Using wave guide theory, we deduce scalar approximate solution about transmissive light through a fiber weak-guide and give the expressions of field in each component.
根据光波导理论，推算出弱导条件下光沿光纤传输场的标量近似解，给出场的各分量表达式，以便分析讨论。
2
For the transmissive mode, no achromatic quarter-wave film is needed.