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Amplified OTDR systems for multipoint corrosion monitoring.

Nascimento JF, Silva MJ, Coêlho IJ, Cipriano E, Martins-Filho JF - Sensors (Basel) (2012)

Bottom Line: The sensor system is multipoint, self-referenced, has no moving parts and can measure the corrosion rate several kilometers away from the OTDR equipment.The first OTDR monitoring system employs a remotely pumped in-line EDFA and it is used to evaluate the increase in system reach compared to a non-amplified configuration.Our experimental results obtained under controlled laboratory conditions show the advantages of the amplified system in terms of longer system reach with better spatial resolution, and also that the corrosion measurements obtained from our system are not sensitive to 3 dB gain variations.

View Article: PubMed Central - PubMed

Affiliation: Polytechnic School of Pernambuco, University of Pernambuco (UPE), Recife, PE, Brazil. jehanfonseca@hotmail.com

ABSTRACT
We present two configurations of an amplified fiber-optic-based corrosion sensor using the optical time domain reflectometry (OTDR) technique as the interrogation method. The sensor system is multipoint, self-referenced, has no moving parts and can measure the corrosion rate several kilometers away from the OTDR equipment. The first OTDR monitoring system employs a remotely pumped in-line EDFA and it is used to evaluate the increase in system reach compared to a non-amplified configuration. The other amplified monitoring system uses an EDFA in booster configuration and we perform corrosion measurements and evaluations of system sensitivity to amplifier gain variations. Our experimental results obtained under controlled laboratory conditions show the advantages of the amplified system in terms of longer system reach with better spatial resolution, and also that the corrosion measurements obtained from our system are not sensitive to 3 dB gain variations.

No MeSH data available.


Multipoint corrosion sensor system (a) without and (b) with amplification (booster EDFA).
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f3-sensors-12-03438: Multipoint corrosion sensor system (a) without and (b) with amplification (booster EDFA).

Mentions: In order to verify the effects of the amplification scheme and the EDFA gain variations on the corrosion monitoring results we setup the configurations shown in Figure 3. It shows a multipoint corrosion sensor system without (Figure 3(a)) and with (Figure 3(b)), amplification. Differently from the configuration shown in Figure 1, where the amplifier is placed in line, among the sensor heads, in Figure 3 the amplifier is placed close to the OTDR, as booster to its signal, before the sensor heads. In the setup of Figure 3 we placed the 25 km long fiber reel between the sensor heads and the OTDR with EDFA arrangement. We choose arbitrarily the 5th sensor head to perform corrosion measurements. This sensor head has 39 nm of aluminum deposited on a cleaved fiber facet by a standard thermal evaporation process. We put an isolator at the end of the system (7th sensor head) to avoid its reflection back into the OTDR, which could cause OTDR saturation. We also had to use a 10 dB attenuator in the amplified system shown in Figure 3(b). This was to avoid the saturation of the OTDR, which is due to the high intensities reflected from the first sensor heads. This effect shows a clear disadvantage of this booster amplification scheme compared to the in line scheme shown in Figure 1(b). In the inline scheme the amplification takes place where the signal has low power, after several sensor heads, whereas in the booster scheme the amplification occurs close to the OTDR emission, where the signal has high power. The excess signal power reflected from the first sensor heads cause the OTDR saturation. Since a 10 dB attenuator corresponds to 50 km of standard single mode fiber (0.2 dB/km), the booster amplification scheme would be useful for ultra-long distances between OTDR and sensor heads.


Amplified OTDR systems for multipoint corrosion monitoring.

Nascimento JF, Silva MJ, Coêlho IJ, Cipriano E, Martins-Filho JF - Sensors (Basel) (2012)

Multipoint corrosion sensor system (a) without and (b) with amplification (booster EDFA).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376602&req=5

f3-sensors-12-03438: Multipoint corrosion sensor system (a) without and (b) with amplification (booster EDFA).
Mentions: In order to verify the effects of the amplification scheme and the EDFA gain variations on the corrosion monitoring results we setup the configurations shown in Figure 3. It shows a multipoint corrosion sensor system without (Figure 3(a)) and with (Figure 3(b)), amplification. Differently from the configuration shown in Figure 1, where the amplifier is placed in line, among the sensor heads, in Figure 3 the amplifier is placed close to the OTDR, as booster to its signal, before the sensor heads. In the setup of Figure 3 we placed the 25 km long fiber reel between the sensor heads and the OTDR with EDFA arrangement. We choose arbitrarily the 5th sensor head to perform corrosion measurements. This sensor head has 39 nm of aluminum deposited on a cleaved fiber facet by a standard thermal evaporation process. We put an isolator at the end of the system (7th sensor head) to avoid its reflection back into the OTDR, which could cause OTDR saturation. We also had to use a 10 dB attenuator in the amplified system shown in Figure 3(b). This was to avoid the saturation of the OTDR, which is due to the high intensities reflected from the first sensor heads. This effect shows a clear disadvantage of this booster amplification scheme compared to the in line scheme shown in Figure 1(b). In the inline scheme the amplification takes place where the signal has low power, after several sensor heads, whereas in the booster scheme the amplification occurs close to the OTDR emission, where the signal has high power. The excess signal power reflected from the first sensor heads cause the OTDR saturation. Since a 10 dB attenuator corresponds to 50 km of standard single mode fiber (0.2 dB/km), the booster amplification scheme would be useful for ultra-long distances between OTDR and sensor heads.

Bottom Line: The sensor system is multipoint, self-referenced, has no moving parts and can measure the corrosion rate several kilometers away from the OTDR equipment.The first OTDR monitoring system employs a remotely pumped in-line EDFA and it is used to evaluate the increase in system reach compared to a non-amplified configuration.Our experimental results obtained under controlled laboratory conditions show the advantages of the amplified system in terms of longer system reach with better spatial resolution, and also that the corrosion measurements obtained from our system are not sensitive to 3 dB gain variations.

View Article: PubMed Central - PubMed

Affiliation: Polytechnic School of Pernambuco, University of Pernambuco (UPE), Recife, PE, Brazil. jehanfonseca@hotmail.com

ABSTRACT
We present two configurations of an amplified fiber-optic-based corrosion sensor using the optical time domain reflectometry (OTDR) technique as the interrogation method. The sensor system is multipoint, self-referenced, has no moving parts and can measure the corrosion rate several kilometers away from the OTDR equipment. The first OTDR monitoring system employs a remotely pumped in-line EDFA and it is used to evaluate the increase in system reach compared to a non-amplified configuration. The other amplified monitoring system uses an EDFA in booster configuration and we perform corrosion measurements and evaluations of system sensitivity to amplifier gain variations. Our experimental results obtained under controlled laboratory conditions show the advantages of the amplified system in terms of longer system reach with better spatial resolution, and also that the corrosion measurements obtained from our system are not sensitive to 3 dB gain variations.

No MeSH data available.