A Time Difference Method for Measurement of Phase Shift between Distributed Feedback Laser Diode (DFB-LD) Output Wavelength and Intensity

Sensors

Yongning Liu¹  Jun Chang²  Jie Lian¹  Zhaojun Liu¹  Qiang Wang¹  Cunguang Zhu¹ 

[1] School of Information Science and Engineering, Shandong University, Jinan 250100, China;

关键词: phase shift;    DFB-LD;    infrared spectroscopy;    fiber optics sensors;   

DOI  :  10.3390/s150716153

来源: mdpi

【 摘 要 】

A time difference method to conveniently measure the phase shift between output wavelength and intensity of distributed feedback laser diodes (DFB-LDs) was proposed. This approach takes advantage of asymmetric absorption positions at the same wavelength during wavelength increase and decrease tuning processes in the intensity-time curve by current modulation. For its practical implementation, a measurement example of phase shift was demonstrated by measuring a time difference between the first time and the second time attendances of the same gas absorption line in the intensity-time curve during one sine or triangle modulation circle. The phase shifts at modulation frequencies ranging from 50 Hz to 50 kHz were measured with a resolution of 0.001π. As the modulation frequency increased the shift value increased with a slowed growth rate.

【 授权许可】

CC BY   
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