Triple coding empowered FDMA-CDMA mode high-security CAOS camera.

For the first time, to the best of our knowledge, the hybrid triple coding empowered frequency division multiple access (FDMA)-code division multiple access (CDMA) mode of the coded access optical sensor (CAOS) camera is demonstrated. Compared to the independent FDMA and CDMA modes, the FDMA-CDMA mode has a novel high-security space-time-frequency triple signal encoding design for robust, faster, linear irradiance extraction at a moderately high dynamic range (HDR). Specifically, this hybrid mode simultaneously combines the linear HDR strength of the FDMA-mode fast Fourier transform (FFT) digital signal processing (DSP)-based spectrum analysis with the high signal-to-noise ratio (SNR) provided by the many simultaneous CAOS pixels' photodetection of the CDMA mode.

CAOS line camera.

Proposed and demonstrated is the coded access optical sensor (CAOS) line camera, a one-dimensional or line version of the two-dimensional (2D) digital-micromirror-device (DMD)-based CAOS camera. The proposed line camera design includes a precise dual-axis mirror scanning galvo system incorporating feedback control that eliminates the need for mechanical motion of either the camera or the target. CAOS line scan imaging experiments using a white light source with two test targets are conducted and compared with non-scan 2D CAOS imaging.

Laser beam imaging via multiple mode operations of the extreme dynamic range CAOS camera.

Demonstrated for the first time, to the best of our knowledge, is laser beam imaging via multiple mode operations of the digital micro-mirror device-based coded access optical sensor (CAOS) camera. Specifically, outlined are novel modes of software programmable CAOS imaging, which include the time division multiple access (TDMA) mode, the code division multiple access (CDMA) mode, the CDMA-TDMA mode, the frequency division multiple access (FDMA)-TDMA mode, the frequency modulation (FM)-CDMA-TDMA mode, FM-TDMA mode, and the FDMA-CDMA-TDMA mode. Engagement of FDMA and CDMA modes enables simultaneous multi-pixel improved signal-to-noise ratio photo detection, while use of TDMA prevents optical point detector saturation.

Optics in Ireland: introduction to the feature issue.

This feature issue provides a snapshot of some of the applied optics and photonics related research and development activities currently taking place across Ireland. The issue contains some thirty papers, including contributions from universities and institutes of technology research groups, state research laboratories and institutes, and commercial companies.

Demonstration of the CDMA-mode CAOS smart camera.

Demonstrated is the code division multiple access (CDMA)-mode coded access optical sensor (CAOS) smart camera suited for bright target scenarios. Deploying a silicon CMOS sensor and a silicon point detector within a digital micro-mirror device (DMD)-based spatially isolating hybrid camera design, this smart imager first engages the DMD starring mode with a controlled factor of 200 high optical attenuation of the scene irradiance to provide a classic unsaturated CMOS sensor-based image for target intelligence gathering. Next, this CMOS sensor provided image data is used to acquire a focused zone more robust un-attenuated true target image using the time-modulated CDMA-mode of the CAOS camera.

Laser display system for multi-depth screen projection scenarios.

Proposed is a laser projection display system that uses an electronically controlled variable focus lens (ECVFL) to achieve sharp and in-focus image projection over multi-distance three-dimensional (3D) conformal screens. The system also functions as an embedded distance sensor that enables 3D mapping of the multi-level screen platform before the desired laser scanned beam focused/defocused projected spot sizes are matched to the different localized screen distances on the 3D screen. Compared to conventional laser scanning and spatial light modulator (SLM) based projection systems, the proposed design offers in-focus non-distorted projection over a multi-distance screen zone with varying depths.

Demonstration of 136 dB dynamic range capability for a simultaneous dual optical band CAOS camera.

For the first time, proposed and demonstrated is a simultaneous dual optical band coded access optical sensor (CAOS) camera design suited for extreme contrast multispectral bright target scenarios. Deploying a digital micromirror devices (DMDs)-based time-frequency agile pixels CAOS-mode within a two point detector spatially and spectrally isolating framework, this imager simultaneously and independently detects pixel selective image information for two different broad spectral bands that further undergo independent spectral image data extraction via finer-tuned wavelength filtering using all-optical or CAOS-mode electronic filters. A proof-of-concept visible-near infrared band CAOS imager is successfully demonstrated using a target scene containing LEDs and engaging narrowband optical filters.

CAOS-CMOS camera.

