论文部分内容阅读
光的外差检测技术和零差检测技术,因它们能提供长中继间距,故引起人们的兴趣。移频键控传输,因为能通过激光二极管的直接调制而容易地完成调制任务,所以比移幅键控或移相键控更有希望。日本NTT电气通信实验室在一条270km长的单模光纤上已实施了400Mbit/s的移频键控传输和外差检测实验。实验中,用工作在1.546μm波长的埋置异质结构的分布反馈(DFB)二极管作移频键控发射器和本地振荡器。发射器的输出功率为+10.6dBm,光纤输入功率为+5.5dBm;本地振荡器的输出功率是+8dBm,光纤输入功率为+2.5dBm;耦合器的耦合比是1:6,附加损耗为0.4dB。光纤在1.546μm的损耗为0.196dB/km。
Light heterodyne detection technology and homodyne detection technology, because they can provide long relay spacing, it is cause for interest. Frequency-shift keying is more promising than shift-keying or phase-shift keying, because modulation can easily be done by laser diode direct modulation. Japan’s NTT Electric Communications Laboratory has implemented 400Mbit / s FSK transmission and heterodyne testing on a 270km single-mode fiber. In the experiment, a distributed heterostructure distributed feedback (DFB) diode operating at a wavelength of 1.546 μm was used as a frequency-shift keying transmitter and a local oscillator. The transmitter output power is + 10.6dBm and the optical fiber input power is + 5.5dBm. The output power of the local oscillator is + 8dBm and the optical fiber input power is + 2.5dBm. The coupling ratio of the coupler is 1: 6 and the additional loss is 0.4 dB. The loss of optical fiber at 1.546 μm is 0.196 dB / km.