Granted Patent B2

US 12,352,571 · App. 17/819,102 · Granted Jul 8, 2025

Inventors: Jan Amir Khan (Windsor, CT); Vijay Ramareddy (Revere, MA)

Assignee: EMCORE CORPORATION

G01B9/0207G01B9/02024G01B9/02051G01C19/721

Abstract

Claims (24)

1. 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.

2. 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.

3. 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.

4. 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.

Assignments (4)

Continuity (2)

References Cited (212)