Evaluation method for the optical feedback factor and linewidth enhancement factor using phase discontinuities in self-mixing interferometry signals

2020 ◽  
Vol 59 (3) ◽  
pp. 687
Author(s):  
Chol-Yong Ri ◽  
Chol-Su Kim ◽  
Guk-Chol Ri ◽  
Jong-Chol Kang ◽  
Chol-Min Pak ◽  
...  
Keyword(s):  
Enhancement Factor ◽  
Evaluation Method ◽  
Optical Feedback ◽  
Feedback Factor ◽  
Linewidth Enhancement Factor ◽  
Linewidth Enhancement

scholarly journals Measuring Linewidth Enhancement Factor by Relaxation Oscillation Frequency in a Laser with Optical Feedback

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 4004 ◽  
Author(s):  
Yuxi Ruan ◽  
Bin Liu ◽  
Yanguang Yu ◽  
Jiangtao Xi ◽  
Qinghua Guo ◽  
...  
Keyword(s):  
Light Beam ◽  
Oscillation Frequency ◽  
Enhancement Factor ◽  
Optical Feedback ◽  
Relaxation Oscillation ◽  
Measurement Methods ◽  
Linewidth Enhancement Factor ◽  
Simulation And Experiment ◽  
Factor Alpha ◽  
Linewidth Enhancement

This paper presents a new method for measuring the linewidth enhancement factor (alpha factor) by the relaxation oscillation (RO) frequency of a laser with external optical feedback (EOF). A measurement formula for alpha is derived which shows the alpha can be determined by only using the RO frequencies and no need to know any other parameters related to the internal or external parameters associated to the laser. Unlike the existing EOF based alpha measurement methods which require an external target has a symmetric reciprocate movement. The proposed method only needs to move the target to be in a few different positions along the light beam. Furthermore, this method also suits for the case with alpha less than 1. Both simulation and experiment are performed to verify the proposed method.

scholarly journals An analytical method for estimation of parameters of Self Mixing Interferometric phase equation over all feedback regimes

2020 ◽  
Author(s):  
Junaid Khan
Keyword(s):  
Semiconductor Lasers ◽  
Enhancement Factor ◽  
Optical Feedback ◽  
External Cavity ◽  
Estimation Of Parameters ◽  
Phase Equation ◽  
Linewidth Enhancement Factor ◽  
Interferometric Phase ◽  
Linewidth Enhancement ◽  
Feedback Level

This paper presents a novel algorithm for measuring the linewidth enhancement factor of semiconductor lasers and the optical feedback level factor in a semiconductor laser with an external cavity. The proposed approach is based on analysis of the self-mixing phase equation to deduce equations for finding parameters given only knowledge of the perturbed phase. The effectiveness of the method has been validated with accuracy of 8.6%and 1.7% for 'C' and alpha respectively while covering all feedback regimes.

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