Accurate chirped synthetic wavelength interferometer

A method comprising:

• chirping a first laser output having a first optical frequency by varying the first optical frequency at a first chirp rate;
• directing a first portion of the first laser output to a calibration unit comprising at least one gas cell having at least one absorption line, wherein the calibration unit is configured to output a calibration signal;
• directing a second portion of the first laser output through a first plurality of optical paths onto a detector to produce a first interference signal;
• and
• determining a distance based at least in part on the first interference signal and the calibration signal, wherein determining the distance comprises:
• determining a first time when the first optical frequency matches a feature of the absorption line of the gas cell during the chirping;
• and
• determining an interferometer phase based, at least in part, on the first time.

A method comprising:

• producing a laser output;
• chirping the optical frequency of the laser output over a chirp bandwidth to produce a chirped beam;
• directing a portion of the chirped beam through a plurality of optical paths onto a detector;
• producing an interference signal comprising a first interference signal based on a first optical path and a second interference signal based on a second optical path, wherein
• the first interference signal and the second interference signal are sub-resolved;
• and
• determining a distance based on the interference signal, wherein determining the distance comprises applying a fitting operation to the interference signal based on fitting parameters, wherein the fitting parameters comprise at least an RF frequency of the first interference signal or the second interference signal and an RF phase of the first interference signal or the second interference signal.

A method comprising:

• producing a first laser output;
• producing a second laser output;
• chirping the optical frequency of the first laser output at a first chirp rate over a first chirp bandwidth to produce a first chirped beam;
• chirping the optical frequency of the second laser output at a second chirp rate over a second chirp bandwidth to produce a second chirped beam;
• directing at least a portion of the first chirped beam through a plurality of optical paths onto a detector to produce a first interference signal;
• directing at least a portion of the second chirped beam through a plurality of optical paths onto the detector to produce a second interference signal peak, wherein the first interference signal and the second interference signal are sub-resolved;
• producing an interference signal based, at least in part, on interference between the first interference signal and the second interference signal;
• and
• determining a distance based on the interference signal, wherein determining the distance comprises applying a fitting operation to the interference signal based on fitting parameters, wherein the fitting parameters comprise at least an RF frequency of the first interference signal or the second interference signal and an RF phase of the first interference signal or the second interference signal.