Browsing by Author "Uyar, Faruk"

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94.8 Km-Range Direct Detection Fiber Optic Distributed Acoustic Sensor
(IEEE, 345 E 47TH ST, NEW YORK, NY 10017 USA, 01.01.2019) Uyar, Faruk; Onat, Talha; Unal, Canberk; Unal, Canberk; Ozdur, Ibrahim; Ozbay, Ekmel; 0000-0003-3552-1650; AGÜ, Mühendislik Fakültesi, Elektrik - Elektronik Mühendisliği Bölümü
This work demonstrates an ultra-long range direct detection fiber optic distributed acoustic sensor which can detect vibrations at a distance of 94.8 km with 10 m resolution along the sensing fiber. (C) 2019 The Author(s)
A Direct Detection Fiber Optic Distributed Acoustic Sensor With a Mean SNR of 7.3 dB at 102.7 km
(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA, 2019) Uyar, Faruk; Onat, Talha; Unal, Canberk; Kertelog, Tolga; Ozbay, Ekmel; Ozdur, Ibrahim; AGÜ, Mühendislik Fakültesi, Elektrik & Elektronik Mühendisliği Bölümü;
In this work, we present the experimental results of a direct detection phi-OTDR based distributed acoustic sensor system. The system uses two cascaded acousto-optic modulators in order to generate optical pulses with very high extinction ratio and dual photodetector scheme for high dynamic range. The proposed schemes are investigated in detail and their performance enhancement is experimentally verified. Four piezoelectric based fiber stretchers are placed on a similar to 104 km single-mode test fiber at the distances of 1 km, 10 km, 87 km and 102.7 km and used for perturbation tests. The stretchers generated vibration signals which are analyzed to quantify the system performance. The signal-to-noise ratio (SNR) of vibration signals at the monitored distances is measured over the 12-hour recorded data within 34-second time windows considering the multi-point random interference of scattered light and fading phenomena. Using the 12-hour data, SNR histograms at four different locations are generated and mean SNR values are obtained. The signals received from 102.7 km has a maximum SNR of 24.7 dB and a mean SNR of 7.3 dB with a spatial resolution of 15 m. To the best of our knowledge, this is the highest-range reported direct detection phi-OTDR based distributed acoustic sensor system.
Experimental Analysis of Non-linear Phenomena due to Perturbation Amplitude in φ-OTDR Based Fiber Optic Distributed Vibration Sensor
(Optica Publishing Group (formerly OSA), 2020) Uyar, Faruk; Kartaloǧlu, Tolga; Ozbay, Ekmel; Ozdur, Ibrahim Tuna; AGÜ, Mühendislik Fakültesi, Elektrik - Elektronik Mühendisliği Bölümü; Ozdur, Ibrahim Tuna
We experimentally analyze the non-linearity effect due to the perturbation amplitude in the φ-OTDR based fiber optic distributed vibration sensor by investigating the effects of large disturbance signal.
Field Test and Fading Measurement of a Distributed Acoustic Sensor System over a 50 km-long Fiber
(SPIE-INT SOC OPTICAL ENGINEERING, 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA, 2018) Uyar, Faruk; Kartaloglu, Tolga; Ozdur, Ibrahim; Ozbay, Ekmel; AGÜ, Mühendislik Fakültesi, Elektrik & Elektronik Mühendisliği Bölümü;
In this study, we present a direct detection distributed acoustic sensor based on phase-sensitive optical time domain reflectometer (phi-OTDR) with long sensing range and high signal-to-noise ratio (SNR), which is field-tested over a 50 km-long fiber. Due to the random nature of Rayleigh backscattered light and fading phenomena, it is hard to characterize the performance of the system. For this reason, the performance of our sensor is specified in a statistical manner in which the mean SNR is determined using the histograms of the SNR. The SNR values are measured for identical acoustic signals in five different days, total of 48 hours and the SNR histograms are obtained for fiber distances of 100 m, 12 km, 21 km, 30 km, 40 km and 50 km. The system is field-tested using external disturbances that are generated from a 50-Hz vibrator. The SNR values are extracted from the power spectral density (psd) of the collected data over the monitored fiber span. Our results show that the phi-OTDR system exhibits a mean SNR of 22.5 dB at 50 km distance.
The Investigation of Rayleigh Backscattered Signal Statistics in a phi-OTDR System Incorporating Optical Pre-Amplifier
(IEEE, 345 E 47TH ST, NEW YORK, NY 10017 USA, 2020) Uyar, Faruk; Kartaloglu, Tolga; Ozbay, Ekmel; Ozdur, Ibrahim; AGÜ, Mühendislik Fakültesi, Elektrik - Elektronik Mühendisliği Bölümü
We theoretically model and experimentally demonstrate the photon statistics of Rayleigh backscattered signal in a phi-OTDR based distributed fiber optical sensor in the presence of amplified spontaneous emission noise caused by optical pre-amplifier.
Performance Analysis of Specialty Fiber Optic Cables for Distributed Acoustic Sensing
(Optica Publishing Group (formerly OSA), 2020) Uyar, Faruk; Kartaloǧlu, Tolga; Erol, Mustafa; Özbay, Ekmel; Ozdur, Ibrahim Tuna; 0000-0001-6452-0804; AGÜ, Mühendislik Fakültesi, Elektrik - Elektronik Mühendisliği Bölümü; Ozdur, Ibrahim Tuna
In this work, we present the signal-to-noise ratio comparison results of six different buried fiber optic cable for identical external perturbations using a home-made direct detection φ-OTDR system.
A Simple Method for Enhancing the SNR in Direct Detection (p-OTDR based Distributed Acoustic Sensors
(IEEE, 345 E 47TH ST, NEW YORK, NY 10017 USA, 2020) Uyar, Faruk; Kartaloglu, Tolga; Unal, Canberk; Ozbay, Ekmel; Ozdur, Ibrahim; AGÜ, Mühendislik Fakültesi, Elektrik - Elektronik Mühendisliği Bölümü
A simple and effective method for increasing the SNR and range in fp-OTDR based direct -detection distributed acoustic sensors is proposed and experimentally verified. The proposed method results in 11 dB SNR improvement at 66 km. (fD 2020 The Author(s)