Group-III-Nitride Superluminescent Diodes for Solid-State Lighting and High-Speed Visible Light Communications

Abstract

Group-III-nitride superluminescent diodes (SLDs) 7 are emerging as light sources for white lighting and visible light 8 communications (VLC) owing to their droop-free, low speckle 9 noise, and large modulation bandwidth properties. In this paper, 10 we discuss the development of GaN-based visible SLDs, and ana-11 lyze their electro-optical properties by studying the optical power-12 bandwidth products and injection current densities. The significant 13 progress in blue SLDs and their applications for white light VLC is 14 highlighted. A blue SLD, with an optical power of >100 mW and 15 large PBP of 536 mW•nm, is utilized to generate white light, result-16 ing in a high color rendering index (CRI) of 88.2. In a modulation 17 experiment designed for an SLD-based VLC system, an on-off key-18 ing scheme exhibits a 1.2 Gbps data rate, with a bit error rate of 1.8 19 × 10 −3 , which satisfies the forward error correction criteria. A high 20 data rate of 3.4 Gbps is achieved using the same SLD transmitter, 21 by applying the 16-quadrature-amplitude-modulation (16-QAM) 22 discrete multitone modulation scheme for high-speed white light 23 communication. The results reported here unequivocally point to 24 the significant performance and versatility that GaN-based SLDs 25 could offer for beyond-5G implementation, where white lighting 26 and high spectral efficiency VLC systems can be simultaneously 27 implemented.

Demonstration of a low-complexity memory-polynomial-aided neural network equalizer for CAP visible-light communication with superluminescent diode

“…The SLD was fabricated by etching a c-plane GaN-based commercial laser epitaxial structure, designed with a facet tilting of 12°, and a ridge waveguide with a length of ~1 mm and a width of ~15 μm is similar to reported elsewhere 23,25 . Figure 1(a-i) shows the electron microscope image of the SLD depicting the etched front facet.…”

“…The SLD has been utilized as a VLC transmitter by using non-return-to-zero on-off keying (NRZ-OOK) 23,24 , which is, however, limited by the binary modulation capacity. With this motivation, advanced multi-carrier modulation schemes, such as discrete-multitone (DMT), have just been demonstrated using the SLD by our group, achieving multi-Gbit/s data rate 25,26 . Nevertheless, SLD-based VLC systems require further understanding to develop a mature platform with potential commercial deployment.…”

“…The necessity for VLC transmission or applications under a high-attenuation channel inevitably requires a high signal amplitude, i.e., more than the 0.5 V used in previous demonstrations 25,26 , to support the required signal-to-noise ratio (SNR) for effective signal transfer. In consequence, the increased signal amplitude will lead to nonlinear distortion.…”

Single-Port Superluminescent-Diode Gain-Chip for Tunable Single-Wavelength and Dual-Wavelength Blue-Laser

“…Nevertheless, combining InGaN-based SLDs with EC configurations has yet to be further explored for tunability and properties achieved herein. Besides, related research on InGaN-based SLDs has continued steadily with particular interests in lighting, displays, and biomedical instrumentation [16], [24]- [26]. These interests have been inspired because the SLD is emitting light in the amplified spontaneous emission (ASE) regime, showing droop-free performance, low temporal coherence, high-power density, and low etendue [16], [24], [26]- [30].…”

Vector Rayleigh Diffraction of High-Power Laser Diode Beam in Optical Communication

“…Considering that laser diodes (LDs) are the efficient light source and easy to integrate, LD-enabled optical wireless communication (OWC) is an emerging technology for realizing highconfidentiality and high-speed point-to-point (PtP), vehicle-tovehicle, and white-lighting data access links in free-space communication [1][2][3][4][5][6], indoor communication [7,8], underwater communication [9][10][11], and optical networks [12][13][14][15][16].…”