Proposed and experimentally demonstrated is the CAOS-CMOS camera design that combines the coded access optical sensor (CAOS) imager platform with the CMOS multi-pixel optical sensor. The unique CAOS-CMOS camera engages the classic CMOS sensor light staring mode with the time-frequency-space agile pixel CAOS imager mode within one programmable optical unit to realize a high dynamic range imager for extreme light contrast conditions. The experimentally demonstrated CAOS-CMOS camera is built using a digital micromirror device, a silicon point-photo-detector with a variable gain amplifier, and a silicon CMOS sensor with a maximum rated 51.

Multi-image acquisition-based distance sensor using agile laser spot beam.

We present a novel laser-based distance measurement technique that uses multiple-image-based spatial processing to enable distance measurements. Compared with the first-generation distance sensor using spatial processing, the modified sensor is no longer hindered by the classic Rayleigh axial resolution limit for the propagating laser beam at its minimum beam waist location. The proposed high-resolution distance sensor design uses an electronically controlled variable focus lens (ECVFL) in combination with an optical imaging device, such as a charged-coupled device (CCD), to produce and capture different laser spot size images on a target with these beam spot sizes different from the minimal spot size possible at this target distance.

Smart laser scanning sampling head design for image acquisition applications.

A smart laser scanning sampling head design is presented using an electronically controlled variable focal length lens to achieve the smallest sampling laser spot possible at target plane distances reaching 8 m. A proof-of-concept experiment is conducted using a 10 mW red 633 nm laser coupled with beam conditioning optics that includes an electromagnetically actuated deformable membrane liquid lens to demonstrate sampling laser spot radii under 1 mm over a target range of 20-800 cm. Applications for the proposed sampling head are diverse and include laser machining and component inspection.

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.

Electronically controlled agile lens-based broadband variable photonic delay line for photonic and radio frequency signal processing.

To the best of our knowledge, proposed for the first time is the design of an optically broadband variable photonic delay line (VPDL) using an electronically controlled variable focus lens (ECVFL), mirror motion, and beam-conditioned free-space laser beam propagation. This loss-minimized fiber-coupled VPDL design using micro-optic components has the ability to simultaneously provide optical attenuation controls and analog-mode high-resolution (subpicoseconds) continuous delays over a moderate (e.g.

Motion-free hybrid design laser beam propagation analyzer using a digital micromirror device and a variable focus liquid lens.

To the best of our knowledge, we propose the first motion-free laser beam propagation analyzer with a hybrid design using a digital micromirror device (DMD) and a liquid electronically controlled variable focus lens (ECVFL). Unlike prior analyzers that require profiling the beam at multiple locations along the light propagation axis, the proposed analyzer profiles the beam at the same plane for multiple values of the ECVFL focal length, thus eliminating beam profiler assembly motion. In addition to measuring standard Gaussian beam parameters, the analyzer can also be used to measure the M(2) beam propagation parameter of a multimode beam.

Smart agile lens remote optical sensor for three-dimensional object shape measurements.

We demonstrate what is, to the best of our knowledge, the first electronically controlled variable focus lens (ECVFL)-based sensor for remote object shape sensing. Using a target illuminating laser, the axial depths of the shape features on a given object are measured by observing the intensity profile of the optical beam falling on the object surface and tuning the ECVFL focal length to form a minimum beam spot. Using a lens focal length control calibration table, the object feature depths are computed.

Direct measurement high resolution wide range extreme temperature optical sensor using an all-silicon carbide probe.

We propose and demonstrate a temperature sensing method using an all-silicon carbide probe that combines wavelength-tuned signal processing for coarse measurements and classical Fabry-Perot etalon peak shift for fine measurements. This method gives direct unambiguous temperature measurements with a high temperature resolution over a wide temperature range. Specifically, temperature measurements from room temperature to 1000 degrees C are experimentally demonstrated with an estimated resolution varying from 0.

Noncontact distance sensor using spatial signal processing.

To the best of our knowledge, proposed is the first distance-measurement sensor using direct spatial signal processing. The sensor is implemented using a laser beam engaged in target-dependent spatial beam processing using an electronically controlled variable focus lens (ECVFL). Specifically, the target-reflected beam is observed by an optical detector while electronically scanning the focal length of the ECVFL in the path of the laser beam.

High-dynamic-range hybrid analog-digital control broadband optical spectral processor using micromirror and acousto-optic devices.

