Title :
Theory of Reduction of Residual Amplitude Modulation in Mid-Infrared Wavelength Modulation Spectroscopy by Injection Locking of Quantum Cascade Lasers
Author :
Yong, Kelvin S. C. ; Haldar, Manas K. ; Webb, Jeffrey F.
Author_Institution :
Fac. of Eng., Comput. & Sci., Swinburne Univ. of Technol., Kuching, Malaysia
Abstract :
A simplified rate equation model is used to investigate suppression of residual amplitude modulation in injection-locked quantum cascade lasers with the master laser modulated by its drive current. Quasi-static and dynamic expressions for intensity modulation suppression and frequency modulation reproduction by the slave laser are presented. The suppression peaks at a specific value of the injection ratio for a given detuning and linewidth enhancement factor. The frequency modulation reproduction is less than 100% and decreases rapidly at frequencies higher than 300 MHz. The intensity modulation suppression remains constant during this frequency range. The effects of injection ratio, detuning, coupling efficiency and linewidth enhancement factor are discussed.
Keywords :
amplitude modulation; frequency modulation; intensity modulation; laser mode locking; optical modulation; quantum cascade lasers; coupling efficiency; drive current; dynamic expressions; frequency modulation reproduction; injection ratio; injection-locked quantum cascade lasers; intensity modulation suppression; linewidth enhancement factor; master laser modulation; mid-infrared wavelength modulation spectroscopy; quasistatic expressions; rate equation model; residual amplitude modulation suppression; slave laser; Frequency modulation; Intensity modulation; Quantum cascade lasers; Steady-state; Injection locking; intensity and frequency modulation; quantum cascade lasers; wavelength modulation spectroscopy;
Journal_Title :
Selected Topics in Quantum Electronics, IEEE Journal of
DOI :
10.1109/JSTQE.2015.2423616
