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Sagnac interferometer including a recirculating ring with an erbium-doped fibre amplifier

Kringlebotn, J.T., Blotekjaer, K. and Pannell, C.N. (1992) Sagnac interferometer including a recirculating ring with an erbium-doped fibre amplifier In Proceedings of 8th Optical Fiber Sensors Conference. Institute of Electrical and Electronics Engineers., pp. 6-9. (doi:10.1109/OFS.1992.762937).

Record type: Conference or Workshop Item (Paper)


The use of a Sagnac interferometer as an acoustic sensor has recently been demonstrated [1]. One reason for using a Sagnac interferometer is that the path imbalance is zero, such that no interferometric conversion of the source phase noise to intensity noise occurs. The low frequency response of a Sagnac interferometer increases with increasing loop length, and a very long length of fibre is needed to achieve high responsivity for acoustical frequencies. In this paper we present a scheme where we enhance the low frequency response using a recirculating ring within the Sagnac loop, as shown in fig. 1, thereby increasing the effective length of the Sagnac loop. To increase the number of recirculations an erbium-doped fibre amplifier is incorporated in the ring to compensate for both the coupling and the intrinsic losses of the ring. We also present the results of a noise analysis of a recirculating ring including a fibre amplifier, and show that the dominating noise in our sensor is the beat noise between the signal and the spontaneous emission produced by the fibre amplifier

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Published date: 1992
Additional Information: Paper W1.2
Venue - Dates: 8th Optical Fibre Sensors Conference, United States, 1992-01-01


Local EPrints ID: 77365
ISBN: 0-7803-0518-3
PURE UUID: d2f22fe7-ccaf-490e-92ad-9f87e57592b7

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Date deposited: 11 Mar 2010
Last modified: 18 Jul 2017 23:33

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Author: J.T. Kringlebotn
Author: K. Blotekjaer
Author: C.N. Pannell

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