Electrically controllable grating, and optical elements having an electrically controllable grating.

摘要

An electrically controllable grating (6) is provided by forming regions (4 and 5) of different refractive index within an electro-optic material (2). Electrodes (10 and 12) are provided so that a readily controllable electric field may be applied to the index grating formed by the alternating regions such that the refractive index of the regions may be varied electrically to form a controllable grating. The grating (6) may be used as an electrically controllable distributed Bragg reflector to allow variable wavelength feedback within a laser cavity. The grating may be used to perform wavelength division multiplexing and/or frequency modulation.