Wavemeter

An apparatus comprising:

• a wavemeter comprising:
• an optical distributor configured to receive an input light beam and distribute light from the input light beam to multiple channels;
• a first module defining a first pair of cavities configured to receive two channels of light from the optical distributor, in which the first pair of cavities has a first free spectral range;
• a second module defining a second pair of cavities configured to receive another two channels of light from the optical distributor, in which the second pair of cavities has a second free spectral range that is smaller than the first free spectral range;
• and
• a processor configured to:
• determine a first estimate of the wavelength or optical frequency of the input light beam based on measurements of interference signals from the first pair of cavities and an initial estimate of the wavelength or optical frequency, and
• determine a second estimate of the wavelength or optical frequency of the input light beam based on measurements of interference signals from the second pair of cavities and the first estimate of the wavelength or optical frequency, in which the second estimate is more accurate than the first estimate.

An apparatus comprising:

• a wavemeter comprising:
• an optical distributor configured to receive an input light beam and distribute light from the input light beam to multiple channels;
• a plurality of modules, each module defining a set of cavities, each set of cavities comprising at least two cavities, each cavity configured to receive a channel of light from the optical distributor;
• and
• a processor configured to estimate the wavelength or optical frequency of the input light beam based on measurements of interference signals from the sets of cavities and an initial estimate of the wavelength or optical frequency, in which a first estimate is determined based on measurements from a first set of cavities having a largest free spectral range, the first estimate is refined using measurements from one or more additional sets of cavities having a smaller free spectral range or smaller free spectral ranges than that of the first set of cavities, and a final estimate is determined using an earlier estimate and measurements from a final set of cavities having a smallest free spectral range among the sets of cavities.

A method comprising:

• receiving an input light beam;
• distributing light from the input light beam to multiple channels;
• receiving, at a pair of interferometer cavities, two of the multiple channels of light;
• measuring intensity of light reflected from the pair of cavities;
• and
• determining a refined estimate of the wavelength or optical frequency of the input light beam based on measurements of interference signals from the pair of cavities and an initial estimate of the wavelength or optical frequency of the input light beam.

An apparatus comprising:

• a wavemeter comprising:
• an optical distributor configured to receive an input light beam and distribute light from the input light beam to multiple channels;
• a set of cavities comprising at least two cavities, each cavity configured to receive a channel of light from the optical distributor;
• and
• a processor configured to determine a refined estimate of the wavelength or optical frequency of the input light beam based on measurements of interference signals from the set of cavities and an initial estimate of the wavelength or optical frequency.