Abstract: A method of producing a planar waveguiding device having a core [10] and a cladding [17]. The cladding has groves [11,12] directly interfacing [15,16] with the core [10]. A layer of core glass [10] is deposited on the surface of a substrate [23,24]. This layer is etched to produce a shaped layer which includes a first core portion [10] having the same configuration as the intended core [10] and an expanded core portion [30] wherein the core glass extends beyond the intended core boundary. A glass covering layer [21] is deposited over the etched core glass and grooves [11,12] are produced by etching through the covering layer [21] and into said expanded core portion [30].

Abstract: A planar waveguiding device includes at least on section of core which is located between and adjacent to two grooves. The refractive index within the grooves is substantially equal to one and the grooves are located so that the evanescent fields of optical signals travelling in the core extend into the grooves. Preferably the grooves have a direct interface with the core and they extend through a layer located above the core into a layer located below the core. Where the cores have bends, e.g. bends with radii of curvature below 2 mm the grooves are located both inside and outside the bends.

Abstract: An arrayed waveguide grating [WDG] comprises I/O slabs (53a, 53b) interconnected by a grating region (51). The grating region (51) comprises many, e.g. at least 25 and preferably 50 to 500, individual cores (61,62,63), which have different lengths so as to provide wavelength selectivity by causing phase changes in light conveyed between the I/O slabs (53a, 53b). There are bends (64) for providing the different lengths and, to improve optical guidance round the bends, empty (R.I.=1) grooves (71) are located adjacent to the inside (71.1) and outside radii (71.2) so that the evanescent fields extend into the grooves (71). In order to keep the dimensions small, which improves the optical accuracy, tight bends (preferred radii of curvature of less than 2 mm and especially less than 500 &mgr;m) are desirable. The grooves conveniently have tapered ends and they extend into straight portions adjacent to the bends.

Abstract: It has been demonstrated that B containing glasses are sensitive to radiation in the band 225-275 nm and, therefore, B2O3 glasses are particularly adapted to receive refractive index modulation, e.g., to make reflection gratings. Glasses containing SiO2 and B2O3 are particularly suitable when the grating is to be localized in the cladding of a fiber. Glasses containing SiO2, GeO2, and B2O3 are suitable when the grating is in the path region of a waveguide, e.g., in the core of a fiber.

Abstract: An optical device includes a waveguiding configuration and an electrical capacitive configuration. The capacitive configuration includes glass electrode region(s) and glass dielectric region(s) with electrical leads, e.g., metallic conductors, for applying electrical control signals to the electrode region(s). The preferred metals for the conductors are Ni, Ti and Au. The waveguiding structure is configured so that the fields associated with optical signals propagating therein interact with dielectric region(s). During the use of the device control signals are applied to the dielectric region(s) by the electrical leads. The control signals have the effect that temporary electric fields are applied to the dielectric region(s). The fields change the optical properties of the dielectric region(s) and this affects the propagation of the optical signals. The device can either be produced in planar or fibre configurations.

Abstract: Boron containing glasses are sensitive to radiation in the band 225-275 nm and therefore, B.sub.2 O.sub.3 glasses are particularly adapted to receive refractive index modulation, e.g., to make reflection gratings. Glasses containing SiO.sub.2 and B.sub.2 O.sub.3 are particularly suitable when the grating is to be localized in the cladding of a fibre. Glasses containing SiO.sub.2, GeO.sub.2 and B.sub.2 O.sub.3 are suitable when the grating is in the path region of a waveguide, e.g., in the core of a fibre.

Abstract: It has been demonstrated that B containing glasses are sensitive to radiation in the band 225-275 nm and, therefore, B.sub.2 O.sub.3 glasses are particularly adapted to receive refractive index modulation, e.g., to make reflection gratings. Glasses containing SiO.sub.2 and B.sub.2 O.sub.3 are particularly suitable when the grating is to be localized in the cladding of a fiber. Glasses containing SiO.sub.2, GeO.sub.2, and B.sub.2 O.sub.3 are suitable when the grating is in the path region of a waveguide, e.g., in the core of a fiber.