Abstract: According to the present invention, a travelling-wave electroabsorption modulator (TW-EAM) comprises: an optical waveguide with a plurality of adjacent regions electrically isolated from each other, the regions being characterized alternately by the properties of electroabsorption (EA) and optical transparency over the same range of optical wavelengths, and a microwave transmission line located above the optical waveguide, such that sections of the transmission line located above EA regions in the optical waveguide are in electrical contact with said EA regions, whereas sections of the transmission line located above transparent regions in the optical waveguide are electrically isolated from said transparent regions. In the absence of a microwave signal, the EA regions are substantially transparent to light in the optical waveguide. When a microwave signal is applied to the EA regions, they become substantially absorbing at the wavelength of the light in the optical waveguide.

Abstract: The invention relates to an electroabsorption modulator (EAM) (300), comprising a first EAM section (302) optically coupled to a second EAM section (304), a transition wavelength in the electroabsorption (EA) spectrum of the first EAM section (302), at which absorption changes substantially, being different to a transition wavelength in the EA spectrum of the second EAM section (304). The EAM (300) compensates for chirp (which is caused by intrinsic absorption effects) by driving the two sections with a signal (312) generated from a common modulating signal (314). The driving signal (312) at the first EAM section (302) being preferably in anti-phase with the driving signal (312) at the second EAM section (304).

Abstract: A method of testing an edge-emitting or edge-coupled opto-electronic device comprises the step of aligning an optical probe with an optical interface of the device so that light is coupled between the optical interface and the optical probe, wherein the optical probe comprises an optical fibre having a light turning structure at a distal tip that changes the direction of propagation of light incident on the light turning structure.