Browsing by Author "Shi, Jin-Wei"

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106-fJ/(bit.km) 2-km OFDM OM4 MMF Transmissions for Energy Efficient Optical Interconnects
(2013)
Lu, I-Cheng
;
Chen, Hsing-Yu
;
Wei, Chia-Chien
;
Shi, Jin-Wei
;
Tsai, Sheng-Fan
Employing high-performance 850-nm VCSELs with oxide-relief and Zn-diffusion structures, we demonstrate 17.8-Gbps 2-km OM4 fiber transmissions. Meanwhile, ultra-low EDDR of 106 fJ/(bit km) with bias current as low as 1.9 mA is achieved.
850 nm Vertical-Cavity Surface-Emitting Laser Arrays With Enhanced High-Speed Transmission Performance Over a Standard Multimode Fiber
(2017-08-01)
Yen, Jia-Liang
;
Chen, Xin-Nan
;
Chi, Kai-Lun
;
Chen, Jason
;
Shi, Jin-Wei
The functionality of novel parallel and series highspeed vertical-cavity surface-emitting laser (VCSEL) arrays, which can greatly relax the tradeoff between output power and modulation speed, is demonstrated. Both types of array structure allow improvement in the output power with no degradation in their maximum modulation speed as compared to a single reference unit. The observed invariant electrical-optical bandwidth shown for these array structures is mainly due to the effective reduction of the differential resistance and parasitic capacitance, arising from the Zn-diffusion and oxide-relief apertures fabricated in the VCSEL unit. This in turn minimizes the degradation in the RC-limited bandwidth with the VCSEL arrays. Furthermore, the dense packing of single VCSELs, with Zn-diffusion apertures for optical mode control, minimizes the coupling loss between the output from the array into a standard multimode fiber (MMF). Compared with the single VCSEL unit, the parallel VCSEL array shows a significant enhancement in transmission performance over a standard OM4 MMF, which includes a larger eye margin, a higher signal-to-noise ratio, as well as a higher error-free data rate (48 versus 44 Gbit/sec). The device modeling technique is used to perform device analysis. From the results we can conclude that the improvement with the parallel array is because the value of the internal impedance is closer to the 50-Omega signal source, which minimizes the microwave reflection induced timing jitter in the eye-patterns.
850 nm Zn-diffusion Vertical-Cavity Surface-Emitting Lasers with Oxide-Relief Structure for High-Speed and Energy-Efficient Optical Interconnects from Very-Short to Medium (2km) Reaches
(2015-01-01)
Shi, Jin-Wei
;
Wei, Chia-Chien
;
(Jyehong) Chen, Jason
;
Yang, Ying-Jay
;
光電工程學系
High-speed and "green" similar to 850 nm vertical-cavity surface-emitting lasers (VCSELs) have lately attracted lots of attention due to their suitability for applications in optical interconnects (OIs). To further enhance the speed and its maximum allowable linking distance of VCSELs are two major trends to meet the requirement of OI in next generation data centers. Recently, by use of the advanced 850 nm VCSEL technique, data rate as high as 64 Gbit/sec over 57m and 20 Gbit/sec over 2km MMF transmission have been demonstrated, respectively. Here, we will review our recent work about 850 nm Zn-diffusion VCSELs with oxide-relief apertures to further enhance the above-mentioned performances. By using Zn-diffusion, we can not only reduce the device resistance but also manipulate the number of optical modes to benefit transmission. Combing such device, which has excellent single-mode (SMSR> 30 dB) and high-power (similar to 7mW) performance, with advanced modulation format (OFDM), record-high bit-rate-distance-product through MMF (2.3 kmx28 Gbit/sec) has been demonstrated. Furthermore, by selective etching away the oxide aperture inside Zn-diffusion VCSEL, significant enhancement of device speed, D-factor, and reliability can be observed. With such unique VCSEL structure, > 40 Gbit/sec energy-efficient transmission over 100m MMF under extremely low-driving current density (< 10kA/cm(2)) has been successfully demonstrated.
