As laser Doppler vibrometers are used more and more widely in scientific research and production, its cost and price have gradually become the bottleneck in expanding its applications. In order to meet the market demand for laser pointer Doppler vibrometers, Zhigan (Suzhou) Photonics Technology Co., Ltd. (hereinafter referred to as Zhizhizhizhi) has launched a series of digital small laser vibration sensors based on integrated optical chip technology (see “Laser displacement transmission Sensing Technology Analysis: New Industrial Laser Sensing Solution”), which has realized the leap from expensive instruments to generalized sensors.
This type of small laser vibration sensor uses a similar laser interferometric vibration measurement design (see the first part of Figure 1), which essentially requires two coherent beams from the same light source to superimpose and interfere: one of them can be regarded as a local reference light, and the other One way is the return light after the actual measurement target. The optical interference method can not only amplify the optical signal intensity of the return light, but also directly obtain the optical phase of the return light signal through the design of the orthogonal interference optical path, so as to realize the relative measurement of phase-velocity-acceleration.
In terms of specific product realization, Zhizhitong completely integrates the key optical components of the laser interferometer into the optical chip (see the second part of Figure 1), and further integrates the optical chip, laser, and detector through hybrid integration. And the optical lens for detection is integrated into a module roughly the size of half a matchbox through an integrated package. This design can not only reduce its volume nearly a hundred times.
At the same time, it greatly facilitates the mass production of green laser pointer vibration sensors, which can reduce its cost by 10 times, laying the foundation for the wide application of laser vibration sensors. In addition to the module design with optical lens, the design with optical fiber pigtail is also realized, making it more flexible in application scenarios. In appearance, the laser pointer Doppler vibrometer used in the smallest industrial production line is compared with the laser vibration sensor of the sensitive photon.
As a complete reference design, Zhizhiguang’s vibration sensor module includes an integrated optical module that includes a customizable lens (or optical fiber), as well as supporting drive circuits and built-in corresponding algorithms. The long-distance vibration signal sensor module of the Zhiguang sub-series shown in Figure 3 is equipped with a large-diameter optical interface and high-speed acquisition circuit and algorithm suitable for long-distance measurement. It can be used as a remote working pickup to collect 30 Audio vibration signals reflected on background objects at a distance of meters or more. Its typical application is that it can be integrated into the currently deployed urban surveillance cameras, so that all kinds of cameras have the function of remote sound pickup.