| 摘要 |
PROBLEM TO BE SOLVED: To provide a technology for detecting damaged VCSELs in a short time and at low cost. SOLUTION: As shown in chart (a) in Fig.3, a multimode VCSEL that has yet to suffer ESD damage exhibits an emission spectrum showing a number of peaks corresponding to the structure of an active layer (MQW) and upper and lower reflectors (DBR). As shown in chart (b) in Fig.3, meanwhile, a VCSEL that has suffered ESD damage exhibits, when it has a damaged active layer, an emission spectrum showing a smaller number of peaks than the initial number of peaks. Thus, when the number of peaks, which is obtained by analyzing an emission spectrum using an optical spectrum analyzer, is a predetermined number for example, two or less, it is determined that ESD damage has occurred. COPYRIGHT: (C)2011,JPO&INPIT
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