Refractometer standard

Fabry-Perot

Fiber Pigtailed Fabry-Perot Etalons consist of a solid or air gap etalon, collimating lenses and input/output fibers. They can be made for different spectral window (UV, VIS, IR) dependent on the specific application. The solid etalon is made of optical quality glass (fused silica, BK7...) while air spaced etalons are built on Zerodur frame. The faces are highly polished in order to achieve very good flatness and parallelism. They are coated with dielectric thin films to assure high finesse and transmission. The etalons are subsequently aligned with optical axis of collimators and fixed on the housing by a low shrinkage optical grade adhesive. This device acts as a narrow bandwidth filter with series of transmission peaks uniformly spaced in frequency domain. They have better spectral resolution and constant FSR than fiber based Fabry-Perot etalons. In applications where temperature stability is critical, air gap etalon offer better thermal stability. See PDF for more on basic of Fabry-Perot interferometer. Fabry-Perot Etalons are use in telecom systems as narrow band filters to lock a laser cavity on a fixed frequency. They are also used as a frequency reference according to ITU grid and in other applications such as optical telecommunication, optical sensing and others.