Abstract

The distributed feedback (DFB) laser was first studied by Kogelnick and Shank¹. They considered the behavior of a system with a flat gain and a periodic spatial modulation of both the gain and index of refraction. Sargent et al. studied the case of finite gain bandwidth with a simple line shape². These systems all exhibited a unique solution for the distributed feedback mode equations. Casperson showed that hole burning in a Doppler lineshape may lead to side-bands in a conventional laser³. We have considered the case of an acoustic wave distributed feedback gas laser (AWDFBGL) in which an acoustic wave provides both periodic index and gain modulation. Our model system is homogeneously broadened CH₃F gas with a complicated gain lineshape due to molecular structure and A. C. Stark effects induced by the intense CO₂ TEA laser pumping⁴. This system is attractive as it allows for large gains (> 10m⁻¹) with narrow line widths and long Bragg spacings.

© 1985 Optical Society of America