2013.2
About Instruments Today No. 192
Fiber-Optic Communication
Self-Starting Optoelectronic Oscillator Pulsed Carrier for 10 Gbit/s Down-Stream RZ-BPSK and Up-Stream Reused RZ-OOK Transmission [ 下載 PDF ]
Yu-Chieh Chi, Gong-Ru Lin
The integrated DFBLD and EAM based self-starting optoelectronic oscillator (OEO) simultaneously generates synthesizer-free microwave clock and pulsed carrier with ultra low jitter at high-repetition-rate, which has emerged as a key component for the high-bit-rate optical time-division multiplexing communication (OTDM) network. In this work, the synthesizer-free 10 GHz return-to-zero (RZ) carriers self-started by the feedback OEO for bidirectional access network with 10 Gbit/s down-stream RZ binary phase-shift keying and reused up-stream RZ onoff-keying data is demonstrated. Optimizing the delay length provides the OEO triggered optical RZ carrier the shortened pulsewidth, improved effective Q-factor and enhanced pulse extinction ratio of 16 ps, 4 × 105, and 10.1 dB, respectively. The bi-directional RZ-BPSK and RZ-OOK transmissions using original and reused RZ carrier require receiving sensitivities of −20 and −17.5 dBm, respectively, to achieve a BER of 10−9.
Indoor Radio over Fiber System [ 下載 PDF ]
Ming-Hsueh Chuang, San-Liang Lee
The applications and services of broadband wireless networks, including the existing WiMAX and upcoming LTE systems, has been developed and deployed rapidly owing to the needs of large bandwidth and flexible operation. However, the radio signals subject to the blocking by building envelops and may have poor indoor signal quality. To improve the coverage of broadband wireless networks inside buildings, the radio-over-fiber (RoF) technology can be used to enhance the indoor radio signal quality.This article introduces the RoF techniques and their applications. We implement an indoor RoF system with low-cost modules and demonstrate the signal quality enhancement by the technology. The goals are to make the RoF modules to be low cost and easy-installation solutions in the building.
High-Speed TO-Can Packaged Optical Modules [ 下載 PDF ]
Tien-Tsorng Shih, Jau-Ji Jou
For high-speed and low-cost optical fiber communication systems, development of low-cost optical transceiver modules is necessary. TO-Can packaged optical modules have the advantages of low cost, compact size, and simple assembly process for mass production. In this paper, the high frequency characteristics of a TO-Can header were simulated through a three dimensional full wave electromagnetic simulator. The S-parameters and eye diagrams of a TO-Can header also were measured using our special K type adaptors. It has been verified that the TO-46 header can be operated at 25 Gb/s. The 25 Gb/s TO-46 vertical cavity surface emitting laser (VCSEL) module has been also fabricated. The 25 Gb/s TO-46 VCSEL module is potential to be applied in high-speed optical data-link networks.
Fiber Optical CATV Transport Systems Based on Upconversion Technique and Phase Modulation Scheme [ 下載 PDF ]
Po-Yi Wu, Hai-Han Lu, Cheng-Ling Ying, Jian-Ying Wen, Fu-Chih Hu
A fiber optical CATV transport system that employed an upconverted technique and a phase modulation scheme to reduce noise and distortion induced by system is proposed and experimentally demonstrated. In contrast to a fiber optical CATV transport system that used a conventional intensity modulation scheme, excellent performances of carrier-to-noise ratio, composite second order, and composite triple beat are obtained in our proposed systems over a 100 km single-mode f ber transmission. It verifies the feasibility of the proposed systems and reveals an outstanding one with excellent transmission performances.
Ultra Broadband 60 GHz Radio-over-Fiber System [ 下載 PDF ]
Hou-Tzu Huang, Ya-Tang Chiang, Huan-Ching Liu, Chung-Shin Sun, Meng-Fan Wu, Hsun-Hao Hsu, Chun-Ting Lin
This paper demonstrates the feasibility of a simple multigigabit-per-second (Gbps) radio-over-fiber (RoF) system employing multilevel orthogonal frequency-division-multiplexing (OFDM) signal modulation at 60 GHz and a single-electrode Mach-Zehnder modulator (MZM). In this paper, the impact of fiber chromatic dispersion and OFDM beat noise on the performance of the RoF system are investigated by theoretical analysis, VPI WDMTransmissionMaker simulation, and experimental demonstration. A more than 40 Gbps OFDM signal occupying the full 7 GHz license-free band at 60 GHz with frequency multiplication for the RoF link is demonstrated. In the proposed system, Levin-Campello rate adaptive bit-loading algorithm and I/Q compensation algorithm were used to maximize the system capacity. At least 40 Gbps under condition of 1 km standard single mode fiber transmission and 10 m wireless distance was achieved.
