An Optical Fibre Depth (Pressure) Sensor for Remote Operated Vehicles in Underwater Applications

• Main Authors: Dinesh Babu Duraibabu, Sven Poeggel, Edin Omerdic, Romano Capocci, Elfed Lewis, Thomas Newe, Gabriel Leen, Daniel Toal, Gerard Dooly
• Format: Article
• Language: English
• Published: MDPI AG 2017-02-01
• Series: Sensors
• Subjects: ROV; OFPTS; Pressure; sensors; ROV control; Fabry-Perot; Fibre Bragg Gratings
• Online Access: http://www.mdpi.com/1424-8220/17/2/406

A miniature sensor for accurate measurement of pressure (depth) with temperature compensation in the ocean environment is described. The sensor is based on an optical fibre Extrinsic Fabry-Perot interferometer (EFPI) combined with a Fibre Bragg Grating (FBG). The EFPI provides pressure measurements while the Fibre Bragg Grating (FBG) provides temperature measurements. The sensor is mechanically robust, corrosion-resistant and suitable for use in underwater applications. The combined pressure and temperature sensor system was mounted on-board a mini remotely operated underwater vehicle (ROV) in order to monitor the pressure changes at various depths. The reflected optical spectrum from the sensor was monitored online and a pressure or temperature change caused a corresponding observable shift in the received optical spectrum. The sensor exhibited excellent stability when measured over a 2 h period underwater and its performance is compared with a commercially available reference sensor also mounted on the ROV. The measurements illustrates that the EFPI/FBG sensor is more accurate for depth measurements (depth of ~0.020 m).