Timmermann C C
Appl Opt. 1977 Sep 1;16(9):2380-2. doi: 10.1364/AO.16.002380.
We found that it is very dangerous to stare directly at thQ free end of an optical cable excited by a GaAlAs laser or by a high radiance LED. We determined the minimum tolerable distance between the human eye and the cable end. In the case of a cable with one multimode fiber, the typical safety zone should be 1 m when using a laser light source and 15 cm when using an LED. In the case of a single mode fiber the critical distance is approximately two to four times as large as in the multimode case; however, when taking into account typical values of the power level in single mode fibers, the critical distance is approximately 1 m as well. For N fibers within the cable the critical distance agrees with that of the single fiber, provided that the fibers are not too closely packaged.
我们发现，直接盯着由GaAlAs激光器或高辐射发光二极管激发的光缆自由端是非常危险的。我们确定了人眼与光缆末端之间的最小可容忍距离。对于包含一根多模光纤的光缆，使用激光光源时典型的安全区应为1米，使用发光二极管时为15厘米。对于单模光纤，临界距离大约是多模情况的两到四倍；然而，考虑到单模光纤中的功率电平典型值时，临界距离也大约为1米。对于光缆内的N根光纤，只要光纤包装不过于紧密，临界距离与单根光纤的相同。
