Semiconductor ring laser diodes (SLD) have been receiving attention for their potential use as source in photonic integrated circuits. Advantages of a ring laser include ease of integration because of no need for cleaved facets and they can be made very compact by folding their cavity . Ring laser have a unique feature, clockwise and counter- clockwise, in their lasing modes. If unidirectional traveling-wave oscillation can be achieved, spatial hole burning effects seen in Fabry-Perot and distributed feedback lasers can be avoided. In this work, the unidirectional oscillation is accomplished by controlling the taper shape structure. The whole laser cavity is formed using four reflection mirrors (TIR) and an output coupler passive waveguide. According to the Beam propagation Method (BPM) simulation, we find that the clockwise and counterclockwise oscillations have different behavior under various taper shape , indicating bidirectional oscillation can be eliminated. Moreover, bending loss¡Bmode transformation and optical gain are all included in calculation model. The waveguide is fabricated in the following steps: (1) ion implantation to get electrical isolation (2) selectively wet etching to form waveguide ridge (3) evaporation n- and p- electrode (4)spatter with Si3N4(5) planarization (6) evaporation microwave transmission line.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18283号 / 工博第3875号 / 新制||工||1594(附属図書館) / 31141 / 京都大学大学院工学研究科電子工学専攻 / (主査)教授 野田 進, 教授 川上 養一, 教授 藤田 静雄 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Abstract Single frequency laser has the advantages of high stability in frequency and low noise. Therefore, single frequency laser is now widely used in applications, such as high precision measurement, holography and data storage. Attempts to generate second harmonic radiation using a linear cavity have typically resulted in significant amplitude fluctuations due to longitudinal mode coupling. Various techniques have been proposed for solving the so called ¡§green problem¡¨ to achieve single longitudinal mode operation, such as inserting optical component in the conventional linear cavity or use ring cavity instead of linear cavity. Uni-directional ring cavity has shown to be the most robust method for producing single frequency laser. The purpose of this study is to develop compact and low-cost single frequency IR and green lasers. A novel symmetrical two-mirror figure ¡§8¡¨ ring cavity is developed. Instead of using several laser mirrors for beam deflection, this ring laser system employs only two spherical mirrors to form the laser cavity for traveling wave oscillation and eliminates ¡§spatial hole burning¡¨ caused by the standing wave operation. In this thesis, we use two-mirror figure ¡§8¡¨ ring cavity for the generation of single frequency IR and green lasers. The polarization status is crucial for high efficient intracavity frequency doubling. The polarization evaluation in a nonplanar and reentrant ring cavity is characterized by measuring the thermally induced linear and circular birefringence and analyzing the polarization rotation due to cavity configuration. We have demonstrated a 2-mirror figure ¡§8¡¨ ring cavity which is compact and has few optical elements. The stable single frequency laser output of our ring cavity promises to make the design widely applicable to solid-state lasers.

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