Showing papers by "Jong H. Chow published in 2006"
Patent•
18 Oct 2006TL;DR: In this article, an apparatus for interferometric sensing, comprising a plurality of single-longitudinal mode laser sources to each provide radiation at a corresponding plurality of selected wavelengths, and at least one modulator to frequency or phase modulate the radiation from each laser, is presented.
Abstract: An apparatus for interferometric sensing, comprising a plurality of single-longitudinal mode laser sources to each provide radiation at a corresponding plurality of selected wavelengths, and at least one modulator to frequency or phase modulate the radiation from each laser; a plurality of Fabry-Perot interferometers formed by Bragg Gratings written into optical fibre, each interferometer being responsive to one of the said plurality of wavelengths to each produce a reflected or transmitted optical output signal dependent on the corresponding interferometer path length; and one or more demodulators to demodulate the optical output signals and produce a corresponding plurality of measurement signals indicative of optical path lengths of the respective interferometers.
35 citations
TL;DR: It is shown that in reflection, the reduced fiber Fabry-Perot linewidth improves the remote system sensitivity to sub-picostrain resolution, which surpasses any other long-distance remote sensing system to date.
Abstract: When a fiber Fabry-Perot is used in an ultra-sensitive strain detection system via a radio-frequency interrogation scheme, its frequency discrimination properties can be enhanced by reducing the linewidth of its resonance. This increases the signal-to-noise ratio, and thus suppresses the strain equivalent noise floor. We demonstrate this improvement in a long-distance high performance remote sensing system and show that in reflection, it can mitigate the effects of random phase noise introduced by Rayleigh back-scattering. In transmission, it improves the remote system sensitivity to sub-picostrain resolution, which surpasses any other long-distance remote sensing system to date. With the reduced fiber Fabry-Perot linewidth, all noise sources in the delivery fiber become irrelevant, as the transmission system is limited only by the pre-stabilized laser frequency noise.
25 citations
TL;DR: The status of research and development being undertaken by the members of the Australian Consortium for Interferometric Gravitational Astronomy (ACIA) is reported in this article, where the authors report the status of their work.
Abstract: We report the status of research and development being undertaken by the members of the Australian Consortium for Interferometric Gravitational Astronomy.
17 citations
05 May 2006
TL;DR: In this article, the authors used a radiofrequency (RF) diode laser modulation technique to interrogate a fiber Fabry-Perot (FFP) and demonstrate unprecedented remote sensitivity performance for measuring fiber dynamic strain.
Abstract: We use a radio-frequency (RF) diode laser modulation technique to interrogate a fiber Fabry-Perot (FFP), and demonstrate unprecedented remote sensitivity performance for measuring fiber dynamic strain. We present results for its experimental demonstration in a 5 km remote strain sensing system, where we have attained sub-picostrain/√Hz resolution in an acoustic signal band from 100 Hz to 100 kHz, with better than 300 femtostrain/√Hz sensitivity above 300 Hz. This is unprecedented in sensitivity and broadband performance, unparalleled over such a long interrogation distance. Strain signals are extracted interferometrically from the differential phase between the carrier and its RF sidebands. This elegant architecture is immune to intensity noise in the laser, as well as ambient acoustic and mechanical perturbations in the remote delivery fiber. The excellent frequency discrimination by the FFP also facilitates a superior signal-to-noise ratio, to effectively overcome the random phase noise due to Rayleigh backscatter in the long length of fiber. Furthermore, the interrogation length can be well beyond the coherence length of the laser source. We show that this performance is limited only by the frequency noise of the diode laser source, as all systemic noise sources in the delivery fiber are effectively transparent to the sensing architecture. This remote sensitivity is a seminal demonstration for a range of applications, such as sea floor acoustic sensing arrays, deep sea hydrophone arrays, and remote surveillance. We will discuss upscaling of this single element experiment to multi-element sensing arrays.
6 citations
23 Oct 2006
TL;DR: By minimizing the fiber resonator linewidth, the authors in this paper achieved laser frequency noise-limited remote sensing in a 31 km transmission system and demonstrated sub-picostrain performance.
Abstract: We attain laser frequency noise-limited remote sensing in a 31 km transmission system and demonstrate sub-picostrain performance. By minimizing the fiber resonator linewidth, we optimize the SNR and overcome all delivery fiber noise sources.
2 citations
21 May 2006
TL;DR: In this paper, the authors demonstrate a remote fiber sensing system with broadband sub-picostrain resolution, which is enhanced by optimization of the fiber resonator design, such that its sensitivity is limited only by the pre-stabilized laser frequency noise.
Abstract: We demonstrate a remote fiber sensing system with broadband sub-picostrain resolution. Its performance is enhanced by optimization of the fiber resonator design, such that its sensitivity is limited only by the pre-stabilzed laser frequency noise.