Abstract: An optical device includes a planar substrate (10) on top of which is deposited a layer of waveguide material (402). A waveguide circuit (404) is etched into the waveguide material (402). A cover (426) selectively encapsulates the substrate (10) around the waveguide circuit (404) while leaving space to provide a gap above the waveguide circuit (404). A liquid material (30) having a lower index of refraction than the waveguide material is filled into the gap above the waveguide circuit (404) such that the liquid acts as an overclad for the waveguide circuit (404).

Abstract: A method of manufacturing a planar or integrated optical circuit in which a core layer (20) is formed on a substrate (10) and patterned to define optical features (such as waveguides) using a mask having a first portion (30) defining the desired core patterns (20a) and a second portion (35) corresponding to one or more alignment marks (20b). After etching the core layer, only the first portion (30) of the mask is removed, the second portion (35) of the mask being left to provide alignment marks (20b) which are highly visible through the subsequently-deposited overclad layer (40). The alignment marks (20b) are very accurately positioned with respect to the core patterns (20a), thus enabling further optical devices to be overlaid on the existing structure with accurate alignment to the underlying core patterns. The mask material (35) left on the alignment marks (20b) may be partially oxidized before the overclad is deposited.

Abstract: A method of fabricating a phased array narrow band wavelength division multiplexer including an arrayed waveguide, a slab waveguide and a transition region between the array waveguide and the slab waveguide comprising etching the transition region with a reactive ion etch to form vertically tapered waveguides between the arrayed waveguides.

Abstract: An optical component comprising one or more optical elements (35′) aligned with the end(s) of one or more waveguides (25′) is fabricated by a process in which, first of all, a doped silica core layer (20) is deposited on a substrate (10) (or on a buffer layer on the substrate), and subsequently a partial overclad layer (30A) typically 1-5 &mgr;m thick is deposited on the core layer. The partial overclad layer and core layer are patterned and etched so as simultaneously to define the optical element(s) and the waveguide core(s). Afterwards, the overclad is completed by depositing a further overclad layer (30B). In the case of application of this fabrication method to a grating-based NBWDM device, the metallisation of the grating can precede or follow the deposition of the second overclad portion (30B). In either case, low-temperature deposition processes are required for deposition of this second overclad portion.

Abstract: A method of manufacturing a planar or integrated optical circuit in which a core layer (20) is formed on a substrate (10) and patterned to define optical features (such as waveguides) using a mask having a first portion (30) defining the desired core patterns (20a) and a second portion (35) corresponding to one or more alignment marks (20b). After etching the core layer, only the first portion (30) of the mask is removed, the second portion (35) of the mask being left to provide alignment marks (20b) which are highly visible through the subsequently-deposited overclad layer (40). The alignment marks (20b) are very accurately positioned with respect to the core patterns (20a), thus enabling further optical devices to be overlaid on the existing structure with accurate alignment to the underlying core patterns. The mask material (35) left on the alignment marks (20b) may be partially oxidized before the overclad is deposited.

Abstract: An optical device includes a planar substrate (10) on top of which is deposited a layer of waveguide material (402). A waveguide circuit (404) is etched into the waveguide material (402). A cover (426) selectively encapsulates the substrate (10) around the waveguide circuit (404) while leaving space to provide a gap above the waveguide circuit (404). A liquid material (30) having a lower index of refraction than the waveguide material is filled into the gap above the waveguide circuit (404) such that the liquid acts as an overclad for the waveguide circuit (404).

Abstract: A method of forming a layer of silicon on a surface comprises the steps of depositing silicon on the surface by a physical deposition process such as electron beam evaporation and, during said deposition process, subjecting the forming film to ionic bombardment. The resultant silicon film has stresses which are considerably reduced compared to a film produced by an ordinary physical deposition process. This method is particularly well adapted to the formation of relatively thick silicon layers (.gtoreq.1 .mu.m) on a layer (or stack of layers) of silica, to serve as an etching mask in a subsequent deep etching of the silica by reactive ion etching.

Abstract: Optical waveguide paths are formed under the surface of a glass substrate by a method comprising (a) forming by ion-exchange a dopant ion path on a first substrate surface, (b) applying an electrode to the second surface, (c) contacting the first surface with a molten salt bath, and (d) applying an electrical field across the substrate to drive the dopant ions deeper into the substrate. The current resulting from high fields can overheat the substrate, thereby causing substrate warping and burying of paths to uneven depths. One aspect of the invention involves cooling the substrate by flowing the molten salt along the first surface of the substrate at a sufficient rate of flow to adequately decrease its temperature and by rapidly flowing the furnace atmosphere over the surface of the substrate. A further aspect of the invention involves initially applying a voltage V.sub.i across the substrate, allowing the current to increase to a predetermined level I.sub.

Abstract: A process for the production of an integrated optical circuit in a glass body by ion exchange between certain regions of the glass body and a metallic salt with the use of a mask defining the regions where the ion exchange occurs, wherein the mask comprises a layer of silicon and the mask is removed by an etching operation preceded by a cleansing operation.

Abstract: A method of making an integrated optical component in which a central planar region includes an optical circuit path and a lateral region includes an optical fiber positioning groove in alignment with the path. A glass body having central and lateral regions is coated with a mask material. A photolithographic technique is used to provide the mask material with a patterned opening in the central region corrsponding in shape to the circuit path and a patterned opening in the lateral region corresponding to the shape of the alignment groove. A layer of resisting material is applied over the mask on the central region and the lateral region is etched to form the groove. The layer of resisting material is removed, and the zone of the central region that is exposed by the opening in the mask is subjected to an ion exchange process in order to form therein an optical path that is in registration with the fiber positioning groove.