Optical transceiver and method with channel binding, clock forwarding, and integrate-and-dump receivers

Patent metadata

Field	Value
Publication number	US-9413520-B2
Application number	US-201314104534-A
Country	US
Kind code	B2
Filing date	Dec 12, 2013
Priority date	Dec 12, 2013
Publication date	Aug 9, 2016
Grant date	Aug 9, 2016

Abstract

An optical transceiver includes N transmitters each transmitting one of N transmitted optically bound channels; a clock forwarding mechanism to transmit a transmitted optical clock signal to an opposing optical receiver; N receivers each receiving one of N received optically bound channels; and a clock recovery mechanism to receive a received optical clock signal from the opposing optical transmitter. A method and photonically integrated system are also disclosed. The optical transceiver, method, and system optimize system design of WDM highly parallelized transceivers with optical bound channels, a simplified clocking architecture, and boosted receiver sensitivity. The optical transceiver, method, and system include clock recovery followed by data recovery and can utilize integrate-and-dump optical receivers with a recovered clock.

First claim

What is claimed is:

1. An optical transceiver, comprising:
N transmitters each transmitting one of N transmitted optically bound channels using intensity modulation;
a clock forwarding mechanism to transmit a transmitted optical clock signal to an opposing optical receiver;
N receivers each receiving one of N received optically bound channels; and
a clock recovery mechanism to receive a received optical clock signal from the opposing optical transmitter;
wherein the N receivers comprise integrate-and-dump optical receivers that utilize an integration time of about 75% of a bit period providing sufficient time for sampling a value of integrated current and resetting an integrator by discharging an integrating capacitor during the remaining about 25% of the bit period.

2. The optical transceiver of claim 1 , further comprising:
a multiplexer combining the N transmitted optically bound channels from the N transmitters; and
a demultiplexer splitting N received optically bound channels to the N receivers.

3. The optical transceiver of claim 2 , wherein the N transmitters, the clock forwarding mechanism, the N receivers, the clock recovery mechanism, the multiplexer, and the demultiplexer are photonically integrated.

4. The optical transceiver of claim 1 , further comprising:
clock distribution and data recovery circuitry coupled to each of the N receivers and the clock recovery mechanism, wherein the clock distribution and data recovery circuitry is configured to recover the received optical clock prior to performing data recovery.

5. The optical transceiver of claim 1 , wherein the clock forwarding mechanism comprises a clock transmitter transmitting the transmitted optical clock signal over a designated clock carrying wavelength; and
wherein the clock recovery mechanism comprises a clock receiver receiving the received optical clock signal over a designated clock carrying wavelength, wherein the clock receiver is a low-power, low-complexity clock signal receiver relative to the N receivers.

6. The optical transceiver of claim 1 , further comprising:
an envelope detector tapping a portion of overall optical power prior to the N receivers and detecting the received optical clock signal with a narrowband clock photodetector, wherein the received optical clock signal is superimposed as an external or internal modulation of an overall intensity envelope of a whole bound channel from an opposing transceiver.

7. The optical transceiver of claim 1 , wherein the transmitted optical clock signal and the received optical clock signal are carried at a much lower sub-harmonic, compared to signal rate of the N transmitters and the N receivers.

8. The optical transceiver of claim 1 , wherein the N receivers do not utilize broadband transimpedance amplifiers and data-driven clock recovery.

9. The optical transceiver of claim 1 , wherein the N transmitted optically bound channels comprise a composite signal X that is comprised of Y 1 , Y 2 , . . . , Y N parts or segments that are each transmitted on a set of optical carriers on a same optical module by the N transmitters to create a composite line side signal where Y 1 +Y 2 + . . . +Y N =X.

10. The optical transceiver of claim 1 , wherein the optical transceiver comprises one of a CFP, CFP2, CFP4, CDFP, CXP, MSA-100GLH, CCRx, QSFP, QSFP+, QSFP2, or 10×10-compliant module.

11. The optical transceiver of claim 1 , wherein the N transmitters utilize any of on-off keying, duobinary, differential phase-shift keying, and multi-level formats.

12. A method, comprising:
transmitting a composite signal split into N optically bound channels and an optical clock signal associated with the N optically bound channels using intensity modulation;
receiving the N optically bound channels and the optical clock signal;
recovering an electrical clock signal from the optical clock signal;
performing data recovery of the N optically bound channels utilizing the recovered electrical clock signal;
utilizing an integration time of about 75% of a bit period providing sufficient time for sampling a value of integrated current and resetting an integrator by discharging an integrating capacitor during the remaining about 25% of the bit period;
transmitting the optical clock signal superimposed as an external or internal modulation of an overall intensity envelope of a whole bound channel; and
receiving the optical clock signal by tapping a portion of overall optical power and detecting the optical clock signal with a narrowband clock photodetector.

13. The method of claim 12 , further comprising:
transmitting the optical clock signal over a designated clock carrying wavelength; and
receiving the optical clock signal over the designated clock carrying wavelength with a clock receiver that is a low-power, low-complexity clock signal receiver relative to a data receiver for the N optically bound channels.

14. The method of claim 12 , further comprising:
transmitting the optical clock signal at a much lower sub-harmonic, compared to signal rate of the N optically bound channels.

15. The method of claim 12 , further comprising:
receiving the N optically bound channels with N integrate-and-dump receivers.

16. A photonically integrated system, comprising:
N transmitters each transmitting one of N transmitted optically bound channels using intensity modulation;
a multiplexer combining the N transmitted optically bound channels from the N transmitters;
a clock forwarding mechanism to transmit a transmitted optical clock signal to an opposing optical receiver;
N receivers each receiving one of N received optically bound channels, wherein the N receivers comprise integrate-and-dump optical receivers that utilize an integration time of about 75% of a bit period providing sufficient time for sampling a value of integrated current and resetting an integrator by discharging an integrating capacitor during the remaining about 25% of the bit period;
a demultiplexer splitting the N received optically bound channels to the N receivers;
a clock recovery mechanism to receive a received optical clock signal from the opposing optical transmitter; and
an envelope detector tapping a portion of overall optical power prior to the N receivers and detecting the received optical clock signal with a narrowband clock photodetector, wherein the received optical clock signal is superimposed as an external or internal modulation of an overall intensity envelope of a whole bound channel from an opposing transceiver.

Assignees

• Pelekhaty Vladimir
• Frankel Michael Y
• Ciena Corp

Inventors

• Pelekhaty Vladimir
• Frankel Michael Y

Classifications

• H04J14/0226

  Fixed carrier allocation, e.g. according to service · CPC title

• H04L7/0075 Primary

  with photonic or optical means · CPC title

• H04J7/00

  Multiplex systems in which the amplitudes or durations of the signals in individual channels are characteristic of those channels · CPC title

• H04B10/40

  Transceivers · CPC title

• H04J14/02

  Wavelength-division multiplex systems · CPC title