Research on Integrated Nonlinear Optic Quasi-Phase-Matched Wavelength Conversion Devices for Wavelength-Division-Multiplexing Optical Communication of Next Generation

研究了未来光网络中准相位匹配波导型非线性光波长转换器件的设计、制作和性能评价及其在超高速光信号处理中的应用。主要研究结果如下：1.建立和改进了基本的制备工艺。建立了用于30×25 mm~2面积准相位匹配的高质量铁电畴倒置光栅的制作技术。证明了形成亚微米周期的磁畴倒置光栅的可能性。发展了低损耗锌扩散LiNbO_3光波导的制备技术。建立了差频产生型波长转换器件的设计技术。在标准配置下，获得了324%/W的归一化转换效率。在为提高效率而提出的高折射率包层波导型中，获得了高达790%/W的效率。3提出了一种新的偏振无关波长转换器件结构。作为初步实验，利用掺锌LiNbO_3O波导制作了准相位调制器件，倍频效率达到15%/W。4提出并制作了一种基于级联二次谐波和差频产生的光开关，以及基于干涉仪和和频集成器件的光门开关。实现了皮秒级的光开关。5研究了高功率集成半导体激光器作为波长转换器件的泵浦源。提出并制作了一种高功率外腔可调谐激光器。输出功率为105 mW，波长调谐范围为22 nm，准直光束输出接近衍射极限。

Design, fabrication, and evaluation of quasi-phase matched waveguide nonlinear-optic wavelength conversion devices for future photonic network and their applications to ultrafast optical signal processing were studied. The obtained results are summarized as follows.1 Elementary fabrication techniques were established and improved. Technique to form high-quality ferroelectric domain- inverted gratings for quasi-phase matching up to 30 X 25 mm^2 area was established. Possibility of forming domain inverted gratings of submicrion period was shown. Technique to fabricate low-loss Zn-diffused LiNbO_3 waveguides was developed.2 Technique for designing wavelength conversion devices of difference-frequency generation type was established. In the standard configuration, normalized conversion efficiency of 324 %/W was obtained. In a high-index cladding waveguide type proposed for improvement of efficiency, an efficiency as high as 790 %/W was accomplished.3 A new device construction was proposed for polarization-independent wavelength conversion. As a preliminary experiment, a QPM device was fabricated using a Zn : LiNbO_3O waveguide, and SHG efficiency of 15 %/W was demonstrated.4 As applications to ultrafast optical signal processing for optical communication, an optical switch based on cascaded second-harmonic generation and difference-frequency generation, and an optical gate switch based on an integrated interferometer and sum-frequency generation device, were proposed and fabricated. Picosecond optical switching was demonstrated.5 Integrated high-power semiconductor lasers for application as a pump-wave source for the wavelength convension devices were studied. A high-power external-cavity tunable laser was proposed and fabricated. Output power of 105 mW, wavelength tuning rage of 22 nm and nearly-diffraction-limited collimated beam output were demonstrated.