单模光纤设计和性能的进展

Advances in Single Mode Fiber Design and Performance

本文对近年来长波长单模光纤设计和性能的进展作了综合评述。常规单模光纤的零色散波长在1.3μm有匹配包层和压低包层两种折射率分布,设计和选择芯径d、折射率差△、归一化频率V截止波长、模场直径d_p等参数时,要使1.3μm的损耗、色散和抗弯能力等性能最佳化。于是考虑波导色散抵消材料色散,使零色散波长移至最低损耗波长1.55μm及其附近窗口。这类光纤称为色散移位和色散平坦单模光纤,其折射率分布有三角形、分隔纤芯和四包层等几种设计。将MCVD、OVD、VAD、PCVD四种工艺的设计和性能列表相互比较。最后总结光纤通信所用单模光纤的现状和前景。

The paper attempts to review the technical advances in the single mode fiber design and performance for use of long wavelength communications.The conven- tional single mode fiber has zero dispersion wavelength at 1.3μm, with step index profile of matched cladding and depressed cladding. The design parameters include core diameter d, index difference A, normalized frequency V, cut-off wave- length λ_c, mode field diameter d_p, and all are considered to obtain the optimum performane for 1.3μm, including loss, dispersion and bending sensitivity. The next design is to shape the waveguide dispersion curve to cancell the material dispersion so as to shift the zero dispersion wavelength to 1.55μm or to flatten the low dispersion around the 1.55μm window. The paper lists the latest compa- rison of the design and performane provided by MCVD, OVD, VAD and PCVD technologies. Concluding remarks are made for the current status and prospects of the single mode fiber technology.