Telecommunications apparatus and instruments; optoelectronics apparatus and instruments; optical apparatus and instruments; optical goods; optical glass; lasers, not for medical purposes; light-conducting filaments; optical waveguides; waveguides for high power beam delivery; laser welding devices; laser cutting devices; optical fibres; optical fibre amplifiers; optical fibre lasers; optical fibre sensors; polarisation maintaining optical fibres; dispersion shifted optical fibres; nonlinear optical fibres; optical multiplexing devices; optical demultiplexing devices; microstructured optical materials; microstructured optical fibres; photonic crystal materials; photonic crystal devices; photonic crystal fibres; photonic crystal lasers; optical frequency metrology devices.