Design and analysis of a piezo-actuated flexure-based scanning system in ECDLs

The principles and structure of the external cavity diode laser (ECDL) without antireflection coating have been analyzed. The core part of an ECDL is an optical resonator, which is essentially a piezoelectric-based scanning system. This paper presents a novel scanning system that is based on an optimized star flexible hinge to improve the tracking performance and the rotation accuracy of these systems. The motion differential equation and the vibration equation of the piezo-based scanning system are derived using a Lagrangian equation and a Duhamel integral, respectively. Static, kinematic and dynamic models of the scanning system are established and analyzed. The critical dimensional parameters of the system have been calculated and optimized by considering the main parameters. The flexible structure was fabricated using the wire electrical discharge machining technique and heat treatment was performed to improve its mechanical properties. A test platform was built and experiments were then conducted to investigate the system performance. The results show that output displacement of the systems is 15.68 μm corresponding to a 75 V voltage triangle signal. The natural frequency of the system is 2187 Hz. The tuning performance of the ECDL was also tested.