Frequency shift in a system of two laser diodes

An easily reproducible construction of two butt-Joint laser diodes based on a GaAs/InGaAs/InGaP structure is fabricated and investigated. The construction forms a composite cavity in which about half of stimulated emissions of a long-wavelength diode transforms into emissions of a ground mode of a wavecguide of a short-wavelength diode. It is found that the emission spectrum from the composite cavity is represented not only by fundamental (close) frequencies of two diodes with a power of similar to 1 W, but also by their sum frequency and second harmonic with a power as high as 1 mu W. The found nonlinear enrichment of the emission spectrum of a two-frequency heterolaser with a composite cavity is caused by a lattice nonlinearity of the semiconductor and allows one to plan equally effective intracavity generation of various frequencies in a far-IR range at room temperature.