High Frequency (>lOGHz) Bragg-Diffraction-Type Electro-optic Deflectors Using Slant Periodic Domain Inversion.

本研究的目的是将我们发明和研究的行位相光栅器件的衍射型从拉曼-纳特型改进为布拉格型，从而研制出一种光学高频(10 GHz)移位器。基于对电光(EO)晶体的窄幅斜周期域反转技术，实现了器件工作的质的改进。目标器件将用于光微波接口、光WDM通信以及科学和工业测量。这种新型移频器类似于声光(AO)移频器。然而，在常规声光器件无法工作的更高频率范围(&gt；10 GHz)，我们将20μm域反转技术应用于LiTaO_3电光晶体，设计并制作了新型移频器。首次从实验上证实了布拉格衍射型移频器的工作频率为16 GHz，转换效率为82%。这一结果将发表在IEEE光子学技术快报上。此外，我们还提出了一种新的超快电光偏转器和平光频率梳产生器，利用周期域反转中反向区宽度的横向变化。这两种新器件都是设计和制造的。实验证实，这种新型偏转器的偏转速度为亚皮秒(&lt；1ps)，有32个可分辨光斑，作为一种外相位调制方法，新型梳状产生器可以产生最宽的平坦边带(0.8THz-3dB带宽)。

The purpose of this study is to develop an optical high frequency (>10 GHz) shifter by improving the diffraction type of the traveling phase grating device, which was invented and has been studied by us, from the Raman-Nath type to the Bragg type. The qualitative improvement on our device operation has been achieved based on the narrow-width slant periodic domain inversion technique to an electrooptic (EO) crystal. The target devices will be useful for an optical microwave interface, optical WDM communication, and scientific and industrial measurements.The new frequency shifter is similar to an acoustooptic (AO) frequency shifter. However, it is possible to operate in the higher frequency range (>10GHz), where conventional AO device never operates.We designed and fabricated new frequency shifter by applying 20μm domain inversion technique to LiTaO_3 electro-optic crystal. The operation of the Bragg diffraction type frequency shifter with 16GHz frequency shift arid 82% conversion efficiency was experimentally confirmed for the first time. This result is to be published on IEEE Photonics Technology Letters.In addition, we proposed anew kind of ultrafast electrooptic deflector and flat-optical frequency comb generator utilizing transversal variation of the widths of reversed areas in periodic domain inversion. Both of new devices were designed and fabricated. It was confirmed experimentally that the new deflector has subpicosecond (<1ps) deflection speed and 32 resolvable spots and new comb generator can generate the widest flat sidebands (0.8THz -3 dB bandwidth) as an external phase modulation method.