Multi-channel wavelength locker using gas tuning
AssigneeFibera, Inc.
InventorGeorge C. K. Chen
Life of this patent
Estimating the term…
Abstract
A method and system for providing wavelength-locked multi-channel signals with respect to a wavelength reference. Wavelengths of a plurality of radiation sources are introduced to at least one etalon having a gas medium. The etalon produces a plurality of equally spaced spectral lines and is tuned by varying its optical index of refraction, by varying the characteristics of its gas medium. The optical index of refraction is then fixed, by fixing the characteristics of its gas medium, and thus locking the plurality of spectral lines with respect to the wavelength reference. In particular, the etalons may be tuned by varying the pressure or composition of their gas-tunable mediums until the spectral lines of the etalon align with the ITU grid.
Claims24
A method for locking the wavelengths of a plurality of radiation sources to a wavelength reference, comprising:
- A) providing at least one etalon that is open within a surrounding enclosure and which includes a gas-tunable medium having a variable optical index of refraction;
- B) introducing radiation into said etalon, whereby a plurality of equally spaced spectral lines is produced;
- C) tuning said etalon by varying said variable optical index of refraction of said gas-tunable medium, to align said plurality of spectral lines with said wavelength reference;
- D) fixing said variable optical index of refraction included in said etalon, so that said spectral line produced remains substantially aligned with said external reference wavelength;
- E) diverting a portion of the radiation from a radiation source whose wavelength is to be locked, introducing said portion of said radiation into said etalon, whereby at least one spectral line is produced;
- F) detecting said at least one spectral line output from said etalon and creating control signals therefrom in response to shifts in wavelength of said spectral line output;
- and
- G) adjusting said radiation source whose wavelength is to be locked in response to said control signals.
A system for providing wavelength-locked multi-channels signal, comprising:
- a plurality of radiation sources providing beams of radiation at wavelengths separated by a predetermined spacing, each spaced wavelength being a channel which is connected to a multiplexer;
- at least one wavelength-locker producing equally-spaced spectral lines which are tuned in comparison to a wavelength reference, said wavelength-locker including at least one etalon that is open within a surrounding enclosure and which includes a gas-tunable medium having a variable optical index of refraction;
- first beam splitters which divert a portion of said beams of radiation into said at least one wavelength locker;
- at least one detector which receives the spectral line output of the wavelength locker, detects shifts in wavelength of said spectral line output and generates control signals;
- and
- means for adjusting the wavelength of said plurality of radiation sources in response to said control signals.
A process for making a wavelength-locked multi-channel multiplexer, comprising the steps of:
- A) forming at least one etalon which includes a pair of reflecting surfaces and that is open within enclosure walls surrounding a cavity filled with gas of variable pressure and composition, and which produces a medium of variable optical index of refraction;
- B) introducing radiation into said etalon, whereby a plurality of equally spaced spectral lines is produced;
- C) tuning said etalon by varying said variable optical index of refraction, to align said plurality of spectral lines with said wavelength reference;
- D) fixing said variable optical index of refraction included in said etalon, so that said spectral line produced remains substantially aligned with said external reference wavelength;
- E) providing a plurality of radiation sources producing radiation at wavelengths separated by a predetermined spacing, each spaced wavelength being a channel which is multiplexed with the other channels;
- F) introducing a portion of the outputs of said plurality of radiation sources to said at least one etalon, and producing etalon output;
- G) detecting shifts in wavelength in said etalon output which are due to shifts in wavelength of said plurality of radiation sources;
- and
- H) adjusting said plurality of radiation sources in response to shifts in wavelength of said plurality of radiation sources to lock the wavelength.
A method for locking the wavelengths of a plurality of channels in a multi channel system, comprising:
- A) providing at least one etalon that is open within a surrounding enclosure and which includes a medium having a variable optical index of refraction;
- B) introducing a beam of incident light into said etalon, whereby a plurality of spectral lines is produced;
- C) comparing said at least one spectral line with at least one external reference wavelength;
- D) tuning said etalon by varying pressure in said etalon to adjust said variable optical index of refraction to align said spectral lines with said at least one external reference wavelength;
- E) fixing said variable optical index of refraction included in said etalon, so that said spectral lines produced remain substantially aligned with said external reference wavelength;
- F) detecting said spectral lines output from said etalon and creating control signals therefrom;
- and
- G) adjusting said optical device whose wavelength is to be locked in response to said control signals.
Dependencies are inferred from the claim text.