Abstract: An optical cavity structure for bending optical signals is provided. The optical cavity structure includes an input port for receiving input optical signals from a first waveguide. The optical cavity structure also includes an interconnecting structure that receives said input optical signals and interconnects said first waveguide to a second waveguide, the interconnecting structure further includes at least four straight edges that orthogonal and of a finite width. The optical cavity structure further includes an output port coupled to the interconnecting structure for providing the second waveguide with the input optical signals. Further, the optical cavity structure may be used to create three dimensional splitter devices and resonators.

Abstract: An optical modulator includes at least one waveguide medium that receives light. An absorption medium absorbs the light under predefined conditions and outputs optically modulated light. The absorption medium is comprised of a Ge-based structure. The Ge-based structure uses the Franz-Keldysh effect to create said optically modulated light.

Abstract: A high density integrated optical chip. The optical chip features an optical function connected to a low minimum bending radius dielectric waveguide, and a large mode field size dielectric waveguide to interface with an external optical device, such as an optical fiber. The large mode field size dielectric waveguide is optically connected to the low minimum bending radius dielectric waveguide on the optical chip.

Abstract: The invention features an optical chip having optical functions in large mode size waveguides. Under one aspect of the invention, the optical chip features one or more large mode field size waveguides, one or more low minimum bending radius waveguides to interconnect the large mode field size waveguides, and one or more optical functions integrated within or connected to the large mode field size waveguides.

Abstract: The invention features a programmable optical chip. The optical chip has a plurality of optical functions, each of which is connected to a waveguide having a core and a cladding. A photosensitive layer is disposed between at least three of the waveguides, and the photosensitive layer has a refractive index similar to that of the cladding prior to exposure to irradiation. The photosensitive layer changes refractive index upon exposure to irradiation to selectively form an optical connection between at least two of the waveguides.

Abstract: An optical mode transformer. The optical mode transformer features a low index core, a high index core having a first tapered region, with the high index core embedded within the low index core and with the low index core serving as a cladding for a waveguide defined by the high index core embedded in the low index core, and a cladding layer surrounding the low index core, with the cladding layer including one or more materials with different refractive indices than those of the low index core and high index core.

Abstract: A method of reducing the scattering losses that involves smoothing of the core/cladding interface and/or change of waveguide geometry in high refractive index difference waveguides. As an example, the SOI-based Si/SiO2 waveguides are subjected to an oxidation reaction at high temperatures, after the waveguide patterning process. By oxidizing the rough silicon core surfaces after the patterning process, the core/cladding interfaces are smoothened, reducing the roughness scattering in waveguides.

Abstract: An integrated device includes a waveguide, which may be connected to a photonic circuit and an external fiber, and an on-chip device formed on an optical chip by forming a region in which the waveguide terminates. The region is bounded by reflective surfaces. Light coming from the waveguide is essentially trapped inside the region and directed to an on-chip device disposed in the region. An integrated device consists of a low index difference waveguide, an on-chip mode converter, a high index difference waveguide, and an on-chip function formed on a single optical chip so that the high index difference waveguide is close to the substrate surface upon which the mode converter is formed. Substrate surface height differences are provided to define different substrate surface mounting heights for a low index difference waveguide, high index difference waveguide, a mode converter, and an on-chip device.

Abstract: Methods of tuning, switching or modulating, or, in general, changing the resonance of waveguide micro-resonators. Changes in the resonance can be brought about, permanently or temporarily, by changing the size of the micro-resonator with precision, by changing the local physical structure of the device or by changing the effective and group indices of refraction of the mode in the micro-resonator. Further changing the asymmetry of the index profile around a waveguide can alter the birefringence of the waveguide and allows one to control the polarization in the waveguide. This change in index profile may be used to change the polarization dependence or birefringence of the resonators.

Abstract: An optical mode transformer. The optical mode transformer features a low index core, a high index core having a first tapered region, with the high index core embedded within the low index core and with the low index core serving as a cladding for a waveguide defined by the high index core embedded in the low index core, and a cladding layer surrounding the low index core, with the cladding layer including one or more materials with different refractive indices than those of the low index core and high index core.

Abstract: A mode transformer that enables low-loss coupling between optical modes of two waveguides with different index difference. The mode size and the effective index are gradually changed between two waveguides to gradually transform the mode shape, size, and speed with minimum power loss. The mode transformer is useful for coupling the mode of an optical fiber waveguide with low index difference to the mode of a planar high index difference waveguide, and vice versa.

Abstract: The invention features a programmable optical chip. The optical chip has a plurality of optical functions, each of which is connected to a waveguide having a core and a cladding. A photosensitive layer is disposed between at least three of the waveguides, and the photosensitive layer has a refractive index similar to that of the cladding prior to exposure to irradiation. The photosensitive layer changes refractive index upon exposure to irradiation to selectively form an optical connection between at least two of the waveguides.

Abstract: A planar waveguide that has a graded index layer at the core/cladding interface to reduce scattering losses due to core/cladding interface roughness. The refractive index at the core/cladding interface is changed from that of the core to that of cladding gradually by having a graded index layer. The graded index layer reduces the scattering of light traveling in the waveguide by reducing the effect of the roughness at the abrupt interface between the core and the cladding. Using a proper design, the graded index layer also minimizes the modal and polarization dispersion of the optical mode traveling in the waveguide.

Abstract: An integrated device includes a waveguide, which may be connected to a photonic circuit and an external fiber, and an on-chip device formed on an optical chip by forming a region in which the waveguide terminates. The region is bounded by reflective surfaces Light coming from the waveguide is essentially trapped inside the region and directed to an on-chip device disposed in the region.

Abstract: An optical device includes a planar waveguide having a core region at least partially surrounded by a cladding, wherein the waveguide includes of a photosensitive germanium-doped silicon oxynitride (Ge:SiON) or germanium-doped silicon nitride (Ge:SiN). An optical device is formed by providing a photosensitive layer comprised of Ge:SiON or Ge:SiN and selectively irradiating the photosensitive layer at a wavelength of light to which the photosensitive material is sensitive, such that an optical feature having a refractive index different than that of the non-irradiated photosensitive layer is formed.

Abstract: A mode coupler that enables low-loss coupling between optical modes of two waveguides with different index difference. The mode size and the effective index are gradually changed between two waveguides to gradually transform the mode shape, size, and speed with minimum power loss. The mode coupler is useful for coupling the mode of an optical fiber waveguide with low index difference to the mode of a planar high index difference waveguide, and vice versa.

Abstract: A tunable waveguide microresonator device includes a core layer and a cladding layer surrounding said core. The cladding including regions surrounding the core where an evanescent field resides and at least one material of the core and the cladding is comprised of a photosensitive material. The resonance position of the microresonator is adjusted by irradiating the device with uv light.

Abstract: The invention features an optical chip having optical functions in large mode size waveguides. Under one aspect of the invention, the optical chip features one or more large mode field size waveguides, one or more low minimum bending radius waveguides to interconnect the large mode field size waveguides, and one or more optical functions integrated within or connected to the large mode field size waveguides.

Abstract: An optical modulator includes at least one waveguide medium that receives light. An absorption medium absorbs the light under predefined conditions and outputs optically modulated light. The absorption medium is comprised of a Ge-based structure. The Ge-based structure uses the Franz-Keldysh effect to create said optically modulated light.