Temperature insensitive filter Ghent University
An integrated wavelength-selective filter device (10; 20; 30; 40) comprises a first optical element (14) for directing received radiation into a direction defined by a first angle (a), and a second optical element (15) being a diffractive element configured diffracting said directed radiation under a second angle. The second angle is such that for a single reference wavelength the diffracted radiation is directed into a propagation medium for advancing therein towards a predetermined position on the first optical element or on a further optical element (14a) for filtering radiation having a ...