The wavelength combining technique has been widely used to increase the power scaling of lasers. The edge filter, which is nonpolarizing for wavelength, has proven to be a critical component for the combining process, and should have high spectral efficiency, high laser induced damage threshold, and excellent thermal stability. Here, we design a superior nonpolarizing long-wavelength pass edge filter using a novel depolarized initial film structure based on a tuned Fabry-Perot interference filter. The coating fabricated by electron beam evaporation can withstand 130kW/cm2 of continuous laser energy with high spectral efficiency at 45° and a small temperature rise.