In-situ residual intensity noise measurement method and system
AssigneeEmcore Corporation
InventorsJan Amir Khan, Vijay Ramareddy
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Abstract
A method of determining residual intensity noise (RIN) of a sensor may comprise determining a first amplitude of a first harmonic of the sensor while a signal propagating through the sensor is modulated at a modulating frequency corresponding to twice an eigenfrequency of the sensor. The method may further comprise determining a second amplitude of a second harmonic of the sensor while the signal propagating through the sensor is modulated the modulating frequency, and determining the RIN of the sensor as a ratio of the first amplitude and the second amplitude.
Claims4
A method of determining residual intensity noise (RIN) of a sensor, comprising:
- determining a first amplitude of a first harmonic of the sensor while a signal propagating through the sensor is modulated at a modulating frequency corresponding to twice an eigenfrequency of the sensor;
- determining a second amplitude of a second harmonic of the sensor while the signal propagating through the sensor is modulated at the modulating frequency;
- and
- determining the RIN of the sensor as a ratio of the first amplitude and the second amplitude.
A method of determining residual intensity noise (RIN) of an interferometer system, comprising:
- propagating a light signal from a light source through the interferometer system;
- modulating the light signal at a modulating frequency that is twice an eigenfrequency of the interferometer system;
- determining a first harmonic amplitude and a second harmonic amplitude produced by the interferometer system;
- and
- determining the RIN of the interferometer system as a ratio of the first harmonic amplitude and the second harmonic amplitude.
A method of determining residual intensity noise (RIN) of an interferometer system, comprising:
- propagating a light signal from a light source through the interferometer system;
- during a first interval, modulating the light signal at a first modulating frequency that is an eigenfrequency of the interferometer system, and determining a primary measurement associated with the interferometer system;
- during a second interval:
- (i) modulating the light signal at a first modulating frequency that is twice the eigenfrequency of the interferometer system;
- (ii) determining, using an optical detector, a first harmonic amplitude and a second harmonic amplitude produced by the interferometer system;
- and
- (iii) determining the RIN of the interferometer system as a ratio of the first harmonic amplitude and the second harmonic amplitude.
A method of tracking an eigenfrequency of an interferometer system, comprising:
- determining residual intensity noise (RIN) of a sensor by:
- determining a first amplitude of a first harmonic of the sensor while a signal propagating through the sensor is modulated at a modulating frequency corresponding to twice a predetermined eigenfrequency of the sensor;
- determining a second amplitude of a second harmonic of the sensor while the signal propagating through the sensor is modulated the modulating frequency;
- and
- determining the RIN of the sensor as a ratio of the first amplitude and the second amplitude;
- repeating the step of determining RIN of the sensor using a modulating frequency selected from a range of frequencies that is centered about the predetermined eigenfrequency;
- determining a modulating frequency from the range of frequencies that produces a minimal determined RIN;
- and
- designating the modulating frequency corresponding to the minimal determined RIN as an updated eigenfrequency of the system.
Dependencies are inferred from the claim text.