New Spatial Optical Filters for Gas Refractometry

• Type: Article in International Conference Proceedings Book
• Date: 2012

Authors

Susana Silva (Author) Other; Coelho, L (Author) FCUP; Andre, RM (Author) Other; Frazao, O (Author) FCUP

Conference proceedings International

Title: 22ND INTERNATIONAL CONFERENCE ON OPTICAL FIBER SENSORS, PTS 1-3

22nd International Conference on Optical Fiber Sensors (OFS)

Beijing, PEOPLES R CHINA, OCT 15-19, 2012

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Other information

Authenticus ID: P-002-EEP

DOI: 10.1117/12.974991

Abstract (EN): A spatial optical filter based on splice misalignment between optical fibers with different cladding dimensions is proposed for gas refractometry. The sensing head is formed by a 2 mm-long optical fiber with 50 mu m diameter spliced with a strong misalignment between two single mode fibers (SMF28) and interrogated in transmission. This fiber structure causes a Fabry-Perot-behavior along the reduced-size fiber giving at its output end a well defined spatial filtering selectivity. Depending on the misalignment position of the lead-out SMF28, it is possible to obtain two different spectral responses, namely, bandpass or band-rejection filters. It is shown that this filter device is highly sensitive to refractive index changes on a nitrogen (N-2) environment by means of the gas pressure variation. A maximum sensitivity of -1390 nm/RIU for the bandpass filter was achieved.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 4