OPTICAL APPARATUS AND INSTRUMENTS; OPTICAL APPARATUS AND INSTRUMENTS FOR MEASUREMENT, INTERROGATION OR PROCESSING OF OPTICAL SIGNALS; OPTICAL COMPONENTS; OPTICAL DEVICES; FIBER-OPTIC COMPONENTS; FIBER-OPTIC DEVICES, OPTICAL FIBER GRATINGS, OPTICAL COMPONENTS INCORPORATING OPTICAL FIBER GRATINGS, OPTICAL DEVICES INCORPORATING OPTICAL FIBER GRATINGS; OPTICAL WAVEGUIDE DEVICES, PLANAR OPTICAL WAVEGUIDE DEVICES, AND PARTS AND FITTINGS FOR ALL OF THE AFORESAID GOODS;