SENSITIVITY IMPROVEMENT OF AN OPTICAL CURRENT SENSOR WITH ENHANCED FARADAY-ROTATION

Citation
Gd. Li et al., SENSITIVITY IMPROVEMENT OF AN OPTICAL CURRENT SENSOR WITH ENHANCED FARADAY-ROTATION, Journal of lightwave technology, 15(12), 1997, pp. 2246-2252
Citations number
29
Language
INGLESE
art.tipo
Article
ISSN journal
0733-8724
Volume
15
Issue
12
Year of publication
1997
Pages
2246 - 2252
Database
ISI
SICI code
0733-8724(1997)15:12<2246:SIOAOC>2.0.ZU;2-R
Abstract
A sensitivity improvement technique is proposed for a class of bulk-gl ass optical current sensors that employ a ferromagnetic field concentr ator, The total effective optical path length is demonstrated theoreti cally to be an invariant regardless of the bulk glass thickness and co nsequently independent of the size of the concentrator gap opening, Th us, if the magnetic field is increased by reducing the gap size, the e ventual Faraday rotation for a given electric current can be increased proportionally, leading to an improved device sensitivity, The depend ence of the gap magnetic field on gap size is calculated with an equiv alent circuit model, and this analytical treatment is compared with a dedicated finite element computer package, By taking account of variou s types of optical power losses present in the bulk glass, the above f ormulated gap dependence of magnetic field is used to aid a realistic assessment of device sensitivity and this serves as a tool to design a nd analyze practical bulk-glass optical current sensors, A detailed ex perimental study to confirm the proposed sensitivity improvement techn ique is also reported.