850-nm VCSELs With p-Type delta-Doping in the Active Layers for Improved High-Speed and High-Temperature Performance
(2016-11)
Chi, Kai-Lun
;
Hsieh, Dan-Hua
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Yen, Jia-Liang
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Chen, Xin-Nan
;
Chen, Jason (Jyehong)
In this paper, we study the influence of p-type modulation doping on the dynamic/static performance of highspeed 850-nm VCSELs with highly strained multiple quantum wells. The studied device structure has a 3/2 lambda asymmetric cavity design, which can let the internal transit time of injected carriers be as short as that of 1/2 lambda cavity design and further improve its performance in terms of speed and output power for high single-mode operation. Our proposed VCSEL structure with p-type doping shows superior modulation speed with an output power comparable with that of the un-doped reference device under room temperature operation. Furthermore, when the operating temperature reaches 85 degrees C, there is a significant improvement in both the modulation speed and maximum power of the p-doped structures. According to our simulation, this can be attributed to the change in the quasi-Fermi levels of the injected carriers after the addition of p-doping in the active layers, which minimizes the electron leakage under high-temperature operation.
93% Complexity Reduction of Volterra Nonlinear Equalizer by l(1)-Regularization for 112-Gbps PAM-4 850-nm VCSEL Optical Interconnect
(2018-01-01)
Huang, Wan-Jou
;
Chang, Wei-Fan
;
Wei, Chia-Chien
;
Liu, Jun-Jie
;
Chen, Yi-Ching
We successfully transmit a 112-Gbps PAM-4 signal over 200-m OM4 fiber using 850-nm VCSEL and Volterra filter. Adopting l(1)-regularization can reduce 93% of computation complexity of Volterra filter at the KP4 FEC limit.
A W-Band Photonic Transmitter-Mixer Based on High-Power Near-Ballistic Uni-Traveling-Carrier Photodiodes for BPSK and QPSK Data Transmission Under Bias Modulation
(2009-08-01)
Shi, Jin-Wei
;
Kuo, F. -M.
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Wu, Y. -S.
;
Chen, Nan-Wei
;
Shih, Po-Tsung
In this study, we demonstrate wireless binary phase-shift keying (BPSK) and quadrature phase-shift keying (QPSK) data transmission at the-band by use of bias modulation on photonic transmitters-mixers, which are composed of near-ballistic uni-traveling-carrier photodiodes and quasi-Yagi antennas without the integration of an Si-lens. By use of such a device and a novel optical millimeter-wave source with octupling optical frequency, we can successfully achieve 1.25-Gb/s BPSK and 0.625-Gb/s QPSK data-transmission at 105 GHz with 5-GHz intermediate-frequency signals.
Bandwidth Enhancement Equalization Enabling a 40-Gbps PAM4 Transmission via a 9.5-GHz Photoreceiver
(2016)
Liu, Jun-Jie
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Wei, Chia-Chien
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Tzu, Ta-Ching
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Chuang, Chun-Yen
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Chi, Kai-Lun
We demonstrate a 40-Gbps PAM4 optical system by employing a photoreceiver with bandwidth of only 9.5 GHz. Following 100 m multimode fiber, the BER of l. 8 x 10(-4) and 1.2 x 10(-4) after FFE and DFE equalizations are successfully achieved
Bandwidth enhancement phenomenon of a high-speed GaAs-AlGaAs based unitraveling carrier photodiode with an optimally designed absorption layer at an 830 nm wavelength
(2006-07-31)
Shi, Jin-Wei
;
Li, Yu-Tai
;
Pan, Ci-Ling
;
Lin, M. L.
;
Wu, Y. S.
In this letter, the authors introduce a GaAs/AlGaAs based unitraveling carrier photodiode (UTC-PD) for a wavelength of around 830 nm. There is significant bias- and output-current-dependent bandwidth enhancement phenomena observed with this device. According to their microwave and optical-to-electrical measurement results, such distinct phenomena can occur under a much lower current density (0.3 mA/mu m(2) vs 0.05 mA/mu m(2)) than previously reported for InP-InGaAs UTC-PDs. This can be attributed to the self-induced field in the absorption region, made possible due to the optimized p-type doping profile. (c) 2006 American Institute of Physics.