High-Power Sub-THz Harmonically Mode-Locked Yb:YAG Laser [ 下載 PDF ]
Wei-Zhe Zhuang, Hsing-Ch'ih Liang, Guo-Wei Huang, Kuan-Wei Su, Yung-Fu Chen
We demonstrated a high-power and high pulse repetition rate harmonic-mode-locked laser with Yb:YAG as the gain medium. Yb:YAG crystals with different crystal lengths were used for mode-locked operations with different repetition rates. The experimental results showed that different mode-locked repetition rate pulses can be attained with various optical cavity lengths using the same Yb:YAG crystal. By employing the Yb:YAG crystal with the optical length of 1.87 mm, we can obtain mode-locked pulses with the repetition rate of 240 GHz and the pulse duration of 0.629 ps. The average output power was 4.6 W under the absorbed pump power of 8.3W. On the other hand, mode-locked pulses at the repetition rate of 450 GHz and with pulse duration of 0.653 ps can be achieved via using gain crystal with optical thickness of 1.00 mm. Under the pump power of 3.08 W, average output power of 1.75 W was obtained. Besides, we can further scale up the repetition rate to 600 GHz by using the scheme of degenerate cavity.
Probing Polymer Nano-Structured Surfaces with Grazing Incidence Small Angle X-Ray Scattering [ 下載 PDF ]
Ya-Sen Sun, Jiun-You Liou, Shih-Wei Chien
This article provides an introduction on the fundamentals of probing nano-structured surfaces of polymers with grazing incidence small angle X-ray scattering (GISAXS). Next, we discuss how to interpret and analyze 2D GISAXS patterns and 1D profiles related to different nanostructures on surface and interface. Finally, few examples, which include destabilized thin fillms of an asymmetric block copolymer and monolayers of amphiphilic diblock copolymer micelles, are presented to demonstrate the application of GISAXS in the studies of polymer nano-structured surfaces.
Study of Electrode Patterning and Annealing Processes of Aluminum-Doped Zinc Oxide Films Using an Ultraviolet Laser [ 下載 PDF ]
Wen-Tse Hsiao, Shih-Feng Tseng, Chien-Kai Chung, Kuo-Cheng Huang, Donyau Chiang
An ultraviolet (UV) laser system performs simultaneously the electrode patterning and annealing on the aluminumdoped zinc oxide (AZO) films in this study. The diameters of the focused laser beam and the positive defocused laser beam in the system employed were 30 µm and 1 mm, respectively. Both beams were adjusted using a UV laser-processing system. AZO films prepared by the magnetron sputtering technology were deposited on Corning Eagle 2000R optical glass sheets. The thickness of the deposited films was approximately 200 nm. The optoelectronic properties of laser treated AZO films strongly depend on the laser pulse frequency and galvanometer scanning speed. The surface morphology, roughness, optical transmittance, and resistivity of the films after the laser patterning and annealing processes were respectively measured using an atomic force microscope (AFM), a field-emission scanning electron microscope (FE-SEM), a three-dimensional confocal laser scanning microscope, a four-point probe instrument, and a spectrophotometer. Experimental results indicate that the ablation depth increased as the pulse repetition frequency increased and decreased with the galvanometric scanning speed increase. The transmittance spectra of the film changed slightly after the laser annealing, and the average transmittance in the visible region was approximately 83%. All resistivity values after the laser-treated AZO films decreased signifi cantly compared to that of as-sputtered films. The grain sizes of the annealed films were calculated from the X-ray diffraction (XRD) spectra using the Scherrer's equation. The calculated grain sizes increased from 7.4 nm to 12 nm as the annealing scanning speed decreased from 800 mm/s to 400 mm/s. The roughness in the root mean square (RMS) values of annealed AZO films treated with a fixed laser scanning speed of 500 mm/s and with pulse repetition frequencies of 40 kHz, 55 kHz, and 70 kHz were 1.1 nm, 1.2 nm, and 1.8 nm, respectively.
Plasmonic Photocatalytic Light-Guide Spinning- Disk Reactor for Water Treatment [ 下載 PDF ]
Hung Ji Huang
The photocatalytic light-guide spinning-disk reactor was applied on the degradation of methyl orange. The surface plasmons were also demonstrated to boost the processing efficiency of the photocatalytic reaction. The plasmonic photocatalytic reaction was demonstrated with dual light sources from low pressure mercury lamp and lamp of red light emission diode (LED). The photocatalytic light-guide spinning-disk reactor was beneficial with high mass transfer of processing liquid and low power consumption. This is very important in the applications of high effi ciency water treatment and development of the plasmonic photocatalytic reaction.
An Introduction to the Principles of Thermal Therapy for Cancer Using Magnetic Particles in Nanometer Scales [ 下載 PDF ]
Kung-Shan Cheng
By combining the technique of generating time-varying and alternating-directional magnetic field with the nanotechnology, a medical device (MD) for thermotherapy of cancer by using magnetic particles in nanometer scales was developed and legally marketed in Europe. In principle, MD of this kind could accomplish the ideal of noninvasive cancer therapy. The article introduced the major components of this kind of MD, the principles of exciting the magnetic particles in nanometer scales (MPNS) to generate heat, and the principles for the MPNS to selectively target the desired cancerous site, etc. The article also introduced and reviewed the risks this kind of MD would bring to the patients and to the operators.
