Optical link architecture based on wireline equalization techniques

Patent metadata

Field	Value
Publication number	US-9654225-B2
Application number	US-201514858321-A
Country	US
Kind code	B2
Filing date	Sep 18, 2015
Priority date	Sep 18, 2015
Publication date	May 16, 2017
Grant date	May 16, 2017

Abstract

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.

First claim

What is claimed is:

1. A system for transmitting an optical signal at a target data rate in an optical communication network, comprising:
a SerializerDeserializer transmitter (SerDes TX) having a feed-forward equalizer, a SerDes TX electrical input port, and a SerDes TX electrical output port capable of generating an optical signal at the target data rate;
an optical modulator capable of operating at only a lower data rate of less than 0.75 of the target data rate, thereby generating inter-symbol interference, and including:
a linear transfer function;
an optical modulator electrical input port in communication with said SerDes TX electrical output port; and
an optical modulator optical output port for optically coupling to an optical carrier having a carrier optical input port in communication with said optical modulator optical output port and a carrier optical output port;

an optical demodulator capable of operating at only a lower data rate of less than 0.75 of the target data rate, thereby generating inter-symbol interference, and including:
a linear transfer function,
a demodulator optical input port in communication with said carrier optical output port, and

an optical demodulator electrical output port; and

a SerializerDeserializer receiver (SerDes RX), including:
at least one of a decision-feedback equalizer, a continuous time linear equalizer, a feed-forward equalizer, and a partial response maximum likelihood equalizer capable of compensating for the lower data rate optical demodulators, and generating an electric signal corresponding to the target data rate,
a SerDes RX electrical input port in communication with said optical demodulator electrical output port, and

a SerDes RX electrical output port.

2. The system of claim 1 , wherein said system is capable of transmitting an optical signal comprising
a linear optical signal, a low power optical signal, and a low bandwidth optical signal.

3. The system of claim 1 , wherein said optical modulator comprises a Mach-Zehnder interferometer, a laser, and a silicon photonic chip.

4. The system of claim 1 , wherein said optical demodulator comprises a photonic silicon chip, a photodetector, a transimpedance amplifier, and a linear amplifier.

5. The system of claim 1 , wherein said optical modulator is configured to operate at a wavelength within the range of a selected one of an O-Band, an E-band, a C-band, an L-Band, an S-Band and a U-band.

6. The system of claim 1 , wherein said SerDes TX includes a limiting amplifier.

7. The system of claim 1 , wherein at least one of said SerDes TX and said SerDes RX is configured to operate using pulse amplitude modulation.

8. The system of claim 7 , wherein said pulse amplitude modulation is a selected one of PAM-4 and PAM-N.

9. A method for transmitting an optical signal at a target data rate in an optical communication system, comprising the steps of:
generating the optical signal at the target data rate using a SerializerDeserializer transmitter (SerDes TX) having a feed-forward equalizer, a SerDes TX electrical input port and a SerDes TX electrical output port;
modulating the optical signal with an optical modulator at a lower data rate of less than 0.75 of the target data rate, thereby generating inter-symbol interference, wherein the optical modulator includes: a linear transfer function; an optical modulator electrical input port in communication with said SerDes TX electrical output port; and an optical modulator optical output port;
transmitting the optical signal over an optical carrier having a carrier optical input port in communication with said optical modulator optical output port and having a carrier optical output port;
demodulating the optical signal using an optical demodulator at a lower data rate of less than 0.75 of the target data rate, thereby generating inter-symbol interference, wherein the demodulator includes a linear transfer function, a demodulator optical input port in communication with said carrier optical output port, and an optical demodulator electrical output port; and
generating an output electrical signal using a SerializerDeserializer receiver (SerDes RX) capable of compensating for the lower data rate optical demodulator and generating an electric signal corresponding to the target data rate, and comprising
at least one of a decision-feedback equalizer, a continuous time linear equalizer, a feed-forward equalizer, and a partial response maximum likelihood equalizer,
a SerDes RX electrical input port in communication with said optical demodulator electrical output port and
a SerDes RX electrical output port.

10. The method of claim 9 , wherein said optical signal comprises a linear optical signal, a low power optical signal, and a low bandwidth optical signal.

11. The method of claim 9 , wherein said optical modulator comprises a Mach-Zehnder interferometer, a laser, and a silicon photonic chip.

12. The method of claim 9 , wherein said optical demodulator comprises a photonic silicon chip, a photodetector, a transimpedance amplifier and a linear amplifier.

13. The method of claim 9 , wherein said optical modulator is configured to operate at a wavelength within the range of a selected one of an O-Band, an E-band, a C-band, an L-Band, an S-Band and a U-band.

14. The method of claim 9 , wherein said SerDes TX includes a limiting amplifier.

15. The method of claim 9 , wherein at least one of said SerDes TX and said SerDes RX is configured to operate using pulse amplitude modulation.

16. The method of claim 15 , wherein said pulse amplitude modulation is a selected one of PAM-4 and PAM-N.

17. A method of transmitting an optical signal at a target data rate in an optical communication network, comprising the steps of:
providing a SerializerDeserializer transmitter (SerDes TX) capable of generating an optical signal at the target data rate, and including: a feed-forward equalizer; a SerDes TX electrical input port; and a SerDes TX electrical output port;
providing an optical modulator having a lower data rate of less than 0.75 of the target data rate, thereby generating inter-symbol interference, and including: a linear transfer function; an optical modulator electrical input port in communication with said SerDes TX electrical output port; and an optical modulator optical output port in communication with a carrier optical input port of an optical carrier;
providing an optical demodulator having a lower data rate of less than 0.75 of the target data rate, thereby generating inter-symbol interference, and including: a linear transfer function; a demodulator optical input port in communication with a carrier optical output port of the optical carrier; and an optical demodulator electrical output port;
providing a SerializerDeserializer receiver (SerDes RX) capable of compensating for the low data rate optical demodulator and generating an electric signal corresponding to the target data rate, and including:
at least one of a decision-feedback equalizer, a continuous time linear equalizer, a feed-forward equalizer, and a partial response maximum likelihood equalizer,
a SerDes RX electrical input port in communication with said optical demodulator electrical output port and
a SerDes RX electrical output port;

providing an electrical signal for transmission using said SerializerDeserializer apparatus at said SerDes TX electrical input port;
recovering an electrical signal at said SerDes RX electrical output port, such that said SerializerDeserializer apparatus communicates over said optical carrier using an optical

Assignees

• Coriant Advanced Tech Llc
• Elenion Tech Llc

Inventors

• Rylyakov Alexander
• Younce Richard
• Ding Ran
• Magill Peter D
• Li Hao
• Hochberg Michael J J

Classifications

• H04B10/58 Primary

  Compensation for non-linear transmitter output · CPC title

• H04B10/69

  Electrical arrangements in the receiver · CPC title

• H04L27/06

  Demodulator circuits; Receiver circuits · CPC title

• H04B10/5059

  using a feed-forward signal generated by analysing the optical or electrical input · CPC title

• H04L2025/03369

  Partial response · CPC title