High sensitive Static fiber Bragg grating strain sensing using lasers locked to relative frequency reference

Kondiparthi, Mahesh (2010) High sensitive Static fiber Bragg grating strain sensing using lasers locked to relative frequency reference. In: Conference on Fiber Optic Sensors and Applications VII, APR 07-08, 2010, Orlando, FL,.

PDF 7677-42.pdf - Published Version Restricted to Registered users only Download (218kB) | Request a copy

Abstract

A novel high sensitive fiber Bragg grating (FBG) strain sensing technique using lasers locked to relative frequency reference is proposed and analyzed theoretically. Static strain on FBG independent of temperature can be measured by locking frequency of diode laser to the mid reflection frequency of matched reference FBG, which responds to temperature similar to that of the sensor FBG, but is immune to strain applied to the same. Difference between light intensities reflected from the sensor and reference FBGs (proportional to the difference between respective pass band gains at the diode laser frequency) is not only proportional to the relative strain between the sensor and reference FBGs but also independent of servo residual frequency errors. Usage of relative frequency reference avoids all complexities involved in the usage of absolute frequency reference, hence, making the system simple and economical. Theoretical limit for dynamic and static strain sensitivities considering all major noise contributions are of the order of 25 (p epsilon) / root Hz and 1.2 n epsilon / root Hz respectively.

Item Type:	Conference Paper
Series.:	Proceedings of SPIE-The International Society for Optical Engineering
Publisher:	The International Society for Optical Engineering
Additional Information:	Copyright of this article belongs to he International Society for Optical Engineering.
Keywords:	Static strain; Relative frequency reference; matched fiber Bragg grating; servo; Residual frequency error
Department/Centre:	Division of Physical & Mathematical Sciences > Instrumentation Appiled Physics
Date Deposited:	07 Mar 2011 06:37
Last Modified:	07 Apr 2011 07:06
URI:	http://eprints.iisc.ac.in/id/eprint/35916

Actions (login required)

View Item