Enhancing functionality of free-space and guided-wave optical MEMS devices by integration with photonic circuits

In this article, we present classification of integrated optical MEMS devices as being free-space or guided-wave based on light propagation method. Free-space optical MEMS devices are limited in performance by precision of micromachining and alignment of optical components. To fully leverage the capacity of the free-space devices, integration of photonic or electronic signal processing on chip is a relevant and ongoing research work. Guided-wave optical MEMS devices where all optical, electrical and mechanical components are integrated are more reliable and have lower costs. Grating coupler based free-space optical MEMS accelerometer with potential for integration of detection circuit is discussed. Waveguide Bragg grating based guided-wave optical MEMS widely tunable filters with potential for integration of electronic channel selectivity circuit to improve the device performance is also presented. Waveguide Bragg gratings based guided-wave optical MEMS accelerometers with potential for integration of optical spectral detection using unbalanced Mach–Zehnder modulators on chip is also discussed in this work. In the conclusion, we argue for development of integrated electronic or photonic integrated devices for both classes of optical MEMS devices to enhance their functionality and improve performance.