High-Accuracy Real Time Calibration of Tunable Fabry-Pérot Filter on Large Range

Wavelength readout system constructed of fiber Fabry-Perot tunable filter and virtual instrument

“…According to the theory of optical coherence, the coherent light bounces back and forth, resulting in optical resonation in F-P cavity, and the intensity of transmission light reaches maximal value when the phase displacement of adjacent beams φ is equivalent to 2kπ . Just as the formula 1 illustrated, the phase displacement φ is related to the length of F-P cavity l and the index of refraction n. Hence, the intensity of reflection or transmission can be adjusted by regulating the length of cavity [3] . The wavelength of transmission fluctuates within a certain range, suppose λ is wavelength of transmission at a certain time t, when the condition that the maximum transmittance of filter is met (Eq.2) and the output voltage of photoelectric detection circuit reaches peak [4,5] .…”