Research On The Effect Of Low Bias Current On The 1/f Noise Correlation Of Semiconductor Lasers

This paper focuses on the quality and reliability of high-power semiconductor lasers,and focuses on the correlation of 1/ f noise at lower bias current.In order to avoid the damage of the experimental samples,this paper takes use of the nondestructive testing method to measure the samples,then evaluates their quality and reliability indirectly through the acquisition of the characteristic parameters and measured curves.In this paper,two kinds of non-destructive testing techniques are used to test the samples,namely the correlation-bias current discriminant method and the electrical derivative detection discriminant method.In this paper,a 1/f noise measurement system based on combination of 9812 D and CF-9200 is used to measure the low frequency electrical noise of high power 976 nm In Ga As quantum well semiconductor lasers in the range of less than 1/30 threshold current.By means of the acquired time domain data and the power spectrum characteristic,the system detects that the noise is purely 1/f noise.Based on the theoretical model of 1/f noise source and the characteristics of wavelet transform coefficients,a "correlation-bias current" analysis model is proposed to replace the traditional "noise amplitude-bias current" analysis model to determine the 1/f noise source.In order to compare the advantages and disadvantages of the two analytical models,the Gaussian white noise is added to the pure 1/f noise as a contrast experiment.The variance characteristics of wavelet coefficients,wavelet coefficient correlation and noise amplitude of the 1/f noise before and after adding the white noise are observed.After repeated measurements,the experimental results show that the "wavelet coefficient correlation-bias current" model proposed in this paper is less susceptible to white noise or is affected by white noise weakly,that is,it is more resistant to the interference of white noise.So the analysis model is more advantageous.In the electrical derivative detection method,this paper designs the photoelectric detection system of semiconductor laser based on S3C2410 in combination with the electrical derivative detection technology.We obtain its terminal voltage and optical power by measuring the samples,and calculate the electrical derivative and draw some relevant curves.Then we determine whether the device is damaged by extracting parameters related with the electrical derivative and observing the shape of initial peaks.In order to improve the experience of human-computer interaction,the GUI interface is also designed to display the real-time data and the curves.The experiment proves that the method is more direct.In summary,the electrical derivative method proposed in this paper can determine whether the device is damaged,and "correlation-bias current" method can accurately reflect the specific damage to the device parts.So these two methods are integrated with each other,which can provide more reference and new ideas for judging the quality and reliability of semiconductor lasers.