Dr. Doris Keh Ting Ng Profile

Dr. Doris Keh Ting Ng

Principal Scientist at A*STAR Institute of Microelectronics

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Author

Publications (26)

Proceedings Article | 15 March 2024 Presentation + Paper

Material characterization of silicon dioxide cladding for photonic devices

Amy S. Tong, Doris K. Ng, Roshan Kanhirakkottil, Jia Sheng Goh, Jiamu Jin, Andrew W. Fong, Steven H. Lee, Hong Cai, Lennon Y. Lee

Proceedings Volume 12887, 128870E (2024) https://doi.org/10.1117/12.3001995

KEYWORDS: Refractive index, Cladding, Plasma enhanced chemical vapor deposition, Coating stress, Silica, Low pressure chemical vapor deposition, Surface roughness, Waveguides, Semiconducting wafers, Photonic devices

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Proceedings Article | 13 March 2024 Presentation + Paper

Low-loss 800nm-thick PECVD silicon nitride photonic platform on 300-mm wafer

Hong Cai, Bo Li, Yiding Lin, Haitao Yu, Steven Hou Jang Lee, Chin Khang Tew, Jae Ok Yoo, Charmaine Goh, Shervonne Woon, Doris Keh Ting Ng, Navab Singh, Xianshu Luo, Lennon Yao Ting Lee

Proceedings Volume 12898, 1289802 (2024) https://doi.org/10.1117/12.3002146

KEYWORDS: Silicon nitride, Waveguides, Semiconducting wafers, Plasma enhanced chemical vapor deposition, Silicon photonics, Film thickness, Fabrication, Chemical mechanical planarization, Photonic integrated circuits

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Proceedings Article | 12 March 2024 Presentation + Paper

Nonlinear optics on deuterated silicon-rich nitride devices

Dawn T. Tan, Xavier Chia, Hongwei Gao, George F. Chen, Doris K. Ng

Proceedings Volume 12889, 128890C (2024) https://doi.org/10.1117/12.3005292

KEYWORDS: Silicon, Nonlinear optics, Resonators, Microresonators, Silicon nitride, Microrings, Waveguides, Telecommunications

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Proceedings Article | 12 March 2024 Presentation + Paper

High aspect ratio Ge-on-Si waveguide platform for miniaturized mid-infrared applications

Andrew Whye Keong Fong, Rachel Chen Fang Ang, Leh Woon Lim, Lennon Yao Ting Lee, Qingxin Zhang, Doris Keh Ting Ng, Xianshu Luo, Landobasa Y. Tobing

Proceedings Volume 12889, 128890I (2024) https://doi.org/10.1117/12.3000110

KEYWORDS: Waveguides, Silicon, Wave propagation, Germanium, Design, Miniaturization, Photonics, Mid infrared, Integrated optics

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Proceedings Article | 12 March 2024 Presentation + Paper

Scandium-doped aluminum nitride photonic integration platform

Nanxi Li, Wing Wai Chung, Jia Sheng Goh, Yat Fung Tsang, Landobasa Y. Tobing, Chong Pei Ho, Binni Varghese, Leh Woon Lim, Minghua Li, Huamao Lin, Qingxin Zhang, Doris K. Ng, Lennon Y. Lee, Xianshu Luo

Proceedings Volume 12889, 128890D (2024) https://doi.org/10.1117/12.3004598

KEYWORDS: Waveguides, Aluminum nitride, Microrings, Photonic integrated circuits, Microresonators, Scandium, Harmonic generation, Optical properties, Semiconducting wafers, Resonators

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Proceedings Article | 12 March 2024 Presentation + Paper

SF6 mixed in N2 gas sensing responses from CMOS-compatible AlN and ScAlN pyroelectric detectors

Doris K. Ng, Weiguo Chen, Linfang Xu, Harmony J. Lau, Landobasa Y. Tobing, Chong Pei Ho, Wing Wai Chung, Norhanani Jaafar, Hanfeng Fu, Qingxin Zhang

Proceedings Volume 12899, 128990J (2024) https://doi.org/10.1117/12.3002138

KEYWORDS: Pyroelectric detectors, Gas sensors, Sensors, Aluminum nitride, Signal detection, Pyroelectricity, Gases, Mid infrared, CMOS sensors

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Proceedings Article | 11 March 2024 Presentation + Paper

Hydrogen sensor (400 ppm - 1%) based on 20% ScAlN pyroelectric detector for a sustainable society

