1885巴尔默 (Johann Jakob Balmer,1825-1898)发现能够描述四种光谱 波长的公式,后来 Angstrom发现这些谱线属于氢原子 1893维恩 Wilhelm Carl Werner Otto fritz franz Wien,1864-1928)在实验 上发现热体最大辐射的波长反比于温度(维恩定律)。维恩在炉子上钻 了一个小孔,模拟理论黑体
What needed? to combine signals and/or to split them multiple ways up to 1000X1000 for WDM LANS three important characteristics Return Loss the amount of power that is reflected and thus lost Insertion LoSs the amount of signal lost in the total transit through the device Excess Loss additional loss of a device
