Tunable laser in an optical access network

Patent metadata

Field	Value
Publication number	US-10171199-B2
Application number	US-201615385798-A
Country	US
Kind code	B2
Filing date	Dec 20, 2016
Priority date	Dec 20, 2016
Publication date	Jan 1, 2019
Grant date	Jan 1, 2019

Abstract

A system includes a multiplexer having a pass-band and an optical network unit (ONU) optically coupled to the multiplexer. The ONU includes a tunable laser configured to continuously transmit an optical signal to the multiplexer in a burst-on state and a burst-off state. While in the burst-on state, the ONU is configured to tune the tunable laser to transmit the optical signal at a transmit wavelength within the wavelength pass-band of the multiplexer. The multiplexer configured to allow passage therethrough of the optical signal at the transmit wavelength. While in the burst-off state, the ONU is configured to tune the tunable laser to transmit the optical signal at a non-transmit wavelength outside of the wavelength pass-band of the multiplexer. The multiplexer configured to block passage therethrough of the optical signal at the non-transmit wavelength.

First claim

What is claimed is:

1. A system comprising:
a multiplexer having a wavelength pass-band; and
an optical network unit (ONU) optically coupled to the multiplexer, the ONU comprising a tunable laser configured to continuously transmit an optical signal to the multiplexer alternating between a burst-on state and a burst-off state, the ONU configured to perform operations comprising:
while in the burst-on state, tuning the tunable laser to transmit the optical signal at a transmit wavelength within the wavelength pass-band of the multiplexer, the multiplexer configured to allow passage therethrough of the optical signal at the transmit wavelength; and
while in the burst-off state, tuning the tunable laser to transmit the optical signal at a non-transmit wavelength outside of the wavelength pass-band of the multiplexer, the multiplexer configured to block passage therethrough of the optical signal at the non-transmit wavelength.

2. The system of claim 1 , wherein the tunable laser comprises a distributed Bragg reflector (DBR) laser configured to receive an wavelength tuning injection current, the wavelength tuning injection current biasing the wavelength of the optical signal.

3. The system of claim 2 , wherein the operations further comprise altering the wavelength of the optical signal between the transmit wavelength and the non-transmit wavelength by altering the wavelength tuning injection current to the tunable laser.

4. The system of claim 1 , wherein the operations further comprise:
receiving a request to transmit a data packet on the optical signal;
triggering the burst-on state;
transmitting the data packet on the optical signal while in the burst-on state; and
triggering the burst-off state.

5. The system of claim 1 , wherein the multiplexer comprises an arrayed wavelength grating.

6. The system of claim 5 , further comprising an optical line terminal (OLT) optically coupled to the arrayed wavelength grating.

7. The system of claim 6 , further comprising:
a plurality of ONUs optically coupled to the arrayed wavelength grating,
wherein the arrayed wavelength grating has a multiplex port optically coupled to the OLT and a plurality of demultiplex ports, each demultiplex port associated with a corresponding wavelength pass-band and optically coupled to a corresponding ONU of the plurality of ONUs.

8. The system of claim 7 , wherein the arrayed wavelength grating is disposed at the OLT.

9. The system of claim 1 , wherein the multiplexer is disposed at a remote node optically coupled to the ONU.

10. A system comprising:
a multiplexer having a wavelength pass-band;
a tunable laser optically coupled to the multiplexer and configured to continuously transmit an optical signal to the multiplexer alternating between a burst-on state and a burst-off state; and
a controller electrically coupled to the tunable laser, the controller configured to perform operations comprising:
receiving a request to transmit a data packet;
triggering the burst-on state of the tunable laser by transmitting a burst-on current to the tunable laser, the burst-on current biasing the tunable laser to transmit the optical signal at a transmit wavelength within the wavelength pass-band of the multiplexer, the multiplexer configured to allow passage therethrough of the optical signal at the transmit wavelength;
instructing the tunable laser to transmit the data packet in the optical signal while the tunable laser is in the burst-on state; and
triggering the burst-off state of the tunable laser by transmitting a burst-off current to the tunable laser, the burst-off current biasing the tunable laser to transmit the optical signal at a non-transmit wavelength outside of the wavelength pass-band of the multiplexer, the multiplexer configured to block passage therethrough of the optical signal at the non-transmit wavelength.

11. The system of claim 10 , wherein the tunable laser comprises a distributed Bragg reflector (DBR) laser.

12. The system of claim 10 , wherein the multiplexer comprises an arrayed wavelength grating.

13. The system of claim 12 , further comprising an optical line terminal (OLT) optically coupled to the arrayed wavelength grating.

14. The system of claim 13 , wherein the arrayed wavelength grating is disposed at the OLT.

15. The system of claim 10 , wherein the multiplexer is disposed at a remote node optically coupled to the tunable laser.

16. A method comprising:
receiving, at data processing hardware, a request to transmit a data packet from an optical network unit (ONU) to an optical line terminal (OLT) of an optical access network having a multiplexer optically coupled between the ONU and the OLT, the multiplexer having a wavelength pass-band, the ONU comprising a tunable laser configured to continuously transmit an optical signal that alternates between a burst-on state and a burst-off state;
triggering, by the data processing hardware, the burst-on state of the tunable laser by transmitting a burst-on current to the tunable laser, the burst-on current biasing the tunable laser to transmit the optical signal at a transmit wavelength within the wavelength pass-band of the multiplexer, the multiplexer configured to allow passage therethrough of the optical signal at the transmit wavelength;
instructing, by the data processing hardware, the tunable laser to transmit the data packet in the optical signal; and
after transmission of the data packet, enabling, by the data processing hardware, the burst-off state of the tunable laser by transmitting a burst-off current to the tunable laser, the burst-off current biasing the tunable laser to transmit the optical signal at a non-transmit wavelength outside of the wavelength pass-band of the multiplexer, the multiplexer configured to block passage therethrough of the optical signal at the non-transmit wavelength.

17. The method of claim 16 , wherein the tunable laser comprises a distributed Bragg reflector (DBR) laser.

18. The method of claim 16 , wherein the multiplexer comprises an arrayed wavelength grating.

19. The method of claim 18 , wherein the arrayed wavelength grating is disposed at the OLT.

20. The system of claim 16 , wherein the multiplexer is disposed at a remote node optically coupled between the ONU and the OLT.

Assignees

• Google Inc
• Google Llc

Inventors

• Zhao Xiangjun
• Wang Daoyi
• Du Liang
• Jiang Changhong Joy
• Lam Cedric Fung

Classifications

• H04B10/27

  Arrangements for networking · CPC title

• H04B10/572 Primary

  Wavelength control · CPC title

• H01S5/06256

  with DBR-structure · CPC title

• H04Q11/0066

  Provisions for optical burst or packet networks · CPC title

• H04J14/0242 Primary

  in WDM-PON · CPC title