Linearity and third-order intermodulation distortion in DFB semiconductor lasers

This paper presents a systematic investigation of the third-order intermodu lation distortion characteristics in distributed feedback (DFB) semiconduct or lasers. The influence of several nonlinearities, such as longitudinal sp atial hole burning, gain compression, and relaxation oscillation, is consid ered. Detailed analysis shows that it is possible to make different nonline arities cancel one another to give a low intermodulation distortion by choo sing the appropriate DFB structure and facet conditions. Specifically, cond itions for cancellation between spatial hole burning and gain compression n onlinearities are introduced.