Optoelectronic packet switch/routers
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.
1. 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.
2. The packet switch of claim 1 , wherein the interface comprises an optical transceiver.
3. The packet switch of claim 1 , wherein the scheduler issues instructions in parallel to the first and second stage switch fabrics.
4. The packet switch of claim 1 , wherein the photoreceiver comprises a burst-mode photoreceiver.
5. The packet switch of claim 1 , wherein each switch stage fabric is connect in a Clos network.
6. The packet switch of claim 1 , wherein the wavelength tunable device comprises a tunable laser.
7. The packet switch of claim 1 , wherein each switch stage fabric comprises 100 layers of 100×100 arrayed waveguide gratings having a per port speed of about 10G.
8. 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. The method of claim 8 , further comprising:
after converting the input optical signal to the electric signal, storing the electrical signal in the input buffer while waiting for routing instructions for routing the packet from a source ingress port on the first switch fabric to a target egress port on the first switch fabric; and
after converting the first optical signal back to the electric signal, storing the electrical signal in the mid-stage buffer while waiting for routing instructions for routing the packet from a source ingress port on the second switch fabric to a target egress port on the second switch fabric.
10. The method of claim 8 , further comprising receiving in parallel routing instructions for converting the electrical signal to the first optical signal and routing instructions for converting the electrical signal to the second optical signal.
11. The method of claim 8 , further comprising converting the second optical signal back to the electric signal using a burst-mode photoreceiver.
12. The method of claim 8 , further comprising connecting the first and second stage switch fabrics in a Clos network.
13. The method of claim 8 , wherein each switch fabric comprises 100 layers of 100×100 arrayed waveguide gratings having a per port speed of about 10G.