Interrogation and mitigation of polarization effects for standard and birefringent FBGs

Ibrahim, Selwan K.; Roosbroeck, J. Van; O'Dowd, J.; Hoe, Bram Van; Lindner, Eric; Vlekken, Johan; Farnan, Martin; Karabacak, Devrez M.; Singer, J.

doi:10.1117/12.2223002

Cited by 6 publications

(7 citation statements)

References 13 publications

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“…The radiation tests shows that attenuation in the fiber and change in reflectivity were at acceptable levels, however improvements needs to be made on the wavelength induced shift on the FBG. In order to evaluate the wavelength shift due to radiation exposure, other effects that also induce wavelength shifts in the FBG peak should be isolated such as polarization dependent frequency shift (PDFS) where >30pm (>3°C temperature error) in certain type of fs-FBGs has been reported [7].…”

Section: Fig 4 Total Ionization Dose (Tid) Vs the Test Timementioning

confidence: 99%

“…The fs-FBGs had a grating period of 537.5nm, reflectivity of ~55%, and full width half maximum (FWHM) of ~0.35nm. The FAZ I4 interrogator system has a polarization switch which was used to evaluate the PDFS of the two fs-FBG samples [7]. The I4 interrogator was scanning @1kHz sweep rate and the pol SW was turned ON while tracking the fs-FBG peaks at room temperature.…”

Section: Fig 4 Total Ionization Dose (Tid) Vs the Test Timementioning

confidence: 99%

See 1 more Smart Citation

Design challenges of a tunable laser interrogator for geo-stationary communication satellites

Ibrahim¹,

Honniball²,

Todd³

et al. 2017

International Conference on Space Optics — ICSO 2016

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Recently optical sensing solutions based on fiber Bragg grating (FBG) technology have been proposed for temperature monitoring in telecommunication satellite platforms with an operational life time beyond 15 years in geo-stationary orbit. Developing radiation hardened optical interrogators designed to be used with FBG sensors inscribed in radiation tolerant fibers offer the capabilities of multiplexing multiple sensors on the same fiber and reducing the overall weight by removing the copper wiring harnesses associated with electrical sensors. Here we propose the use of a tunable laser based optical interrogator that uses a semiconductor MG-Y type laser that has no moving parts and sweeps across the C-band wavelength range providing optical power to FBG sensors and optical wavelength references such as athermal Etalons and Gas Cells to guarantee stable operation of the interrogator over its targeted life time in radiation exposed environments. The MG-Y laser was calibrated so it remains in a stable operation mode which ensures that no mode hops occur due to aging of the laser, and/or thermal or radiation effects. The key optical components including tunable laser, references and FBGs were tested for radiation tolerances by emulating the conditions on a geo-stationary satellite including a Total Ionizing Dose (TID) radiation level of up to 100 krad for interrogator components and 25 Mrad for FBGs. Different tunable laser control, and signal processing algorithms have been designed and developed to fit within specific available radiation hardened FPGAs to guarantee operation of a single interrogator module providing at least 1 sample per second measurement capability across >20 sensors connected to two separate optical channels. In order to achieve the required temperature specifications of ±0.5°C across a temperature range of -20°C to +65°C using femtosecond inscribed FBGs (fs-FBG), a polarization switch is used to mitigate for the polarization dependent frequency shift (PDFS) induced from fs-FBG which could be in the order of > 20 pm causing > 2°C error in the measurement. Also special transducers were designed to isolate the strain from the FBGs to reduce any strain influence on the FBG temperature measurements while ensuring high thermal conductivity.In this paper we demonstrate the operation of an optical FBG interrogator as part of a hybrid sensor bus (HSB) engineering model system developed in the frame of an ESA-ARTES program and is planned to be deployed as a flight demonstrator on-board the German Heinrich Hertz geo-stationary satellite.