Doris K. Ng, Weiguo Chen, Huanhuan Wang, Zhonghua Gu, Md Hazwani Khairy Md Husni, Isabel Judith Wee Yi Koh, Linfang Xu, Kristel Pei Xuan Wee, Chong Pei Ho, Jia Sheng Goh, Qingxin Zhang

Proceedings Volume 12885, 128850Z (2024) https://doi.org/10.1117/12.3021874

KEYWORDS: Pyroelectric detectors, Signal detection, Sensors, Gas sensors, Sustainability, Thermal sensing, Hydrogen, Gases, CMOS sensors

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Proceedings Article | 15 March 2023 Presentation + Paper

Low-power contactless button system based on MEMS ScAlN pyroelectric detector

Linfang Xu, Doris K. Ng, Weiguo Chen, Nanxi Li, Chong Pei Ho, Duan Jian Goh, Yao Zhang, Qingxin Zhang, Lennon Y. Lee

Proceedings Volume 12434, 1243405 (2023) https://doi.org/10.1117/12.2648806

KEYWORDS: Pyroelectricity, Pyroelectric detectors, Signal detection, Power consumption, Thermography, Microelectromechanical systems, Infrared imaging, Infrared sensors, Infrared detectors

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Proceedings Article | 13 March 2023 Presentation + Paper

On-chip CO2 sensor integrated with MEMS emitter and pyroelectric detector

Hong Cai, Md Hazwani Khairy, Rachel Chen Fang Ang, Linfang Xu, Doris Keh Ting Ng, Nanxi Li, Zhonghua Gu, Anmin Kong, Weiguo Chen, Wen Wei Seit, Eva Wai Leong Ching, Norhanani Jaafar, Huanhuan Wang, Landobasa Y. Tobing, Leh Woon Lim, Qingxin Zhang, Lennon Yao Ting Lee

Proceedings Volume 12426, 124260H (2023) https://doi.org/10.1117/12.2650363

KEYWORDS: Sensors, Pyroelectric detectors, Microelectromechanical systems, Gas sensors, Carbon dioxide, Pyroelectricity, CMOS sensors, Temperature metrology, Environmental monitoring

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Proceedings Article | 5 March 2021 Presentation + Paper

Improved CMOS-compatible ultra-silicon-rich nitride for non-linear optics

Doris K. Ng, P. Xing, George F. Chen, H. Gao, Y. Cao, Dawn T. Tan

Proceedings Volume 11682, 116820L (2021) https://doi.org/10.1117/12.2582841

KEYWORDS: Nonlinear optics, Absorption, Silicon, Waveguides, Integrated optics, Chemistry, Photonics, Signal processing, Semiconductor lasers, Refractive index

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Proceedings Article | 5 March 2021 Presentation + Paper

Optical parametric gain in CMOS-compatible photonic crystal waveguides

Ezgi Sahin, Doris K. Ng, Dawn T. Tan

Proceedings Volume 11689, 1168918 (2021) https://doi.org/10.1117/12.2581925

KEYWORDS: Geometrical optics, Waveguides, Photonic crystals, Silicon, Structural engineering, Silicon photonics, Signal processing, Optical signal processing, Four wave mixing, Telecommunications

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Proceedings Article | 5 March 2021 Presentation + Paper

CMOS compatible MEMS pyroelectric infrared detectors: from AlN to ScAlN

Doris K. Ng, Chong-Pei Ho, Tantan Zhang, Linfang Xu, Li-Yan Siow, Wing-Wai Chung, Hong Cai, Lennon Y. Lee, Qingxin Zhang, Navab Singh

Proceedings Volume 11697, 116970N (2021) https://doi.org/10.1117/12.2582707

KEYWORDS: Infrared sensors, Infrared radiation, Absorption, Thin films, Sensors, Pyroelectric detectors, Infrared detectors, Aluminum nitride, Microelectromechanical systems, Thermography

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Proceedings Article | 23 September 2020 Presentation + Paper

Advances in CMOS nonlinear optics: amplification, solitons, and optical waveform manipulation

D. T. H. Tan, D. K. Ng, J. W. Choi, E. Sahin, P. Xing, B.-U. Sohn, H. Gao, Y. Cao, A. Gupta, G. F. Chen

Proceedings Volume 11461, 1146125 (2020) https://doi.org/10.1117/12.2567332

KEYWORDS: Waveguides, Solitons, Nonlinear optics, Refractive index, Dispersion, Photonic crystals, Four wave mixing, Bragg gratings

