Elenion Technologies, LLC

Nokia Solutions and Networks Oy

Mellanox Technologies Silicon Photonics Inc.

Saeed Fathololoumi

Thomas Wetteland Baehr-Jones

Yang Liu

Yangjin Ma

Ruizhi Shi

Yaojia Chen

Mehdi Asghari

Dazeng Feng

Michael J Hochberg

Ari Jason Novack

Ran Ding

Matthew Streshinsky

Yi Zhang

Jacob Levy

Kishore Padmaraju

Shuyu Yang

Amir Ali Tavallaee

Tal Galfsky

Pegah Seddighian

Yury Dziashko

Michael Caverley

Conventional integrated optical amplifiers, which combine different types of platforms, e.g. silicon photonic integrated circuit for the device layer, and a Group III-V material for the gain medium, typically include a curved waveguide extending through the gain medium coupled to waveguides in the main device layer. Unfortunately, the radius of curvature of the curved waveguide becomes a limiting factor for both size and amplification. Accordingly, an optical amplifier which eliminates the need for the curved waveguide by including a coupler for splitting an input optical signal into two sub-beams, for passage through the gain medium, and a reflector, such as a U-turn, for reflecting or redirecting the two sub-beams back through the gain medium to the coupler for recombination, would be a welcome improvement. A phase tuner may also be provided to ensure coherence cancellation between the two sub-beams to maximize output and minimize back reflection without requiring an isolator.

Optical amplifier

The back reflection in photodiodes is caused by an abrupt index contrast between the input waveguide and the composite waveguide/light absorbing material. In order to improve the back reflection, it is proposed to introduce an angle between the waveguide and the leading edge of the light absorbing material. The angle will result in gradually changing the effective index between the index of the waveguide and the index of the composite section, and consequently lower the amount of light reflecting back.

Reducing back reflection in a photodiode

An on-chip optical filter including three different arm sections comprised of three different types of waveguides, e.g. shape, material or polarization, can achieve the same performance quality as external commercially available solutions with no addition costs of fabrication of the photonic integrated chip (PIC) and a footprint several orders of magnitude smaller than any of the conventional filters.

Thermally stable optical filter

Conventional hybrid photonic integrated circuits (PIC) combine one type of semiconductor platform for the main PIC, and a different type of semiconductor platform for a secondary chip. Conventional mounting processes include forming a recess in the main PIC, and mating electrical connectors from the secondary chip and the main PIC within the recess. Mating the first and second electrical connectors in the recess increases the complexity of forming the main PIC, and hampers heat dissipation from secondary chip through oxide layers in the main PIC. Providing a conductive, e.g. redistribution, layer from the first electrode along the bottom and sides of the recess eliminates the complexity in forming the main PIC, and enables the first electrical connector to be mounted directly onto a more thermally conductive substrate material.

Flip chip bonding onto a photonic integrated circuit

Practical silicon-based light sources are still missing, despite the progress in germanium lasers, because both silicon and germanium are indirect-band semiconductors and inefficient at light generation. A tunable and single mode external cavity laser comprising: a gain medium for generating light between a reflective surface at one end of the gain medium; and a wavelength selective reflector at the other end of a laser cavity. A splitter disposed in the laser cavity includes an input port optically coupled to the gain medium, an input/output port optically coupled to the wavelength selective reflector, and an output port for outputting laser light at selected wavelengths. The wavelength selective reflector reflects light of one or more selected periodic wavelengths back to the gain medium via the input/output port, and passes light of non-selected wavelengths out of the laser cavity.

External cavity laser

Conventionally, wavelength locking and monitoring has been achieved used various components, including calibrated etalon filters, gratings, and arrays of color filters, which offer fairly bulky solutions that require complicated controls. An improved on-chip wavelength monitor comprises: a combination comb filter comprising a plurality of comb filters, each for receiving a test beams, and each comb filter including a substantially different FSR, e.g. 10&#xd7; to 20&#xd7; the next closest FSR. A controller dithers a phase tuning section of each comb filter to generate a maximum or minimum output in a corresponding photodetector indicative of the wavelength of the test signal.

Wavelength locker

Higher power tunable lasers are feasible using photonics integrated circuit based external cavity laser configurations by using multiple RSOAs inside a single cavity to provide multiple on-chip coherent optical output at the same wavelength. The total collective output power in various output branches potentially adds up being higher than what commercial lasers can provide. Using multiple RSOA increases and distributes the number of gain materials, which keeps them in a linear regime and avoids available gain saturation, which thereby removes gain saturation limitation in optical amplifications.

Tunable lasers

A hybrid single or multi-wavelength laser using an optical gain element, such as a semiconductor optical amplifier (SOA), for example a QD RSOA, and a semiconductor, e.g. silicon, photonics chip is demonstrated. A plurality, e.g. four, lasing modes at a predetermined, e.g. 2 nm, spacing and less than 3 dB power non-uniformity may be observed, with over 20 mW of total output power. Each lasing peak can be successfully modulated at 10 Gb/s. At 10BER, the receiver power penalty is less than 2.6 dB compared to a conventional commercial laser. An expected application is the provision of a comb laser source for WDM transmission in optical interconnection systems.

Semiconductor laser

An optical system includes a laser cavity on a base. The laser cavity generates a light signal in response to application of an electrical current to the laser cavity. The system includes first electronics that apply a target level of the electrical current to the laser cavity so as to cause the laser cavity to generate the light signal. The light signal experiences mode hops at electrical current levels that shift to higher current levels in response to increasing laser operation times. A first one of the mode hops occurs at a first current level and a second one of the mode hops occurs at a second current level that is higher than the first current level. The system also includes a phase shifter that interacts with the laser cavity so as to shift the mode hops to lower current levels than occur in the absence of the phase shifter.

Growing community of inventors

San Gabriel, CA, United States of America

Saeed Fathololoumi