Abstract: An optical switching device, comprises an optical switch and an optical connector receiving means mateable with a connector., means for effectuating switching by engaging a connector in said receiving means, characterised in that said switching effectuating means acts or is acted upon once a connector is sufficiently engaged in the receiving means for optical communication with the connector to occur.

Abstract: To facilitate the use of relatively high frequency data transmission services over a wireline communication resource originally deployed to support low frequency voice band services, an assessment of the wireline communication resource (50-52) is based on attenuation of high frequency test signals, of known original level, that are generated (18) injected into the wireline communication resource from a test point (12). A detector (60) at a potential point of service, e.g. at a customers' premises (14), detects an attenuated level of the test signals and generates a control signal (70, 82), such as a drive current, indicative of the attenuation caused by the wireline communication resource (50-52). The control signal (70, 82) is then indirectly communicated back to the test point (12) in a coded form, and preferably within a voice band transmission.

Abstract: A planar waveguide structure has, supported on a lower refractive index buffer layer (5), a pair of optical cores (1, 2) that, over at least a portion of their length, are closely spaced. These cores are covered with a layer (6) of cladding material comprising boron and phosphorus doped silica glass deposited by PECVD as a succession of individually annealed layers in order to minimize the incidence of voids in the deposit between the cores.