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Publication Metadata only A 35--μm pitch IR thermo-mechanical MEMS sensor with AC-coupled optical readout(IEEE-Inst Electrical Electronics Engineers Inc, 2015) Ferhanoğlu, Onur; Torun, Hamdi; N/A; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Adiyan, Ulaş; Çivitçi, Fehmi; Ürey, Hakan; PhD Student; Researcher; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Sciences; College of Engineering; N/A; 194282; 8579A thermo-mechanical MEMS detector with 35-mu m pixel pitch is designed, fabricated, and characterized. This fabricated design has one of the smallest pixel sizes among the IR thermo-mechanical MEMS sensors in the literature. The working principle of the MEMS detector is based on the bimaterial effect that creates a deflection when exposed to IR radiation in the 812-mu m waveband. The nanometer level out of plane mechanical motion is observed in response to IR heating of the pixel, which is detected by a diffraction grating-based optical readout. Performance of MEMS sensor arrays with optical readout have been limited by a large DC bias that accompanies a small AC signal. We developed a novel optical setup to reduce the DC term and the related noise using an AC-coupled detection scheme. Detailed noise characterization of the pixel and the readout system is reported in this paper. The noise equivalent temperature difference of our detector is measured as 216 mK using f/0.86 lens with the AC-coupled optical readout. Finally, we obtained a thermal image using a single MEMS pixel combined with a scanning configuration. Despite the reduced pixel size, the measured noise levels are comparable to the state-of-the-art thermo-mechanical IR sensors.Publication Metadata only A magnetically actuated resonant mass sensor with integrated optical readout(Ieee-Inst Electrical Electronics Engineers Inc, 2008) N/A; N/A; Department of Electrical and Electronics Engineering; N/A; Department of Electrical and Electronics Engineering; Department of Chemical and Biological Engineering; Department of Mechanical Engineering; Öztürk, Alibey; Ocaklı, Hüseyin İlker; Özber, Natali; Ürey, Hakan; Kavaklı, İbrahim Halil; Alaca, Burhanettin Erdem; Master Student; Researcher; Master Student; Faculty Member; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Department of Chemical and Biological Engineering; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; College of Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; College of Engineering; N/A; N/A; N/A; 8579; 40319; 115108Nickel cantilevers with integrated diffraction gratings are used as resonant mass sensors with a resolution of 500 femtograms. Their applicability to biosensing is demonstrated with human opioid receptors. The device is fabricated through a single-mask lithographic process. The microoptical readout provides a simple measurement platform with one external photodiode. Thanks to its ac operation principle, the device is immune to environmental noise and entails a high tolerance to fabrication defects. Obtained signal-to-noise ratio is comparable to that of a high-end Doppler vibrometer. The device with these aspects for systems integration and microarray technology is a candidate for low-cost portable sensors.Publication Open Access A MEMS based visible-NIR Fourier transform microspectrometer - art. no. 61860C(Society of Photo-optical Instrumentation Engineers (SPIE), 2006) Wolter, A.; Department of Electrical and Electronics Engineering; Ataman, Çağlar; Ürey, Hakan; Işıkman, Serhan Ömer; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 8579; N/ADesign, fabrication and characterization of a novel out-of-plane vertical comb-drive actuator based Fourier transform microspectrometer (FTS) is presented. The spectrometer utilizes resonant mode vertical comb actuators as a variable-depth diffraction grating and a single photodetector to monitor the 0th order of the diffraction pattern. The spectrum of the source illuminating the gratings is computed by Fourier transforming the 0th order intensity as a function of the optical path difference. The vertical comb actuators have a travel range of 100 mu m under atmospheric pressure with 28V excitation, which yields a theoretical spectral resolution of 0.5nm in the visible and better than 5nm in the telecom wavelengths.Publication Metadata only A prism-based optical readout method for MEMS bimaterial infrared sensors(IEEE-Inst Electrical Electronics Engineers Inc, 2016) Civitçi, Fehmi; Ferhanoğlu, Onur; Torun, Hamdi; N/A; Department of Electrical and Electronics Engineering; Adiyan, Ulaş; Ürey, Hakan; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 8579This letter demonstrates a novel prism-based optical-readout, which uses a single prism to detect the incoming TM polarized wave just below the critical angle. The method is used with a 35-mu m-pixel pitch MEMS thermal sensor, whose inclination angle changes with the absorbed infrared (IR) radiation that results in an increase in the reflectivity at the prism's glass-air interface. We compared this approach with the conventional knife-edge method. Noise equivalent temperature difference for a single sensor was measured as 200 mK for knife-edge method, and 154 mK for the proposed critical angle approach. Our approach shows a significant improvement for the sensitivity of the IR sensor. Both methods utilize an AC-coupled readout method for a single MEMS pixel using a photodetector, which responds only to changes in the scene. This method can be scaled to achieve smart pixel cameras for read sensor arrays with low-noise and high-dynamic range.Publication Metadata only A simple approach to biological single-cell lasers via intracellular dyes(Wiley-VCH, 2015) Lee, Kyung-Bok; Gather, Malte C.; Kim, Ki Su; Jeon, Mijeong; Kim, Seonghoon; Humar, Matjaz; Yun, Seok-Hyun; Department of Electrical and Electronics Engineering; Nizamoğlu, Sedat; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 130295N/APublication Metadata only A wideband silicon photonic duplexer constructed from a deep photonic network of custom Mach-Zehnder interferometers(Society of Photographic Instrumentation Engineers (SPIE), 2024) Department of Electrical and Electronics Engineering; Amiri, Ali