基于光外差技术的超宽带频率响应测量系统

Measurement System of Ultra-Wideband Frequency Response Based on Optical Heterodyne Technique

介绍了一种利用光外差技术测量光电探测器超宽带频率响应的测试方法。将一个可调谐外腔激光器和一个固定波长的分布反馈激光器(DFB-LD′s)产生的激光输入到光电探测器进行混频。通过对可调激光器腔长的控制,可以在光电探测器产生从DC到上百GHz的拍频信号,在无需额外校准光源的情况下就可以进行光电探测器超宽带频率响应特性的测试,这是该方法最突出的优点。实验证明该方法比较准确、简便、易于操作。在实验中,对两个不同的InGaAs p-i-n探测器进行测量,得到器件的3 dB带宽分别为14.4 GHz和40 GHz。该测量方法对同类实验的研究和应用都具有实用意义。

An ultra-wideband frequency response measurement system for optoelectronic devices has been established using the optical heterodyne detection method utilizing a tunable laser and wavelength-fixed distributed feedback-laser diode. By controlling the laser diode cavity length, the beat frequency is swept from DC to beyond 100 GHz, and ultra-wideband frequency response character can be measured without using any high-speed light modulation source and additional calibration. This is the major advantage of this method. In the measurement, two InGaAs p-i-n detectors have been tested, and their 3 dB bandwidths are 14. 4 GHz and 40 GHz, respectively. Experiments show that this method is accurate and easy to carry out. Finally, several suggestions for improving measurement accuracy are given.