This question is related to that one: Can laser diode be operated with lower than specified voltage?
I am driving a laser diode in a current controlled fashion. What actually happens below the lasing threshold?
In experiments, I can clearly observe some "fluorescence". The fluorescence intensity makes up for only ~0.2% of electrical power. Even more interestingly, the fluorescence intensity stagnates at a nearly constant level, independently of current. Also the voltage remains at a constant level.
Can one theoretically predict some sort of curve for the I / V - characteristics of a Laser Diode below threshold? Similar to the shockley equation for ideal diodes?