Browsing by Author "Chen, Bo-Yan"

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Anti-guiding and guiding effects in GaN-based vertical-cavity surface-emitting lasers
(2020-02-01)
Chen, Lih-Ren
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Chen, Bo-Yan
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Kuo, Shiou-Yi
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Hong, Kuo-Bin
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Lu, Tien-Chang
We study the lateral optical confinement effect on the performance and lasing characteristics of GaN-based vertical-cavity surface-emitting lasers (VCSELs). The anti-guiding and guiding structures are designed by calculating the effective refractive index difference of active and cladding regions. By varying the compensation layer configuration and thickness, the designed effective refractive index of the active region is 0.44% higher than peripheral for the guiding structure. The threshold current density of VCSEL with the guiding structure is 25.4 kA/cm(2), which is almost half of that with the anti-guiding structure showing 53.5 kA/cm(2). For the anti-guiding structure, the signals from both active and cladding regions are observed by the far-field angle-resolved spectrum at 1.4 x I-th driving current, which agrees well with our simulation. Throughout the study, we show the advantage of the guiding structure both theoretically and experimentally. Moreover, an effective guiding structure is obtained by a proper design and simple device process, which will be very promising for mass production.
Charging Architecture for M2M Communications
(2016-01-01)
Lin, Fuchun Joseph
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Chen, Bo-Yan
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Lin, Bo-Ting
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Hu, Wan-Hsun
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交大名義發表
Machine to Machine (M2M) communications or the Internet of Thing (IoT) is emerging as a new form of communications in our society. With such proliferation of the IoT/M2M, we have started to experience various smart services such as smart home, connected car, e-health, smart grid, etc. These IoT/M2M services are set to improve our life significantly. However, in IoT/M2M many things only exchange a small amount of data while generate a large amount of requests such as network connectivity requests, notification requests and storage requests. The traditional charging models such as those based on amount of data transfer are no longer adequate for M2M communications. As new charging factors and charging models are identified for M2M communications, a new charging architecture needs to be designed for M2M communications. This paper proposes such an M2M charging architecture that is designed to collect charging information for M2M communications based on the notions of charging factors and charging models.
High Output Power GaN-Based Green Resonant-Cavity Light-Emitting Diodes With Trapezoidal Quantum Wells
(2020-09-01)
Wu, Haocheng
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Li, Heng
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Kuo, Shiou-Yi
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Chen, Bo-Yan
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Lu, Tien-Chang
Green resonant-cavity light-emitting diode (RCLED) has great potential in optical communication but suffers low efficiency. In this study, GaN-based flip-chip green RCLED incorporated with nitrogen face-oriented inclination asymmetric trapezoidal quantum wells (NOAT-QWs) is proposed to enhance the light-output power (LOP). Samples with NOAT-QWs and normal symmetric square quantum wells (SS-QWs) were fabricated and characterized. Although their electrical characteristics and emission spectra are similar, the LOP and emission efficiency are significantly improved. At a driving current of 450 mA, the improvement of LOP for RCLED with NOAT-QWs can be as high as 1.44 times in comparison to the sample with SS-QWs. The unprecedented high output power of 115 mW and the narrow full-width-at-half-maximum (FWHM) of 6.4 nm in the emission spectrum give great potential in optical communication. The inherent mechanism was investigated by the finite element analysis, from which the simulation results match well with the experimental measurements. The simulation results reveal that the NOAT-QWs are beneficial in alleviating the quantum confined stark effect and facilitating easier hole carriers' flow across the barriers, leading to more electron-hole wave function overlaps and higher radiative recombination rate.