A CMOS Infrared Optical Signal Processor for Remote Control

In the last few years, a considerable effort has been expended on the development of a number of both active and passive guided-wave devices, such as laser diodes, electrooptic modulators, acoustooptic transducers, photodetectors and microlens arrays, for optical signal processing applications including optical computing 1-3. Many simple optical devices can be easily fabricated by using mature and reproducible technologies. The interest in optical processors involving simple devices is mainly due to a lower power consumption, reduced size, cost and weight and high throughput with respect to the corresponding electronic processors. A number of guided-wave optical circuits for communications, signal processing and optical computing have been demonstrated using the acoustooptic, magnetooptic and electrooptic effects 4. Moreover, fields of application of particular interest are synthetic aperture radar (SAR), remote sensing and beam forming of linear array antennas, which are all well suited for optics-based processing because of the parallel processing allowed by optical architectures. Therefore, guided-wave optical processors can be successfully applied to the optical control of microwaves, to the reconstruction of two-dimensional images using both spatial and time integration, to data classification and identification in satellite applications and for performing a number of signal processing and optical computing functions.

Tracheal intubation is older than the recognized his-tory of general anesthesia itself. In the late 18th cen-tury, The Royal Humane Society of London used tra-cheal intubation for resuscitating the near-drowned.Approximately 100 years later, MacEwan (1) per-formed a digital tracheal intubation in an awake pa-tient before a chloroform and air general endotrachealanesthetic for the resection of a tongue tumor, and in1928, Magill (2) incorporated blind nasal tracheal in-tubation as a part of a general anesthetic. Althoughlaryngoscopes were invented in the 19th century, tra-cheal intubation under direct visualization was greatlyenhanced by the development of a special laryngo-scope blade by Macintosh (3) in 1943.The first reported use of a lighted stylet used tofacilitate intubation came in 1957 when (by now SirRobert) Macintosh (4) described an 18-inch illumi-nated tracheal tube introducer, which was designed tostiffen the tube and better illuminate the cords bysupplementing the light of the laryngoscope. Berman(5) described a similar device in 1959 and said it wasuseful “when the fickle light of the laryngoscope hasgone out at the most inopportune time.” In the sameyear, Yamamura et al. (6) described a light bulb-tippedwire that was inserted into the tracheal tube beforeblind nasal intubation in awake patients. The tubeposition was then determined by the medial transillu-mination of the external throat and neck.In 1977, Foster (7) used a transilluminating fiberop-tic bundle to facilitate tracheal intubation in a youngchild with trismus, and Ducrow (8), in the followingyear, used a flexible surgical light (Flexi-lum™, Con-cept Corporation, Clearwater, FL) to achieve the sameend by first passing a guide (two plastic suction cath-eters connected end-to-end) into the trachea followedby passage of the tracheal tube over the guide. In acorrespondence to the latter article, Rayburn (9) com-mented that the Flexi-lum™ could be positioned in-side the tracheal tube, thereby shortening the intuba-tion sequence and claimed that the technique,nicknamed “lightwand intubation,” had been used forsome years at the Brooke Army Medical Center.

This review article is the second of the comprehensive series on survey of the microwave photochemical and photocatalytic processes, and is focused specially on the microwave-assisted photochemical applications of the electrodeless discharge lamps (EDLs) in organic synthesis. The concept of microwave organic photochemistry is an important issue in synthetic chemistry and material science, and is presented in several schemes. Likewise, the various microwave photochemical reactor types (batch with external or internal light source, flow-through with external light source, annular flow-through with internal EDL, cylindrical flow-through surrounded with EDL, and mixed flow-through with internal EDL) with different arrangement of the lamps are described.

A bandpass microwave photonic filter based on an integrated optical signal processor is proposed and demonstrated by numerical sim- ulation. The optical signal processor consisting of double-bus-coupled and series-cascaded silicon microrings (MRs) is used to produce two bandpass responses to process optical carrier signal and sideband signal separately. Because of the tunability of MRs, variable −3 dB bandwidth and tunable operating frequency are achieved. The −3 dB bandwidth and operating frequency can be tuned from 1.5 to 12 GHz and from 15 to 34 GHz, respectively. The loss impact, tuning method, and fabrication error tolerance are also discussed. © 2013 Society of Photo-Optical Instrumentation

An optical crossbar interconnected signal processor, proposed previously, is reviewed. The ability to implement difficult -to-parallelize algorithms on this processor with reasonable efficiency is illustrated using optimal least square filtering. An inversefilter for removing the effects of a ringing source from reflected data is used as an example. A large number of Toeplitz matrixequations must be solved to determine the optimum inverse filter length and phase. Efficient parallel computation is required. Equations for Levinson's algorithm are provided and an implementation on the optical system is suggested. Performance estimates suggest that interleaving may be used to improve efficiency from 5% to approximately 30 %. Introduction An optical crossbar interconnected signal processor was proposed previously that has a large number of processing element.connected via optical fibers to an optical crossbar switch'''. A deformable mirror device is used to construct the crossbar switch.I previously showed how to efficiently implement basic signal processing algorithms such as an FFT, systolic filter, and matrix -

We have investigated an optical signal processor using electro-optic polymer waveguides operating at a wavelength of 1.55 mum. Due to recent developments, many useful optical devices have become available such as optical filters, modulators, switches, and multiplexers. It will be useful to have a single optical device, which is reconfigurable to implement all of these functions. We call such a device an ldquooptical signal processor,rdquo which will play a similar role to digital signal processors in electrical circuits. We realize such an optical device in a planar lightwave circuit. Since the planar lightwave circuits are based on the multiple interference of coherent light and can be integrated with significant complexity, they have been implemented for various purposes of optical processing such as optical filters. However, their guiding waveguides are mostly passive, and the only viable mechanism to reconfigure their functions is thermal effects, which is slow and cannot be used for high-speed applications such as optical modulators or optical packet switches. On the other hand, electro-optic polymer has a very high electro-optic coefficient and a good velocity match between electrical and optical signals, thus, permitting the creation of high-speed optical devices with high efficiency. Therefore, we have implemented a planar lightwave circuit using the electro-optic polymer waveguides. As a result, the structure is complex enough to generate arbitrary functions and fast enough to obtain high data rates. Using the optical signal processor, we investigate interesting applications including arbitrary waveform generators.

