Oracle International Corporation

Stevan S Djordjevic

Ashok V Krishnamoorthy

Xuezhe Zheng

John E Cunningham

Shiyun Lin

Ivan Shubin

Jin Yao

Guoliang Li

Hiren D Thacker

Jock T Bovington

Kannan Raj

An integrated circuit is described. This integrated circuit includes an optical waveguide defined in a semiconductor layer, and a dielectric optical waveguide disposed on the semiconductor layer and that overlaps a region of the optical waveguide. Moreover, the dielectric optical waveguide includes an optical device (such as a mirror) on a facet separating a first portion of the dielectric optical waveguide and a second portion of the dielectric optical waveguide. The facet may be at an angle relative to a plane of the dielectric optical waveguide and may include a metal layer. During operation, an optical signal conveyed by the optical waveguide is evanescent coupled to the dielectric optical waveguide. Then, the optical signal may be reflected by the optical device. For example, the angle of the facet may be 45&#xb0;, so that the optical signal is reflected normal to the plane of the dielectric optical waveguide.

Wafer-scale fabrication of vertical optical couplers

A laser includes a reflective gain medium (RGM) comprising an optical gain material coupled with an associated reflector. The RGM is coupled to a spot-size converter (SSC), which optically couples the RGM to an optical reflector through a silicon waveguide. The SSC converts an optical mode-field size of the RGM to an optical mode-field size of the silicon waveguide. A negative thermo-optic coefficient (NTOC) waveguide is fabricated on top of the SSC. In this way, an optical signal, which originates from the RGM, passes into the SSC, is coupled into the NTOC waveguide, passes through the NTOC waveguide, and is coupled back into the SSC before passing into the silicon waveguide. During operation, the RGM, the spot-size converter, the NTOC waveguide, the silicon waveguide and the silicon mirror collectively form a lasing cavity for the athermal laser. Finally, a laser output is optically coupled to the lasing cavity.

Thermally compensating spot-size converter for an athermal laser

An electro-refraction modulator includes a series of layers with different doping levels surrounding a single-crystal regrown p-n junction implemented in a silicon-on-insulator (SOI) technology. The regrown p-n junction is spatially abrupt and precisely defined, which significantly increases the tuning efficiency of the electro-refraction modulator while maintaining acceptable insertion loss. Consequently, the electro-refraction modulator (such as a resonator modulator or a Mach-Zehnder interferometer modulator) can have high bandwidth, compact size and reduced drive voltage. The improved performance of the electro-refraction modulator may facilitate silicon-photonic links for use in applications such as wavelength-division multiplexing.

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An optical device is described. This optical device includes optical components having resonance wavelengths that match target values with a predefined accuracy (such as 0.1 nm) and with a predefined time stability (such as permanent or an infinite time stability) without thermal tuning and/or electronic tuning. The stable, accurate resonance wavelengths may be achieved using a wafer-scale, single (sub-second) shot trimming technique that permanently corrects the phase errors induced by material variations and fabrication inaccuracies in the optical components (and, more generally, resonant silicon-photonic optical components). In particular, the trimming technique may use photolithographic exposure of the optical components on the wafer in parallel, with time-modulation for each individual optical component based on active-element control. Note that the physical mechanism in the trimming technique may involve superficial room-temperature oxidation of the silicon surface, which is induced by deep-ultraviolet radiation in the presence of oxygen.

Single shot correction of resonant optical components

An integrated optical device includes an electro-absorption modulator disposed on a top surface of an optical waveguide. The electro-absorption modulator includes germanium disposed in a cavity between an n-type doped silicon sidewall and a p-type doped silicon sidewall. By applying a voltage between the n-type doped silicon sidewall and the p-type doped silicon sidewall, an electric field can be generated in a plane of the optical waveguide, but perpendicular to a propagation direction of the optical signal. This electric field shifts a band gap of the germanium, thereby modulating the optical signal.

Integrated electro-absorption modulator

A hybrid optical source includes a substrate with an optical amplifier (such as a III-V semiconductor optical amplifier). The substrate is coupled at an angle (such as an angle between 0 and 90&#xb0;) to a silicon-on-insulator chip. In particular, the substrate may be optically coupled to the silicon-on-insulator chip by an optical coupler (such as a diffraction grating or a mirror) that efficiently couples (i.e., with low optical loss) an optical signal into a sub-micron silicon-on-insulator optical waveguide. Moreover, the silicon-on-insulator optical waveguide optically couples the light to a reflector to complete the hybrid optical source.

Vertical integration of a hybrid optical source

A hybrid optical source that provides an optical signal having a wavelength is described. This hybrid optical source comprises an optical amplifier (such as a III-V semiconductor optical amplifier) that is butt-coupled or vertically coupled to a silicon-on-insulator (SOI) platform, and which outputs an optical signal. The SOI platform comprises an optical waveguide that conveys the optical signal. A temperature-compensation element included in the optical waveguide compensates for temperature dependence of the indexes of refraction of the optical amplifier and the optical waveguide. In addition, a reflector, included in or in-line with the optical waveguide and after the temperature-compensation element, reflects a portion of the optical signal and transmits another portion of the optical signal that has the wavelength.

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San Diego, CA, United States of America

Stevan S Djordjevic