Related Experiment Video
Updated: Sep 25, 2025

Fabrication and Testing of Microfluidic Optomechanical Oscillators
Published on: May 29, 2014
Suppression of undamped relaxation oscillation in a laser self-mixing interferometry sensing system
Abstract:
Undamped relaxation oscillation (RO) in a laser self-mixing interferometry (SMI) system may occur in some common application conditions, which may impact the stable operation of the system and degrade its sensing performance. In this work, we proposed to suppress the undamped RO by controlling the system operation parameters in a laser SMI sensing system. By numerically solving the famous Lang Kobayashi equations, the stability of a laser SMI system in a 3-parameter space of external cavity length, injection current and optical feedback factor were investigated. Based on the stability analyses, we determined the system operation conditions required for suppressing the undamped RO and derived an analytical expression for describing the relationship between the operation parameters. An experimental SMI system based on a laser diode (Sanyo, DL4140-001s) was implemented and verified the suppressing method. The experimental results showed that the SMI system in a moderate feedback regime can operate in steady state without undamped RO by setting proper operation parameters. This work provides useful guidance to design a stable SMI sensing system for practical applications.
Related Concept Videos
Damped Oscillations
Although friction and other non-conservative...
Oscillations In An LC Circuit
Forced Oscillations
Types of Damping
RLC Circuit as a Damped Oscillator
Consider a series RLC circuit. Here, the presence of resistance in the circuit leads to energy loss due to joule heating in the resistance. Therefore, the total electromagnetic energy in the circuit is no longer constant and decreases with time. Since the magnitude of charge, current, and potential difference continuously decreases, their oscillations are said to be damped. This is...

