Google Inc.

Vijayanand Vusirikala

Valey Kamalov

Bikash Koley

Matthew Eldred Newland

Hong Liu

Mattia Cantono

Massimiliano Salsi

Vinayak Dangui

Ralph Hofmeister

Rene Marcel Schmogrow

Systems and methods are provided for generating a model for detection of seismic events. In this regard, one or more processors may receive from one or more stations located along an underwater optical route, one or more time series of polarization states of a detected light signal during a time period. The one or more processors may transform the one or more time series of polarization states into one or more spectrums in a frequency domain. Seismic activity data for the time period may be received by the one or more processors, where the seismic activity data include one or more seismic events detected in a region at least partially overlapping the underwater optical route. The one or more processors then generate a model for detecting seismic events based on the one or more spectrums and the seismic activity data.

Systems and methods for detecting mechanical disturbances using underwater optical cables

Systems and methods of undersea optical communication are provided. An undersea optical amplifier assembly can include a water-tight housing and a photonic integrated circuit disposed within the housing. The photonic integrated circuit includes a plurality of optical fiber inputs, each configured to receive an end of a respective optical fiber of a first fiber optic cable bundle, and a plurality of optical fiber outputs. Each optical fiber output corresponds to a respective optical fiber input to form a fiber optic input-output pair, and is configured to receive an end of a respective optical fiber of a second fiber optic cable bundle. The photonic integrated circuit includes an optical amplifier optically coupled to each respective fiber optic input-output pair. The housing includes a first water-tight access port configured to receive the first fiber optic cable bundle, and a second water-tight access port configured to receive a second fiber optic cable bundle.

Low signal to noise ratio submarine communication system

A reconfigurable optical add/drop multiplexer (ROADM) includes a plurality of interconnected ROADM blocks. Each ROADM block includes an ingress switchable-gain amplifier, an output power detector coupled to an output of the ingress switchable gain amplifier, and a wavelength-selective switch coupled to the output of the ingress switchable gain amplifier. Each ROADM block includes a plurality of add/drop blocks coupled to the wavelength-selective switches of the plurality of ROADM blocks. The ROADM includes a controller configured to receive an indication of an output signal power from the output power detector and adjust gain and equalization parameters of the ingress switchable-gain amplifier based on the received indication of the output signal power.

Open, modular, and scalable optical line system

Apparatus and methods are provided for application layer optimization in a modern data network. The optimization incorporates variable rate transmission across one or more optical data channels. Data throughput is maximized by enabling quality of service profiles on a per transmission channel basis. According to one aspect, a system is provided in which the application layer is aware of and controls the underlying transmission rate and quality of the transmission. This enables the system to fully utilize the transmission capacity of the channel. The application layer may map different applications to different transmission classes of service. The services can be classified based on data throughput rate, guaranteed error rates, latency and cost, among other criteria. This provides flexibility to the application layer to map some loss tolerant applications to a lower cost (per bit) transmission class.

Service and application layer optimization using variable rate optical transmission

A method for overlapping spectrum amplification includes receiving an optical signal and splitting the optical signal into a first split signal having a first wavelength band and a second split signal having a second wavelength band. The splitting results in a band gap between the first wavelength band and the second wavelength band. The method further includes delaying the first split signal by a threshold period of time relative to the second split signal and combining the first split signal and the second split signal, resulting in a combined signal having the first wavelength band and the second wavelength band without the band gap therebetween. The path difference between the first split signal along the first signal path and the second split signal along the second signal path is within a threshold multipath interference compensation range.

Overlapping spectrum amplification

A communication system includes a first and second trunk terminals, a plurality of communication trunks disposed along a floor of a body of water, and power feed equipment. Each communication trunk couples the first trunk terminal to the second trunk terminal and includes at least one signal amplifier configured to amplify a signal conveyed along the corresponding communication trunk. The power feed equipment is coupled to the plurality of communication trunks and is configured to deliver power along each communication trunk to power the at least one signal amplifier of the communication trunk. The power feed equipment is also configured to receive a shunt fault notification identifying an electrical shunt fault along a faulted communication trunk of the plurality of communication trunks. In response to the shunt fault notification, the power feed equipment is configured to cease delivery of power along at least one communication trunk.

Subsea optical communication network

Aspects of the invention provide transmitters and receivers for managing multiple optical signals. High order modulation, such as phase and/or amplitude modulation, is used to achieve multiple bits per symbol by transporting multiple asynchronous data streams in an optical transport system. One or more supplemental multiplexing techniques such as time division multiplexing, polarization multiplexing and sub-carrier multiplexing may be used in conjunction with the high order modulation processing. This may be done in various combinations to realize a highly spectrally efficient multi-data stream transport mechanism. The system receives a number of asynchronous signals which are unframed and synchronized, and then reframed and tagged prior to the high order modulation. Differential encoding may also be performed. Upon reception of the multiplexed optical signal, the receiver circuitry may employ either direct detection without a local oscillator or coherent detection with a local oscillator.

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Palo Alto, CA, United States of America

Vijayanand Vusirikala