Optical link architecture based on wireline equalization techniques
View Patent ↗A high data rate, high sensitivity, low power optical link using low-bandwidth components and low-bandwidth E/O drivers and receivers and method of building same. The method is based on the idea of making the optical part of the link look like a bandwidth limited lossy electrical channel, so that the powerful equalization methods used in the wireline electrical links can be applied to recover the transmitted data in a situation with low bandwidth and/or high loss and strong inter-symbol interference. Linear and non-linear optical channel components, E/O drivers and receivers can benefit from the apparatus and the methods of the invention.
1. A system for transmitting an optical signal to an optical carrier in an optical communication network and generating an optical signal at a target data rate, comprising:
an optical modulator capable of receiving an electrical signal at the target data rate, but only capable of operating at a lower data rate of less than 0.75 of the target data rate, thereby generating inter-symbol interference, and including:
a modulator optical output port in communication with an optical carrier optical input port, and
an optical modulator electrical input port; and
a SerializerDeserializer transmitter (SerDes TX), capable of compensating for the lower data rate optical modulator, and generating an optical signal corresponding to the target data rate, including:
a SerDes TX electrical input port; and
a SerDes TX electrical output port in communication with said optical modulator electrical input port, wherein the target data rate at least 28 GB/s, and wherein the optical modulator comprises a bandwidth of less than 21 GHz.
2. The system of claim 1 , wherein said optical modulator comprises a Mach-Zehnder interferometer, a laser, and a silicon photonic chip.
3. The system of claim 1 , wherein the SerDes TX comprises at least one of a decision-feedback equalizer, a continuous time linear equalizer, a feed-forward equalizer, and a partial response maximum likelihood equalizer.
4. The system of claim 1 , wherein the SerDes TX comprises a feed-forward equalizer.
5. The system of claim 1 , wherein the optical modulator comprises a linear transfer function.
6. The system of claim 5 , wherein said SerDes TX is configured to operate using pulse amplitude modulation.
7. The system of claim 6 , wherein said pulse amplitude modulation is a selected one of PAM-4 and PAM-N.
8. A method of modulating an optical signal at a target data rate to an optical carrier in an optical communication system, comprising the steps of:
modulating the optical signal using an optical modulator at a lower data rate of less than 0.75 of the target data rate, thereby generating inter-symbol interference, the modulator including: a modulator optical output port optically coupled to said carrier optical input port, and an optical modulator electrical input port;
generating an output optical signal using a SerializerDeserializer transmitter (SerDes TX) capable of compensating for the lower data rate optical modulator and generating an optical signal corresponding to the target data rate, and comprising: a SerDes TX electrical input port; and a SerDes TX electrical output port in communication with said optical modulator electrical input port; and
transmitting the output optical signal to the optical carrier at the carrier optical input port, wherein the target data rate at least 28 GB/s, and wherein the optical modulator comprises a bandwidth of less than 21 GHz.
9. The method of claim 8 , wherein said optical modulator comprises a Mach-Zehnder interferometer, a laser, and a silicon photonic chip.
10. The method of claim 8 , wherein the SerDes TX comprises at least one of a decision-feedback equalizer, a continuous time linear equalizer, a feed-forward equalizer, and a partial response maximum likelihood equalizer.
11. The method of claim 8 , wherein the SerDes TX comprises a feed-forward equalizer.
12. The method of claim 8 , wherein the optical modulator comprises a linear transfer function.
13. The method of claim 12 , wherein said SerDes TX uses pulse amplitude modulation.
14. The method of claim 13 , wherein said pulse amplitude modulation is a selected one of PAM-4 and PAM-N.
15. A method of generating an optical signal at a target data rate from an electrical signal to transmission to an optical carrier in an optical communication network, comprising the steps of:
providing an optical modulator for modulating the optical signal, the optical modulator capable of modulating the optical signal only at a lower data rate of less than 0.75 of the target data rate, thereby generating inter-symbol interference, and including: a modulator optical output port in communication with a carrier optical input port of the optical carrier; and an optical modulator electrical input port;
providing a SerializerDeserializer transmitter (SerDes TX) capable of compensating for the low data rate optical modulator and generating an optical signal corresponding to the target data rate, and including:
a SerDes TX electrical input port; and
a SerDes TX electrical output port in communication with said optical modulator electrical input port, wherein the target data rate at least 28 GB/s, and wherein the optical modulator comprises a bandwidth of less than 21 GHz.
16. The method of claim 15 , wherein said optical modulator comprises a Mach-Zehnder interferometer, a laser, and a silicon photonic chip.
17. The method of claim 15 , wherein the SerDes TX comprises at least one of a decision-feedback equalizer, a continuous time linear equalizer, a feed-forward equalizer, and a partial response maximum likelihood equalizer.
18. The method of claim 15 , wherein the SerDes TX comprises a feed-forward equalizer.
19. The method of claim 15 , wherein the optical modulator comprises a linear transfer function.
20. The method of claim 19 , wherein said SerDes TX is configured to operate using pulse amplitude modulation.
21. The method of claim 20 , wherein said pulse amplitude modulation is a selected one of PAM-4 and PAM-N.