Wide-field-of-view optical detectors using fused fiber-optic tapers
Citation
Alkhazragi, O., Trichili, A., Ashry, I., Ng, T. K., Alouini, M.-S., & Ooi, B. S. (2021). Wide-field-of-view optical detectors using fused fiber-optic tapers. Optics Letters, 46(8), 1916–1919.
Keywords
- Photodetectors
- Wide Field of View (FOV)
- High Optical Gain
- Fused Fiber-Optic Tapers (FFOTs)
- Signal-to-Noise Ratio (SNR)
- Optical Wireless Communication (OWC)
- Modulation Bandwidth
- Near Infrared (NIR)
- Transmission Efficiency
- Bit Error Ratio (BER)
Brief
A versatile imaging light-focusing element is demonstrated, which features a wide field of view and high optical gain using fused fiber-optic tapers for use in optical wireless communication. This addresses the trade-off between response speeds and active areas that limits the signal-to-noise ratio in photodetectors used in wireless applications.
Summary
This article introduces a novel approach to designing wide-field-of-view (FOV) optical detectors for applications like optical wireless communication (OWC). The authors present a design based on fused fiber-optic tapers (FFOTs) that overcomes the limitations of traditional detectors, particularly the trade-off between active area and bandwidth.
Here's a breakdown of the key findings:
- FFOTs as a Solution: The researchers address the challenge of achieving both high speed and wide FOV in optical detectors. They propose using FFOTs, which consist of thousands of tapered optical fibers fused together. Each fiber acts as a segment pointing in a specific direction, guiding light towards the detector. This design offers several advantages over existing methods:
- High Bandwidth: Unlike luminescent detectors with limited bandwidths (below 100 MHz), the FFOT-based design achieved a bandwidth of 1 GHz, limited only by the photodetector used.
- High Efficiency: The FFOTs exhibited a transmission efficiency of 55-70.7%, significantly higher than the 1.5% reported for some fluorescence-based detectors.
- Wide Wavelength Range: FFOTs function effectively over a wide range of wavelengths, unlike fluorescence-based detectors that require specific excitation wavelengths.
- Flexibility and Stability: FFOTs allow FOV modification based on the application and offer indefinite stability compared to organic dyes used in other detectors.
- Experimental Validation: The researchers demonstrated the practicality of their design through experiments:
- Wide FOV: A convex-surface FFOT achieved a -3 dB FOV semiangle of 30°, significantly wider than traditional lenses.
- High Gain: The FFOT detector exhibited an optical gain of over two orders of magnitude, surpassing the performance of luminescent detectors and even exceeding that of a comparable compound parabolic concentrator.
- Successful OWC Link: A 1 Gbit/s OWC link using the FFOT detector demonstrated a bit error rate below the forward error correction limit for a range of angles and translations, proving the detector's effectiveness in real-world scenarios.
- Future Potential: The article concludes by highlighting the potential of FFOT-based detectors in various applications beyond OWC, such as free-space optical communication and integration with fiber-optic networks. The authors also suggest further research avenues to improve the detector's performance, including enhancing transmission efficiency and exploring different FFOT designs tailored for specific applications.