High resolution wide dynamic range distance sensor using spatial signal processing

This paper presents a non-intrusive, non-contact object distance mapping sensor using an Electronically Controlled Variable Focus Lens (ECVFL). The proposed sensor is a free-space-based optical sensor that uses ECVFL-based agile optics to direct light from a object that requires terrain height mapping. The presented compact design makes the proposed sensor ideal for use in environments where laser illuminated objects are in a hazardous environment such as in environments with radiation, heat, cold, harmful machine parts, etc. The proposed design uses a few optical components and smart detection optics for making its object distance/terrain measurements. The presented sensor can find potential remote sensing applications in ground and space vehicle maneuvering, machine parts inspection and in chemical, transportation and aerospace industri

Multimode laser beam analyzer instrument using electrically programmable optics

Presented is a novel design of a multimode laser beam analyzer using a digital micromirror device (DMD) and an electronically controlled variable focus lens (ECVFL) that serve as the digital and analog agile optics, respectively. The proposed analyzer is a broadband laser characterization instrument that uses the agile optics to smartly direct light to the required point photodetectors to enable beam measurements of minimum beam waist size, minimum waist location, divergence, and the beam propagation parameter M(2). Experimental results successfully demonstrate these measurements for a 500 mW multimode test laser beam with a wavelength of 532 nm. The minimum beam waist, divergence, and M(2) experimental results for the test laser are found to be 257.61 mu m, 2.103 mrad, 1.600 and 326.67 mu m, 2.682 mrad, 2.587 for the vertical and horizontal directions, respectively. These measurements are compared to a traditional scan method and the results of the beam waist are found to be within error tolerance of the demonstrated instrument. (C) 2011 American Institute of Physics

Broadband fiber-optic 1x2 switch using an electrically controlled liquid lens

To the best of our knowledge, proposed is the first liquid lens technology-based 1x2 fiber optic switch using a single Electronically Controlled Variable Focus Lens (ECVFL). By controlling the focal length of the liquid ECVFL, the input optical beam is spatially adjusted to couple into the respective output fiber port. The switch demonstrates a 3-dB bandwidth of 175.67 nm, with a center frequency of 1550 nm, and features low power consumption suitable for mobile applications. The proposed switch can be useful in communication and control systems, in roadway sensor systems, vehicle detection systems, and monitoring systems

Power smart in-door optical wireless link design

Presented for the first time, to the best of the authors 'knowledge, is the design of a power smart in-door optical wireless link that provides lossless beam propagation between Transmitter (T) and Receiver (R) for changing link distances. Each T/R unit uses a combination of fixed and variable focal length optics to smartly adjust the laser beam propagation parameters of minimum beam waist size and its location to produce the optimal zero propagation loss coupling condition at the R for that link distance. An Electronically Controlled Variable Focus Lens (ECVFL) is used to form the wide field-of-view search beam and change the beam size at R to form a low loss beam. The T/R unit can also deploy camera optics and thermal energy harvesting electronics to improve link operational smartness and efficiency. To demonstrate the principles of the beam conditioned low loss indoor link, a visible 633 nm laser link using an electro-wetting technology liquid ECVFL is demonstrated for a variable 1 to 4 m link range. Measurements indicate a 53% improvement over an unconditioned laser link at 4 m. Applications for this power efficient wireless link includes mobile computer platform communications and agile server rack interconnections in data centres

Digital micromirror device-based robust object boundary mapping sensor

This paper presents a novel, non-intrusive, non-contact object boundary mapping sensor using a Digital Micromirror Device (DMD) and real-time pixel processing. The presented sensor is ideal for use in environments where brightly illuminated or radiating objects are in a hazardous environment such as in environments with radiation, heat, cold, harmful machine parts, etc. Experimental results demonstrate the boundary mapping sensor for a rectangular target and a multi-square target illuminated by visible wavelengths

A high-speed vertical transition for multi-layer A1N carrier boards designed by time-domain reflectometry

High density, high speed photonic integrated circuits (PICs) have large numbers of closely spaced DC and RF contacts, which must be connected in the package. The use of multilayer carrier boards to interface between the contacts and the package gives high performance and high density. In order to be effective as a packaging solution, these multi-layer carrier boards need high-speed electrical channels with good performance. Also, the boards usually need high thermal conductivity to manage the heat. Co-fired aluminium nitride (A1N) has the needed high thermal conductivity. However, there are no designs of multi-layer high-speed channels in the literature for co-fired A1N. Therefore, this article presents a high-speed multi-layer channel for co-fired A1N and its measured results. Two transmission lines were designed that showed a measured loss of Ë 0.09dBmm-1 at 40GHz. The vertical transition allows for arbitrary planar rotations of the channel and showed a measured 3 dB bandwidth of 33 GHz and small penalties in the eye diagram with a 44 Gbits-1 signal. The channels showed crosstalk below -30 dB

