Interaction of modules in discharge tube

We have shown experimentally that by choosing the value of the direct component of the discharge current and the frequency of modulation of alternating component it is possible to control the coupling of modules in a multi-module gas-discharge CO 2 -laser with series connection of modules having common resonator and gas space. The depth of intermodulation was measured when one of modules is supplied with only direct current, while other one by the modulated.