A proposal for second and third derivative electronic resistance- based laser stabilization.

The subject of this paper is a proposal that high order derivatives of the I-V characteristic be used to stabilize the dc bias of an injection laser at threshold. Experimental evidence is presented that second and third order laser voltage derivatives d(2)v/dI(2) and d(3)v/dI(3) can be measured with sufficient precision to display the large peaks identified with the onset of lasing, even while the laser is being pulse modulated. The higher order derivatives offer advantages over previously utilized electronic parameters when used in stabilization circuits because of the sharp isolated peaks identifying threshold, and because of their insensitivity to series resistance.