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: 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: A planar waveguide grating device has a slab waveguide defining an input channel and a plurality of output channels. An echelle grating has a multitude of facets, each of the facets being blazed with respect to a preselected output channel. Each facet has an elliptical curvature so as to be astigmatic with respect to the input channel and the preselected output channel. The echelle grating is preferably based on a Rowland circle design. The astigmatic design of the facets reduces aberrations at high orders.

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: 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 device is provided for demultiplexing a DWDM composite light signal into distinct signal channels or frequencies. The device includes a plurality of resonators, which each acts to slice an incoming signal into two equal parts. The free spectral range characteristics (FSR) of the resonators are successively increased by an even multiple to achieve the slicing effect. As a result, the resonators of the subject invention can be formed with relatively low finesse values because of the slicing effect.

Abstract: A thermally tunable resonator includes a resonator body having a resonance wavelength which changes as a function of temperature, a trench formed inside the resonator body, and a disk formed inside the trench and which is made from semiconductor layers, the layers being doped to form a forward biased junction. A first electrode, which does not cover the resonator body, is located atop the disk and in electrical contact with the forward biased junction, and a second electrode is located beneath and in electrical contact with the forward biased junction. When current is applied through the electrodes, heat is generated, changing the resonator body's resonance wavelength. Another thermally tunable resonator has a resonator body and heater in which two contact pads are electrically connected to a resistance above the resonator body. When current is applied to the resistance, heat is generated, changing the resonator body's resonance wavelength.

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: A Mach-Zehnder interferometer has first and second arms with first and second optical paths, and an optical phase shifter for introducing a phase into an optical signal passing through the second optical path. The optical phase shifter includes first and second waveguides, and a phase shift element disposed in a trench between the waveguides and selective movable between a first position in which the optical signal passing from the first waveguide to the second waveguide does not pass through the phase shift element, and a second position in which the optical signal passing from the first waveguide to the second waveguide passes through the phase shift element to shift the optical signal in phase relative to an optical signal passing along the first optical path.

Abstract: A semiconductor dry etching process that provides deep, smooth (RMS of less than approximately 5 nm), and vertical etching of InP-based materials with ICP RIE using a chlorinated plasma with the addition of hydrogen gas. Inert gases such as nitrogen, argon, or both may also be included. To produce relatively high anisotropy with exceptionally smooth surfaces, the amount of hydrogen gas added preferably exceeds the volumetric measure of chlorinated gas in standard cubic centimeter per minute (sccm); at a ratio of greater than 1:1. The present invention provides an improved dry etching process for InP-based semiconductor materials that yields deep, vertical etch profiles with improved surface smoothness (i.e., morphology) and high manufacturing etch rates.

Abstract: An optical waveguide includes a first waveguide section providing weak confinement of an optical signal in a direction generally transverse to its propagation direction, a second waveguide section providing strong confinement of the optical signal in all directions relative to the propagation direction, a tapered neck between the first and second waveguide sections to optically couple those waveguide sections, and a core defined through the first and second waveguide sections and tapered neck, and through which the optical signal may propagate in the propagation direction. A method for making such an optical waveguide.

Abstract: Optical devices employing a Mach-Zehnder interferometer (“MZI”) device having a phase shifter provided in one arm that enables the construction of significantly smaller optical devices than typical photonic devices, and significantly reduces the amount of on-chip real estate occupied by such devices, while not affecting the ability of such devices to introduce a predetermined phase shift in an optical signal. The present invention takes advantage of the extremely small mechanical actuators which can be fabricated using small-scale fabrication techniques, and so significantly reduces the room needed on a chip for optical switches. These more compact switches require less chip space and so provide for denser integration of a plurality of optical devices in an optical component.

Abstract: An optical resonator having a non-continuous waveguide having first and second confrontingly opposite end faces between which is defined a region and having a continuous optical path defined through the waveguide. The optical resonator can be tuned to a particular resonant wavelength by providing a phase shifter in the region between the first and second end faces and positioning the phase shifter so as to introduce a phase shift in an optical signal propagating through the waveguide and along the optical path. A method for effecting such a phase shift.

Abstract: A strongly confined ridge waveguide that provides substantially reduced polarization sensitivity, without significant compromise for other waveguide characteristics such as, for example, single-mode condition, and low propagation and bending losses for the fundamental mode. The present invention considers waveguide material composition and thickness for guiding and cladding layers, bend radius, ridge width and etch depth at which the modal indices of the fundamental TE and TM modes are equal. With those parameters, the losses (e.g., the imaginary parts of the modal indices) of the fundamental and first-order modes may be calculated. By considering the previously mentioned criteria, a low-loss, single-mode ridge waveguide may be constructed in accordance with the present invention having losses of the fundamental modes in the range of less than approximately 1.

Abstract: A Mach-Zehnder interferometer includes a continuous arm defining a first optical path having a length and a non-continuous arm having first and second parts with a trench defined therebetween, the non-continuous arm defining a second optical path the length of which differs from that of the first optical path. A phase shifter is selectively movable between a first position in which the phase shifter introduces no phase shift to a signal traveling along the second optical path and at least a second position at which the phase shift introduces a phase shift to the optical signal traveling along the second path relative to a signal traveling through the first optical path. A M×M optical switch using such a Mach-Zehnder interferometer.