Performance of two coupled lasers

The theory of Spencer and Lamb (1972) for the performance of two coupled lasers is generalized to account for intercavity phase shifts (transmitted wave minus reflected wave) other than + or - pi/2. The results are directly applicable to the case of two coupled single-line Fabry-Perot resonators with intercavity losses. Analytic expressions are given for steady-state performance and for the regions of stable operation. It is concluded that it is generally not possible to achieve stable operation on all potential laser lines for two multiline coupled lasers. Competition between stable and unstable lasing modes in these devices may result in stable operation on a reduced number of lines.