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Proceedings Article | 30 April 2019 Presentation + Paper

Supercontinuum enhancement using Bragg solitons on a CMOS-compatible chip

Ezgi Sahin, Andrea Blanco-Redondo, Doris K. Ng, Ching Png, Benjamin Eggleton, Dawn T. Tan

Proceedings Volume 11026, 1102607 (2019) https://doi.org/10.1117/12.2520506

KEYWORDS: Solitons, Dispersion, Waveguides, Picosecond phenomena, Supercontinuum generation, Wave propagation, Bragg gratings, Channel waveguides, Silicon, Cladding, Nonlinear optics

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Proceedings Article | 23 May 2018 Presentation

Ju Won Choi, Byoung-Uk Sohn, George F. R. Chen, Doris K. T. Ng, Dawn T. H. Tan

Proceedings Volume 10684, 106840T (2018) https://doi.org/10.1117/12.2306492

KEYWORDS: Waveguides, Wavelength division multiplexing, Optical transfer functions, Single photon, CMOS technology, Optical amplifiers, Linear filtering, Quantum computing, Quantum communications, Electronics

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Correlated single photons provide a means to drive applications such as quantum computing and quantum communications. Correlated single photons can be generated via parametric down conversion in second–order nonlinear media or spontaneous four–wave mixing in third–order nonlinear media. In particular, complementary metal–oxide–semiconductor (CMOS) technology allows for seamless integration with electronics, providing the potential for a completely on-chip solution for quantum information processing. Ultra–silicon–rich nitride platform is a backend CMOS compatible platform, that has already been used to obtain high gain optical parametric amplification, wideband supercontinuum and enhanced nonlinearity in photonic crystal waveguides due to its large nonlinearity. In this work, we demonstrate correlated photon pair generation based on spontaneous four–wave mixing using ultra-silicon-rich nitride waveguides for the application in CMOS–based optical quantum technologies. A CW pump at a wavelength of 1555.747nm amplified using an EDFA is filtered through five wavelength division multiplexers (WDM) with a bandwidth of 1.2nm, providing 175dB suppression of EDFA induced pump sideband noise. The filtered quasi–TE pump, adjusted using a fiber polarization controller, is coupled into an ultra–silicon–rich nitride waveguide using a lensed fiber. A SiO2 cladded waveguide with a width of 550nm and height of 300nm possesses a high nonlinear parameter of 530W^-1/m with anomalous dispersion necessary for spontaneous four-wave mixing. The waveguide output is coupled into a lensed fiber and 7 cascaded WDMs are used to provide 245dB of residual pump filtration. The pump–suppressed output is spectrally separated into signal/idler part using WDMs. We refer to lower (higher) frequency photon as the signal (idler). The spontaneously generated signal and idler photons are filtered using cascaded tunable band pass filters (OTF) centered at 1571.24nm and cascaded WDMs centered at 1540.56nm, respectively. The bandwidth of the tunable OTF and WDM is 0.5nm and 1.2nm, therefore the correlated signal/idler photons are observed within the bandwidth window of 0.5nm induced by the OTF. The signal and idler photons are measured using InGaAs/InP avalanche photodetectors. The time correlation between signal and idler photons is obtained using a time interval analyzer with a detection efficiency of 20% and dead time of 15μs.The time bin is set to 81ps and the photon collection time is 240s. The coincidence peak is located ~11ns in the time–bin histogram due to the optical-path difference between the tunable OTF and WDM at respective signal and idler sides. The experimental raw coincidence counts (Hz), calculated by subtracting the accidental rate from the coincidence peak, show a quadratic increase with respect to coupled pump power. At the maximum coupled power of 5mW, the raw coincidence count is ~1Hz. We achieve a raw coincidence–to–accidental ratio (CAR) of up to 3. Therefore, we succeeded to observe correlated photon pair generation based on spontaneous four–wave mixing using the ultra–silicon–rich-nitride waveguide as a CMOS compatible platform, for future applications in quantum technologies.

