Abstract: An athermalized integrated optical waveguide device in which thermal spectral shifts are inhibited is provided and in which the light transmitting properties are insensitive to temperature variations and fluctuations. The athermalized integrated optical waveguide device has at least two waveguide core arms, preferably comprised of a silica glass, with the core arms cladded with a waveguide cladding composition, preferably a silica glass that has a boron concentration different than the cores. The first waveguide arm and the second waveguide arm have a difference in an effective index thermal slope in order to provide an athermalized device such as an intereferometer on a substantially planar substrate. In addition the at least two waveguide core arms are comprised of path segments having different waveguide core dimensions.

Abstract: An athermalized integrated optical waveguide device in which thermal spectral shifts are inhibited is provided and in which the light transmitting properties are insensitive to temperature variations and fluctuations. The athermnalized integrated optical waveguide device has at least two waveguide core arms, preferably comprised of a silica glass, with the core arms cladded with a waveguide cladding composition, preferably a silica glass that has a boron concentration different than the cores. The first waveguide arm and the second waveguide arm have a difference in an effective index thermal slope in order to provide an athermalized device such as an intereferometer on a substantially planar substrate. In addition the at least two waveguide core arms are comprised of path segments having different waveguide core dimensions.

Abstract: A new multiplexer/demultiplexer includes a compound focusing mechanism having adjacent focal points. Multiple images of one or more input pathways for each different wavelength signal are projected onto one or more output pathways. The resulting spectral response is flattened in the vicinity of the center wavelength of each different wavelength signal. The number and spacing of the focal points, as well as the mode field radii of the input and output pathways, can be optimized for desired combinations of channel bandwidth, insertion loss, and crosstalk.

Abstract: The device consists of a dual-mode waveguide 1 that has a longitudinal axis ?X!, a length ?L!, and a width ?W!, and two pairs of monomode waveguides 2, 3 and 4, 5, for entry and exit, respectively. In accordance with the invention, the length ?L! and the width ?W! of the dual-mode waveguide ?1! are selected in such a way as to establish, in this guide, light coupling that is greater in the window from 1260 to 1360 nm than in the window from 1480 to 1580 nm, so as to compensate for the significant contrary proximity coupling in these windows, as created between the monomode entry guides 2 and 3 on the one hand and the monomode exit guides 4 and 5 on the other hand.

Abstract: A method for forming a substantially flat planar lightwave optical circuit which has a substantially flat planar silica substrate and a sintered glassy lightguiding layer over the silica substrate. The structure is given a post treatment at an elevated temperature for a time sufficient to flatten said structure and overcome any distortion caused by the difference in the coefficient of thermal expansion of the substrate and any glassy layers formed over the substrate. Alternatively, the silica substrate may be heated and presagged to a predetermined degree to compensate for distortion or warpage which will occur in later processing.

Abstract: A tradeoff between crosstalk and channel bandwidth in dense wavelength demultiplexers is achieved by varying mode fields of input and output waveguides. Funnels are formed between inner and outer ends of the input and output waveguides to increase mode field radii, which results in decreased crosstalk attenuation but larger bandwidth channels.

Abstract: The invention comprises (a) a divider (D) by 2 of the optical power received at one input (E.sub.1, E.sub.2) and (b) two groups of single mode waveguides coplanar to the divider and symmetrical relative to the axis of symmetry (Z) of the divider (D), each group being composed of waveguide sections connected in tree and branch fashion by Y junctions (J.sub.ii) between one input junction (J.sub.11, J.sub.12) connected to one of the outputs of the divider and N sections of waveguide difining N outputs (S.sub.1 to S.sub.16) of the coupler parallel to the axis of the divider. According to the invention, each of these input junctions (J.sub.11, J.sub.12) has a rectilinear input branch (B.sub.1) with predetermined length such that the transverse distribution of the optical power at the output of the rectilinear input branch (B.sub.1) is centered to a large degree on the axis of this input branch.

Abstract: The present invention relates to a coupler having one input port and 2.sup.n output ports which includes a plurality of essentially coplanar waveguides connecting the input port to one of the 2.sup.n output ports. The plurality of waveguides are arranged in two symmetrical groups in relation to the axis of the coupler and have points of inflection. Each of the waveguides includes branches connected in a tree-like manner by n levels of Y-junctions where the waveguides connecting at least two of the output ports that are located furthest from the axis of the coupler to the input port have no singularities and between the first level and the nth level of the Y-junction have points of inflection located outside the junctions. Further, the junctions located along these waveguides have axes of symmetry which are not parallel to the axis of the coupler.