半導体レーザの自己結合効果を用いた微小変位センサの研究

Abstract

Recently, using self-coupling effect of semiconductor laser, a compact distance or vibration meter has been studied. In this work, a new type of micro displacement sensor using self-coupling effect of semiconductor laser is studied. The displacement more than 1/2 wavelength can be measured from the peak number of interference output by self-coupling effect. To measure the displacement below 1/2 wavelength, this sensor is made from a movable structure. Adding micro vibration of 6KHz to the sensor and ajusting DC bias voltage applied to the sensor, a displacement of the sensor is controlled so that the vibration output becomes a maximum value. When the target displaces, it is again controlled to get a maximum vibration output. The micro displacement of the target is measured from the sensor displacement. It is found that the micro displacement can be measured with resolution power of several 10 nm.