Measuring apparatus comprising a fabry-perot interferometer

An apparatus (500) for spectral measurements comprises: - a Fabry-Perot interferometer (FP1) having an adjustable mirror gap (dGAP), and - a control unit (CNT1) for controlling the mirror gap (dGAP), wherein the apparatus (500) is arranged to: - set the mirror gap (dGAP) to a first mirror gap value (dGAP,1) to provide a first spectral transmittance peak (P1,A) at a first wavelength (?A), wherein the first spectral transmittance peak (P1,A) has an effective spectral width (DELTA?1,A,EFF), - change the mirror gap (dGAP) to a second different mirror gap value (dGAP,2) to provide a second spectral transmittance peak (P2,A) at the first wavelength (?A), and a third spectral transmittance peak (P1,C) at a second wavelength (?C), and - control the position of a mirror (M2) of the Fabry-Perot interferometer (FP1) near the second different mirror gap value (dGAP,2) such that the effective spectral width (DELTA?2,A,EFF) of the second spectral transmittance peak (P2,A) is substantially equal to the effective spectral width (DELTA?1,A,EFF) of the first spectral transmittance peak (P1,A).

Patent family as of 14.7.2026
CA3306826 AA, EP4767036 A1, FI131821 B, FI20236129 A, WO25078722 A1