Photonic integrated circuit chip for distributed acoustic sensing

An optical sensing device for distributed acoustic sensing using a sensing fiber, comprising:

• a substrate;
• a laser supported by the substrate to produce laser light;
• an optical modulator supported by the substrate and located to receive the laser light from the laser to produce laser pulses for sensing local phase disturbances at various locations along the sensing fiber by detecting backscattering light of the laser pulses reflected at the various locations along the fiber;
• a 2-state polarization generator (PSG) or a polarization controller with an output polarizer coupled to receive the backscattered light from the sensing fiber and to control optical polarization of the received backscattered light from the sensing fiber;
• an optical coupler configured to split light from the 2-state polarization generator (PSG) or the polarization controller into first optical beam and a second optical beam in a common polarization traveling in waveguides of different lengths;
• an optical coherent receiver supported by the substrate to receive the first optical and the second optical beam to produce different optical coherent receiver output signals that carry information of local phase disturbances at various locations along the sensing fiber.

An optical sensing device for distributed acoustic sensing using a sensing fiber, comprising:

• a substrate;
• a laser supported by the substrate to produce laser light;
• an optical modulator supported by the substrate and located to receive the laser light from the laser to produce laser pulses for sensing local phase disturbances at various locations along the sensing fiber by detecting backscattering light of the laser pulses reflected at the various locations along the sensing fiber;
• a polarization device outside the substrate to receive the backscattered light from the sensing fiber and to split the received backscattered light from the sensing fiber into first optical beam in a first polarization and a second optical beam in a second polarization that is orthogonal to the first polarization;
• a first optical coupler to receive the first optical beam in the first polarization and to split the first optical beam into two first optical beams in the first polarization;
• a second optical coupler to receive the second optical beam in the second polarization and to split the second optical beam into two second optical beams in the second polarization;
• a first optical coherent receiver supported by the substrate to receive the two first optical beams in the first optical polarization to produce two or more first optical coherent receiver output signals that carry information of local phase disturbances at various locations along the sensing fiber;
• and
• a second optical coherent receiver supported by the substrate to receive the two second optical beams in the first optical polarization to produce two or more second optical coherent receiver output signals that carry information of local phase disturbances at various locations along the sensing fiber.

An optical sensing device for distributed acoustic sensing using a sensing fiber, comprising:

• a substrate;
• a laser supported by the substrate to produce laser light;
• an optical modulator supported by the substrate and located to receive the laser light from the laser to produce laser pulses for sensing local phase disturbances at various locations along the sensing fiber by detecting backscattering light of the laser pulses reflected at the various locations along the sensing fiber;
• a polarization device supported by the substrate to receive the backscattered light from the sensing fiber and to split the received backscattered light from the sensing fiber into first optical beam in a first polarization and a second optical beam in a second polarization that is orthogonal to the first polarization and to rotate the second polarization of the second optical beam by 90 degrees to produce a second polarization beam in the first polarization;
• a first optical coherent receiver supported by the substrate to receive (1) the first optical beam in the first optical polarization and (2) a first portion of the laser light from the laser as a first local optical oscillator signal for optical coherent detection to produce two or more first optical coherent receiver output signals that carry information of local phase disturbances at various locations along the sensing fiber;
• and
• a second optical coherent receiver supported by the substrate to receive (1) the second optical beam in the second optical polarization and (2) a second portion of the laser light from the laser as a second local optical oscillator signal for optical coherent detection to produce two or more second optical coherent receiver output signals that carry information of local phase disturbances at various locations along the sensing fiber.

An optical sensing device for distributed acoustic sensing using a sensing fiber, comprising:

• a substrate;
• a laser supported by the substrate to produce laser light;
• an optical modulator supported by the substrate and located to receive the laser light from the laser to produce laser pulses for sensing local phase disturbances at various locations along the sensing fiber by detecting backscattering light of the laser pulses reflected at the various locations along the sensing fiber;
• a polarization controller supported by the substrate and coupled to receive the backscattered light from the sensing fiber and to control optical polarization of the received backscattered light from the sensing fiber;
• a polarizer supported by the substrate to select a portion of output light from the polarization controller as a polarized output light;
• and
• an optical coherent receiver supported by the substrate to receive (1) the polarized light and (2) a portion of the laser light from the laser as a local optical oscillator signal for optical coherent detection to produce different optical coherent receiver output signals that carry information of local phase disturbances at various locations along the sensing fiber.