theory in a temperature

range of 10  90 8C, which corresponds to the index change of 1.4808  1.4499,

respectively. The distance of the flat from the core center (4.705 mm) has been

determined as a least-fit parameter. The power loss for the fast mode is approxi-

mately 0.2 dB larger than that for the slow mode in the whole index range, as

shown in Fig. 16.21b. The purpose of the study is for a temperature sensor,

although in-fiber optic attenuators have been proposed under the same principle.

16.7.6 Optical Absorption Monitoring

The D-shape fiber, with its evanescent field accessible by exposing the fiber

core, is a reasonable approach to monitor the absorption spectra of gas and

contaminations ...