Recent advances in the application of semiconductor nanocrystals, or quantum dots, as biochemical sensors are reviewed. Quantum dots have unique optical properties that make them promising alternatives to traditional dyes in many luminescence based bioanalytical techniques. An overview of the more relevant progresses in the application of quantum dots as… (More)
An integrated optical refractometer based on multimode interference, with sensitivity enhancement due to sub-micrometer axial features, is demonstrated with experimental sensitivity as high as 3200 nm/RIU and resolution limits on the order of 5 ppm.
This paper presents the implementation of an all-optical interferometric technique to optimize the detection of small coherent signals burried under the presence of a strong incoherent background noise. The influence of interferometer path-length imbalance, the coherence properties of the optical source and the sources of noise in an optical interferometer,… (More)
Semiconductor nanocrystals have unique optical properties that make them promising alternatives to traditional dyes in many luminescence based analytical techniques. An overview of the more relevant progresses in the application of quantum dots (QDs) as analytical probes in optical fibre sensing and imaging application will be addressed. Experimental… (More)
A novel combined fiber Bragg grating (FBG) and interferometric based quasi-distributed sensor network is proposed and simulated. The sensor network consists of a series of FBGs used as wavelength selective mirrors and overlapped Michelson interferometers working at different wavelengths in a Sagnac loop make it possible to measure the changes in between the… (More)
Wavelength multiplexing/demultiplexing devices are considered to be one of the key elements in optical networks. Here we propose a new class of wavelength MUX/DEMUX devices which are based on change in the geometry of the multimode interference (MMI) waveguide region. This modification enables us to optimize device performances for a given set of refractive… (More)
We present a closed-loop technique for measuring wavelength shifts associated with fiber Bragg gratings by using a fused biconical wavelength division multiplexer (WDM). The spectral response of the WDM is actively tuned by stretching of the coupling region to maintain a fixed coupling ratio at the reflected Bragg wavelength. The closed-loop operation… (More)