Wavelength calibration method, apparatus, and system for microring filter

Patent metadata

Field	Value
Publication number	US-11320677-B2
Application number	US-202016932515-A
Country	US
Kind code	B2
Filing date	Jul 17, 2020
Priority date	Jan 18, 2018
Publication date	May 3, 2022
Grant date	May 3, 2022

Abstract

A wavelength calibration method for a microring filter includes selecting N wavelengths from M wavelengths, and performing operations on the microring filter for each of the N wavelengths, thereby obtaining N sets of calibrated voltages, and obtaining, based on N sets of calibrated voltages, M−N sets of calibrated voltages corresponding to M−N wavelengths of the M wavelengths. The operating include adjusting thermal tuning power of the plurality of microrings in response to one set of voltages, and obtaining a plurality of sets of voltages that enable monitored optical power to have an extreme value, and using the plurality of sets of voltages as a reference, adjusting the thermal tuning power of the plurality of microrings in response to another set of voltages, and determining one of the N sets of calibrated voltages from the plurality of sets of voltages.

First claim

What is claimed is:

1. A wavelength calibration method for a microring filter, and the method comprises:
selecting N wavelengths from M wavelengths, and performing operations A1 and A2 on the microring filter for each of the N wavelengths, thereby obtaining N sets of calibrated voltages, the microring filter comprises a plurality of microrings, wherein N is less than M;
wherein the operations A1 include: adjusting thermal tuning power of the plurality of microrings in response to one set of voltages, and obtaining a plurality of sets of voltages that enable monitored optical power to exceed a first threshold and less than a second threshold; and
wherein the operations A2 include: using the plurality of sets of voltages as a reference, adjusting the thermal tuning power of the plurality of microrings in response to another set of voltages, and determining one of the N sets of calibrated voltages from the plurality of sets of voltages, wherein the N sets of calibrated voltages enables the monitored optical power to converge, and the monitored optical power is not less than a preset value in response to the monitored optical power having a maximum value, or the monitored optical power is not greater than another preset value in response to the monitored optical power having a minimum value; and

obtaining, based on the N sets of calibrated voltages, M−N sets of calibrated voltages corresponding to M−N wavelengths of the M wavelengths.

2. The method according to claim 1 , wherein the adjusting thermal tuning power of the plurality of microrings in response to the one set of voltages, and obtaining the plurality of sets of voltages that enable monitored optical power to exceed the first threshold and less than the second threshold comprises:
adjusting the thermal tuning power of the plurality of microrings in response to the one set of voltages, and obtaining a plurality of sets of other voltages that enable the monitored optical power to exceed the first threshold and less than the second threshold, wherein each of the plurality of sets of other voltages corresponds to one of the plurality of microrings; and
determining the plurality of sets of voltages based on the plurality of sets of other voltages, wherein each of the plurality of sets of voltages is determined by including one voltage value from each of the plurality of sets of other voltages for combination.

3. The method according to claim 2 , wherein the obtaining the plurality of sets of other voltages that enable the monitored optical power to exceed the first threshold and less than the second threshold comprises performing low-pass filtering processing on obtained voltages and a monitored optical power data.

4. The method according to claim 1 , wherein a voltage adjustment range in the operations A1 is greater than a voltage adjustment range in the operations A2.

5. The method according to claim 1 , wherein the N wavelengths are evenly distributed in the M wavelengths.

6. The method according to claim 1 , wherein the monitored optical power has an extreme value that is a maximum value of the monitored optical power or a minimum value of the monitored optical power.

7. The method according to claim 1 , wherein the method further comprises: after the operations A1 and before the operations A2, sorting the plurality of sets of voltages in ascending order of values.

8. The method according to claim 1 , wherein N/M is less than or equal to 0.2.

9. The method according to claim 1 , wherein the obtaining, based on the N sets of calibrated voltages, M−N sets of calibrated voltages corresponding to M−N wavelengths of the M wavelengths comprises:
calculating, based on the N sets of calibrated voltages, M−N sets of calibrated voltage values according to the following equation:

λ
2

-

λ
1

=

η
⁡

(

U
2
2

-

U
1
2

)

2
⁢

⁢
π
⁢

⁢

R
·

R
m

·

λ
m

n
g

,

where
λ 2 -λ 1 represents a difference between two wavelengths,

(

U
2
2

-

U
1
2

)

R
m

represents a difference between detected optical powers corresponding to the two wavelengths, η represents a thermo-optical tuning value, R represents a radius of a microring, R m represents a resistance value of the microring, λ m represents value of a wavelength with a known set of calibrated voltages in the two wavelengths, and n g represents a refractive index.

10. An apparatus, configured for wavelength calibration for a microring filter, and comprising:
a processor,
an optical power detector, and
a driver, wherein
the optical power detector is configured to obtain monitored optical power of the microring filter and provide the monitored optical power to the processor;
the driver is configured to apply a drive voltage specified by the processor to a plurality of microrings of the microring filter; and

the processor is configured to:
select N wavelengths from M wavelengths, and perform operations A1 and A2 on the microring filter for each of the N wavelengths, thereby obtaining N sets of calibrated voltages, wherein N is less than M;
wherein the operations A1 include: adjusting thermal tuning power of the plurality of microrings in response to one set of voltages, and obtaining a plurality of sets of voltages that enable the monitored optical power to exceed a first threshold and less than a second threshold; and
wherein the operations A2 include: using the plurality of sets of voltages as a reference, adjusting the thermal tuning power of the plurality of microrin

Assignees

• Huawei Tech Co Ltd

Inventors

• Zhou Sujie
• Luo Long
• Ji Ruiqiang
• Li Yanbo
• Wang Mai

Classifications

• G02F1/0147 Primary

  based on thermo-optic effects (G02F1/132 takes precedence) · CPC title

• G02B6/29343 Primary

  Cascade of loop resonators · CPC title

• G02F2203/055

  wavelength filtering · CPC title

• G02F1/011

  in optical waveguides, not otherwise provided for in this subclass · CPC title

• G02B6/29395

  configurable, e.g. tunable or reconfigurable (switching G02B6/35) · CPC title