Stress dependence of transmission frequency of a fiber Fabry‐Perot etalon buried in a fiber ferrule

The transmission characteristics of a fiber Fabry‐Perot etalon formed by mirror‐finishing both ends of an optical fiber are dependent on the external stress applied. A theoretical study and an experimental confirmation of a fiber Fabry‐Perot etalon with a ferrule diameter of 2.5 mm and a resonator length of 4 mm are carried out to investigate variations of the transmission frequencies as a function of the stress. It is confirmed that there is a proportional relationship of 1.5 GHz/N and −0.1 GHz/N in the transmission frequency variations versus the stress in the axial and radial directions. Arbitrary transmission frequencies within FSR can be obtained by adjustment of the stress at values less than 17 N, so that the fiber Fabry‐Perot etalon can be used as a tunable optical frequency filter.