Title :
Suppression of double Rayleigh scattering-induced excess noise in remotely interrogated fiber-optic interferometric sensors
Author :
Cranch, G.A. ; Dandridge, A. ; Kirkendall, C.K.
Author_Institution :
Naval Res. Lab., Washington, DC, USA
Abstract :
This letter describes experimental observations of excess noise due to coherent double Rayleigh scattering in the input fiber of a remotely interrogated fiber-optic interferometric sensor. This noise source is generally only observable when a high coherence length laser is used to interrogate the sensor and the fiber length connecting the sensor is in excess of /spl sim/10 km. We present a simplified model to explain how this noise source affects the sensor resolution and demonstrate a method based on laser source modulation to reduce this noise by /spl sim/20 dB in a fiber-optic Michelson interferometric sensor with a 25-km input fiber, at frequencies less than 10 kHz.
Keywords :
Michelson interferometers; Rayleigh scattering; acousto-optical devices; fibre optic sensors; hydrophones; light coherence; optical fibre telemetry; optical modulation; optical noise; signal resolution; 10 kHz; 10 to 25 km; coherent double Rayleigh scattering; double Rayleigh scattering-induced excess noise suppression; fiber length; fiber-optic Michelson interferometric sensor; high coherence length laser; input fiber; laser source modulation; noise source; optical hydrophone; remotely interrogated fiber-optic interferometric sensors; sensor resolution; simplified model; Coherence; Fiber lasers; Frequency; Joining processes; Laser modes; Laser noise; Noise reduction; Optical fiber sensors; Rayleigh scattering; Sensor phenomena and characterization;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2003.818626