Bipolar Cascade Superluminescent Diodes at the 1.04-mu m Wavelength Regime
(2009-03-01)
Guol, Shi-Hao
;
Wang, Jr-Hung
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Wu, Yu-Huei
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Lin, Wei
;
Yang, Ying-Jay
In this study, we investigate the performance of GaAs-based bipolar cascade superluminescent diodes with different cavity lengths. The device operates around the important bio-optical therapeutic 1.04-mu m wavelength window. The introduction of tunnel junctions tends to minimize the nonuniform carrier distribution between distinct multiple quantum-wells (QWs), which is a problem in conventional SLDs, whose electroluminescent spectra are governed by the center wavelength of QWs near the p-side. Our devices exhibit nice electrical characteristics of low leakage current and overcome the limitation of nonuniform carrier distribution, thereby presenting a promising prospect for the near infrared white-light sources.
BJT-Type Optical Phase Shifter With Small Power Consumption and Fast Response Time on a Silicon Photonics Foundry Platform
(2020-03-01)
Chao, Rui-Lin
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Ahmad, Zohauddin
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Chen, Jason
;
Lai, Yinchieh
;
Shi, Jin-Wei
We demonstrate a novel optical phase shifter with a bipolar junction transistor (BJT) type of device structure based on the silicon photonics foundry platform. By operating such a device in saturation mode, we obtain measured output I-EC-V-EC characteristics very similar to those of an ideal diode, which has a nearly zero turn-on voltage and an extremely small differential resistance. The huge amount of injected current under a small voltage swing (0.1 V) in the operation window makes it possible to obtain significant plasma induced change of the refractive index in the optical waveguide with an extremely small driving-voltage. The device has a small foot-print (500 mu m in length), but exhibits small static power consumption for the pi phase-shift (P-pi: 4.1 mW), reasonable propagation loss (0.02 dB/mu m), small driving-voltage (V-pi: 0.12 V), fast switching time (rise/fall <1.6/1 ns), a residue amplitude modulation (RAM) as small as 0.18 dB, and a very-low power consumption (0.45 mW) during dynamic operation.
Characterization and Comparison of GaAs/AlGaAs Uni-Traveling Carrier and Separated-Transport-Recombination Photodiode Based High-Power Sub-THz Photonic Transmitters
(2010-01-01)
Li, Yu-Tai
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Shi, Jin-Wei
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Huang, C. -Y.
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Chen, Nan-Wei
;
Chen, Shu-Han
We describe in detail the characterization of two high-power photonic transmitters based on two different kinds of high-power photodiodes, one a GaAs/AlGaAs based uni-traveling-carrier photodiode (UTC-PD) and the other a separated-transport-recombination photodiode (STR-PD). The diodes operate under optical pulse excitation at the 800 nm wavelength. Both PDs have the same total depletion layer thickness (same theoretical RC-limited bandwidth) and are m integrated with the same broadband micro-machined circular disk monopole antennas to radiate strong sub-THz pulses. However the STR-PD based transmitter exhibits very different dynamic and static performance from that of the UTC-PD based transmitter due to the existence of a low-temperature-grown GaAs (LTG-GaAs) based recombination center inside the active region, and the much thinner thickness of effective depletion layer. Under optical pulse excitation (similar to 480 pJ/pulse), the STR-PD based transmitter exhibits a much lower maximum averaged output photocurrent (1.2 mA versus 0.3 mA) than that of the UTC-PD transmitter, although the radiated electrical pulse-width and maximum peak-power, which are measured by the same THz time-domain spectroscopic (TDS) system, of both devices are comparable. These results indicate that although the recombination center in the STR-PD degrades its DC responsivity, it effectively improves the high-speed and output power performance of the device and eliminates the DC component of the photocurrent, which should minimize device-heating problem during high-power operation. The radiated waveforms of both devices under intense optical pulse illumination also exhibit excellent linearity and strong bias dependent magnitude. This suggests their suitability for application as photonic emitters and possibly as a data modulator in sub-THz impulse-radio communication systems.
