Tunable optical network unit for multi-wavelength passive optical network system and operating method thereof

Patent metadata

Field	Value
Publication number	US-9397778-B2
Application number	US-201514694224-A
Country	US
Kind code	B2
Filing date	Apr 23, 2015
Priority date	Apr 23, 2014
Publication date	Jul 19, 2016
Grant date	Jul 19, 2016

Abstract

A tunable optical network unit (ONU) for a multi-wavelength passive optical network (MW PON) system and an operation method thereof are provided. The tunable ONU includes a cyclic tunable filter configured to have cyclic wavelength transmission properties that allow all wavelength channels of both a downstream signal and an upstream signal and to vary a wavelength to pass therethrough; a wavelength splitter configured to split an upstream signal wavelength band and a downstream signal wavelength band; a photodetector element configured to detect a downstream signal that is transmitted through the wavelength splitter, passing through the cyclic tunable filter which is aligned to a specific downstream signal wavelength channel; and a tunable transmitter configured to output to the wavelength transmitter an upstream signal of a wavelength channel that is determined based on an aligned downstream signal wavelength channel of the cyclic tunable filter.

First claim

What is claimed is:

1. A tunable optical network unit (ONU) for a multi-wavelength passive optical network (MW PON) system, the tunable ONU comprising:
a cyclic tunable filter configured to have cyclic wavelength transmission properties that allow all wavelength channels of both a downstream signal and an upstream signal and to vary a wavelength to pass therethrough;
a wavelength splitter configured to split an upstream signal wavelength band and a downstream signal wavelength band;
a photodetector element configured to detect a downstream signal that is transmitted through the wavelength splitter, passing through the cyclic tunable filter which is aligned to a specific downstream signal wavelength channel; and
a tunable transmitter configured to output to the wavelength transmitter an upstream signal of a wavelength channel that is determined based on an aligned downstream signal wavelength channel of the cyclic tunable filter.

2. The tunable ONU of claim 1 , wherein the cyclic tunable filter is a Fabry-Perot Etalon filter that is made of a material that varies its transmission properties according to temperature change or changes in applied voltage.

3. The tunable ONU of claim 1 , wherein the cyclic tunable filter is a thermal arrayed waveguide grating (AWG).

4. The tunable ONU of claim 3 , wherein the thermal AWG is made of silicon.

5. The tunable ONU of claim 1 , further comprising:
an upstream signal monitoring component configured to monitor a wavelength of an upstream signal output through the cyclic tunable filter.

6. The tunable ONU of claim 5 , wherein the upstream signal monitoring component comprises a tap filter to branch off a part of the upstream signal that has passed through the cyclic tunable filter and a monitoring photodiode to detect an upstream signal branched by the tap filter.

7. An operating method of a tunable ONU in an MW PON system, the operating method comprising:
receiving a downstream signal by aligning a cyclic tunable filter of the tunable ONU to a specific downstream signal wavelength channel;
setting an output wavelength of a tunable transmitter of the tunable ONU based on an aligned downstream signal wavelength channel of the cyclic tunable filter; and
transmitting an upstream signal using the set output wavelength through the tunable transmitter.

8. The operating method of claim 7 , being applied to operations of the tunable ONU to perform activation process in Initial state.

9. The operating method of claim 7 , being applied to operations subsequent to an operation in which the tunable ONU under normal operation receives a request to change or calibrate an upstream signal wavelength channel.

Assignees

• Korea Electronics Telecomm

Inventors

• Lee Jie Hyun
• Park Heuk
• Lee Jyung Chan
• Lee Sang Soo

Classifications

• H04J14/0278 Primary

  WDM optical network architectures · CPC title

• H04B10/272 Primary

  Star-type networks {or tree-type networks} · CPC title

• H04J14/0241

  Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths · CPC title

• H04J14/023 Primary

  in WDM passive optical networks [WDM-PON] · CPC title