Bandpass Tunable Filter | SIMTRUM Photonics Store

1,Light enters through the "Fiber Optic Input Collimator" and ultimately exits from the "Fiber Optic Output Collimator".

2,Collimator: Its function is to convert the divergent light emitted from the optical fiber into collimated light (parallel beams), and simultaneously to efficiently couple collimated light from free space back into the optical fiber.

3,Grating: The grating causes diffraction and interference. According to the diffraction equation, light of different wavelengths is diffracted at different angles.

4,Fourier Transform Lens: It is used to focus the light dispersed by the grating and perform a Fourier transform. This focuses light of different wavelengths onto distinct spatial positions, converting angular differences into spatial displacement.

5,Movable Blocker: By precisely moving this blocker (via a manual micrometer or a motorized stepper motor), the cutoff point of the transmitted spectrum can be accurately selected. This achieves the effect of allowing either long-wavelength or short-wavelength components to pass, thus realizing passband wavelength tuning.

6,Inverse Fourier Transform Lens: It reconverts the spatially distributed waves, which have undergone the Fourier transform, back into an angular distribution.

7,Grating: It compensates for the angular deviation introduced by the first grating, eliminates residual dispersion, and ensures the output beam is correctly aligned into the optical fiber.