Theory for optimum design and analysis of distributed-feedback lasers

Theory for optimum design of a distributed-feedback (DFB) laser is presented, based on a new set of coupled-power equations. A novel /spl lambda//4 phase shift index-coupled AR-coated DFB laser structure, which theoretically exhibits a longitudinally uniform power density, is proposed. It is shown that the theory is very simple and provides an easy way to analytically understand the physical mechanism crucial for the optimum design. Our theory can also be easily applied to the optimization of the design of gain-coupled, complex-coupled DFB laser structures as well as high power DFB lasers.