Direct monitoring of the coupling constant in vectorial lasers

The partial separation of two laser eigenstates is used to differentially modulate their net gains, hence permitting to demonstrate a simple method to measure the coupling constant C in bistable vectorial lasers. The same experimental setup works equally well for weak coupling. A good agreement between theoretical and experimental values is obtained in both cases. Moreover, the method is applied to the case of external cavity VCSELs used in optical clocking experiments.