Evaluation of optical fibre sensors in the electrical domain

Abstract

Optical fibre sensors cover a wide range of applications. They offer versatile advantages including resilience to electromagnetic interference, biocompatibility and chemical resistivity. Even in environments with restricted accessibility, integration difficulties can be overcome by using radio-over-fibre (RoF) technology that allows a wireless read-out. Conventionally, optical fibre sensors are evaluated in the optical domain by analysing the amplitude or spectrum of either the transmitted or the reflected light. A novel approach is to feed a radio frequency-modulated laser into the optical sensor and carry out a full electrical analysis of the resulting radio frequency (RF) signal, which is changed by the sensor's characteristics. This method will be investigated in this paper for fibre Bragg grating-based and chirped fibre Bragg grating-based sensors in reflection and transmission configuration. Their applicability for this new evaluation scheme will be discussed. Subsequent studies may cover additional types of sensors and the testing of the novel evaluation method within an application-related scenario, including packaging.