Proceedings Article | 23 May 2018 Presentation

Broadband four-wave mixing and optical parametric gain of broadband incoherent light using ultra-silicon-rich nitride waveguides (Conference Presentation)

Ju Won Choi, Byoung-Uk Sohn, George F. R. Chen, Doris K. T. Ng, Dawn T. Tan

Proceedings Volume 10684, 106840X (2018) https://doi.org/10.1117/12.2306075

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Four–wave mixing (FWM) serves as the physical basis for various nonlinear phenomena including wavelength conversion, parametric amplification, and frequency combs. FWM on a chip has been implemented using CMOS platforms, chalcogenide glasses and III–V materials. On-chip, waveguide based stimulated FWM techniques have been mostly demonstrated using a coherent pump and coherent signal to focus on broadband spectral tuning for operation in high–speed and multi–channel wavelength division multiplexing network. Though FWM using incoherent light has the potential to provide large optical conversion efficiency, such demonstrations remain largely confined to fiber–experiments and involved narrow–band signals/idlers. Furthermore, the FWM based on a pulsed laser and a broadband incoherent source has yet to be implemented. In this work, we demonstrate integrated ultra–silicon–rich nitride parametric converters that perform wavelength conversion of a broadband incoherent source with a bandwidth of ~100nm at the -20dB level. A 500fs pulsed pump is combined with an incoherent superluminescent diode (SLD) as the signal and parametric gains between 12dB – 27dB is demonstrated as well as cascaded FWM. A 500fs pulsed laser centered at 1.555μm and an incoherent SLD with a 20dB bandwidth spanning from 1.6 – 1.7μm are used as the pump and signal respectively. The pump and signal are combined with a wavelength division multiplexer and coupled into an ultra–silicon–rich nitride waveguide with 10mm length, 700nm width and 400nm height. The waveguide is designed to have a larger nonlinear parameter of 330W^-1/m while possessing anomalous dispersion of -0.92ps^2/m, necessary for phase matched parametric conversion. At a coupled peak power of 4.6W, an idler spanning from 1.43 – 1.52μm at the -20dB level is generated. At a maximum input signal power of 0.71mW, a second idler appears at the blue side of the first generated idler because of cascaded FWM induced between pump of 1.555μm and the first idler peak of 1.48μm. At a coupled peak power of 2.8W, an idler spanning from 1.46 to 1.52μm is generated. The experimental idler bandwidth agrees well with the calculation based on degenerate FWM phase–matching condition. The broadened idler powers are calculated by integrating the energy of each signal and idler with respect to wavelength to obtain optical conversion efficiencies. The integrated idler power is 3.4dBm and 13.4dBm, corresponding to idler parametric gain of 12dB and 18dB respectively at a coupled peak power of 2.8 and 4.6W, respectively. The application of the SLD signal to a supercontinuum that is generated at a coupled peak power of 26W spectrally spanning 1.1 – 1.7μm is observed to generate an idler power of 14dBm within the wavelength range of 1.18 – 1.42μm as well as an idler conversion efficiency/gain of 27dB. Therefore, we achieved broadband wavelength conversion based on stimulated FWM using a pulsed pump and broadband incoherent signal that facilitate the spectrum spanning from 100nm, sufficient to cover parts of the E– and S–bands an representing large conversion efficiency and parametric gains of 12dB – 27dB.

Proceedings Article | 14 May 2018 Presentation + Paper

High gain optical parametric amplification in ultra-silicon-rich nitride (USRN) waveguides

K. J. Ooi, D. K. Ng, J. Choi, E. Sahin, P. Xing, T. Wang, A. K. Chee, L. Kimerling, A. Agarwal, D. T. Tan

Proceedings Volume 10684, 1068406 (2018) https://doi.org/10.1117/12.2306238

KEYWORDS: Waveguides, Nonlinear optics, Silicon, Four wave mixing, Refractive index, Dispersion, Absorption, Photonic crystals, Optical parametric oscillators, Optical amplifiers, Kerr effect

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Proceedings Article | 3 May 2016 Paper

Generic heterogeneously integrated III-V lasers-on-chip with metal-coated etched-mirror

Chee-Wei Lee, Doris Keh-Ting Ng, Min Ren, Yuan-Hsing Fu, Anthony Yew Seng Kay, Vivek Krishnamurthy, Jing Pu, Ai Ling Tan, Febiana Tjiptoharsono, Soo Bin Choo, Qian Wang

Proceedings Volume 9751, 97510M (2016) https://doi.org/10.1117/12.2218395

KEYWORDS: Silica, Mirrors, Semiconductor lasers, Silicon, Laser bonding, Waveguides, Metals, Laser damage threshold, Reflectivity, Etching

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Proceedings Article | 3 March 2016 Paper

Ultra-thin oxide interlayer wafer bonding for heterogeneous III-V/Si photonics integration