Novel smart modules for imaging, communications, and displays

This dissertation proposes and demonstrates novel smart modules to solve challenging problems in the areas of imaging, communications, and displays. The smartness of the modules is due to their ability to be able to adapt to changes in operating environment and application using programmable devices, specifically, electronically variable focus lenses (ECVFLs) and digital micromirror devices (DMD). The proposed modules include imagers for laser characterization and general purpose imaging which smartly adapt to changes in irradiance, optical wireless communication systems which can adapt to the number of users and to changes in link length, and a smart laser projection display that smartly adjust the pixel size to achieve a high resolution projected image at each screen distance. The first part of the dissertation starts with the proposal of using an ECVFL to create a novel multimode laser beam characterizer for coherent light. This laser beam characterizer uses the ECVFL and a DMD so that no mechanical motion of optical components along the optical axis is required. This reduces the mechanical motion overhead that traditional laser beam characterizers have, making this laser beam characterizer more accurate and reliable. The smart laser beam characterizer is able to account for irradiance fluctuations in the source. Using image processing, the important parameters that describe multimode laser beam propagation have been successfully extracted for a multi-mode laser test source. Specifically, the laser beam analysis parameters measured are the M2 parameter, w0 the minimum beam waist, and zR the Rayleigh range. Next a general purpose incoherent light imager that has a high dynamic range (>100 dB) and automatically adjusts for variations in irradiance in the scene is proposed. Then a data efficient image sensor is demonstrated. The idea of this smart image sensor is to reduce the bandwidth needed for transmitting data from the sensor by only sending the information which is required for the specific application while discarding the unnecessary data. In this case, the imager demonstrated sends only information regarding the boundaries of objects in the image so that after transmission to a remote image viewing location, these boundaries can be used to map out objects in the original image. The second part of the dissertation proposes and demonstrates smart optical communications systems using ECVFLs. This starts with the proposal and demonstration of a zero propagation loss optical wireless link using visible light with experiments covering a 1 to 4 m range. By adjusting the focal length of the ECVFLs for this directed line-of-sight link (LOS) the laser beam propagation parameters are adjusted such that the maximum amount of transmitted optical power is captured by the receiver for each link length. This power budget saving enables a longer achievable link range, a better SNR/BER, or higher power efficiency since more received power means the transmitted power can be reduced. Afterwards, a smart dual mode optical wireless link is proposed and demonstrated using a laser and LED coupled to the ECVFL to provide for the first time features of high bandwidths and wide beam coverage. This optical wireless link combines the capabilities of smart directed LOS link from the previous section with a diffuse optical wireless link, thus achieving high data rates and robustness to blocking. The proposed smart system can switch from LOS mode to Diffuse mode when blocking occurs or operate in both modes simultaneously to accommodate multiple users and operate a high speed link if one of the users requires extra bandwidth. The last part of this section presents the design of fibre optic and free-space optical switches which use ECVFLs to deflect the beams to achieve switching operation. These switching modules can be used in the proposed optical wireless indoor network. The final section of the thesis presents a novel smart laser scanning display. The ECVFL is used to create the smallest beam spot size possible for the system designed at the distance of the screen. The smart laser scanning display increases the spatial resoluti on of the display for any given distance. A basic smart display operation has been tested for red light and a 4X improvement in pixel resolution for the image has been demonstrated

Broadband 2 × 2 Free-Space Optical Switch Using Electronically Controlled Liquid Lenses

To the best of our knowledge, proposed is the first liquid lens technology-based 2 × 2 free-space optical switch using a pair of Electronically Controlled Variable Focus Lenses (ECVFLs). By independently controlling the focal lengths of two cascaded liquid ECVFLs, the two input optical beams are spatially adjusted to couple to their respective output beam ports. At 633-nm, the experimental switch demonstrates 26.3 dB crosstalk, 23.0 dB within-channel isolation, 1.1 dB optical loss, and 0.2 dB Polarization Dependent Loss (PDL). A 0.2 dB Wavelength Dependent Loss (WDL) is measured over 633-nm and 514-nm wavelengths. A 1 × 2 optical-fiber coupled switch version is also tested. The proposed switch can be useful in free-space laser systems as well as fiber-based modules. © 2010 Elsevier B.V

Multimode laser beam analyzer instrument using electrically programmable optics

Presented is a novel design of a multimode laser beam analyzer using a digital micromirror device (DMD) and an electronically controlled variable focus lens (ECVFL) that serve as the digital and analog agile optics, respectively. The proposed analyzer is a broadband laser characterization instrument that uses the agile optics to smartly direct light to the required point photodetectors to enable beam measurements of minimum beam waist size, minimum waist location, divergence, and the beam propagation parameter M(2). Experimental results successfully demonstrate these measurements for a 500 mW multimode test laser beam with a wavelength of 532 nm. The minimum beam waist, divergence, and M(2) experimental results for the test laser are found to be 257.61 mu m, 2.103 mrad, 1.600 and 326.67 mu m, 2.682 mrad, 2.587 for the vertical and horizontal directions, respectively. These measurements are compared to a traditional scan method and the results of the beam waist are found to be within error tolerance of the demonstrated instrument. (C) 2011 American Institute of Physics

Smart multiple-mode indoor optical wireless design and multimode light source smart energy-efficient links

We present the design of a smart multiple-mode indoor optical wireless system that combines line-of-sight (LOS) and non-LOS optical wireless methods to smartly adapt to changes in environment and application. The proposed design is able to operate in three optical wireless modes called directed LOS, non-directed LOS, and diffuse non-LOS. These modes smartly accommodate for changes in the number of users and their mobility, along with providing optimal light coverage area and increased robustness to receive light blocking. Experiments for the first time demonstrate the use of multimode light sources in the proposed smart links using electronically controlled variable focal length lenses. Specifically demonstrated is a visible 670-nm multimode laser-based directed LOS link with variable range of 0.2 to 1.5 m and a 650-nm LED-based nondirected LOS link with variable range of 0.2 to 1.1 m. Compared to nonsmart links, these smart links demonstrate an improvement in the received optical power of 1.7× and 2.1× for the laser and LED links, respectively