| dc.description.abstract | High-speed and high-brightness vertical-cavity surface-emitting laser (VCSEL) arrays, which can serve as an efficient light source for optical wireless communication (OWC), plays a crucial role in the next generation wireless communication network e.g, 6G and satellite communications. However, the traditional high-power, high-brightness, and (quasi-) single-mode (SM) VCSEL usually suffers the problems of high relative intensity noise (RIN) and spatial hole burning effect, which seriously limit their performances in high-speed data transmission. In this work, a novel VCSEL array structure is demonstrated to fundamentally overcome the trade-off among the maximum SM output power, brightness, RIN, and modulation speed. Compared with the traditional VCSEL arrays, which have several independent VCSEL cavities in parallel, the novel array structure demonstrated here has additional passive optical waveguides connecting the neighboring VCSEL unit and an extra electroplated cooper substrate integrated with the backside of our chip. As compared to the reference array without cooper substrate and connected waveguides, the demonstrated array exhibits higher (quasi-) SM output power, narrower divergence angle (higher brightness), a lower RIN (-130 vs. -140 dB), and a flatter E-O response. This is turn leads to smaller jitters (4.5 vs. 5.9 ps) and less intensity noise in the measured 12.5 Gbit/sec eye-patterns. The demonstrated 7x7 array exhibits around 100mW maximum SM output power with 1/e^2 divergence angle as norrow as 8°(FWHM:5°), single polarized output (10dB polarization suppression ratio), and clear eye-opening under 12.5 Gbit/sec modulation. These remarkable static/dynamic performances in our array are due to the dilution of photon density in the SM output pattern by the extended passive waveguide and the external strain induced by the electroplating cooper substrate. It leads to the single polarized lasing mode and the increase of fundamental mode selectivity, which reduces the RIN and enhances the brightness of output beam, respectively. | en_US |