虽然光纤所传输的大多数光被封闭在光纤内,但整个辐射场的一小部分光,即迅衰波,是在靠近纤芯的包层区运行的。根据这一原理,大多数光纤分支方法是通过使包层产生某种物理或机械变形,来使光纤内的信号脉冲发生作用。无论是利用激光或离子束对光纤刻槽,或是把光纤焰融到另一根光纤,分支工作总是一项极为细致的工艺过程, Although most of the light transmitted by an optical fiber is enclosed within an optical fiber, a fraction of the light in the entire field, fast decay, runs in the cladding near the core. According to this principle, most optical fiber branching methods make signal pulses within an optical fiber function by causing some physical or mechanical deformation of the cladding. Whether using a laser or ion beam to notch a fiber, or melting a fiber flame to another fiber, branching is always an extremely detailed process,