Effect of Near-field Distribution on Transmission Characteristics of Fiber-fed Fabry–Perot Etalons

Fiber-fed etalons are widely employed in advanced interferometric instruments such as gravitational-wave detectors, ultrastable lasers and calibration reference for high-precision spectrographs. We demonstrate that variation near-field distribution of the feeding fiber would deteriorate spectrum precision fiber-fed Fabry-Perot etalon, especially when at order 3 * 10-10 or higher is required. The octagonal reinforced with double scrambler could greatly improve steadiness uniformness distribution. When building wavelength calibrators sub-m s-1 radial-velocity instruments, should be considered meticulously.