An optical add drop component uses wavelength-selective reflectors which are switchable between first and second positions. This enables an add or drop function to be selectively applied. When the add or drop function is not required, there is no signal attenuation or degradation of an input signal. When an add or drop function is required, selected frequencies are added or dropped and other signal frequencies can pass through the wavelength-selective reflector. No demultiplexing operation is required.