**6. High CRI lighting and high-speed visible light communication**

The laser based white-light has demonstrated with a color rendering index (CRI) of 78, color temperature of 6000–7000 K, and luminous flux up to 600 lm for a singlechip device [55]. The frequency response of the system adhering phosphor film, is shown in **Figure 13(a)**. The throughput modulation response was reduced mainly due to the relevant absorption and scattering by the phosphorous film. The -10 dB bandwidth of the system is approximately 1500 MHz, at the driving current of 750 mA.

*Blue Laser Diode-Based Visible Light Communication and Solid-State Lighting DOI: http://dx.doi.org/10.5772/intechopen.100106*

#### **Figure 13.**

*(a) Frequency response of LD laser VLC system. (b) Measured date rate at different bandwidths in the LD laser VLC system [54].*

#### **Figure 14.**

*(a) Spectrum of generated white light (b) measured bit-error rates at different data rates.*

The data rate achievable at different signal bandwidths is shown in **Figure 13(b)**. It indicates that the white laser VLC system is capable of a high data rate up to 4.72 Gbps at 1300 MHz. At higher signal bandwidths beyond 1400 MHz, the data rate of the VLC system will not steadily increase due to the system's power limitation.

We demonstrated a color-rendering index (CRI) of 93.8, a correlated color temperature (CCT) of 4435 K, and a data rate of 1.6 Gbps under NRZ-OOK modulation by an exciting blue laser diode polymethyl methacrylate (PMMA) doped phosphor film based on cesium lead bromide quantum dot (CsPb*Br*<sup>3</sup> -QD) and potassium fluorosilicate <sup>4</sup> 2 6 *K SiF Mn* : <sup>+</sup> (KSF) [56]. **Figure 14(a)** shows the optical spectrum of generated white light in which blue, red, and green fluorescent components are observed. In terms of peak emission, the blue light is at 445 nm, the green light is at 510 nm with an FWHM of 22.42 nm, and the red light is at 631 nm with an FWHM of 3.02 nm. Unlike traditional phosphorous materials, CsPbBr QD <sup>3</sup> − and KSF have a relatively narrow FWHM. The BER at different data rates is shown in **Figure 14(b)**, where the BER of 2.7× <sup>3</sup> 10<sup>−</sup> is measured at 1.6 Gbps. The obtained BER measurement adheres to the standard FEC threshold of ≤ <sup>3</sup> 3.8 10<sup>−</sup> × .
