Analysis of distributed feedback organic semiconductor lasers

An analysis is undertaken of a DFB structure designed to lower the threshold gain of organic semiconductor lasers operating at 632 nm. Coupling coefficients in the structure are found to be of order 350 cm ^-1 using a 200 nm grating period. Incorporating a DFB grating reduces gain threshold by approximately 50% of that required for an equivalent FP structure. Surface relief gratings are found to be a good means of providing the feedback, offering high coupling coefficients in respect to their position away from the field maxima as well as cost advantages in manufacturing using imprinting techniques