Najjar; Görgülü, Kazım; Mağden, Emir Salih; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of EngineeringUsing a highly-scalable and physics-informed design platform with custom Mach-Zehnder interferometers (MZIs), we design and experimentally demonstrate a 1 x 2 wideband duplexer on silicon operating within 1450-1630 nm. The device is constructed from six layers of cascaded MZIs whose geometries are optimized using an equivalent artificial neural network, in a total timeframe of 75 seconds. Experimental results show below 0.72 dB deviation from the arbitrarily-specified target response, and less than 0.66 dB insertion loss. Demonstrated capabilities and the computational efficiency of our design framework pave the way towards the scalable deployment of custom MZI networks in communications, sensing, and computation applications.Publication Metadata only Active control of focal length and beam deflection in a metallic nanoslit array lens with multiple sources(Optical Soc Amer, 2010) Department of Electrical and Electronics Engineering; Department of Physics; Department of Physics; Çetin, Arif Engin; Güven, Kaan; Müstecaplıoğlu, Özgür Esat; Master Student; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Department of Physics; College of Engineering; College of Sciences; College of Sciences; N/A; 52290; 1674We propose an all-optical method to actively control the transmission of nanoslit arrays for scanning and lensing applications. We show that by utilizing two lateral control slits, the transmitted beam can be actively steered. (C) 2010 Optical Society of AmericaPublication Metadata only Adaptive receiver structures for fiber communication systems employing polarization division multiplexing: high symbol rate case(Institute of Electrical and Electronics Engineers (IEEE), 2010) Öktem, Turgut M.; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Erdoğan, Alper Tunga; Demir, Alper; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; College of Engineering; 41624; 3756Polarization division multiplexing (PDM) has been proposed as a scheme for increasing data rates in fiber optic communication systems. In the PDM scheme, the use of two orthogonal polarizations as alternative data paths is a promising approach in terms of doubling the information rate relative to conventional schemes. However, due to the severe distortion caused by the propagation medium, especially the Polarization mode dispersion (PMD), the development of receiver compensation methods are critical for the deployment of PDM based transceivers. This article proposes a receiver compensation method for high symbol rate fiber optic communication links, where the two data streams sent through orthogonal polarizations are mixed by the fiber channel not only in space but also in time. The proposed receiver algorithm adaptively recovers the original pair of data streams from their space-time mixtures. We also provide simulation results for an end-to-end fiber communication link to illustrate the performance of the proposed approach.Publication Metadata only Adaptive receiver structures for fiber communication systems employing polarization-division multiplexing(IEEE-Inst Electrical Electronics Engineers Inc, 2009) Öktem, Turgut; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Erdoğan, Alper Tunga; Demir, Alper; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; College of Engineering; 41624; 3756Polarization-division multiplexing (PDM) is emerging as a promising technique for increasing data rates without increasing symbol rates. However, the distortion effects of the fiber transmission medium poses severe barriers for the implementation of this technological alternative. Especially, due to the fiber-induced polarization fluctuation orthogonally transmitted PDM signals are mixed at the receiver input. Therefore, a receiver compensation structure needs to be implemented to recover the original orthogonal transmitted components from their mixtures at the end of the fiber channel. This is in fact the focus of this article where a receiver algorithm is based on a recently proposed blind source separation scheme exploiting magnitude boundedness of digital communication signals. Through the use of this scheme, new receiver algorithms for recovering the original polarization signals in an adaptive manner are proposed. The key feature of these algorithms is that they can achieve high separation performance while maintaining the algorithmic complexity in a fairly low level that is suitable for implementation in optical fiber communication receivers. The performance of these algorithms are illustrated through some simulation examples.Publication Metadata only Advanced imaging with dynamic focus and extended depth using integrated FR4 platform(Optical Society of America (OSA), 2009) Varghese, Samuel; Abdullah, Fahd; Augustine, Robin; Sprague, Randy B.; Andron, Voytek; N/A; Department of Electrical and Electronics Engineering; Işıkman, Serhan Ömer; Ürey, Hakan; Master Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 8579A two-degrees-of-freedom scanned beam imaging system with large dynamic range and dynamic focusing is demonstrated. The laser diode, photo-detector and the optical components are integrated on a moving platform that is made of FR4 (Flame-Retardant 4), a common polymeric substrate used in printed circuit boards. A scan angle of 52 degrees is demonstrated at 60Hz resonant frequency while the laser is moved 250um in the out-of-plane direction to achieve dynamic focusing. The laser is scanned by physically rotating the laser diode and the collection optics to achieve high signal-to-noise ratio and good ambient light rejection. The collection optics is engineered such that the collection efficiency decreases when collecting light from close distances to avoid detector saturation. The detection range is extended from contact distance up to 600mm while the collected power level varies only by a factor of 30 within this long range. Slight modifications will allow increasing the detection range up to one meter. This is the first demonstration of a laser scan engine with such a high degree of integration of electronics, optoelectronics, optics and micromechanics on the same platform.