A Study of Distributed Feed-Back Fiber Laser Sensor for Aeronautical Applications Using COMSOL Multiphysics

I. Lancranjan[1], C. Gavrila[2], S. Miclos[3], and D. Savastru[3]
[1]Advanced Study Centre - National Institute for Aerospace Research Elie Carafoli, Bucharest, Romania
[2]Technical University of Civil Engineering Bucharest, Romania
[3]National Institute R&D of Optoelectronics, INOE 2000, Bucharest, Romania

Distributed Feedback Fiber Laser (DFB-FL) sensors are increasingly used in aeronautical applications. One of the newest such applications consists in detecting the “transition” zone between laminar and turbulent air flow upon the extrados surface of an aircraft wing. In this specific application DFB-FL are operated as air pressure sensors monitoring amplitude variations of ~1 Pa (laminar flow) up to ~10Pa (turbulent flow) with repetition frequencies in the range 500 Hz – 10kHz. DFB-FL sensors consist in single mode rare earth ions doped optic fiber in which Bragg grating are created by using UV radiation. In most cases, as laser active centers, Er3+ ions are used for doping the optic fiber. DFB-FL use as extremely sensitive sensors relies on laser resonator parameter variation induced by the environment factor. In this paper, we propose a study of an Er3+ DFB-FL sensor using COMSOL Multiphysics. The main purpose of this study is to provide essential data for a proper design of a device of this type.