A photoluminescence technique for characterizing the InP-InGaAsP channeled substrate buried heterostructure wafer for lasing wavelength.

A photoluminescence technique to predict the lasing wavelength of channeled substrate buried heterostructure lasers at wafer level is described. The technique consists of optically-pumping a piece from the As-grown wafer at 80K to achieve lasing action and determining the lasing wavelength at 300K after correcting for the wafer dependent temperature shift of the bandgap. By comparing the optically determined wavelength against the lasing wavelength measured on the device, the accuracy of the technique to predict wavelength is found to be +-20 nm. The factors which limit the accuracy are discussed. The optical pumping technique enables fast feed-back to the crystal grower when melt compositions are being optimized to achieve a certain device wavelength.