Photonic circuits with selectable number of input ports
View Patent ↗In one aspect, the disclosure relates to an apparatus including a photonic integrated circuit (PIC) including an optical network including V optical output channels and U optical input ports, wherein a selectable subset of the U optical input ports can be connected to L lasers, wherein L is less than or equal to U, and wherein the PIC is operable to output light on some or all of the V optical output channels in response to different number of active lasers connected to the U optical input ports.
1. An apparatus, comprising:
a photonic integrated circuit (PIC) comprising:
a semiconductor substrate;
an optical interconnect comprising
V optical parallel output channels; and
U optical laser input ports,
wherein a selectable subset of the U optical input ports are selectable for a first use case and connected to L lasers, wherein L is less than or equal to U, and
wherein the PIC is operable to output light on some or all of the V optical output channels in response to a different number of active lasers connected to the U optical laser input ports, wherein the optical interconnect comprises W optical elements, wherein each of the W optical elements comprises at least two optical output channels, wherein each of the U optical laser input ports is in optical communication with at least two of the V optical output channels, wherein V is greater than U, wherein each of the W optical elements are formed in or on a portion of the semiconductor substrate, wherein L is one or more lasers, wherein at least three W optical elements in the PIC are in optical communication in a Y-shaped topology, wherein W is greater than or equal to three, wherein at least two of the W optical elements are four port devices, wherein at least one of the W optical elements is a three port device, and wherein one of the W optical elements is an active optical splitter having an adjustable splitting ratio.
2. The apparatus of claim 1 , wherein the W optical elements are optical signal distributors selected from a group consisting of optical splitter, active optical splitter, passive optical splitter, optical coupler, optical multiplex, and optical circulator.
3. The apparatus of claim 1 , wherein the W optical elements comprise a first optical element comprising a single optical input; a second optical element comprising two optical inputs; and third optical element comprising two optical inputs.
4. The apparatus of claim 1 , where V is 4, and L is 1 or 2.
5. The apparatus of claim 1 , where V is 8, and L is 1, 2 or 4.
6. The apparatus of claim 1 , wherein the optical interconnect comprises a plurality of 1×2 optical splitter and a plurality of 2×2 optical splitters.
7. The apparatus of claim 1 , wherein the optical interconnect comprises passive and/or active optical splitters.
8. The apparatus of claim 1 , wherein the PIC comprises V modulators, wherein each of the V modulators is connected to one of the V output channels.
9. The apparatus of claim 1 further comprising one or more lasers, wherein each of the one or more lasers is connected to only one of the U optical input channels.
10. The apparatus of claim 1 , wherein U is 3 and V is 4.
11. The apparatus of claim 1 , wherein U is 6 and V is 8.
12. The apparatus of claim 1 wherein the L lasers are selected to mitigate splitting losses from the optical interconnect splitting light received at the U optical laser input ports.
13. The apparatus of claim 1 , wherein the selectable subset of the U optical input ports are selectable for a second use case and connected to L lasers.
14. The apparatus of claim 13 , wherein the first use case is configured such that V is 4 and each output channel is configured to use 4-levels of pulse amplitude module.
15. The apparatus of claim 13 , wherein the selectable subset of the U optical input ports are selectable for a third use case and connected to L lasers, wherein U is 4.
16. The apparatus of claim 15 , wherein the first use case is one or more transmitters with four lasers and four parallel channels, wherein one laser is used for each channel, wherein each laser is in optical communication with one optical input port, wherein for the second use case L is 2, and wherein for the third use case L is 1.
17. A method of using an optical interconnect that has V optical parallel output channels, U optical laser input ports, and a selectable subset of the U optical laser input ports can be connected to a variable number L of lasers to provide optical power to V optical output channels, the method comprising:
determining the number L of lasers to be used;
select a subset of user selectable L optical laser input ports from the U optical laser input ports that map the L lasers to the V output channels, wherein V is greater than U, wherein the L optical laser input ports are selectable for a first use case;
connect the L lasers to a subset of the L optical laser input ports;
splitting light from at least one of the L lasers using a first optical splitter;
splitting light exiting the first optical splitter using a second optical splitter or a third optical splitter, wherein the first optical splitter, the second optical splitter, and the third optical splitter are in optical communication in a Y-shaped topology;
modulating, using a modulation format, the light exiting the second optical splitter, wherein the L optical laser input ports, the first optical splitter, and the second optical splitter are integrated in a photonic integrated circuit, wherein L is one or more lasers, wherein one or more of the optical splitters is an active optical splitter; and
controlling one or more of the active optical splitters using a control element to adjust a splitting ratio of the one or more active optical splitters.
18. The method of claim 17 , wherein the modulation format is pulse amplitude modulation.
19. The method of claim 17 , wherein two of the optical splitters are four port devices, wherein one of the optical splitters is a three port device.
20. The method of claim 17 , wherein the first use case is configured such that V is 4 and each output channel is configured to use 4-levels of pulse amplitude module.