An article from OSE team selected by the Optical Society of America (OSA)
The article titled "Effect of injection current and temperature on signal strength in a laser diode optical feedback interferometer" of Jalal Al Roumy (OSE team), published in Applied Optics in January 2015, has been selected by the Optical Society of America (OSA) for inclusion in the " Spotlight on Optics "which highlights the best work published by OSA (Optics Letters, Optics Express, Applied Optics, ...).
The article presents a simple analytical model that describes the injection current and temperature dependence of optical feedback interferometry signal strength for a single-mode laser diode. The model is derived from the Lang and Kobayashi rate equations, and is developed both for signals acquired from the monitoring photodiode and for those obtained by amplification of the corresponding variations in laser voltage.
The model shows that both the photodiode and the voltage signal strengths are dependent on the laser slope efficiency, which itself is a function of the injection current and the temperature. Moreover, the model predicts that the photodiode and voltage signal strengths depend differently on injection current and temperature, which was proven experimentally.
Therefore, this simple model provides important insight into the radically different biasing strategies required to achieve optimal sensor sensitivity for both interferometric signal acquisition schemes.