Abstract: An optical device 201, having one or more input waveguides 25 coupled to one side of a slab waveguide 20 and an array of output waveguides 26 coupled to an other side of the slab waveguide, is improved by including a transition region 22 immediately adjacent to the slab that operates to reduce insertion loss between the waveguide array 26 and the slab waveguide. The transition region includes a number of silica paths (a.sub.I . . . a.sub.n) that intersect the waveguide array. The silica paths have widths W(a.sub.n) that progressively decrease as they become further away from the slab waveguide. The silica paths are parallel to each other and perpendicular to the waveguide array. Disclosed embodiments include an M.times.N star coupler, a Dense Waveguide Division Multiplexer, and a 1.times.N power splitter. In each of these embodiments, insertion loss is substantially reduced over similar devices not employing such a transition region.

Abstract: An optimized waveguide structure enables the functional integration of various passive optic components on a single substrate. The optimized waveguide structure is characterized by a thicker core layer than used for square core waveguides and a core width that changes according to different functional regions of the optic circuit within which it is incorporated. The height (H) of the waveguide core is determined by the thickness of the core layer defined during the fabrication process and is ideally uniform across the circuit. The width (W) of the core, however, is changed between functional regions by the photo-lithographic mask and the chemical etching during the fabrication process. By way of example, an optimized waveguide structure for a P-doped silica planar waveguide with a .DELTA. approximately 0.6% for wavelength .lambda.=1.2-1.7 .mu.m, has a single uniform height of H=6.7 .mu.m and a width that changes between W=4 .mu.m in a coupler region, W=5.5 .mu.m in a bend region, W=9 .mu.

Abstract: A wavelength routing device 500 includes a pair of dielectric slabs 10, 20 that are interconnected by an optical grating 30. The first dielectric slab 10 includes input ports for receiving optical signals that are routed to output ports of the second dielectric slab 20 according to their wavelengths. Y-branch splitters 70-1 are connected to the first dielectric slab. Splitters 70-1 each include a pair of adjacent waveguides, having widths (w.sub.1), that are separated from each other by a center-to-center distance (c.sub.1). Y-branch splitter 70-2 is connected to the second dielectric slab. Splitter 70-2 includes a pair of adjacent waveguides, having widths (w.sub.2), that are separated from each other by a center-to-center distance (c.sub.2). Preferably, 4w.sub.2 >w.sub.1 >1.5w.sub.2, and 4c.sub.2 >c.sub.1 >1.5c.sub.2. Associated with this routing device is a figure-of-merit (B.sub.1 /B.sub.2) that exceeds 0.5, which represents a substantial improvement over prior art designs.

Abstract: A comb splitting system demultiplexes and/or multiplexes a plurality of optical signal channels at various wavelengths. The comb splitting system has at least two interconnected successive stages of wavelength division multiplexers (WDMs). A WDM of a first stage communicates bands of channels to respective WDMs of the second stage via suitable optical paths. Each of the bands has a plurality of the individual channels that are separated by at least one other of the channels. Each second stage WDM, which is allocated to a particular band, is interconnected to optical paths, each for carrying one or more individual channels. Furthermore, in accordance with a significant feature of the present invention, the bandpasses and bandpass periodicity (free spectral range) associated with the first stage WDM are smaller than the bandpasses and bandpass periodicity associated with the second stage WDMs. The foregoing feature has numerous advantages.

Abstract: The present invention relates to a waveguide taper. The waveguide taper has a first end and a second end for being coupled with a fiber. The core has an overall width that progressively increases from the waveguide end toward the fiber end such that the width of the fiber end of the taper corresponds to the diameter of the core of the fiber. Side-gaps are disposed in the sides of the core and extend into the core but not across the entire width of the core. The depth of the side-gaps progressively increases from the waveguide end to the fiber end of the taper. In one embodiment, the side-gaps may be aperiodically and/or randomly disposed along the length of the taper and the side-gaps can be disposed at different angles to a direction of light propagation along a length of the core.

Abstract: In accordance with the invention, a new type of monolithic optical waveguide filter comprises a chain of optical couplers of different effective lengths linked by differential delays of different lengths. The transfer of the chain of couplers and delays is the sum of contributions from all possible optical paths, each contribution forming a term in a Fourier series whose sum forms the optical output. A desired frequency response is obtained by optimizing the lengths of the couplers and the delay paths so that the Fourier series best approximates the desired response. The filter is advantageously optimized so that it is insensitive to uncontrolled fabrication errors and is short in length. The wavelength dependence of practical waveguide properties is advantageously incorporated in the optimization. Consequently, the filter is highly manufacturable by mass production. Such filters have been shown to meet the requirements for separating the 1.3 and 1.551 .mu.

Abstract: Integrated optical devices which utilize a magnetostrictively, electrostrictively or photostrictively induced stress to alter the optical properties of one or more waveguides in the device are disclosed. The integrated optical devices consist of at least one pair of optical waveguides preferably fabricated in a cladding material formed on a substrate. A stress applying material, which may be a magnetostrictive, electrostrictive or photostrictive material, is affixed to the upper surface of the cladding material near at least one of the optical waveguides. When the appropriate magnetic, electric or photonic field is applied to the stress applying material, a dimensional change tends to be induced in the stress applying material. The constrained state of the stress applying material, however, caused by its adhesion to the cladding material, causes regions of tensile and compressive stress, as well as any associated strains, to be created in the integrated optical device.