Fiber Laser

Asynchronously Mode-Locked Er-Fiber Soliton Laser and Its Long-Term Stabilization [ 下載 PDF ]

Wei-Wei Hsiang, Yinchieh Lai

By employing the technique of asynchronous mode-locking, direct generation of stable 10 GHz 0.8 ps pulse trains with a supermode-suppression ratio > 70 dB from a mode-locked Er-fiber soliton laser has been demonstrated successfully. When the modulation frequency is deviated from the cavity harmonic frequency by 15–40 kHz, stable femtosecond soliton pulses are formed. Besides, without using high speed RF feedback electronics, a novel and economic long-term stabilization scheme for this asynchronously mode-locked Er-fiber soliton laser is proposed and demonstrated by controlling the cavity length to lock the deviation frequency at 25 kHz.

Review of High Power Fiber Lasers and Related Technologies [ 下載 PDF ]

Chun-Jen Weng, Wei-Yao Hsu, Jyh-Rou Sze, Sheng-Lung Huang

Fiber lasers are unique optical sources that offer a variety of advantages, especially for high efficiency and excellent beam quality at high power operation. Therefore, fiber lasers are often called the lasers of the 21st century. High power fiber lasers are entering the realm of kilowatt continuous-wave powers with diffraction limited beam quality. In this article, we review the progress of fiber laser development in terms of technology breakthrough and challenges. Potential approaches to move the fiber laser technology forward will also be discussed. It is expected that 10 kW will be obtained in the near future.

Efficient Nd:YAG Crystal Fiber Laser [ 下載 PDF ]

Chia-Yao Lo, Tsai-Shuan Chou, Sheng-Lung Huang

Efficient Nd:YAG lasers were demonstrated using gradient-index guided crystal fibers. A laser output power of 145 mW was achieved along with a slope efficiency of 28.9%. Up to 40% higher Nd ion concentration compared to that in the source rod at the center of the crystal fiber was obtained. Measurement by optical low-coherence reflectometry indicated an index difference of 0.0284 between the center and the edge of the crystal fiber.

Dynamics of Optical Backward Injection Induced Gain-Depletion Modulation and Mode-Locking in Semiconductor Optical Amplifier Fiber Laser [ 下載 PDF ]

Gong-Ru Lin, Yu-Sheng Liao, Kun-Chieh Yu

The optical gain-depletion-induced mode-locking dynamics of a semiconductor optical-amplifierbased fiber ring laser (SOAFL) backward injected by a purely sinusoidally modulated or digitally encoded distributed feedback laser diode are theoretically and experimentally demonstrated. The effect of gain depletion and waveform on the mode-locked pulse width, pulse shape, and power of the SOAFL are interpreted from theoretical simulations. The shortest pulse width of 12 ps can be generated from an optically sinusoidal-wave-modulated SOAFL. By backward injecting the SOAFL with a digitally encoded optical signal of adjustable duty cycle, one can observe the optimized gain depletion time of 400–600 ps required for mode locking the SOAFL.

Passively Mode-Locked Fiber Laser and the Application in Optical Frequency Metrology [ 下載 PDF ]

Jin-Long Peng, Ren-Huei Shu

Passively mode-locked fiber laser and the application in optical frequency metrology were introduced. The frequency of an unknlown laser was measured using two fiber laser combs operated in different repetition rates. The difference in mode number and the mode number were determined by simple processes. An optical frequency counter can be realized when the whole measurement process can be operated automatically. The measurement of optical frequency can be as simple as that of microwave frequency in the near future.

The Applications of Fiber Lasers in Sensor Systems [ 下載 PDF ]

Peng-Chun Peng, Kuan-Yan Huang, Fang-Ming Wu

Fiber grating sensor systems using fiber laser schemes have been the focus of a great deal of research. In contrast with a conventional fiber grating sensor system, the advantages of a fiber-laserbased sensor system includes its high resolution for sensing signals, high optical signal-to-noise ratio, and high output power against the noisy environments. The content of this paper includes a fiber ring laser for a long-distance sensor system and a linear-cavity fiber laser for a sensor network with self-healing functions. These investigations will be useful in the fields of sensor systems.

S-Band Single-Frequency Fiber Laser Technology [ 下載 PDF ]

Chien-Hung Yeh

Conventional erbium-doped fiber ring laser with single-longitudinal-mode outputs in the C- and Lbands were discussed and applied extensively. However, the operating bandwidth in S-band has not studied and investigated enough. In this paper, we will introduce the design and operating principle in S-band erbium-doped fiber amplifier. Simultaneously, using two laser architectures will retrieve the single-frequency operation. In addition, the stability of stable output has also been demonstrated experimentally.

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Property Characterization and Biological Function of High Far-Infrared-Emitting Ceramic Powders [ 下載 PDF ]

Yung-Sheng Lin, Ming-Yu Lin, Ting-Kai Leung, Chi-Hung Liao, Tsung-Tao Huang, Hui-Shun Huang

Far-infrared ray (FIR) is one of the topics in energy medicine which is hot for the past few years. There are numerous FIR products in markets but their FIR emissivities are almost insufficient and biological effects are quite limited. This study develops high efficient FIR-emitting ceramic powders composed of several metal oxides. The emissivity of this material in life light between 6 to 14 µm is above 0.98. Experiments reveal this material is antibacterial and it can miniature water clusters. The small water clusters can benefit cell metabolism, germination and growth of seeds and enhance in antioxidant activity of tea leaf. Besides it increase the skin temperature and microcirculation of human bodies. These results show this FIR material can be widely applied in human daily life in the future.

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The Principle and Application of Two-Dimensional Gas Chromatograph and Two-Dimensional Gas Chromatograph/Mass Spectrometer [ 下載 PDF ]

Wei-Chun Lin, Chin-Yuan Cheng, Wang-Hsien Ding

Comprehensive two-dimensional gas chromatography (GC × GC) has been designed more than 15 years, currently, it develops to the consummation and related literatures published continuously. The two-dimensional gas chromatography is one of the most powerful analytical tools for the analysis of very complex samples. This technique is based on the application of two GC columns coated with different stationary phases (different polarity), connected in series through a special interface (modulator), the modulator ensures the preservation of the separation achieved in the first column. Compounds coeluting from the first column undergo additional separation in the second column. This leads to increased separation power of the technique compared to conventional 1D GC. If mass spectrometry is used as the detector, the mass spectra from the sample are highly identical to the mass spectra from the library.

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Overview of Nonvolatile Memory Technology—SONOS and Nanocrystal Device [ 下載 PDF ]

Po-Tsun Liu, Ting-Chang Chang, Chun-Hao Tu, Shih-Ching Chen, Chih-Hung Chen

For nonvolatile semiconductor memories (NVSM), there are two limitations encountered at the present time. (1) The limited potential for continued scaling of the device structure: this scaling limitation stems from the extreme requirements on the tunnel oxide layer. To balance between program/erase speed and retention time, there is a trade-off between speed and reliability for the optimal tunnel oxide thickness. (2) The quality and strength of tunnel oxide after plenty of program/erase cycles, once a leaky path has been created in tunnel oxide, all charges stored in the floating gate will be lost. Therefore, two approaches, the silicon-oxide-nitride-oxide-silicon (SONOS) and the nanocrystal nonvolatile memory devices, have investigated to overcome this oxide quality limit of the conventional floating gate NVSM.