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

本研究的目的是通过改进我们发明和研究的行相光栅器件的衍射类型，从拉曼-纳特型到布拉格型，开发一种光学高频（> - 10ghz）移频器。基于窄宽斜周期畴反转技术的电光晶体，实现了器件操作的质的改进。目标器件将用于光微波接口、光波分复用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，它可以在更高的频率范围内工作（bbb10ghz），而传统的AO设备永远不会在这个频率范围内工作。将20μm畴反演技术应用于LiTaO_3电光晶体，设计制作了新型移频器。实验首次证实了移频16GHz、转换效率82%的Bragg衍射型移频器的工作原理。这一结果将发表在《IEEE光子技术快报》上。此外，我们还提出了一种利用周期域反演中反转区域宽度横向变化的超快电光偏转器和平面光频梳发生器。设计并制造了这两种新装置。实验证实，新型偏转器具有亚皮秒（<1ps）的偏转速度和32个可分辨的光斑，作为一种外部相位调制方法，新型梳状发生器可以产生最宽的平边带（带宽为0.8THz -3 dB）。

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.