Influence of the refractive index of liquids in the speckle pattern of multimode fibers

Carlos Galindez; Mauro Lomer; Luis Rodriguez-Cobo; J. M. Lopez-Higuera

doi:10.1117/12.978219

11 September 2012 Influence of the refractive index of liquids in the speckle pattern of multimode fibers

Carlos Galindez, Mauro Lomer, Luis Rodriguez-Cobo, J. M. Lopez-Higuera

Proceedings Volume 8413, Speckle 2012: V International Conference on Speckle Metrology; 84131Q (2012) https://doi.org/10.1117/12.978219
Event: SPECKLE 2012: V International Conference on Speckle Metrology, 2012, Vigo, Spain

Abstract

The distribution of the intensity of each speckle depends on the relative phases of modes in the multimode fiber, so they are extremely sensitive to external perturbations of the fiber. These perturbations can locally appear in the fiber without disrupting the entire optical assembly. If the refractive index of the outside medium of the fiber is changed, it can cause variations in the speckle pattern at the fiber output. Thus, by changing the refractive index of the outside medium the speckle pattern at the output fiber varies and its influence can be observed. In this paper we demonstrate the influence of the refractive index of liquids in the speckle pattern obtained by a multimode fiber. In order to obtain greater sensitivity of the experimental measurement, the fiber is bent in a U-shape and immersed in a liquid. The core and cladding are 240 microns and 250 microns, respectively. The intensity speckle field is then captured by a CCD camera in digital image format and processed by the computer with a Matlab program. The portion of fiber exposed to the disturbance of the liquid is located 2 meters before the exit of the fiber. The portion of the fiber in contact with the liquid is curved with a radius of 2 mm.

Citation Download Citation

Carlos Galindez, Mauro Lomer, Luis Rodriguez-Cobo, and J. M. Lopez-Higuera "Influence of the refractive index of liquids in the speckle pattern of multimode fibers", Proc. SPIE 8413, Speckle 2012: V International Conference on Speckle Metrology, 84131Q (11 September 2012); https://doi.org/10.1117/12.978219

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available