A laser interferometer includes a light source that emits first laser light, an optical modulator that includes a vibrator and modulates the first laser light by using the vibrator to generate second laser light including a modulated signal, a photodetector that receives interference light between third laser light including a sample signal generated by reflecting the first laser light on an object and the second laser light to output a light reception signal, a demodulation circuit that demodulates the sample signal from the light reception signal based on a reference signal, and a signal generator that outputs the reference signal input to the demodulation circuit and outputs a drive signal input to the optical modulator, in which Vd/Vr<10, where Vr is a voltage of the reference signal and Vd is a voltage of the drive signal.

A laser interferometer includes a light source that emits first laser light, an optical modulator that includes a vibrator and modulates the first laser light by using the vibrator to generate second laser light including a modulated signal, a photodetector that receives interference light between third laser light including a sample signal generated by reflecting the first laser light on an object and the second laser light to output a light reception signal, a demodulation circuit that demodulates the sample signal from the light reception signal based on a reference signal, and a signal generator that outputs the reference signal input to the demodulation circuit and outputs a drive signal input to the optical modulator, in which Vd/Vr<10, where Vr is a voltage of the reference signal and Vd is a voltage of the drive signal.

Detecting the source of a defect in a cable may be difficult, in part because present systems may be configured to wind and unwind the cable on many different spools, capstans or other transport equipment. Provided are systems and methods in which a laser speed gauge is used to measure the rotation of a cable assembly component and determine any abnormalities in the rotation (e.g., vibrations, periodic increases/decreases in speed). An example method includes receiving, by a computing device and from a laser speed gauge, a first reading of a rotating cable assembly component. The computing device may covert the first reading of the rotating cable assembly component to a frequency analysis of the rotating cable assembly component and determine based on the frequency analysis of the rotating cable assembly component, a structural defect in a cable caused by the rotating cable assembly component.

Detecting the source of a defect in a cable may be difficult, in part because present systems may be configured to wind and unwind the cable on many different spools, capstans or other transport equipment. Provided are systems and methods in which a laser speed gauge is used to measure the rotation of a cable assembly component and determine any abnormalities in the rotation (e.g., vibrations, periodic increases/decreases in speed). An example method includes receiving, by a computing device and from a laser speed gauge, a first reading of a rotating cable assembly component. The computing device may covert the first reading of the rotating cable assembly component to a frequency analysis of the rotating cable assembly component and determine based on the frequency analysis of the rotating cable assembly component, a structural defect in a cable caused by the rotating cable assembly component.