• Title, Summary, Keyword: CMOS photonics

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SOI CMOS-Based Smart Gas Sensor System for Ubiquitous Sensor Networks

  • Maeng, Sung-Lyul;Guha, Prasanta;Udrea, Florin;Ali, Syed Z.;Santra, Sumita;Gardner, Julian;Park, Jong-Hyurk;Kim, Sang-Hyeob;Moon, Seung-Eon;Park, Kang-Ho;Kim, Jong-Dae;Choi, Young-Jin;Milne, William I.
    • ETRI Journal
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    • v.30 no.4
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    • pp.516-525
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    • 2008
  • This paper proposes a compact, energy-efficient, and smart gas sensor platform technology for ubiquitous sensor network (USN) applications. The compact design of the platform is realized by employing silicon-on-insulator (SOI) technology. The sensing element is fully integrated with SOI CMOS circuits for signal processing and communication. Also, the micro-hotplate operates at high temperatures with extremely low power consumption, which is important for USN applications. ZnO nanowires are synthesized onto the micro-hotplate by a simple hydrothermal process and are patterned by a lift-off to form the gas sensor. The sensor was operated at $200^{\circ}C$ and showed a good response to 100 ppb $NO_2$ gas.

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Performance Comparison of Two Types of Silicon Avalanche Photodetectors Based on N-well/P-substrate and P+/N-well Junctions Fabricated With Standard CMOS Technology

  • Lee, Myung-Jae;Choi, Woo-Young
    • Journal of the Optical Society of Korea
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    • v.15 no.1
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    • pp.1-3
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    • 2011
  • We characterize and analyze silicon avalanche photodetectors (APDs) fabricated with standard complementary metal-oxide-semiconductor (CMOS) technology. Current characteristics, responsivity, avalanche gain, and photodetection bandwidth of CMOS-APDs based on two types of PN junctions, N-well/P-substrate and $P^+$/N-well junctions, are compared and analyzed. It is demonstrated that the CMOS-APD using the $P^+$/N-well junction has higher responsivity as well as higher photodetection bandwidth than N-well/P-substrate. In addition, the important factors influencing CMOS-APD performance are clarified from this investigation.

Effect of Multi-Wavelength Irradiation on Color Characterization with Light-Emitting Diodes (LEDs)

  • Park, Hyeong Ju;Song, Woosub;Lee, Byeong-Il;Kim, Hyejin;Kang, Hyun Wook
    • Journal of the Korean Physical Society
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    • v.70 no.11
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    • pp.1011-1015
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    • 2017
  • In the current study, a multi-wavelength light-emitting diode (LED)-integrated CMOS imaging device was developed to investigate the effect of various wavelengths on multiple color characterization. Various color pigments (black, red, green, and blue) were applied on both white paper and skin phantom surfaces for quantitative analysis. The artificial skin phantoms were made of polydimethylsiloxane (PDMS) mixed with coffee and $TiO_2$ powder to emulate the optical properties of the human dermis. The customized LED-integrated imaging device acquired images of the applied pigments by sequentially irradiating with the LED lights in the order of white, red, green, and blue. Each color pigment induced a lower contrast during illumination by the light with the equivalent color. However, the illumination by light with the complementary (opposite) color increased the signal-to-noise ratio by up to 11-fold due to the formation of a strong contrast (i.e., red $LED=1.6{\pm}0.3$ vs. green $LED=19.0{\pm}0.6$ for red pigment). Detection of color pigments in conjunction with multi-wavelength LEDs can be a simple and reliable technique to estimate variations in the color pigments quantitatively.

Enhancement of Light Guiding Efficiency in CMOS Image Sensor by Introducing an Optical Thin Film (광학 박막을 채용한 CMOS 이미지 센서 픽셀의 수광 효율)

  • Kang, Myung-Hoon;Ko, Eun-Mi;Lee, Je-Won;Cho, Guan-Sik
    • Korean Journal of Optics and Photonics
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    • v.20 no.1
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    • pp.57-60
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    • 2009
  • We consider introducing an optical thin film to the light guiding wall of a pixel in order to enhance the light guiding efficiency of a CMOS image sensor. Simulating the reflectance as a function of the incidence angle using the Essential Macleod program, we find that the range of total internal reflection is greatly increased for several materials. Particularly when air is chosen as the thin film material, the critical angle of total internal reflection could be shifted to about 50 degrees.

A study on the amorphous s-i-n photodiode integrated with CMO IC (CMOS IC와 집적 가능한 비정질 p-i-n 광 수신기 제작에 관한 연구)

  • Kwak, Chol-Ho;Yoo, Hoi-Jun;Jang, Jin;Moon, Byoung-Yeon
    • Korean Journal of Optics and Photonics
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    • v.8 no.6
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    • pp.500-505
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    • 1997
  • Experimental amorphous photodiode is fabricated on CMOS IC using a-Si:H p-i-n structure. Amorphous photodiode is scuccessfully integrated on CMOS IC using amorphous Si produced by PECVD system. The PECVD system can deposit a-Si:H at low temperature so that photodiode can be integrated with CMOS IC structure without any process incompatibility. The fabricated amorphous photodiode has a breakdown voltage of below -20 V, a leakage current of about 1 $\mu\textrm{A}$, and turn-on voltage of 0.6~0.8 V. It is demonstrated that the photocurrent of optical signal can be turned on and off by a small voltage and the fabricated amorphous p-i-n photodiode can be used as an optical switch.

