APPARATUS FOR FILTERING OPTICAL RADIATION AT AN OPERATING WAVELENGTH

摘要

Apparatus for filtering optical radiation at an operating wavelength (19), which apparatus comprises a grating (1) written into a waveguide (2), and which grating (1) has a first end (3), a second end (91), a first bandwidth (24), a maximum reflectivity (29), a first group delay variation (17) defined with respect to the first end (3), and a second group delay variation (18) defined with respect to the second end (91), wherein the first and second group delay variations (17), (18) are with respect to the first bandwidth (24), the maximum reflectivity (29) is greater than 50 %, the first group delay variation (17) is between 0.1ps and 100ps, and the second group delay variation (18) is between 0.1ps and 100ps.