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US 11,885,677 B2Granted
High-performance on-chip spectrometers and spectrum analyzers
AssigneeMassachusetts Institute of Technology
InventorsDerek Kita, Carlos Andres Rios Ocampo, Juejun Hu
Life of this patent
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Abstract
We disclose an on-chip photonic spectroscopy system capable of dramatically improving the signal-to-noise ratio (SNR), dynamic range, and reconstruction quality of Fourier transform spectrometers. Secondly, we disclose a system of components that makes up a complete on-chip RF spectrum analyzer with low-cost and high-performance.
Claims18
A method of operating a spectrometer, the method comprising:
- splitting incident light into a first portion and a second portion;
- transmitting the first portion through at least one delay stage switchable between a first waveguide having a first optical path length and a second waveguide have a second optical path length different than the first optical path length;
- transmitting the second portion through a reference waveguide;
- attenuating at least one of the first portion or the second portion to compensate for loss imbalance between the at least one delay stage and the reference waveguide;
- detecting interference between the first portion with the second portion;
- and
- determining a spectrum of the incident light based on the interference of the first portion and the second portion,
- wherein attenuating the first portion comprises modulating a relative phase between the first portion and the second portion such that the interference of the first portion with the second portion has a null at a desired frequency.
5 more elements
A spectrometer comprising:
- a beam splitter to split incident light into a first portion and a second portion;
- a delay stage, in optical communication with a first output of the beam splitter and switchable between a first waveguide having a first optical path length and a second waveguide have a second optical path length different than the first optical path length, to delay the first portion with respect to the second portion;
- a reference waveguide, in optical communication with a second output of the beam splitter, to guide the second portion;
- an attenuator, in optical communication with at least one of the delay stage and the reference waveguide, to attenuate at least one of the first portion or the second portion;
- a detector, in optical communication, via the attenuator, with the delay stage and the reference waveguide, to detect interference of the first portion with the second portion;
- a processor, operably coupled to the detector, to determine a spectrum of the incident light based on the interference of the first portion and the second portion;
- a tap, in optical communication with the delay stage, to couple a fraction of the first portion out of the delay stage;
- and
- a monitor photodetector, in optical communication with the tap, to monitor an intensity of the fraction of the first portion.
6 more elements
A spectrometer comprising:
- a beam splitter to split incident light into a first portion and a second portion;
- a delay stage, in optical communication with a first output of the beam splitter and switchable between a first waveguide having a first optical path length and a second waveguide have a second optical path length different than the first optical path length, to delay the first portion with respect to the second portion;
- a reference waveguide, in optical communication with a second output of the beam splitter, to guide the second portion;
- an attenuator, in optical communication with at least one of the delay stage and the reference waveguide, to attenuate at least one of the first portion or the second portion;
- a detector, in optical communication, via the attenuator, with the delay stage and the reference waveguide, to detect interference of the first portion with the second portion;
- a processor, operably coupled to the detector, to determine a spectrum of the incident light based on the interference of the first portion and the second portion;
- and
- a phase modulator, in optical communication with the beam splitter, to modulate a relative phase between the first portion and the second portion such that interference of the first portion with the second portion creates a null at a desired frequency.
5 more elements
Dependencies are inferred from the claim text.