Optical broadcast systems and methods
Embodiments of the present invention are directed to optical broadcast systems. The nodes of the system can be any combination of cores, caches, input/output devices, and memory, or any other information processing, transmitting, or storing device. The optical broadcast system includes an optical broadcast bus. Any node of the system in optical communication with the broadcast bus can broadcast information in optical signals to all other nodes in optical communication with the broadcast bus.
1. An optical broadcast system for broadcasting information from any node to all nodes of a system, the optical broadcast system comprising:
an optical broadcast bus having a modulator portion and a detector portion, the optical broadcast bus configured so that the modulator portion passes each node and the detector portion passes each node;
modulators optically coupled to the modulator portion and controlled by the nodes to generate optical signals carrying information from the modulator portion into the detector portion; and
detectors optically coupled to the detector portion and controlled by the nodes so that all of the nodes receive the optical signals,
wherein each modulator is configured to modulate unmodulated light by modulating different wavelengths of the unmodulated light by evanescently coupling each wavelength of the unmodulated light into a first resonator that is electronically controlled by an associated node.
2. The system of claim 1 further comprises an optical power source that injects the unmodulated light into the optical broadcast bus, wherein the unmodulated light is modulated by the nodes in the modulator portion to generate the optical signals.
3. The system of claim 1 wherein the detector portion further comprises:
branching waveguides, each branching waveguide being optically coupled to at least one of the detectors; and
optical taps configured to couple a portion of the optical signals from the optical broadcast bus, the optical broadcast bus comprising a wrap-around bus waveguide, into one of the branching waveguides.
4. The system of claim 3 wherein the optical taps are configured to distribute the optical signals so that each detector receives the optical signals with approximately the same optical power.
5. The system of claim 1 wherein the modulator portion and the detector portion further comprise portions of a broadcast tree bus configured to distribute the optical signals to the detectors with approximately the same optical power.
6. The system of claim 5 the broadcast tree bus further comprises:
a wrap-around bus waveguide optically coupled to the modulators;
optical taps configured to split optical signals into a number of optical signals having approximately the same optical power; and
wrap-around branching waveguides configured to carry the optical signals between optical tap and into the detectors.
7. The system of claim 1 wherein the first resonators are disposed adjacent to the modulator portion, each first resonator being configured to evanescently couple with one wavelength of light carried by the modulator portion when an electronic signal is applied by a node, and wherein the detectors further comprise second resonators optically coupled to the detector portion, wherein each second resonator evanescently couples an optical signal of a particular wavelength from the detector portion and generate a corresponding electronic signal transmitted to a node.
8. The system of claim 7 wherein the first resonators further comprise microrings, each microring configured to evanescently couple light of a particular wavelength from an adjacent waveguide.
9. The system of claim 1 wherein the optical broadcast bus is implemented on a single integrated circuit chip.
10. A method for broadcasting information from any node to all nodes of a system comprising:
injecting unmodulated light into an optical broadcast bus having a modulator portion and a detector portion, the optical broadcast bus having a wrap-around configuration wherein the modulator portion passes each node and the detector portion passes each node;
arbitrating to determine which node can broadcast over the optical broadcast bus;
modulating the unmodulated light in the modulator portion of the optical broadcast bus to produce optical signals that travel from the modulation portion into the detector portion; and
receiving the optical signals at all of the nodes in the detector portion of the optical broadcast bus,
wherein modulating the unmodulated light further comprises modulating different wavelengths of the unmodulated light by evanescently coupling each wavelength of the unmodulated light into a resonator that is electronically controlled by an associated node.
11. The method of claim 10 wherein injecting the unmodulated light into the optical broadcast bus further comprises using wavelength division multiplexing or dense wavelength division multiplexing to inject multiple wavelengths of light into the optical broadcast bus.
12. The method of claim 10 wherein receiving the optical signals at each node further comprises distributing the optical signals so that each node receives the optical signals with substantially the same optical power.
13. The method of claim 12 wherein distributing the optical signals further comprises evanescently coupling a portion of each optical signal into each detector so that each detector receives the same optical signals with substantially the same optical power.
14. The method of claim 12 wherein distributing the optical signals further comprises splitting the optical signals into a number of substantially identical optical signals each have approximately the same optical power that are carried to the detectors.