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Lau W.K.,NSRRC | Lee A.P.,NSRRC | Chou M.C.,NSRRC | Hwang J.Y.,NSRRC | Huang N.Y.,Institute of Photonics Technologies
FEL 2012 - 34th International Free Electron Laser Conference | Year: 2012

GHz-repetition-rate relativistic electron pulses with duration shorter than 100 fs can be produced from the thermionic rf gun injector system which is now under construction at NSRRC. Experiments for production of coherent sub-THz or THz radiations by passing this prebunched electron beam through an 8 cm period bifilar helical undulator are suggested. The undulator will be powered by a 200 μ current pulser at 10 Hz repetition frequency. Conditions for obtaining coherent emission and expected properties of the radiations are discussed. Copyright © 2012 by the respective authors.

Lau W.K.,NSRRC | Chou M.C.,NSRRC | Hwang C.S.,NSRRC | Lee A.P.,NSRRC | And 3 more authors.
IPAC 2012 - International Particle Accelerator Conference 2012 | Year: 2012

The feasibility of using a high intensity short pulse laser to produce ultrafast x-raypulses from the Taiwan Photon Source (TPS) by bunch slicing is being investigated. In ourstudy, a modulator wiggler with period length of 25 cm is placed in one 7 m straightsection and is operated at low field strength to minimize possible side-effects that maylimit the performances of the low emittance TPS ring. With proper beam separationtechnique, undulators in straight sections at downstream of the modulator wiggler can beused to produce ultrafast soft and hard x-ray 100 fs pulses at moderate flux. Thisinstallation will offer the opportunity to study ultrafast phenomena of condensed mattersat atomic resolution. Copyright © 2012 by IEEE.

Chiu W.-C.,National Tsing Hua University | Lu C.-Y.,National Tsing Hua University | Lee M.-C.M.,Institute of Photonics Technologies | Lee M.-C.M.,National Tsing Hua University
IEEE Journal on Selected Topics in Quantum Electronics | Year: 2011

A new technology using hydrogen annealing and thermal oxidation is proposed to fabricate a very compact 2-D multimode interference coupler monolithically integrated with two-layer silicon photonic wires. Two devices, a 1 × 1 cross-power coupler and a 1 × 2 2 power splitter, are presented and characterized. The experimental result shows that a 3-dB transmission bandwidth of 1.1 nm, and the on-chip coupler losses of 8.6 dB and 2.84 dB were accomplished for the 1 × 1 cross-power coupler and the 1 × 2 2 power splitter. This paper demonstrates the possibility of realizing 3-D photonic integration for silicon-on-insulator lightwave circuits. © 2006 IEEE.

Yeh C.-H.,Industrial Technology Research Institute of Taiwan | Chow C.-W.,National Chiao Tung University | Chow C.-W.,National Tsing Hua University | Chiang M.-F.,Industrial Technology Research Institute of Taiwan | And 3 more authors.
Optical Engineering | Year: 2011

In a wavelength division multiplexed-passive optical network (WDM-PON), different fiber lengths and optical components would introduce different power budgets to different optical networking units (ONUs). Besides, the power decay of the distributed optical carrier from the optical line terminal owing to aging of the optical transmitter could also reduce the injected power into the ONU. In this work, we propose and demonstrate a carrier distributed WDM-PON using a reflective semiconductor optical amplifier-based ONU that can adjust its upstream data rate to accommodate different injected optical powers. The WDM-PON is evaluated at standard-reach (25 km) and long-reach (100 km). Bit-error rate measurements at different injected optical powers and transmission lengths show that by adjusting the upstream data rate of the system (622 Mb/s, 1.25 and 2.5 Gb/s), error-free (<10-9) operation can still be achieved when the power budget drops. © 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

Huang Y.-C.,Institute of Photonics Technologies | Huang Y.-C.,National Tsing Hua University | Zhang Z.,SLAC | Chen C.-H.,National Synchrotron Radiation Research Center | Wu M.-H.,Institute of Photonics Technologies
Physical Review Special Topics - Accelerators and Beams | Year: 2015

When a short electron bunch traverses an undulator to radiate a wavelength longer than the bunch length, intense superradiance from the electron bunch can quickly deplete the electron's kinetic energy and lead to generation of an isolated chirped radiation pulse. Here, we develop a theory to describe this novel chirped pulse radiation in a superradiant free-electron laser and show the opportunity to generate isolated few-cycle high-power radiation through chirped-pulse compression after the undulator. The theory is completely characterized by how fast the electron energy is depleted for a given length of an undulator. We further present two design examples at the THz and extreme-ultraviolet wavelengths and numerically generate isolated three- and nine-cycle radiation pulses, respectively. © 2015 authors. Published by the American Physical Society.

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