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Parametric Frequency-conversions Using Nonlinear-Optical Fibers

使用非线性光纤的参数频率转换

基本信息

批准号：
11450032
负责人：
UMEGAKI Sinsuke
金额：
$ 9.28万
依托单位：
Keio University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

In optical-communication systems instead of telecommunication ones, silica-glass fibers are being installed , while in LAN, plastic optical fibers(POF) will be used for considering cost performance. However, interconnection between these two kinds of fibers is not easy, since their tranparent wavelength-range and radii of their cores are different from each other.This research is a propsal to simultaneously solve the above two problems by using a nonlinear-optical fiber and an axicon. The fiber with a core of a nonlinearoptical organic crystal will provide parametric interconversion of wavelengths of 1.32 and 0.66 μm or 1.55 and 0.775 μm which are used in silica fibers and POFs, respectively, while an axicon or a conical prism can convert the beam radii radiated from these fibers. There, the Cerenkov-radiation type phase-matching is used in the interconversion, that is, the second-harmonic generation(SHG) and the degenerate optical parametric generation(OPG) . We have tried to realize the proposal and have obtained the following results.1. We succeeded in the preliminary experiment of SHG from 1.064 to 0.532 μm and also in the experiment of SHG from 1.32 to 0.66 μm with efficiencies of around 1%, for fundamental powers of several 10s mW using one-mm long fibers. As for OPG, we optimized the nonlinear-optical fiber by selecting the cladd glass and evaluated the gain coefficient based on our theory, although we have not yet obtained the OPG signal.2. Using an axicon, the radiated second-harmonic wave with a conical wavefront was collimasted and the radius of the second-harmonic ring could be controlled by changing the distance between the nonlinear-optical fiber and the axicon, by which we demonstrated a possibility of optical interconnection of the silica and plastic fibers.We are now trying to obtain the OPG signal and to realize the opticalinterconnection.

在光通信系统中，石英玻璃光纤正在取代电信系统，而在局域网中，考虑到成本性能，塑料光纤（POF）将被使用。然而，由于这两种光纤的透射波长范围和纤芯半径不同，使得它们之间的互连并不容易，本研究提出用非线性光纤和轴棱锥同时解决上述两个问题。以非线性光学有机晶体为纤芯的光纤可实现石英光纤和POF中波长分别为1.32和0.66 μm或1.55和0.775 μm的参量相互转换，而轴棱锥或圆锥棱镜则可转换从这些光纤辐射出的光束半径。其中，切伦科夫辐射型相位匹配用于相互转换，即二次谐波产生（SHG）和简并光学参量产生（OPG）。我们已经努力实现这个建议，并取得了以下成果。我们成功地进行了1.064 ~ 0.532 μm的二次谐波初步实验和1.32 ~ 0.66 μm的二次谐波实验，在1 mm长的光纤上，基波功率为几十mW，效率约为1%。对于OPG，我们通过对包层玻璃的选择对非线性光纤进行了优化，并根据理论计算了增益系数，虽然我们还没有得到OPG信号.利用轴棱锥对辐射出的具有锥形波前的二次谐波进行准直，并通过改变非线性光纤与轴棱锥之间的距离来控制二次谐波环的半径，从而证明了石英光纤与塑料光纤光互连的可能性，并试图获得OPG信号，实现光互连。