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Section: Fig 4 Total Ionization Dose (Tid) Vs the Test Timementioning

confidence: 99%

Section: Fig 4 Total Ionization Dose (Tid) Vs the Test Timementioning

confidence: 99%

Design challenges of a tunable laser interrogator for geo-stationary communication satellites

Ibrahim¹,

Honniball²,

Todd³

et al. 2017

International Conference on Space Optics — ICSO 2016

Self Cite

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“…Globally, the performance of this I-OFDR reflectometer for RBS characterization is similar to that of conventional I-OFDR systems based on VNA for sensor interrogation [17,42] or in-line monitoring [31], but with the identified limitations of polarization-dependent detection and echoes induced by harmonic distortion. The first can be solved by incorporating polarization switching [43,44] or scrambling [23]; the second represents a deterministic impairment that can be avoided, if necessary, by a previous calibration of the distortion and subsequent equalization.…”

Section: Resultsmentioning

confidence: 99%

“…Polarization control at the receiver’s side mitigates this problem, but this option is only viable for low ranges. The standard approaches to overcome this issue include the use of polarization-maintaining fiber [43]; the use of depolarizers or polarization scramblers to average the response over polarization at the price of an additional 3 dB power penalty [23]; or the use of polarization switching [43,44]. In our measurements of point reflectors, we implemented polarization switching, as described below.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Incoherent Optical Frequency-Domain Reflectometry Based on Homodyne Electro-Optic Downconversion for Fiber-Optic Sensor Interrogation

Clement

Maestre

Torregrosa

et al. 2019

Sensors

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Fiber-optics sensors using interrogation based on incoherent optical frequency-domain reflectometry (I-OFDR) offer benefits such as the high stability of interference in the radio-frequency (RF) domain and the high SNR due to narrowband RF detection. One of the main impairments of the technique, however, is the necessity of high-frequency detectors and vector network analyzers (VNA) in systems requiring high resolution. In this paper, we report on two C-band implementations of an I-OFDR architecture based on homodyne electro-optic downconversion enabling detection without VNA and using only low-bandwidth, high-sensitivity receivers, therefore alleviating the requirements of conventional I-OFDR approaches. The systems are based on a pair of modulators that are synchronized to perform modulation and homodyne downconversion at a reference frequency of 25.5 kHz. In the first system, we attain centimeter resolution with a sensitivity down to −90 dB using the modulation frequency range comprised between 3.2 and 14.2 GHz. In the second, we measured, for the first time using this approach, Rayleigh backscattering traces in standard single mode fiber with resolution of 6 m and a sensitivity of −83 dB by use of the 10.1–30.1 MHz range. These results show the feasibility of these simple, homodyne downconversion I-OFDR systems as compact interrogators for distributed or quasi-distributed optical fiber sensors.

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“…This method requires an extra tube as the substrate for each cable, which occupies more channel space if it is to be integrated into the continuum manipulator. Pattanshetti et al 41 and Karthikeyan 42 integrated a PM-FBG fibre 43 with a pre-tensioned Kevlar fibre to accomplish the sensorised tendons with a steerable needle for force sensing and the preliminary results successfully validated the effectiveness. It requires the bonding of the PM-FBG fibre and Kevlar fibre, which leaves smaller space inside the needle's inner lumen.…”

Section: Literature Reviewmentioning

confidence: 99%

Laser-Profiled Continuum Robot with Integrated Tension Sensing for Simultaneous Shape and Tip Force Estimation

et al. 2020

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The development of miniaturised continuum robots has a wide range of applications in minimally invasive endoluminal interventions. In order to navigate inside tortuous lumens without impinging on the vessel wall and causing tissue damage or the risk of perforation, it is necessary to have simultaneous shape sensing of the continuum robot and its tip contact force sensing with the surrounding environment. Miniaturisation and size constraint of the device have precluded the use of conventional sensing hardware and embodiment schemes. In this paper, we propose the use of optical fibres for both actuation and tension/shape/force-sensing. It uses a model-based method with structural compensation, allowing direct measurement of the cable tension near the base of the manipulator without increasing the dimensions. It further structurally filters out disturbances from the flexible shaft. In addition, a model is built by considering segment differences, cable interactions/cross talks and external forces. The proposed model-based method can simultaneously estimate the shape of the manipulator and external force applied onto the robot tip. Detailed modelling and validation results demonstrate the accuracy and reliability of the proposed method for the miniaturised continuum robot for endoluminal intervention.

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Interrogation and mitigation of polarization effects for standard and birefringent FBGs

Cited by 6 publications

References 13 publications

Design challenges of a tunable laser interrogator for geo-stationary communication satellites

Design challenges of a tunable laser interrogator for geo-stationary communication satellites

Incoherent Optical Frequency-Domain Reflectometry Based on Homodyne Electro-Optic Downconversion for Fiber-Optic Sensor Interrogation

Laser-Profiled Continuum Robot with Integrated Tension Sensing for Simultaneous Shape and Tip Force Estimation

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