Abstract: A standard CMOS process is used to fabricate optical and electronic devices at the same time on a monolithic integrated circuit. In the process, a layer of metallic salicide can be depsoited on those selected portions of an integrated circuit, where it is desired to have metallic contacts for electronic components, such as transistors. The deposition of a salicide into the core of an optical waveguide will damage the waveguide and prevent the passage of light through that section of the waveguide. Prior to the deposition of the salicide, a salicide blocking layer is deposited on those parts of an integrated circuit, such as on an optical waveguide, which are to be protected from damage by the deposition of salicide. The salicide blocking layer is used as one layer of the cladding of a silicon waveguide.

Abstract: A polarization splitting grating coupler (PSGC) connects an optical signal from an optical element, such as a fiber, to an optoelectronic integrated circuit. The PSGC separates a received optical signal into two orthogonal polarizations and directs the two polarizations to separate waveguides on an integrated circuit. Each of the two separated polarizations can then be processed, as needed for a particular application, by the integrated circuit. A PSGC can also operate in the reverse direction, and couple two optical signals from an integrated circuit to two respective orthogonal polarizations of one optical output signal sent off chip to an optical fiber.

Abstract: Optoelectronic devices of the present invention include several embodiments of an electronically active optical waveguide made of a strip loaded waveguide with a lateral, self-aligned diode fabricated in a layer of silicon. A voltage applied across the diode changes the free carrier density in a portion of the active waveguide, which can change the refractive index in that portion of the waveguide. Changing the refractive index can cause a phase shift of an optical signal propagating down the waveguide and this effect can be used to control the optical signal. Changing the free carrier density can also change the amount of optical attenuation in a section of an active waveguide. Optoelectronic devices such as: modulators, attenuators, switches, beam diverters, tunable filters and other devices can be fabricated on a standard SOI substrate (silicon on insulator), which is typically used in the fabrication of CMOS integrated circuits.

Abstract: A standard CMOS process is used to fabricate optical, optoelectronic and electronic devices at the same time on a monolithic integrated circuit. FIG. 6 shows a polysilicon and silicon dioxide light scattering element formed on a silicon waveguide. The polysilicon light scatterer is formed on the core of the waveguide with a silicon dioxide layer between the polysilicon and the core. A standard CMOS process is used to form the waveguide and the light scattering element. FIG. 6A is a table summarizing the elements of the light scatterer and the waveguide of FIG. 6 and the CMOS transistors of FIGS. 1 and 2, which are formed from the same materials at the same time on the same substrate. Forming multiple light scatterers on the core of a waveguide can make a grating coupler.

Abstract: The index of refraction of waveguide structures can be varied by altering carrier concentration. The waveguides preferably comprise semiconductors like silicon that are substantially optically transmissive at certain wavelengths. Variation of the carrier density in these semiconductors may be effectuated by inducing an electric field within the semiconductor for example by apply a voltage to electrodes associated with the semiconductor. Variable control of the index of refraction may be used to implement a variety of functionalites including, but not limited to, tunable waveguide gratings and resonant cavities, switchable couplers, modulators, and optical switches.

Abstract: Methods for deposition of a Ge layer during a CMOS process on a monolithic device are disclosed. The insertion of the Ge layer enables the conversion of light to electrical signals easily. As a result of this method, standard metals can be attached directly to the Ge in completing an electrical circuit. Vias can also be used to connect to the Ge layer. In a first aspect of the invention, a method comprises the step of incorporating the deposition of Ge at multiple temperatures in a standard CMOS process. In a second aspect of the invention, a method comprises the step of incorporating the deposition of poly-Ge growth in a standard CMOS process.

Abstract: A multi-wavelength light source with a gain medium and an optical equalizer. The gain medium emits light of a plurality of wavelengths in response to pumping. The gain medium is disposed in an optical cavity that repetitively passes light through the gain medium. The optical cavity supports a plurality of different optical modes having wavelengths coinciding with the plurality of wavelengths emitted by the gain medium. The optical equalizer is also in the optical cavity. The optical equalizer adjusts the optical power of at least one of the different optical modes so as to provide more even optical power distribution among the optical modes propagating through the optical cavity.

Abstract: A polarization splitting grating coupler (PSGC) connects an optical signal from an optical element, such as a fiber, to an optoelectronic integrated circuit. The PSGC separates a received optical signal into two orthogonal polarizations and directs the two polarizations to separate waveguides on an integrated circuit. Each of the two separated polarizations can then be processed, as needed for a particular application, by the integrated circuit. A PSGC can also operate in the reverse direction, and couple two optical signals from an integrated circuit to two respective orthogonal polarizations of one optical output signal sent off chip to an optical fiber.

Abstract: An optical wavelength grating coupler incorporating one or more distributed Bragg reflectors (DBR) or other reflective elements to enhance the coupling efficiency thereof. The grating coupler has a grating comprising a plurality of scattering elements adapted to scatter light along a portion of an optical path, and the one or more DBRs are positioned with respect to the grating such that light passing through the grating towards the substrate of the grating coupler is reflected back by DBRs toward the grating. The DBR comprises a multilayer stack of various materials and may be formed on the substrate of the grating coupler. The grating coupler may include a gas-filled cavity, where the cavity is formed by a conventional etching process and is used to reflect light toward the grating. The grating coupler may also incorporate an anti-reflection coating to reduce reflective loss on the surface of the grating.

Abstract: An optical waveguide grating coupler for coupling light between a planar waveguide and an optical element such as an optical fiber. The optical waveguide grating coupler includes a grating comprising a plurality of elongate scattering elements. The optical waveguide grating coupler is preferably flared, and in various embodiments has hyperbolically shaped sidewalls. The elongate scattering elements are preferably curved, and in some embodiments, the scattering elements have elliptically curved shapes. Preferably, the elongated scattering elements have grating widths selected to accommodate the desired optical intensity distribution.

Abstract: Methods for deposition of a Ge layer during a CMOS process on a monolithic device are disclosed. The insertion of the Ge layer enables the conversion of light to electrical signals easily. As a result of this method, standard metals can be attached directly to the Ge in completing an electrical circuit. Vias can also be used to connect to the Ge layer. In a first aspect of the invention, a method comprises the step of incorporating the deposition of Ge at multiple temperatures in a standard CMOS process. In a second aspect of the invention, a method comprises the step of incorporating the deposition of poly-Ge growth in a standard CMOS process.

Abstract: The index of refraction of waveguide structures can be varied by altering carrier concentration. The waveguides preferably comprise semiconductors like silicon that are substantially optically transmissive at certain wavelengths. Variation of the carrier density in these semiconductors may be effectuated by inducing an electric field within the semiconductor for example by apply a voltage to electrodes associated with the semiconductor. Variable control of the index of refraction may be used to implement a variety of functionalites including, but not limited to, tunable waveguide gratings and resonant cavities, switchable couplers, modulators, and optical switches.