Devices for Transmitter, Wave-Propagation, and Receiver in Coherent Optical Communication Systems

相干光通信系统中的发射机、波传播和接收机设备

• 批准号: 61420031
• 负责人: KIKUCHI Kazuro
• 金额: $ 12.54万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (A)
• 财政年份: 1986
• 资助国家: 日本
• 起止时间: 1986 至 1988
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-61420031/
• 关键词: Coherent Optical Communication; Semiconductor Laser; 光ファイバ; ダイバーシティ; コヒーレント光ファイバ通信; コヒーレント受信機; サイドトンネル型光ファイバ; ホモダイン受信機; 光ファイバ干渉計

The improvement of the spectral purity of the sdignal laser and the local laser is a crucial step to realize practical coherent optical communication systems. The effect of the 1/f noise on the spectral spread of semiconductor lasers is investigated, and the results are given in the following: In the high power limit, the narrowest linewidth is determined from the 1/f noise. Since the 1/f noise is harmless in the high bit-rate system, it is most important to achieve the high power state keeping a high longitudinal mode stability.The frequency modulation is also a key technology in coherent optical communication systems. We show that DFB lasers haveing the separated-electrode structure are suitable for frequency modulation.We develop two methods for analyzing polarization maintaining optical fibers with the asymmetrical refractive-index distribution: One is based upon the finite-element method, and the other the boundary-integral method. Both are used for the design of new refractive-index distributions.We propose two countermeasures to cope with the polarization fluctuation of the transmitted signal. One is the polarization recombining scheme, and the other is the polarization diversity scheme. The latter is especially useful in practical systems, because the power penalty is less than 0.5dB and the phase diversity can be implemented in the same receiver.

提高卫星激光器和本地激光器的光谱纯度是实现实用相干光通信系统的关键一步。研究了1/f噪声对半导体激光器频谱扩展的影响，结果表明：在高功率极限下，最窄的线宽由1/f噪声决定。由于1/f噪声在高码率系统中是无害的，因此获得保持高纵模稳定度的高功率状态至关重要，而频率调制也是相干光通信系统中的一项关键技术。提出了两种分析折射率分布不对称的保偏光纤的方法：一种是基于有限元方法，另一种是边界积分法。这两种方法都被用来设计新的折射率分布。针对传输信号的偏振起伏，我们提出了两种对策。一种是极化重组方案，另一种是极化分集方案。后者在实际系统中特别有用，因为功率损失小于0.5dB，并且可以在同一接收机中实现相位分集。

项目成果

T.Okoshi: IEEE/OSA Jour.of Lightwave technology. LT-4. 1556-1562 (1986)

T.Okoshi：IEEE/OSA Jour.of 光波技术。

K. Hotate: "Drift of an optical fiber gyroscope caused by the Faraday effect:Influence of the earth's magnetic field" OSA Applied Optics. 25. 1086-1092 (1986)

K. Hotate：“法拉第效应引起的光纤陀螺仪的漂移：地球磁场的影响”OSA 应用光学。

K.Iwatsuki: "Backscattering in an optical passive ring-resonator gyro: Experiment" OSA Applied Optics. 25. 4448-4451 (1986)

K.Iwatsuki：“光学无源环形谐振陀螺仪中的反向散射：实验”OSA 应用光学。

N.Kishi: "Proposal for a boundary-integral method without using Green's function" IEEE Trans. on MTT. MTT-35. 887-892 (1987)

N.Kishi：“关于不使用格林函数的边界积分方法的提案”IEEE Trans。

T. Okoshi: "Four-port homodyne receiver for optical fibre communications comprising phase and polarisation diversities" Electron. Lett.23. 377-378 (1987)

T. Okoshi：“用于光纤通信的四端口零差接收器，包括相位和偏振分集” Electron。