Multielement laser-diode linewidth theory.
A simple formula is presented for the linewidth-power product of multielement laser diodes, under the condition that the active elements are submitted to the same field. The theory is particularly applicable to laser diodes incorporating two thin active layers of different composition. Such diodes can be modeled by two active conductances in parallel with a linear admittance. If the injected current exhibits full shot noise, the laser linewidth is given by the same expression as for a single active element, except that alpha and alpha(2) must be replaced by their average values weighted by the injected bias currents, where alpha denotes the phase-amplitude coupling factor. The same result is applicable to conventional index-guided laser diodes.
Arnaud
J
J