Browsing by Author "Liu, Cheng-Yi"

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High-power and single-mode VCSEL arrays with single-polarized outputs by using package-induced tensile strain
(2020-09-01)
Shi, Jin-Wei
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Khan, Zuhaib
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Horng, Ray-Hua
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Yeh, Hsiao-Yun
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Huang, Chun-Kai
In this work, we demonstrate a novel high-power vertical-cavity surface-emitting laser (VCSEL) array with highly single-mode (SM) and single-polarized output performance without significantly increasing the intra-cavity loss and threshold current (Ith). By combining a low-loss zinc-diffusion aperture with an electroplated copper substrate, we can obtain a highly SM output (side mode suppression ratio >50 dB) with a wry narrow divergence angle (1 / e(2) : similar to 10 degrees) under high output power (3.1 W; 1% duty cycle) and sustain a single polarization state, with a polarization suppression ratio of around 9 dB, under the full range of bias currents. Compared to the reference device without the copper substrate, the demonstrated array can not only switch the output optical spectra from quasi-SM to highly SM but also maintain a close threshold current value (Ith: 0.8 versus 0.7 mA per unit device) and slope efficiency. The enhancement in fundamental mode selectivity of our VCSEL structure can be attributed to the single-polarized lasing mode induced by tensile strain, which is caused by the electroplated copper substrate, as verified by the double-crystal x-ray measurement results. (C) 2020 Optical Society of America
Research on a Novel GaN-Based Converted Mini-LED Backlight Module via a Spectrum-Decouple System
(2020-01-01)
Huang, Che-Hsuan
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Chang, Shu Hsiu
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Liaw, Been-Yu
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Liu, Cheng-Yi
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Chou, Chia-Yueh
Owing to the development of modern display technology, micro- and mini-light-emitting diodes (LEDs) have affected technological advancements in the display industry. The structure of mini-LEDs is completely different than that of traditional LED backlights because the former employs a display technology with an LED array structure, optical resonant cavity, and color conversion layer. Display backlight technology encounters difficulty in achieving a truly effective energy-loss mechanism when designing or measuring mini-LED performance. The present study proposes three major mini-LED energy loss mechanisms: cross-talk, resonant, and quantum conversion losses. Herein, the spectrum was obtained through the integrating sphere system, and the calculation mechanism was formed by the down-conversion theorem as the decoupling principle, which successfully calculated the independent energy-loss efficiency of each mechanism and effectively deduced the brightness and color saturation performance of this design combination.
Single-hidden-layer feed-forward quantum neural network based on Grover learning
(2013-09-01)
Liu, Cheng-Yi
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Chen, Chein
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Chang, Ching-Ter
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Shih, Lun-Min
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資訊工程學系
In this paper, a novel single-hidden-layer feed-forward quantum neural network model is proposed based on some concepts and principles in the quantum theory. By combining the quantum mechanism with the feed-forward neural network, we defined quantum hidden neurons and connected quantum weights, and used them as the fundamental information processing unit in a single-hidden-layer feed-forward neural network. The quantum neurons make a wide range of nonlinear functions serve as the activation functions in the hidden layer of the network, and the Grover searching algorithm outstands the optimal parameter setting iteratively and thus makes very efficient neural network learning possible. The quantum neuron and weights, along with a Grover searching algorithm based learning, result in a novel and efficient neural network characteristic of reduced network, high efficient training and prospect application in future. Some simulations are taken to investigate the performance of the proposed quantum network and the result show that it can achieve accurate learning. (C) 2013 Elsevier Ltd. All rights reserved.
User Authentication with Anonymity for Roaming Service with Smart Cards in Global Mobility Networks
(2014)
Chen, Chia-Chen
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Huang, Hui-Feng
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Liu, Cheng-Yi
;
Lai, Chi-Wen
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資訊工程學系
Rapid development of wireless network has raised a number of security concerns in mobile communications. User authentication is an important security mechanism for recognizing legal roaming users. The traditional message authentication schemes are impractical for the mobility network due to limited computation, energy resources of mobile clients, and network dynamics, etc. This article will present a new efficient authentication scheme for roaming user so that a more secure and safe living environment is possible. In addition, the proposed method could provide complete functionality because: (1) no password table is required by the home agent; (2) users can freely choose their own passwords; (3) it provides mutual authentication between the user and the foreign agent; (4) user may update their password after the registration phase; (5) session key agreement is generated by the user and the foreign agent for each session; (6) lower communication cost; (7) mobile user anonymity property is provided. Finally, the proposed scheme is more suitable for mobile clients and smart-card users. It can be applied into mobile applications in the future smart living environments.