Measurement of the linewidth enhancement factor in DFB lasers using a high-resolution optical spectrum analyzer

GaAs-Based Quantum Dot Lasers

“…Thus, the a H -factor appears as an optical power-dependent parameter strongly influenced by nonlinear gain and/or carrier-heating effects (Agrawal, 1990). Finally, the modified linewidth method relies on the measurement of SL's linewidth as a function of emitted power under and above the laser's threshold, and the ratio of the slopes of the curves linewidth as a function of the inverse power gives directly the a H -factor value (Villafranca et al, 2005). This accumulation of carriers in the ES arises even though lasing in the GS is still occurring and therefore increases the effective a H -factor of the GS transition introducing a nonlinear dependence with the injected current (Grillot et al, 2008b).…”

Investigation on the linewidth enhancement factor of multiple longitudinal mode semiconductor lasers

“…There are mainly three categories of measurement methods: those relying in the measurement of the phase noise in the optical spectrum [17][18][19], those based on modulating the laser and analyze the frequency chirp [11,12,[20][21][22][23], and those based on optical feedback and the Lang-Kobayashi theory [9,10,24].…”

The Linewidth Broadening Factor: A Length-Scale-Dependent Analytical Approach

“…b) The Linewidth method measures the spectrum linewidth and fits the results to known parameters, so that the α-factor can be extracted by applying Henry formula (equation (26) [2]). c) The Modified Linewidth method measures the linewidth in terms of the emitted power in the threshold region, and the ratio of the slope of the linewidth vs. inverse power curve gives directly the α-factor [3]. d) The FM/AM method [4] relies on high-frequency current modulation which generates both amplitude (AM) and optical frequency (FM) modulation.…”