测量了光纤面板、光锥、耦合光纤面板以及耦合光锥的光谱透过率和调制传递函数。光谱透过率测量结果表明, 光纤面板的光谱透过率与光纤面板的厚度以及入射光的波长有关。光纤面板的厚度越厚, 透过率越低。对相同厚度的光纤面板而言, 漫射光的透过率低于准直光的透过率。原因是漫射光在光纤面板中的传输远距离大于准直光在光纤面板中的传输距离, 因此吸收更多。光纤面板除玻璃产生吸收外, 玻璃中的稀土元素也会产生杂质吸收。调制传递函数的测量结果表明, 光纤面板的调制传递函数不仅与光纤的丝径有关, 还与光纤面板的厚度有关, 光纤面板的厚度越厚, 调制传递函数越低。原因是少部分光线在光纤中传输时会发生串光。光锥与光纤面板相比, 光谱透过率和调制传递函数均较低。当光锥与光纤面板耦合后, 特别是在漫射光入射条件下, 光谱透过率更低。对 550 nm的波长而言, 透过率仅为 11.7%。光锥与光纤面板耦合后, 不仅光谱透过率有损失, 而且调制传递函数也降低, 30l p/mm处的调制传递函数仅为 47%。

Spectrum transmittance and modulation transfer function(MTF)of fiber optic faceplate(FOP), fiber optic taper(taper), FOP coupled each other and taper coupled with FOP are measured. The measured results of spectrum transmittance indicate that the transmittance of FOP is affected by the thickness of FOP and the wavelength of incident light. For the FOP with the same thickness, the transmittance of diffused light is lower than that of collimated light. The reason is that the transmission distance of the diffused light is far longer than that of the collimating light in channel of FOP. This leads to more light absorption for diffused light than collimated light in fiber channel. In addition of the light absorption of the glass in FOP, rare earth element in the glass can generate impurity absorption as well. The measured result of the modulation transfer function shows that the modulation transfer function of FOP is not only associated with fiber diameter, but also associated with the thickness of the FOP because optical crosstalk may happen during transmission in optical fiber. Both the spectrum transmittance and the modulation transfer function of the taper are lower than those of the FOP. After a fiber optic taper is coupled to a FOP, especially in the case of diffused light, the spectrum transmittance is much lower. For the wavelength at 550 nm, the transmittance is only 11.7%. After a taper is coupled to a FOP, not only the spectrum transmittance reduces, but also the modulation transfer function becomes lower. The measured modulation transfer function at 30 lp/mm is only 47%.