Torsion sensor based on a high-birefringent Sagnac loop interferometer

• Type: Article in International Conference Proceedings Book
• Date: 2011

Authors

Ferreira, MS (Author) Other; Silva, RM (Author) Other; Frazao, O (Author) FCUP

Conference proceedings International

Title: International Conference on Applications of Optics and Photonics

International Conference on Applications of Optics and Photonics

Braga, Portugal, 3 a 7 de Maio de 2011

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Other information

Authenticus ID: P-002-X8A

DOI: 10.1117/12.890514

Abstract (EN): In this work, a high-birefringent Sagnac loop interferometer torsion sensor is presented. The sensing head is inserted between the output ports of a high-birefringent coupler and it is formed by a section of standard single mode fiber. The sensing head characterization is done for torsion, temperature and strain measurements. The spectral response of this sensing head presents two interferometers, which are dependent on the light polarization states. Interference occurs due to the different lengths of the coupler output arms. This configuration allows the exclusion of a polarization controller, since it is possible to manipulate directly the polarization of light that travels inside the coupler. When the sensing head is subjected to torsion, it is possible to observe a beat between the two interferometers. In this case, there is a simultaneous pi/4 excitation of the two polarization states in the splices region. The torsion sensitivity is related to the sensing head length. The sensor response is periodic and the twist range can be from -2 pi to 2 pi. The sensor is unaffected by temperature and strain variations. This configuration is simple and when compared to the conventional configuration, the polarization controller is suppressed. The setup can be used in specific applications, such as in mechanical engineering.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6