| 摘要 |
Proposed is a technique for detecting a damaged VCSEL in a short time and at low cost. It shows the light emission spectrum of a multi-mode VCSEL before an ESD damage, and the light emission spectrum which shows several peaks corresponding to the structure of the active layer (MQW) and the upper and lower reflectors (DBR) is obtained. On the other hand, when the VCSEL which has an ESD damage has a damage in the active layer, the light emission spectrum which shows fewer peaks than the original number of peaks is obtained. Accordingly, the light spectrum analyzer analyzes the light emission spectrum, and it is determined that ESD damage has occurred when the number of peaks is equal to or smaller than a predetermined number, e.g., two peaks. |