In this paper, a new technique that can suppress the dominant phase-induced intensity noise (PIIN) in general delay-line signal processor structures is presented. It is based on a delayed differential technique using a complementary output electro-optic modulator together with appropriate time delay and polarization effects to cancel the PIIN noise at the filter passband frequency. Experimental results using the delayed differential technique demonstrate a PIIN noise reduction of 19 dB at the filter passband for an amplified recirculating delay-line bandpass filter, together with a fourfold increase in the free spectral range and a 10 dB increase in the bandpass filter rejection level.

Even in this digital age, SAW and Optical devices remain indispensable analogue signal processing technologies whose operation and success derive from common wave propagation phenomena. In this review I hope to explain why this is so, and will remain so for the foreseeable future. Historically, the development and exploitation of these technologies arose during the Cold War primarily from the military need for an unsurpassed signal processing capability, although both are now widely exploited in civil applications as well. Following the Introduction, this paper briefly reviews the construction, operation, attractions, and selected applications of the SAW devices developed since the invention of the Interdigital Transducer (IDT) in 1965. These devices include delay lines, bandpass filters, and the first SAW device used in anger, the dispersive delay line which was vital to the realisation of pulse compression radar. I shall also review the attractions of SAW oscillators, which I believe still enjoy an opportunity to contribute to the insatiable military need for improved overall stability. Following this I introduce some components and techniques devised by the optics community for signal and image processing since the invention of the laser in 1960, beginning with techniques for pattern recognition and the ingenious technique devised to realise real-time Synthetic Aperture Radar, (SAR) image formation. More recently, the invention and development of laser diodes and fibre optics by the telecommunications industry has led to the realisation of optical signal processing techniques whose functionality is in many respects complementary to that of SAW devices. In particular, optical techniques are now useful for the generation, delay, sampling, and distribution of signals at higher rf frequencies (and bandwidths) than SAW devices, ie at microwave and mm- wave frequencies and above, leading to the modern field of activity known as Microwave Photonics. Some current research topics in this field are described, including stable microwave generation, phased array antenna beamforming, and A/D conversion, each being relevant to future military and civil systems.

Potential areas of development in optically based adaptive signal processing are considered together with an assessment of current technological directions. The rapid adoption of superhigh‐throughput lightwave communications media and systems suggests that fully optical signal processing would be very desirable to take advantage of the speed. The broad conclusion of this analysis is that at present it is not feasible to implement fully optical adaptive signal processors but that in time it might be so. ‘Not yet’ is our surmise. A brief literature survey and description of existing prototype optoelectronic adaptive systems is also provided.

A new application of the acoustooptic triple-product processor is described. Processing of spread spectrum communications and radar data for self-synchronization, message demodulation, and high-resolution ranging with a large processing gain for large time-bandwidth product signals is possible on the optical signal processor described.

Design and analysis of all-optical 4 × 1 multiplexer based on 2D photonic crystal

We discuss the light signals that are coherently emitted by some optical absorbers sub-sequent to excitation by a series of three laser excitation pulses. In some cases, the light signal emitted by the material duplicates the temporal shape of one of the laser in-put pulses. In other cases, the emitted signal represents the convolution or cross-correlation of two of the laser input pulses. In principle, digitally encoded signals of multi-gigahertz bandwidth can be convolved in real time, or, in suitable materials, stored for long periods. Output signals on the order of a few percent as intense as the inputs are possible. We provide experimental demonstrations of these effects, and discuss their implementation in optical signal processing and data storage systems.

A novel multitap optical transversal signal processor based on wavelength multiplexed Bragg grating arrays is presented. This structure enables the realization of a large number of taps for obtaining sharp bandpass filtering with high resolution and also enables arbitrary tap weight profiles to be obtained. Results on a 4-GHz, 29-tap filter demonstrates a sharp bandpass filter response, and windowing techniques on the tap profiles are demonstrated to enhance the sidelobe suppression characteristics.

In this paper, we report the design, simulation, and some applications of a tunable graphene-based cylindrical resonator by analytical and numerical two-dimensional finite-difference time-domain methods. The base structure operates as a bandpass filter in the mid-infrared region. The tunability of the filter is achieved by changing the radius and/or the chemical potential of the graphene cylinder. Based on the proposed cylindrical resonator, a two-channel wavelength selector and some novel linear plasmonic logic gates are designed and proposed. The even- and the odd-order resonance modes are separated in the two-channel wavelength selector and are transmitted to the output graphene waveguides. Moreover, the plasmonic logic gates including XOR, XNOR, NAND, and NOT having the significant features such as linearity, compact size, and low loss are proposed. The analytical approach and the numerical simulations prove the excellent performance of the logic gates in comparison to the reported ones in the literature. The simulation results demonstrate that the maximum ON/OFF ratios for these plasmonic logic gates are 29.09, 28.78, 28.78, and 29.09 dB, respectively. The proposed functional ultra-compact nano-scale graphene-based structures offer potential basic blocks for mid-infrared optical computing and signal processing.

GaAs optical processing escapes the laboratories