Optical Communication Systems Using Quantum State Control

这项研究被归类为自1974年以来由Yuen，Helstrom和Hirota研究的量子通信领域。在本研究中，我们澄清了许多新的结果，高质量的光通信系统，使用量子态控制，这是由玉川大学于1988年提出的，并已开发的庆应义塾大学，玉川大学，东京研究所。山梨大学自1990年以来本课题是庆应义塾大学和玉川大学合作研究完成的。结果我们得到了以下结果.研究了简并参量放大器的特性和光学双稳特性。结果表明，在较宽的带宽范围内，压缩光的产生条件和量子噪声的压缩.当具有量子态控制的光被传输时，其上级特性被传输损耗破坏。因此，系统性能的劣化应根据损失程度加以澄清。我们证明了使用量子态控制光的系统的性能上级任何损失量的标准量子极限.我们展示了Hirota4提出的量子态控制系统的一些例子。我们研究了Hirota定义的条件酉过程的性质，并证明了线性衰减过程就是其中的一个例子.为了实现对接收量子态的控制，需要降低输入量子态的内积。指出非线性分束器是内积约化现象的一个例子.提出了一些用于光通信和测量系统的压缩光调制方案。推导了它们在调制过程中的频谱变换。并给出了最佳调制条件。

This research is classified as the field of the quantum communication which has been studied by Yuen, Helstrom, and Hirota since 1974. In this research, we have clarified many new results for high quality optical communication system by using quantum state control which was proposed by Tamagawa University in 1988, and has been developed by Keio University, Tamagawa University, Tokyo Inst.Tech. and Yamanashi University since 1990. This project has been accomplished as a research cooperation between Keio University and Tamagawa University. As a result we have obtained the following results.1. Properties of degenerate parametric amplifier and optical bistability were investigated. As a result, we showed conditions of generation of squeezed light and squeezing the quantum noise over wide bandwidth of them.2. When the light with quantum state control is transmitted, its superior properties are destroyed by the transmission loss. Therefore the degradations of system performance should be clarified with respect to the degree of loss. We showed that the performance of the systems using the quantum state controlled light is superior to the standard quantum limit with any amount of loss.3. We showed some examples of the received quantum state control systems which has been proposed by Hirota4. We investigated the properties of the conditional unitary process which was defined by Hirota and showed that the linear attenuation process is one of the examples.5. In order to realize the received quantum state control, the reduction of the inner product of the input quantum states is required. It was pointed out that the nonlinear beamsplitter is one of examples of the reduction phenomena of the inner product.6. Some modulation schemes of squeezed light were proposed for optical communication and measurement systems. Their spectrum transformations through the modulations were derived. The optimum condition for modulation was also given.