Research Experience

Undergraduate Research Experience

     My undergraduate study in Physics integrated my scientific understanding of the universe and strengthened me for advanced researches. Among the major courses taken, my favorites were Fundamentals of Experimental Physics (I)(II)(III)(IV), in which I always got leading grades. From these experiments, I became familiar with not only cryo and vacuum techniques but also skills in electronics and data acquisition. I enjoyed the challenges encountered during each project and believe that physical intuition, which is vital to brilliant researchs, can be enhanced by hands-on experience.

     In 1993, I participated in a summer project on holography. This program, though preliminary, not only refreshed my understanding of light but initiated my interest in optics as well. Then, I chose many optics-related graduate courses and took a special project directed by Prof. C. F. Lin in the Institute of Electro-Optical Engineering. This project was on the study of bending optical waveguides which reduce feedback from facets of semiconductor photonics and maintain a nearly symmetric beam profile at the same time. My effort was to figure out a suitable configuration via numerical simulations, and the results accorded with experiments. This work was presented in PIERS 1997 and made me skillful in numerical techniques and familiar with fundamentals of semiconductor lasers.
 

Graduate Research Experience

       I was admitted with honor in 1996 to the MS program of the Institute of Electro-Optical Engineering in National Taiwan University. My graduate study in NTU mainly focused on Quasi-Phase-Matched Second-Order Nonlinear Effects and was composed of three topics: numerical simulation, device fabrication and optical application.

       To develop state-of-the-art second-order nonlinear devices, powerful numerical tools are indispensable since exact analytical modeling is generally not available. It is only in recently years did techniques like the Beam Propagation Method be applied to this subject. As a major part of my research, I contrived accurate and efficient iterative methods, the IFD-BPM and the ISS-BPM, to model second-order nonlinear effects. Both of these methods were proved to outperform previously published ones. I believe that these novel methods will play important roles in the booming research of QPM second-order nonlinearities. With IFD-BPM and ISS-BPM, I also investigated non-ideal implementations of QPM devices. I have published two journal papers regarding the numerical issues in Journal of Lightwave Technology and four conference papers in CLEO/EQEC, IPC'98, and Optics and Photonics/Taiwan'97. Through these works, I gained confidence that I am capable of conducting independent and competitive researches and being a contributing member of the engineering society.

       I also studied the fabrication of QPM devices during the MS program. Although electrical poling techniques seem to dominate, Prof. C. F. Lin and I think that fabrication methods based entirely on processing still remain attractive in view of mass production. Nevertheless, the inversion depth induced by conventional chemical methods is generally not deep enough for efficient operation. As a preliminary attempt to overcome this obstacle, I reproduced the work of S. Makio et al., which involved one-direction heated proton exchange, and induced approximately 16 um deep spike-like anti-domains with a 20 um period. Despite of the fact that this result was far from ideal, I learned essential techniques in photolithography and clean-room processing.

       In the application aspect of QPM technique, I designed a difference frequency generation as a tunable source of mid-IR radiation using periodically poled lithium niobate (PPLN). I setup a diode-pumped 1064nm Nd:YVO₄ solid state laser as the pumping source. It is worthy of note that some delicate mounts as well as the temperature control system necessary for this experiment were made by myself. In addition, I also demonstrated a diode-pumped second-harmonic generation in LiIO₃ crystal, emitting blue light at 404nm. From these experiments, I acquired lots of hands-on knowledge of optics and learned many of the quirks that can only be understood through experience.

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