Random ring photonic integrated circuit spectrometer

A method of calibrating and operating an integrated optical spectrometer comprising:

• providing an optical bus configured to accept a light to be measured, and an array of integrated ring resonators and detectors, each ring resonator optically coupled to said optical bus and each ring resonator optically coupled to at least one detector, wherein each ring resonator in the array of ring resonators is an optical cavity;
• generating a calibration matrix for said array of integrated ring resonators and detectors by scanning at least once, a wavelength of the light to be measured with a spectral channel interval dλ;
• and
• decomposing an incoming spectrum of light into a linear combination of ring resonator modes to determine a spectral content of the light to be measured based on data from each detector of said array of integrated ring resonators and detectors and said calibration matrix.

A method to generate a calibration matrix for an array of ring resonators of a photonic integrated circuit (PIC) spectrometer comprising:

• determining a spectrometer wavelength and bandwidth;
• determining a scanning interval dλ by the full width half maximum (FWHM) of a spectral correlation function;
• tuning a tunable wavelength tunable light source or a wavelength selectable light source to a starting wavelength λ0 with one unit of power, where a bandwidth of the tunable laser is smaller than dλ;
• recording data obtained from the array of ring resonators a set of detectors, wherein each ring resonator in the array of ring resonators has at least one detector optically coupled to it, and each ring resonator is an optical cavity, which data forms a first column of a calibration matrix;
• tuning the wavelength tunable light source or the wavelength selectable light source to a wavelength of λ0+dλ with the same amount of power;
• recording data from the detectors, which data forms a next column of the calibration matrix;
• and
• repeating the measurements of tuning the wavelength tunable light source or the wavelength selectable light source to a wavelength of λ0+dλ and recording data from the detectors to an end wavelength to complete the calibration matrix.