| 摘要 |
PURPOSE:To obtain a light chopper useful in characteristic measurement for optical communication system, photo-devices and others by an arrangement wherein the lens is disposed in such a way that incident light is focused on the light chopping means arranged between two lenses. CONSTITUTION:Light introduced from a connector 15 connecting with optical fibers is image-transformed by a lens 11 so as to be focused on a shutter 14 opened or closed at the natural frequency of a tuning fork vibrator 13. The interrupted light enters into a lens 16 and then focuses so as to enter into optical fibers connecting with a connector 16. In this arrangement, when resonant frequency of the tuning fork vibrator is set at 280Hz, vibration of 400mum is produced with the application of 20Vpp, and the rod lenses are disposed to make the image transformation of 1:1 therebetween, the diameter of the focused light becomes 60mum upon connecting to optical fibers with the core diameter of 60mum. Rising and falling times of thus arranged light chopper become about 50mus and thus light pulse very near to a square wave is obtained. By so doing, it becomes possible to provide the light chopper useful in characteristic measurement for optical communication system, photo- device and others. |
