“Theoretical Analysis of Coupling Constant, Longitudinal Modes, and Threshold Gain for Coupled-Cavity Semiconductor Lasers”, J. eng. sustain. dev., vol. 13, no. 3, pp. 1–12, Sep. 2009, Accessed: Jul. 03, 2024. [Online]. Available: https://jeasd.uomustansiriyah.edu.iq/index.php/jeasd/article/view/1522