Twin beam in fibers ; its production with a wave-guide type nonlinear crystal

双束光纤；

基本信息

批准号：
08554011
负责人：
KUGA Takahiro
金额：
$ 9.79万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

项目摘要

Twin beam is a pair of optical beams that have the same statistical properties of light. Twin beam is described only by a Quantum theory and there is no classical analogue to it. In many years, twin beam has been utilized to clarify the Quantum nature of light, such as an intensity interference, photon entanglement, non-local correlation (EPR paradox) etc. Since twin beams were generated by a parametric down-conversion with bulk nonlinear crystals in most of the former works, there were unavoidable difficulties so called a geometrical problem. In the parametric down-conversion, pairs of photons are emitted in a fairly large solid angle as long as a phase match condition is satisfied. Therefore, it is almost impossible to collect all photons in pairs. On the other hand, if one uses a wave-guide type nonlinear crystal as the down-converter, pairs of photons are confined in the wave-guide and it is easy to couple them to optical fibers and detect all pairs of photons.We utilized the wave-guide type crystal to generate the twin beam. First of all, we characterized the crystal by means of a second harmonics generation (SHG). We made a laser diode with an extended cavity oscillating in 1.55 mu m range. We measured SHG spectra and efficiency of the crystal by changing the frequency and power of the laser diode and compared them with theoretical calculations. We found a small discrepancy between experiments and calculations, but the discrepancy was acceptable if we took account of an inhomogeneity of the crystal.Unfortunately, we can not complete our project within a given period for lack of efficient detectors in 1.55 mum region and the limitation of time to develop such detectors. However, we accumulated the basic information and data to realize twin beam in fibers. We will continue the project and complete it in the near future.

双光束是一对光束，具有相同的光的统计特性。双光束仅通过量子理论来描述，并且没有经典的类似物。多年来，双光束已被用来阐明光的量子性质，例如强度干扰，光子纠缠，非本地相关性（EPR悖论）等。在大多数以前的作品中，晶体都存在不可避免的困难，因此被称为几何问题。在参数下转换中，只要满足相位匹配条件，光子对就以相当大的实体角度发射。因此，几乎不可能成对收集所有光子。另一方面，如果一个人使用波化型非线性晶体作为下连接器，则将对光子对限制在波导中，并且很容易将它们搭配到光纤并检测所有成对的光子。波引物型晶体生成双子束。首先，我们通过第二次谐波（SHG）来表征晶体。我们制作了一个激光二极管，并在1.55 mu m范围内进行延伸的腔振荡。我们通过更改激光二极管的频率和功率来测量晶体的SHG光谱和效率，并将其与理论计算进行了比较。我们发现实验和计算之间存在很小的差异，但是如果我们考虑了晶体的不均匀性，则可以接受。开发此类探测器的时间。但是，我们积累了基本信息和数据，以实现纤维中的双光束。我们将继续该项目并在不久的将来完成该项目。