dynamic light scattering at the scripps research institute

Dynamic light scattering at the scripps research institute series#

Using two or more fiber instances of the same cable may allow an increase in the SNR, e.g., by stacking each fiber’s instance measurements. The distortions are interpreted as signal saturation, and optical noise can reduce the chances of interpreting them.Ĭonventional telecom cables often have several fibers (12 to 80), but distributed fiber optic sensing methods only use one dedicated fiber. Despite this, both fibers can exhibit distortion in their signal due to strong motion events or high-frequency events, as there is a maximum measurable strain limited by survey configurations. It consists of setting precise scattered centers (imperfections) uniformly distributed along the fiber, which allows them to achieve up to 100× (20 dB) improved sensitivity compared to conventional standard fibers. While standard fibers are best designed to transmit information, engineered fibers are made to intensify back-scattered light while probing as much length as possible. In consequence, engineered fibers are made with the purpose of overcoming this challenge in DDSS deployments. However, some of the imperfections in the glass do not guarantee a uniform high-intensity scattering of the light, so it affects the dynamic range and introduces noise. Proper phase readings depend on the intensity of the back-scattered signal, and so does the signal-to-noise ratio (SNR). We present measurement strategies to increase the dynamic range and avoid saturation. Nevertheless, the algorithm can restore the strain-rate amplitude from saturated DDSS signals of the engineered fiber, allowing us to exceed the dynamic range of the record. Although stacking is able to reduce optical noise, it is not sufficient for restoring the strain-rate amplitude from saturated signals in standard fiber DDSS.

Dynamic light scattering at the scripps research institute series#

We also present an algorithm to correct artifacts in the time series that stem from dynamic range saturation. Our findings indicate that the stack of DDSS records from five standard fiber instances, each 1.5 km long, can reduce optical noise of up to 20%. We analyze how stacking can improve signal quality. Both cables were buried in an area located 2.5 km NE from the craters of Mt. In this study, we compare DDSS data from stack instances of standard multi-fiber cable with DDSS data from a co-located single-fiber engineered cable.

Nevertheless, standard fibers already have extensive coverage around the Earth’s surface, so it motivates the use of the existing infrastructure in DDSS surveys to avoid costs and logistics. A new generation of engineered fibers is being developed to improve sensitivity and reduce the noise floor in comparison to standard fibers, which are conventionally used in telecommunication networks. Distributed Dynamic Strain Sensing (DDSS), also known as Distributed Acoustic Sensing (DAS), is becoming a popular tool in array seismology.