Course Description This is an advanced course in which we explore the field of Statistical Optics. Topics covered include such subjects as the statistical properties of natural (thermal) and laser light, spatial and temporal coherence, effects of partial coherence on optical imaging instruments, effects on imaging due to randomly inhomogeneous media, and a statistical treatment of the detection of light. Development of this more comprehensive model of the behavior of light draws upon the use of tools traditionally available to the electrical engineer, such as linear system theory and the theory of stochastic processes.

http://ieeexplore.ieee.org/iel5/3/23094/01073023.pdf

Statistical optics

We report on experimental studies of gas sensing using air-guiding photonic bandgap fibers. The photonic bandgap fibers have at one end been spliced to standard single mode fibers for ease of use and improved stability

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Gas sensing using air-guiding photonic bandgap fibers

We demonstrate evanescent-wave sensing of Cy5-DNA-molecules in an aqueous solution using a photonic crystal fiber. Less than 0.8µL sample volume placed in the holes of the fiber is sufficient for reliable detection.

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Photonic crystal fiber based evanescent-wave sensor for detection of biomolecules in aqueous solutions

We demonstrate highly efficient evanescent-wave detection of fluorophore-labeled biomolecules in aqueous solutions positioned in the air holes of the microstructured part of a photonic crystal fiber. The air-suspended silica structures located between three neighboring air holes in the cladding crystal guide light with a large fraction of the optical field penetrating into the sample even at wavelengths in the visible range. An effective interaction length of several centimeters is obtained when a sample volume of less than 1 µL is used.

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The development of microstructured fibres offers the prospect of improved fibre sensing for low refractive index materials such as liquids and gases. A number of approaches are possible. Here we present a new approach to evanescent field sensing, in which both core and cladding are microstructured. The fibre was fabricated and tested, and simulations and experimental results are shown in the visible region to demonstrate the utility of this approach for sensing.

Microstructured-core optical fibre for evanescent sensing applications.

We report the modeling results of an all-fiber gas detector that uses photonic crystal fiber (PCF). The relative sensitivity of the PCF as a function of the fiber parameters is calculated. Gas-diffusion dynamics that affect the sensor response time is investigated theoretically and experimentally. A practical PCF sensor aiming for high sensitivity gas detection is proposed.

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Design and modeling of a photonic crystal fiber gas sensor

Genetic algorithm is used to improve the performance of FBG sensors within in a wavelength-division multiplexed sensor network. Simulations and experiments demonstrated wavelength detection accuracy of a few microstrains even when the spectrums of FBGs within the network are partially or completely overlapped.

Improving the performance of a FBG sensor network using a genetic algorithm

A 3-component fiber-optic accelerometer for well logging

Adaptive simulated annealing algorithm for the fiber Bragg grating distributed strain sensing

A cantilever optical vibrometer using a fiber Bragg grating (FBG) is developed. The sensor head is made by attaching an FBG to a triangular beam to provide position-independent strain for the purpose of acceleration measurement. The vibrometer demonstrates a noise-limited acceleration resolution of 2.8×10 –4 √Hz with repeatability error of less than 2.4%.

C.Z. Shi

Papers

Design and modeling of a photonic crystal fiber gas sensor

Improving the performance of a FBG sensor network using a genetic algorithm

A 3-component fiber-optic accelerometer for well logging

Adaptive simulated annealing algorithm for the fiber Bragg grating distributed strain sensing

Cantilever optical vibrometer using fiber Bragg grating