A transmit reflect detection system for fiber Bragg grating photonic sensors

Abstract

Traditional Fibre Bragg Grating (FBG) sensing systems acquire data about the measurand via the spectral response of the FBG. Edge filter methods are also used in the acquisition of data from FBGs. In edge filter systems, the spectral shift in the FBG due to the measurand is converted into an optical power change. This optical power change can then be easily measured using conventional optoelectronic devices. We demonstrate the use of a Transmit Reflect Detection System (TRDS) for Fibre Bragg Grating (FBG) sensors. The TRDS is in essence a dual edge filter detection method. In conventional edge filter detection schemes, the reflected portion of the incident spectrum is monitored to determine the change in the measurand. In the TRDS, both the transmitted and reflected portions of the input spectrum, from a narrow band light source, are utilised. The optical power of the transmitted and reflected signals are measured via two separate photoreceivers, where each generates a single edge filter signal. As the spectral response of the FBG shifts due to the measurand, the transmitted power will increase, and the reflected power will decrease, or vice versa. By differentially amplifying the transmitted and reflected components, the overall signal is increased. This results in improved sensitivity and efficiency of the photonic sensor. In this work, the FBG sensor and TRDS are used in the measuring and monitoring of temperature, force and strain. As such, results are presented for the FBG TRDS for all of the measurands.

An Intensiometric Detection System for Fibre Bragg Grating sensors

“…The TRDS differentially amplified the transmitted and reflected signals from a single edge filter detected FBG sensor. The result of the TDRS was improved sensitivity and efficiency, specifically with high frequency dynamic signals, such as ultrasound [4].…”

“…The IDS is an extension of initial work done on a Transmit Reflect Detection System (TRDS) [3]. The TRDS differentially amplified the transmitted and reflected signals from a single edge filter detected FBG sensor.…”

“…Due to the generation of balance signals for the differential amplifier, a transmit-reflect detection system was used as the input to the IDS. The sensing system was used to monitor the longitudinal strain applied to a steel sample, previously done with the TRDS [3]. The FBG was bonded to the sample using cyanoacrylate.…”

Optical Fiber Bragg grating based intrusion detection systems for homeland security

“…Experiments on lateral loading of an FBG had proven to be very positive in terms of using this as a switch with a TRDS [9]. As such, the same setup as the acoustic sensing experiment was used, but now instead of actively generated acoustic signals or acoustic emissions from drop tests, pressure in terms of a lateral load was applied to the various flooring materials.…”

In-ground optical fibre Bragg grating pressure switch for security applications

“…This detection principle is depicted in Figure 1. The change in transmitted and reflected optical power signals was then detected using the previously reported Intensiometric Detection System (IDS) [9], based on the Transmit Reflect Detection System (TRDS) [10]. Here the two signals were measured via two photodetectors.…”