Chirped optical fibre grating with variable apodisation

摘要

A chirped optical fibre grating has a predetermined desired wavelength-dependent response across an operational bandwidth. The grating is formed by apodising it so that the degree of apodisation varies along the grating to provide a degree of loss at a given longitudinal position which, when combined with the response of the chirped grating before apodisation gives the desired response at the optical wavelength reflected at that longitudinal position along the grating. The grating may be incorporated into an optical system which includes an optical processing element having a wavelength-dependent response connected to the grating. The combination of the apodised grating and the response of the optical element provides a desired wavelength-dependent response.