Patent ID: 6862312

Claim:
A method of making a laser diode for use in a tunable laser, said laser diode having a particular gain spectrum at least about 100 nm wide to permit tuning over a broad tuning range, comprising: a) selecting a barrier material and a quantum material such that the degree of lattice-mismatch dictates a critical thickness required to obtain spontaneous island formation of quantum dots and the bandgap difference determines the number of possible confined zero or one-dimensional states; b) growing same thickness of said barrier material in an active region between an electron emitting layer and a hole emitting layer on a substrate, said electron and hole emitting layers having a lattice constant dose to that of said substrate; c) determining the size and shape of the quantum dots and the number of quantum dots per unit area required to achieve said particular gain spectrum; d) determining growth parameters required to achieve said size and shape and said number of dots per unit area determined in step c; e) depositing said quantum material using said growth parameters determined in step d; f) waiting a specified amount of time allow for the self-assembling growth to form said quantum dots to achieve zero or one dimensionality of states and in said shapes and sizes and number per unit volume determined in step d while permitting inhomogeneous broadening to occur during said self-assembling growth so that said gain spectrum extends over said broad range due to said inhomogeneous broadening and perturbation effects; and g) growing some thickness of said barrier material to cover the quantum dots and return to a planar growth front.