At the mirrors of a laser diode self-mixing interferometer,the output beams carry anti-correlated(i.e.f in phase opposition)interferometric signals,whereas the superposed noise fluctuations are(partially)correlated.Th...At the mirrors of a laser diode self-mixing interferometer,the output beams carry anti-correlated(i.e.f in phase opposition)interferometric signals,whereas the superposed noise fluctuations are(partially)correlated.Therefore,by using an instrumental output of the interferometer as the difference of the two,we double the amplitude of the self-mixing useful signal,while the superposed noise is reduced.To validate the idea,we first calculate the noise reduction by means of a second-quantization model,finding that in a laser diode the signal-to-noise ratio(SNR)can be improved by 8.2 dB,typically.Then,we also carry out an experimental measurement of SNR and find very good agreement with the theoretical result.展开更多
文摘At the mirrors of a laser diode self-mixing interferometer,the output beams carry anti-correlated(i.e.f in phase opposition)interferometric signals,whereas the superposed noise fluctuations are(partially)correlated.Therefore,by using an instrumental output of the interferometer as the difference of the two,we double the amplitude of the self-mixing useful signal,while the superposed noise is reduced.To validate the idea,we first calculate the noise reduction by means of a second-quantization model,finding that in a laser diode the signal-to-noise ratio(SNR)can be improved by 8.2 dB,typically.Then,we also carry out an experimental measurement of SNR and find very good agreement with the theoretical result.
