US 8,792,787 B1Granted

Optoelectronic packet switch/routers

AssigneeGoogle Inc.

InventorsXiaoxue Zhao, Bikash Koley, Vijay Vusirikala, Edward Crabbe, Paul Phillip Germano, Hong Liu, Philip Michael Wells

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Abstract

A packet switch/router including a first stage switch fabric receiving an electrical signal, a mid-stage buffer receiving and storing the electrical signal from the first stage switch fabric, and a second stage switch fabric receiving the electrical signal from the mid-stage buffer. Each switch fabric includes N layers of N×N arrayed waveguide gratings (AWGs), and each AWG has ingress ports and egress ports. A wavelength tunable device, such as a tunable laser, communicates with a source ingress port of an AWG and converts the received electrical signal to an optical signal having a wavelength selected for routing a packet from the source ingress port to a target egress port of the arrayed waveguide grating. A photoreceiver, such as a burst-mode photoreceiver, receives the propagated optical signal from the target egress port and converts the optical signal to the electrical signal.

Claims13

Dependent claims

A packet switch comprising:

an interface receiving an optical signal and converting the optical signal to an electrical signal;
a non-transitory input buffer receiving and storing the electrical signal from the interface;
a first stage switch fabric receiving the electrical signal from the input buffer;
a mid-stage buffer receiving and storing the electrical signal from the first stage switch fabric;
a second stage switch fabric receiving the electrical signal from the mid-stage buffer;
wherein each switch fabric comprises:
N layers of N×N arrayed waveguide gratings, each arrayed waveguide grating having ingress ports and egress ports;
a wavelength tunable device in communication with a source ingress port of an arrayed waveguide grating, the wavelength tunable device converting the received electrical signal to an optical signal having a wavelength selected for routing a packet from the source ingress port to a target egress port of the arrayed waveguide grating;
and
a photoreceiver receiving the propagated optical signal from the target egress port and converting the optical signal to the electrical signal;
and
a scheduler in communication with the interface, the input buffer, the mid-stage buffer, and wavelength tunable devices, the scheduler receiving notification from the interface of a received packet on the electronic signal and issuing steering instructions to the wavelength tunable devices for routing the packet from a source ingress port to a target egress port on each switch fabric.

9 more elements

A method of packet switching, the method comprising:

receiving an input optical signal and converting the input optical signal to an electric signal;
receiving notification of a received packet on the electronic signal;
storing the electrical signal in a non-transitory input buffer while waiting for routing instructions for routing the packet from a source ingress port to a target egress port on first and second switch fabrics;
determining the routing instructions;
converting the electric signal to a first optical signal based on the routing instructions;
propagating the first optical signal through the first stage switch fabric, the first stage switch fabric comprising N layers of N×N arrayed waveguide gratings, each arrayed waveguide grating having ingress ports and egress ports, the first optical signal having a first wavelength that results in routing the packet from a source ingress port to a target egress port of an arrayed waveguide grating of the first stage switch fabric;
converting the first optical signal back to the electric signal;
after converting the first optical signal back to the electric signal, storing the electrical signal in a non-transitory mid-stage buffer;
converting the electric signal to a second optical signal based on the received routing instructions;
propagating the second optical signal through the second stage switch fabric, the second stage switch fabric comprising N layers of N×N arrayed waveguide gratings, each arrayed waveguide grating having ingress ports and egress ports, the second optical signal having a second wavelength that results in routing the packet from a source ingress port to a target egress port of an arrayed waveguide grating of the second stage switch fabric;
and
converting the second optical signal back to the electric signal.

9 more elements

Dependencies are inferred from the claim text.