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Demonstration of Time- and Wavelength-Division Multiplexed Passive Optical Network Based on VCSEL Array

  • Mun, Sil-Gu;Lee, Eun-Gu;Lee, Jie Hyun;Park, Heuk;Kang, Sae-Kyoung;Lee, Han Hyub;Kim, Kwangok;Doo, Kyeong-Hwan;Lee, Hyunjae;Chung, Hwan Seok;Lee, Jong Hyun;Lee, Sangsoo;Lee, Jyung Chan
    • ETRI Journal
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    • v.38 no.1
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    • pp.9-17
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    • 2016
  • We demonstrate a time- and wavelength-division multiplexed passive optical network system employing a vertical-cavity surface-emitting laser array-based optical line terminal transceiver and a tunable bidirectional optical subassembly-based optical network terminal transceiver. A packet error-free operation is achieved after a 40 km single-mode fiber bidirectional transmission. We also discuss an arrayed waveguide grating, a photo detector array based on complementary metal-oxide-semiconductor photonics technologies, and low-cost key devices for deployment in access networks.

Surface Emitting Terahertz Transistor Based on Charge Plasma Oscillation

  • Kumar, Mirgender;Park, Si-Hyun
    • Current Optics and Photonics
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    • v.1 no.5
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    • pp.544-550
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    • 2017
  • This simulation based study reports a novel tunable, compact, room temperature terahertz (THz) transistor source, operated on the concept of charge plasma oscillation with the capability of radiating within a terahertz gap. A vertical cavity with a quasi-periodic distributed-Bragg-reflector has been attached to a THz plasma wave transistor to achieve a monochromatic coherent surface emission for single as well as multi-color operation. The resonance frequency has been tuned from 0.5 to 1.5 THz with the variable quality factor of the optical cavity from 5 to 290 and slope efficiency maximized to 11. The proposed surface emitting terahertz transistor is able to satisfy the demand for compact solid state terahertz sources in the field of teratronics. The proposed device can be integrated with Si CMOS technology and has opened the way towards the development of silicon photonics.

The Optical Measurement and Quantitative Analysis of Algesia in Spodoptera litura Larva

  • Chen, Ying-Yun;Chang, Rong-Seng;Tsai, Mi-Yin;Chen, Der-Chin
    • Journal of the Optical Society of Korea
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    • v.19 no.2
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    • pp.169-174
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    • 2015
  • Muscle vibration measurement has long been an unique scientific study, in general, and the direct reaction of animals to feel pain (algesia), either from vascular or muscle contraction, is a complex perceptual experience. Thus this paper proposes a way to measure animal algesia quantitatively, by measuring the changes in muscle vibration due to a pinprick on the surface of the skin of a Spodoptera litura larva. Using the laser optical triangulation measurement principle, along with a CMOS image sensor, linear laser, software analysis, and other tools, we quantify the subtle object point displacement, with a precision of up to $10{\mu}m$, for our chosen Spodoptera litura larva animal model, in which it is not easy to identify the tiny changes in muscle contraction dynamics with the naked eye. We inject different concentrations of formalin reagent (empty needle, 12% formalin, and 37% formalin) to obtain a variety of different muscle vibration frequencies as the experimental results. Because of the high concentrations of reagent applied, we see a high frequency shift of muscle vibration, which can be presented as pain indices, so that the algesia can be quantified.

Trend and Issues of van der Waals 2D Semiconductor Devices (반데르발스 2차원 반도체소자의 응용과 이슈)

  • Im, Seongil
    • Vacuum Magazine
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    • v.5 no.2
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    • pp.18-22
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    • 2018
  • wo dimensional (2D) van der Waals (vdW) nanosheet semiconductors have recently attracted much attention from researchers because of their potentials as active device materials toward future nano-electronics and -optoelectronics. This review mainly focuses on the features and applications of state-of-the-art vdW 2D material devices which use transition metal dichalcogenides, graphene, hexagonal boron nitride (h-BN), and black phosphorous: field effect transistors (FETs), complementary metal oxide semiconductor (CMOS) inverters, Schottky diode, and PN diode. In a closing remark, important remaining issues of 2D vdW devices are also introduced as requests for future electronics and photonics applications.

Single-pixel Autofocus with Plasmonic Nanostructures

  • Seok, Godeun;Choi, Seunghwan;Kim, Yunkyung
    • Current Optics and Photonics
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    • v.4 no.5
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    • pp.428-433
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    • 2020
  • Recently, the on-chip autofocus (AF) function has become essential to the CMOS image sensor. An auto-focus usually operates using phase detection of the photocurrent difference from a pair of AF pixels that have focused or defocused. However, the phase-detection method requires a pair of AF pixels for comparison of readout. Therefore, the pixel variation may reduce AF performance. In this paper, we propose a color-selective AF pixel with a plasmonic nanostructure in a 0.9 μ㎡ pixel. The suggested AF pixel requires one pixel for AF function. The plasmonic nanostructure uses metal-insulator-metal (MIM) stack arrays instead of a color filter (CF). The color filters are formed at the subwavelength, and they transmit the specific wavelength of light according to the stack period and incident angles. For the optical analysis of the pixel, a finite-difference time-domain (FDTD) simulation was conducted. The analysis showed that the MIM stack arrays in the pixels perform as an AF pixel. As the primary metric of AF performance, the resulting AF contrasts are 1.8 for the red pixels, 1.6 for green, and 1.5 blue. Based on the simulation results, we confirmed the autofocusing performance of the MIM stack arrays.