Publications de Malak Mohamed Hossameldeen Omar Mohamed Galal

[Erratum] Study of backward Brillouin scattering in gas-filled anti-resonant fibers (vol 8, 086104, 2023)

Luc Thévenaz, Li Zhang, Malak Mohamed Hossameldeen Omar Mohamed Galal

AIP Publishing2025

Investigations on assembly and coverage for modular focal planes of multiplexed telescopes

Jean-Paul Richard Kneib, Malak Mohamed Hossameldeen Omar Mohamed Galal

Multiplexed surveys have the ambition to grow larger for the next generation of focal plane instruments.Future projects such as Spec-S5, MUST, and WST have an ever-growing need for multi-object spectroscopy (13,000-20,000 simultaneous objects) which demand ...

SPIE2024

Study on the possibility of Φ-OTDR sensing in hollow-core fibres

Luc Thévenaz, Malak Mohamed Hossameldeen Omar Mohamed Galal, Yuting Yang

The backscattering process in hollow core fibres shows a large similarity with Rayleigh scattering, offering the potential to be exploited for distributed sensing. A classical Φ-OTDR implementation is used to observe the backscattering signal from the surf ...

SPIE2023

New Avenues in Optical Fiber Sensing Using Gas

Luc Thévenaz, Flavien Gyger, Marcelo Alfonso Soto Hernandez, Li Zhang, Malak Mohamed Hossameldeen Omar Mohamed Galal, Yuting Yang

Gases turn out to be a very attractive medium for optical fiber sensing, showing highly flexible possibilities though widely unexploited so far. A new era opens for fiber sensing, exploiting the unprecedented potentialities of fluids. ...

Optica Publishing Group2023

Study of backward Brillouin scattering in gas-filled anti-resonant fibers

Luc Thévenaz, Li Zhang, Malak Mohamed Hossameldeen Omar Mohamed Galal

Brillouin scattering in gas shows unmatched gain properties in hollow-core optical fibers filled at high pressure. Here, the gain characteristics are studied for two common gases, namely, N2 and CO2, which show distinct features and are compared to expecte ...

2023

Analytical prediction of the final error due to noise in a ϕ-OTDR system

Luc Thévenaz, Li Zhang, Malak Mohamed Hossameldeen Omar Mohamed Galal, Suneetha Sebastian, Yuting Yang

An analytical expression to estimate the uncertainty on the frequency shift in ϕ-OTDR systems is established and confirmed by actual data. ...

Optica Publishing Group2022

Distributed Temperature Sensing Using Gas-filled Conjoined-tube Anti-resonant Fiber

Luc Thévenaz, Li Zhang, Malak Mohamed Hossameldeen Omar Mohamed Galal

Distributed temperature measurement is conducted for the first time in a gas-filled conjoined-tube hollow-core anti-resonant fiber (HC-CAF) at a pressure of 34.7 bar. A Brillouin gain of 0.08 m−1W−1 and a temperature sensitivity of 2 MHz/K are yielded. ...

Optica Publishing Group2022

Investigating Novel Optical Fibres for More Advanced Distributed Optical Fibre Sensing

Malak Mohamed Hossameldeen Omar Mohamed Galal

The ever-growing need for distributed optical fibre sensors (DOFS) in numerous fields and applications demands continuous research towards the advancement of the existing sensing systems. The convenience in the field of DOFS lies in the several degrees of ...

EPFL2022

Enhanced Signal-Associated Noise in a φ-OTDR System

Luc Thévenaz, Malak Mohamed Hossameldeen Omar Mohamed Galal, Suneetha Sebastian

Owing to their high sensitivity with respect to external measurands, Rayleigh-based distributed optical fiber sensors (DOFS) find their way into applications in many industrial and academic sectors. To further transcend the limit of these sensors in terms ...

2022

On the Measurement Accuracy of Coherent Rayleigh-based Distributed Sensors

Luc Thévenaz, Simon Adrien Zaslawski, Li Zhang, Malak Mohamed Hossameldeen Omar Mohamed Galal, Suneetha Sebastian

The phase change of back-scattered light due to external perturbations is retrieved in coherent Rayleigh-based distributed sensors by estimating the frequency shift (FS) between the traces of different measurements. The uncertainty associated with the esti ...

2021

Determination of the Measurement Accuracy of a Phase-sensitive OTDR

Luc Thévenaz, Zhisheng Yang, Malak Mohamed Hossameldeen Omar Mohamed Galal, Suneetha Sebastian

This paper presents the measurement accuracy of a phase-sensitive optical time-domain reflectometer (ϕ-OTDR) as a function of SNR and pulse width. A method to determine the absolute SNR of a ϕ-OTDR system is also proposed. ...

OSA2021

Distributed Temperature Sensing Based on φ-OTDR Using Back-reflection-enhanced Fiber

Luc Thévenaz, Li Zhang, Malak Mohamed Hossameldeen Omar Mohamed Galal, Suneetha Sebastian

Distributed temperature sensing with 10 dB back-reflection-enhanced fiber is performed based on φ-OTDR. While the temperature sensitivity of such fibers is similar to that of standard single-mode fibers, a 3-times higher temperature resolution is observed. ...

Optical Society of America2021

Distributed and dynamic strain sensing with high spatial resolution and large measurable strain range

Luc Thévenaz, Zhisheng Yang, Li Zhang, Malak Mohamed Hossameldeen Omar Mohamed Galal

A distributed and dynamic strain sensing system based on frequency-scanning phase-sensitive optical time domain reflectometry is proposed and demonstrated. By utilizing an RF pulse scheme with a fast arbitrary waveform generator, a train of optical pulses ...

2020