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提出了一种光纤波导折射率渐变的新型锥形（Taper）耦合器件，其原理是基于光纤中Ge缺陷在紫外光照射下而产生的光致折射率的变化。利用光纤在高压、低温下渗氢技术使单模光纤的光致折射率变化△n达6×10-3数量级；通过控制曝光条件就可以在光纤中产生一定规律的锥形结构，使单模光纤的模场半径由4．8μm缩小到3．2μm。由耦合波理论分析表明该器件具有较好的基模传输特性。
A novel Taper coupling device with a gradual index refraction of fiber waveguide is proposed. Its principle is based on the change of photoinduced refractive index caused by the Ge defect in the fiber under UV irradiation. The use of optical fiber under high pressure, low temperature hydrogen permeation technology to make single-mode optical fiber refractive index change Δn up to 6 × 10-3 orders of magnitude; by controlling the exposure conditions can produce certain regular tapered structure in the optical fiber, so that single-mode The mode field radius of the optical fiber is reduced from 4.8 μm to 3.2 μm. Coupled wave theory shows that the device has better fundamental mode transmission characteristics.