Dual-interrogated interferometer for fluid measurements

A method comprising:

• emitting light into an environment;
• receiving reflected light from the environment;
• interfering the light with the reflected light to provide interfered light;
• detecting the interfered light at a high-rate sensor, the high-rate sensor providing high-rate measurements;
• detecting the interfered light at a two-dimensional detector array, the two-dimensional detector array providing two-dimensional detector array measurements;
• perform a statistical comparison of the two-dimensional detector array measurements to the high-rate measurements, wherein the statistical comparison identifies the portion of the two-dimensional detector array measurements that most closely resembles the high-rate fringe;
• and
• calculating a phase shift of the reflected light based on the portion of the two-dimensional detector array measurements;
• and
• calculate a fluid velocity associated with the phase shift.

A system comprising:

• a laser source that generates light;
• an emitter that emits the light into an environment of the system;
• a receiver that receives reflected light, where the reflected light is the light reflected by particles in the environment;
• an interferometer that produces interfered light by interfering the light with the reflected light to create interference fringes;
• a coupler that couples the interfered light onto a first output path and a second output path;
• a first sensor coupled to the first output path that provides a first set of measurements of the interfered light;
• a second sensor coupled to the second output path that provides a second set of measurements of the interfered light, wherein the first sensor has a smaller number of detectors and a lower dynamic range than the second sensor;
• and
• one or more processors that calculate fluid velocity in relation to the system wherein the one or more processors are configured to:
• identify a receive fringe for the second set of measurements;
• identify a high-rate fringe for the first set of measurements;
• perform a statistical comparison of the receive fringe, wherein the statistical comparison identifies a portion of the receive fringe that most closely resembles the high-rate fringe;
• identify a phase difference between the portion of the receive fringe and a transmit fringe associated with the emitted light from the system;
• and
• calculate the fluid velocity associated with the phase difference.