Design and Analysis of Waveguide-Coupled Photonic THz Transmitters With an Extremely Wide Fractional Bandwidth
(2018-10-01)
Chen, Nan-Wei
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Wun, Jhih-Min
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Wang, Hao-Chen
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Chao, Rui-Lin
;
Koh, Christopher
The design and analysis of novel waveguide-coupled photonic transmitters, which can have an extremely wide +/- 3-dB fractional optical-to-electrical (O-E) bandwidth at near the tera-hertz (THz) operating frequency regime (100%; 0.1-0.3 THz), are presented. This novel module is composed of a customized WR-10-based wideband antenna and an ultrafast/high-power photodiode with a 0.33-THz 3-dB O-E bandwidth, which is flip-chip bonded onto an aluminum nitride substrate, integrated with an impedance matching circuit as well as a bow-tie radiator to serve as the antenna feed. The WR-10-based dual-ridge horn structure is adopted to realize the extremely wideband antenna because the dominant TEM mode supported by the dual ridges has no cutoff frequency. The proposed antenna exhibits more than 18 dB gain across the whole operating bandwidth (0.1-0.3 THz). With the transmitter operating at an output photocurrent of 10 mA and employing the same dual ridge-horn antenna at the receiving end, we can detect a reasonable power (31.6 mu W) at 0.24 THz through 1 cm wireless transmission.
Dynamic Analysis of Cascaded Laser Power Converters for Simultaneous High-Speed Data Detection and Optical-to-Electrical DC Power Generation
(2011-07-01)
Shi, Jin-Wei
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Kuo, F. -M.
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Yang, Chan-Shan
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Lo, S. -S.
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Pan, Ci-Ling
We analyze the dynamic behaviors of a novel device, i.e., cascaded high-speed laser power converters (LPCs), which can detect the direct-current (dc) component of an incoming highspeed optical data stream and efficiently convert its dc component to dc electrical power. By utilizing a p-type photoabsorption layer in our LPC, the problem of slow-motion holes can be eliminated, and only the electrons act as the active carriers. We can thus achieve high-speed performance with the LPC under forward-bias operation with a small electric field inside. Furthermore, according to our modeling and measurement results, there are a significant alternating-current capacitance reduction and an electron-trapping effect at the interface between the absorption and collector layers with a significant degradation in the carrier drift velocity. These become more serious with the increase in optical pumping power and forward-bias voltage and truly limit the net optical-to-electrical (O-E) bandwidth of the device. In order to overcome such a transient-time-limited bandwidth and further increase the maximum dc output voltage of the LPC, we connect two single LPCs in series (cascade). Error-free data detection of 10-Gb/s and an O-E dc power-generation efficiency of 21.1% can be achieved simultaneously at a wavelength of 850 nm by the use of such two cascaded LPCs.
Effect of Thermal Management on the Performance of VCSELs
(2020-09-01)
Pan, Po-Chou
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Nag, Dhiman
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Khan, Zuhaib
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Chen, Ching-Jung
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Shi, Jin-Wei
This study investigated the effect of thermal management on the performance of vertical-cavity surface-emitting lasers (VCSELs). It was found that the thickness of silicon substrate, which can serve as the submount for VCSEL packages, has a strong influence on the thermal dissipation of on-chip laser sources, and eventually impacts on their output characteristics. Moreover, the improvements in optical characteristics of the on-chip VCSELs were the best heat dissipation through thinning silicon substrates to 50-mu m thickness combined with electroplated Cu with 100-mu m thickness. In addition, this study also performed COMSOL simulations. The simulation results were consistent with experimental results.
Employing Deep Neural Network for High Speed 4-PAM Optical Interconnect
(2017-01-01)
Chuang, Chun-Yen
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Wei, Chia-Chien
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Lin, Tien-Chien
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Chi, Kai-Lun
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Liu, Li-Chun
We implement a deep neural network (DNN) to attain a 64-Gbps 4-PAM, 4-km MMF link by using 850-nm VCSEL, with BER of 4.41 x 10(-5). The data-rate-distance product achieves recorded high of 256-Gbps.km for Inter-data center applications.
Energy Efficient 850 nm Vertical-Cavity Surface-Emitting Lasers with Extremely Low Driving-Current Density for > 40 Gbit/sec Error-Free Transmissions from RT to 85 degrees C
(2015)
Chi, Kai-Lun
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Jiang, Jia-Wei
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Yen, Jia-Liang
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Lu, I-Cheng
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Kuo, H. -C.
