Real time self-mixing interferometric laser sensor for embedded applications
نویسندگان
چکیده
A Self-Mixing (SM) interferometric laser displacement sensor is presented that is capable of providing correct target measurement in real-time even when it is subject to extraneous parasitic movements. The sensor achieves such robustness by using an embedded MEMS Solid-State Accelerometer (SSA) that has been coupled with the laser sensor. The SSA thus measures the extraneous movement acting on the laser sensor and this information is used to provide correct sensing. The proposed SSA-SM sensing system uses Consecutive-Samples based Unwrapping (CSU) to process the SM interferometric signal while a Digital Signal Processor (DSP) takes care of band-pass filtering, double integration as well as phase and gain corrections needed for the acceleration signal. Hence, a compact, real-time, precise and selfaligned SSA-SM sensor has been designed that has a displacement measurement precision of approximately 100 nm with a parasitic movement elimination of 31dB for a laser diode
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