The condition of lubricating oil used in automotive and industrial gearboxes must be controlled in order to guarantee optimum performance and prevent damage to machinery parts. In normal practice, this is done by regular oil change intervals and routine laboratory analysis, both of which involve considerable operating costs. In this paper, we present a compact and robust optical sensor that can...

All pass filters (APFs) are used in dispersion compensation which is the foremost requirement in an optical fiber link. All pass filters can correct any order of dispersion by the careful design of multistage all pass filters starting from very simple components with the use of N port devices. Multiple channels, as in wavelength division multiplexed (WDM) system, can be compensated with a singl...

The point spread function (PSF) of aberrated optical system apodized with Hanning and Lanczos amplitude filters has been determined. The influence of phase mask also considered for various zones of the aperture. For this study rotationally symmetric coherent optical system has been considered. INTRODUCTION Coherent illumination of the object is essential in order to get narrow bandwidth spectra...

We report on the formulation and electrical control of the position and bandwidth of reflective bandpass filters prepared from cholesteric liquid crystal (CLC) in the infrared (3-5 μm). These filters are prepared from alignment cells employing infrared transparent electrodes and substrates. The optical nature of the electrodes is shown to strongly influence the resulting transmission of the ban...

Solid-spaced filters are composed of one or several thin wafers of excellent optical quality acting as Fabry-Perot spacer layers. We study the different steps of the design and the manufacture of filters following dense-wavelength-division-multiplexing specifications. The design method of such filters requires a tight synergy between numerical simulations and experimental characterizations to c...

We developed a new method aimed at designing short-pass filters, long-pass filters and filters blocking sidebands of Fabry-Perot bandpasses. The method is an automated version of a non-straightforward empirical approach invented as a result of many years' experience in design and production of optical coatings. The method allows obtaining near-quarter-wave solutions in a few seconds. In many ca...

The Hough transform is a powerful feature extraction algorithm transforming parametric curves of objects into a smaller feature space called the parameter domain. Optical implementation of the Hough transform by space-variant holographic filters is discussed, and a computer controlled system for generating such filters is described. Employing this system, filters for images of space bandwidth p...

All Semrock filters are proven to be exceptionally durable and environmentally reliable, even in hot and high-humidity conditions, and are capable of withstanding high optical intensities. Semrock filters either have laser damage threshold (LDT) specifications, or, depending on the application, have been tested with intense broadband sources for extended periods of time with no noticeable degra...

The paper analyses the selected optical parameters of protective optic filters used for protection of the eyes against hazardous radiation within the visible (VIS) and near infrared (NIR) spectrum range. The indexes characterizing transmission and reflection of optic radiation incident on the filter are compared. As it follows from the completed analysis, the newly developed interference filter...

In this review paper we showcase recent activities on silicon photonics science and technology research in Hong Kong regarding two important topical areas — microresonator devices and optical nonlinearities. Our work on silicon microresonator filters, switches and modulators have shown promise for the nascent development of on-chip optoelectronic signal processing systems, while our studies on ...