Chee-Wei Lee, Ying Shun Liang, Doris Keh-Ting Ng, Yi Yang, Hnin Yu Ko, Qian Wang

Proceedings Volume 9751, 97510G (2016) https://doi.org/10.1117/12.2218598

KEYWORDS: Silicon, Wafer bonding, Photonics, Epitaxy, Silicon photonics, Silica, Semiconducting wafers, Oxygen, Interfaces, Plasma

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Proceedings Article | 3 March 2016 Paper

Development of broadband antireflection of high-index substrate using SiNx/SiO2

Kim Peng Lim, Doris K. T. Ng, Qian Wang

Proceedings Volume 9751, 97510B (2016) https://doi.org/10.1117/12.2217751

KEYWORDS: Antireflective coatings, Refractive index, Thin films, Plasma, Chemical vapor deposition, Algorithms, Silicon, GRIN lenses, Fabrication, Compound semiconductors, Reflectivity, Multilayers, Silica

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Proceedings Article | 18 March 2015 Paper

Design, fabrication and demonstration of heterogeneously III-V/Si laser with a compact optical vertical interconnect access

Jing Pu, Doris Keh Ting Ng, Kim Peng Lim, Vivek Krishnamurthy, Chee Wei Lee, Kun Tang, Anthony, Yew Seng Kay, Ter Hoe Loh, Qian Wang

Proceedings Volume 9366, 93660G (2015) https://doi.org/10.1117/12.2086929

KEYWORDS: Silicon, Waveguides, Semiconductor lasers, Etching, Integrated optics, Laser applications, Geometrical optics, Wafer-level optics, Nanophotonics, Plasma

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Proceedings Article | 10 March 2015 Paper

Demonstration of continuous-wave microsquare lasers and comparison to microdisk laser

Chee-Wei Lee, Qian Wang, Yicheng Lai, Doris Ng, Siu Kit Ng

Proceedings Volume 9382, 93821D (2015) https://doi.org/10.1117/12.2074237

KEYWORDS: Laser damage threshold, Optical microcavities, Laser applications, Etching, Laser scattering, Continuous wave operation, Semiconductor lasers, Laser optics, Laser stabilization, Light sources

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Proceedings Article | 27 February 2015 Paper

Graded refractive index optics based on dual-layer ultrathin films: theory, design and applications in integrated photonics

Qian Wang, Kim Peng Lim, Doris K. Ng

Proceedings Volume 9366, 93660K (2015) https://doi.org/10.1117/12.2085445

KEYWORDS: Refractive index, Thin films, Waveguides, Silicon, Silicon films, GRIN lenses, Integrated optics, Reflectivity, Multilayers, Titanium dioxide

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Proceedings Article | 14 March 2013 Paper

Fabrication of low-loss silicon nanophotonic waveguide for photonic device integration

Doris Ng, Kim-Peng Lim, Qian Wang, Jing Pu, Kun Tang, Yicheng Lai, Chee-Wei Lee, Seng-Tiong Ho

Proceedings Volume 8629, 86290E (2013) https://doi.org/10.1117/12.2002791

KEYWORDS: Silicon, Silica, Photomasks, Etching, Plasma enhanced chemical vapor deposition, Waveguides, Nanolithography, Photonic devices, Nanophotonics, Wave propagation

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Proceedings Article | 6 March 2013 Paper

Fabrication of high-efficiency heterogeneous Si/III-V integration with short optical vertical interconnect access

Doris K. Ng, Jing Pu, Qian Wang, Kim-Peng Lim, Yongqiang Wei, Yadong Wang, Yicheng Lai, Seng-Tiong Ho

Proceedings Volume 8628, 86280M (2013) https://doi.org/10.1117/12.2002786

KEYWORDS: Silicon, Waveguides, Geometrical optics, Integrated optics, Optical alignment, Semiconducting wafers, Scanning electron microscopy, Light wave propagation, Etching, Nanophotonics

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Proceedings Article | 10 January 2013 Paper

Formation of nanoscale structures by inductively coupled plasma etching

Colin Welch, Deirdre Olynick, Zuwei Liu, Anders Holmberg, Christophe Peroz, Alex P. Robinson, M. David Henry, Axel Scherer, Thomas Mollenhauer, Vince Genova, Doris K. Ng

Proceedings Volume 8700, 870002 (2013) https://doi.org/10.1117/12.2017609

KEYWORDS: Etching, Silicon, Photomasks, Ions, Plasma, Cryogenics, Polymers, Nanoimprint lithography, Silica, Chromium

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Showing 5 of 26 publications

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