850nm VCSELs with record-low driving-current-density (8kA/cm(2)) small resistance (6012), wide-bandwidth (26GHz), and small energy-to-data-rate ratio (228fJ/bit; 3.5mA) for >41Gbit/sec error-free transmission over 100 (2) meter OM4 fiber at room-temperature (85 degrees C) have been demonstrated. (C) 2014 Optical Society of America
Enhancement in speed and responsivity of uni-traveling carrier photodiodes with GaAs0.5Sb0.5/In0.53Ga0.47As type-II hybrid absorbers
(2019-05-27)
Naseem
;
Ahmad, Zohauddin
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Chao, Rui-Lin
;
Chang, Hsiang-Szu
;
Ni, C-J
We demonstrate a top-illuminated high-speed uni-traveling carrier photodiode (UTC-PD) with a novel design in the p-type absorber, which call effectively shorten the photon absorption depth at telecommunication wavelengths (1.31 similar to 1.55 mu m) and further enhance the bandwidth-efficiency product of UTC-PD. In our proposed new UTC-PD structure, the p-type In0.53Ga0.47As absorption layer is replaced by the type-II GaAs0.5Sb0.5 (p)/In0.53Ga0.47As (i) hybrid absorber. Due to the narrowing of the bandgap and enhancement of the photo-absorption process at the type-II interface between the GaAs0.5Sb0.5 and In0.53Ga0.47As layers, our device shows an over 16.7% improvement in the responsivity compared with that of UTC-PD with the same thickness of pure In0.53Ga0.47As absorber (0.7 mu m) and a zero optical coupling loss. Our demonstrated device with a simple top-illuminated structure offers a large active mesa (25 mu m). a wide optical-to-electrical (O-E) bandwidth (33 GHz), a high responsivity (0.7 A/W), and a high saturation current (>5 mA) under 1.31 mu m optical wavelength. These promising results suggest that our proposed PD structure can fundamentally overcome the trade-off among bandwidth. efficiency. and device active diameter of high-speed PDs. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Fully Integrated Photonic Microwave Tracking Generator on Heterogeneous III-V/Si Platform
(2017-01-01)
Chao, Rui-Lin
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Liang, Linjun
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Shi, Jin-Wei
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Hulme, Jared
;
Kennedy, M. J.
Fully-integrated photonic microwave tracking generators are demonstrated for the first time. By sweeping the wavelength separation among two-locked DFBs and one tunable laser, a two-tone photo-generated RF signal with tunable difference in frequency can be generated. 2017 Optical Society of America
Fully Integrated Photonic Millimeter-Wave Tracking Generators on the Heterogeneous III-V/Si Platform
(2018-05-15)
Chao, Rui-Lin
;
Liang, Linjun
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Shi, Jin-Wei
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Komljenovic, Tin
;
Hulme, Jared
Fully integrated photonic microwave/millimeterwave (MMW) tracking generators, which include wavelength-tunable lasers, distributed feedback lasers, phase modulators, and high-speed photodiodes (PDs), are demonstrated on the heterogeneous integrated III-V-on-Si photonic platform. Two on-chip lasers are locked by an external optical phase-locked loop (OPLL), and the two-tone radio-frequency (RF) signals from the on-chip fast PDs can be photonically generated through the heterodyne-beating process between the wavelengthtunable laser and the OPLL output. Furthermore, the frequency spacing between such two-tone RF signals can be tracked by the oscillation frequency in the OPLL with a wide tunability (near dc to 10 GHz). Fast and truly continuous scanning of photo-generated MMW signals thus becomes feasible by simultaneously tuning the OPLL and the central wavelength of the tunable laser in the demonstrated photonic integrated circuit.
Heterogeneously Integrated InP Based 14,vanescentlyCoupled High-Speed and High-Power p-i-n Photodiodes on Silicon-on-Insulator (SOI) Substrate
(2016)
Hulme, Jared
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Kennedy, M. J.
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Chao, Rui-Lin
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Komljenovic, Tin
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Shi, Jin-Wei
we demonstrate InP based evanescently-coupled pi-n photodiodes heterogeneously integrated onto silicon-on insulator substrate. Using advanced waveguide structures and fabrication processes, it simultaneously achieves 67 GHz O-E bandwidth (RC-free), broad optical window (1520-1600nm) with 0.5 A/W internal responsivity, and high saturation currents (9 mA at 70 GHz).