Composite Cavity Fiber Laser for Sensor Applications

• Main Authors: Asrul Izam AZMI, Ian LEUNG, Paul CHILDS, Gang-Ding PENG
• Format: Article
• Language: English
• Published: IFSA Publishing, S.L. 2010-05-01
• Series: Sensors & Transducers
• Subjects: Composite cavity fiber laser; Strain sensor; Long cavity; Dual cavity laser
• Online Access: http://www.sensorsportal.com/HTML/DIGEST/may_2010/P_610.pdf

Composite Cavity Fiber Lasers (CCFLs) are investigated for their potential in sensing applications. We have theoretically studied the frequency and intensity related sensing characteristics of CCFLs. A CCFL can be fabricated simply by writing three wavelength-matched Bragg gratings directly into a continuous length of doped fiber. Using an in-house grating writing facility we have fabricated CCFLs of varying composite cavity lengths. We have simulated and experimentally examined the sensing capabilities of CCFLs under different strain conditions, and found that CCFLs give rise to significantly distinctive responses from those of a FBG or single cavity fiber laser based sensor. We also noted significant intensity and / or frequency (wavelength) responses under different loading conditions, thus making them suitable for intensity or frequency-based sensing. A particular example of application is to use an asymmetrically strained CCFL to achieve increased sensitivity, decreased gauge length, and very confined spectral requirements.