Showing papers by "Jong H. Chow published in 2011"
TL;DR: This work presents what it believes to be the first demonstration of DI's signal multiplexing capabilities, showing simultaneous length sensing of three sections of an optical fiber.
Abstract: This research was supported by the Australian
Research Council Discovery Projects funding scheme
(project number DP0986003).
23 citations
15 May 2011
TL;DR: In this article, the authors demonstrate the use of digitally enhanced interferometry for the interrogation of a multi-element sensing system and obtain sub-frequency noise displacement resolution without the need for high performance sensors.
Abstract: The resolution of fiber optic interferometry sensors is often limited by frequency noise in the laser. For this reason, prestabilization
techniques have been used to reduce laser frequency fluctuations and improve signal resolution. However,
for multi-element systems this becomes cumbersome and difficult to implement. In this paper, we demonstrate the use of
digitally-enhanced interferometry for the interrogation of a multi-element sensing system. Over 50 dB of cross-talk
rejection was found, with displacement resolutions of ~ 100 pm. Furthermore, using this technique, sub-frequency noise
displacement resolution was obtained without the need for high performance sensors.
28 Aug 2011
TL;DR: In this paper, the phase and magnitude of the feedback system which is used to lock a resonant cavity to a pre-stabilised laser are manipulated to study the cavity system in the optical damping and/or optical spring regimes.
Abstract: In this experiment, we actively manipulate the phase and magnitude of the feedback system which is used to lock a resonant cavity to a pre-stabilised laser. By doing so, we can freely modify the effective optical spring to study the cavity system in the optical damping and/or optical spring regimes.
15 May 2011
TL;DR: In this article, a DFB CW diode laser is locked to a fiber Fabry-Perot sensor, transferring the detected signals onto the laser frequency and suppressing laser frequency noise, then read off using an H 13 C 14 N absorption line.
Abstract: Steady developments in cost and reliability in fiber optic sensors have seen an increase of their deployment in numerous
monitoring and detection applications. In high-end applications, greater resolution is required, especially in systems
where the environment is quiet, but the signal is weak. In order to meet these requirements the most dominant noise
source, laser frequency noise, must be reduced. In this paper we present a quasi-static strain sensing referenced to a
molecular frequency reference. A DFB CW diode laser is locked to a fiber Fabry-Perot sensor, transferring the detected
signals onto the laser frequency and suppressing laser frequency noise. The laser frequency is then read off using an
H 13 C 14 N absorption line. Phase modulation spectroscopy is used to both lock the laser to the sensor and read off the
signals detected by the sensor. The technique is capable of resolving signals below 1 nanostrain from 20 mHz, reaching a
white noise floor of 10 picostrain at several Hz.