Miniature optical fiber curvature sensor via integration with GaN optoelectronics

Abstract

Optical fiber curvature sensors have been considered as a promising option for human motion detection due to its good toughness, bending flexibility and anti-electromagnetic interference. However, for wearable devices, the miniature configuration is preferred, and a high integration of the light emitter, receiver and guided fiber is essential to configure the miniaturized sensing system. Here, we present a miniaturized curvature sensing system by integrating a GaN-based optoelectronic chip with the plastical optical fiber (POF). The light emitter and detector are fabricated on a GaN-on-sapphire wafer to form a tiny chip sized at 2.5 $$\times$$ × 1.5 mm2. The on-chip photodetector (PD) effectively senses the reflected light intensity, extracting information on the fiber bending deformation. A compact curvature sensing system is demonstrated for finger motion detection with movement angles of 30–90° and frequencies of 0.4, 1, and 1.6 Hz. The results show that the monolithically integrated LED and PD chip can be combined with the POF with reliable operation. The demonstration of the monolithically integrated optoelectronic device suggests a promising potential technology for future wearable fiber optical sensor system.

Packaged Elastomeric Optical Fiber Sensors for Healthcare Monitoring and Human‐Machine Interaction

“…Typically, to fabricate an EPOF with a core of high refractive index and a cladding of low refractive index, one can employ coaxial 3D printing, [ 28 ] clad coating, [ 29 ] coextrusion, [ 30 ] thermal drawing [ 31 ] or molding [ 32 ] methods. Recently, EPOF‐enabled sensors have been widely used for body movement monitoring [ 33,34 ] or robotic skin. [ 35 ] These reports shed light on the development of flexible optical sensors.…”

Unification of Irreversibility and Energy Diagram Theory

“…The EL and responsivity spectra show an approximate 50 nm wavelength overlap for the response to higher-energy photons, suggesting that the QW diode can detect and modulate photons emitted by itself. Two diodes sharing identical QW structures can be separately used as a transmitter and a receiver to form a wireless light communication system. − Gao et al monolithically integrated different diodes with identical QW structures into a single chip to produce a waterproof optoelectronic system, in which the QW diodes acted as a transmitter, a receiver, and an energy harvester. In particular, the simultaneous emission-detection phenomenon occurs when we shine a shorter-wavelength light beam onto the device and apply a forward voltage to it at the same time, providing a number of promising applications from full-duplex light communication to simultaneous illumination imaging.…”

Deep learning-based approach for high spatial resolution fibre shape sensing

“…It is well known that light power loss increases when optical fibers bend 33 , 45 . This bending loss is typically observed as spectral modulations caused by coherent coupling between the core mode and the radiated field reflected by the cladding-coating and the coating-air interfaces (commonly referred to as whispering gallery modes) 34 , 46 .…”