Modeling of the fringe shift in multiple beam

interference for glass fibers

A M HAMED¹

Physics Department, Faculty of Science, Ain Shams University, Cairo, Egypt

¹Present address: Physics Department, Sur College of Applied Science,

P.O. Box 484, Postal Code 411, Sultanate of Oman

E-mail: amhamed73@hotmail.com

Abstract. A quadratic model is suggested to describe the fringe shift occurred due to

the phase variations of uncladded glass fiber introduced between the two

plates of the liquid wedge interferometer. The fringe shift of the phase

object is represented in the harmonic term which appears in the denominator

of the Airy distribution formula of Fabry--Perot's interferometer. A

computer program is written to plot the computed fringe shifts of the

described model.

An experiment is conducted using liquid wedge interferometer where the fiber

of a nearly quadratic thickness variation is introduced between the two

plates of the interferometer. The obtained fringe shift shows a good

agreement with the proposed quadratic model. Also, it is compared with the

previous theoretical shift based on ray optics of semi-circular

shape.

Keywords. Multiple beam interference; laser radiation; computerized

images.

PACS No. 42.25.Hz