For the first time, to the best of our knowledge, the design and demonstration of a programmable spectral filtering processor is presented that simultaneously engages the power of an analog-mode optical device such as an acousto-optic tunable filter and a digital-mode optical device such as the digital micromirror device. The demonstrated processor allows a high 50 dB attenuation dynamic range across the chosen 1530-1565 nm (~C band). The hybrid analog-digital spectral control mechanism enables the processor to operate with greater versatility when compared to analog- or digital-only processor designs.

Silicon-carbide-based extreme environment temperature sensor using wavelength-tuned signal processing.

A wavelength-tuned signal-processing approach is proposed for enabling direct unambiguous temperature measurement in a free-space targeted single-crystal silicon carbide (SiC) temperature sensor. The approach simultaneously exploits the 6H SiC fundamental Sellmeier equation-based wavelength-sensitive refractive index change in combination with the classic temperature-dependent refractive index change and the material thermal-expansion path-length change to encode SiC chip temperature with wavelength. Presently, the technique is useful for fast coarse temperature measurement as demonstrated from room temperature to 1000 degrees C using a 10-peak count wavelength-tuned measurement with a 0.

Smart value-added fiber-optic modules using spatially multiplexed processing.

Intelligent fiber-optic value-added modules (VAMs) are proposed using what we believe to be a novel spatially multiplexed processing technique implemented with both reconfigurable and nonreconfigurable predesigned pixels per impinging beam that enables desired optical power split states needed for realizing a two state reconfigurable VAM. The preferred design uses broadband micromirrors such as ones fabricated via optical microelectromechanical systems technology. The basic VAM design uses two broadband micromirror pixels, where each pixel has its specific location and area and only one of these pixels is electrically driven to adjust its small tilt angle.

Compact tunable microwave filter using retroreflective acousto-optic filtering and delay controls.

Programmable broadband rf filters are demonstrated using a compact retroreflective optical design with an acousto-optic tunable filter and a chirped fiber Bragg grating. This design enables fast 34 micros domain analog-mode control of rf filter time delays and weights. Two proof-of-concept filters are demonstrated including a two-tap notch filter with >35 dB notch depth and a four-tap bandpass filter.

Wide-aperture no-moving-parts optical beam profiler using liquid-crystal displays.

To the best of our knowledge, we demonstrate the first no-moving-parts largest aperture profiler design that is also cost effective. Specifically exploited is the large-scale production of thin-film transistor liquid-crystal displays (LCDs) to produce a high intrinsic reliability low-cost profiler. Today, the maximum beam diameter under test can reach 70 cm using 117 cm diagonal LCDs.

Optoelectronic approach to adaptive radio-frequency transversal filter implementation with negative coefficients by using optical spectrum shaping.

A multitap negative and positive coefficient radio-frequency transversal filter is implemented by using a digital-micromirror-device spatial light modulator for weighting-factor control and a chirped fiber Bragg grating for time-delay control. The demonstrated architecture is reconfigurable, has high speed and low loss, and is robust through digital programmability for a wide variety of filtering algorithms. A design using an interleaver for differential detection realizes an ultrahigh bandwidth with a maximum processable frequency of 33.

Bulk acousto-optic wavelength agile filter module for a wavelength-multiplexed optical scanner.

An acousto-optic tunable filter-based wavelength-selection module with features optimized for a wavelength-multiplexed optical scanner (W-MOS) is proposed and demonstrated. The W-MOS produces high-speed multiple scan beams if it is engaged with an agile tunable source with multiwavelength generation capability. In particular, the proposed fiber-connected module features high-speed, low-loss, narrow-linewidth, and single-multiple wavelength selection by means of radio frequency drive signal control for single- or multiple-beam scan operations.

Fiber-optic tunable multiwavelength variable attenuator and routing module designs that use bulk acousto-optics.

A compact fiber-coupled bulk acousto-optical multiwavelength variable optical attenuator module design that uses a retroreflective double-pass geometry within a single bulk acousto-optic tunable filter device is presented. The proposed attenuator module demonstrates a high 17-dB notch dynamic range at a low 100-mW drive power and uses a single bulk collinear-interaction acousto-optic tunable-filter device. Experiments show a low (<1.

Liquid-crystal-deflector based variable fiber-optic attenuator.

A compact, low-component-count, no-moving-parts variable optical attenuator (VOA) is demonstrated for the first time by means of beam spoiling that is implemented via an electrically reconfigurable nonpixelated nematic liquid-crystal deflector. The VOA design features an in-line alignment polarization-insensitive design that does not use bulky polarization splitting and combining optics. The proof-of-concept VOA at 1550 nm demonstrates a 30-dB attenuation range, a 2.