Optical module, signal processing system, and signal processing method

A signal processing system comprising:

• an optical module;
• and
• a signal processing device that is electrically connected to the optical module,
• wherein the optical module includes,
• a mirror device that includes a base, a movable mirror including a mirror surface, an elastic support portion that is connected between the base and the movable mirror and supports the movable mirror so that the movable mirror is movable along a direction intersecting the mirror surface, a first comb electrode that is provided in the base and includes a plurality of first comb fingers, and a second comb electrode that is provided in at least one of the movable mirror and the elastic support portion and includes a plurality of second comb fingers arranged alternately with the plurality of first comb fingers,
• at least one fixed mirror,
• at least one beam splitter that constitutes an interference optical system in combination with the movable mirror and the at least one fixed mirror,
• a first light detector that detects interference light of measurement light emitted from the interference optical system, and
• a second light detector that detects interference light of laser light emitted from the interference optical system, and
• the signal processing device includes a processer configured to,
• control a voltage signal having a frequency for causing the movable mirror to resonate in the mirror device, so that the voltage signal is applied between the first comb electrode and the second comb electrode, and
• perform an intensity acquisition process of acquiring a measurement light intensity of the interference light of the measurement light M times (M is an integer of two or greater) at a first time interval based on the frequency in each of a plurality of cycles among P cycles (P is an integer of two or greater) continuous in the voltage signal, acquiring an addition value of a plurality of the measurement light intensities mutually corresponding for the same number of times, acquiring a laser light intensity of the interference light of the laser light N times (N is an integer of two or greater) at a second time interval based on the frequency in each of the plurality of cycles, and acquiring an addition value of a plurality of the laser light intensities mutually corresponding for the same number of times.

A signal processing method that is carried out to detect interference light of measurement light emitted from an interference optical system and interference light of laser light emitted from the interference optical system, the interference optical system being constituted by a mirror device that includes a base, a movable mirror including a mirror surface, an elastic support portion that is connected between the base and the movable mirror and supports the movable mirror so that the movable mirror is movable along a direction intersecting the mirror surface, a first comb electrode that is provided in the base and includes a plurality of first comb fingers, and a second comb electrode that is provided in at least one of the movable mirror and the elastic support portion and includes a plurality of second comb fingers arranged alternately with the plurality of first comb fingers, at least one fixed mirror, and at least one beam splitter, the method comprising:

• a step of controlling a voltage signal having a frequency for causing the movable mirror to resonate in the mirror device, so that the voltage signal is applied between the first comb electrode and the second comb electrode;
• and
• a step of performing an intensity acquisition process of acquiring a measurement light intensity of the interference light of the measurement light M times (M is an integer of two or greater) at a first time interval based on the frequency in each of a plurality of cycles among P cycles (P is an integer of two or greater) continuous in the voltage signal, acquiring an addition value of a plurality of the measurement light intensities mutually corresponding for the same number of times, acquiring a laser light intensity of the interference light of the laser light N times (N is an integer of two or greater) at a second time interval based on the frequency in each of the plurality of cycles, and acquiring an addition value of a plurality of the laser light intensities mutually corresponding for the same number of times.