**2. Optical transmitters**

One of the critical components in VLC and SSL to achieve high data rate data link and high CRI lighting is the optical transmitter. The modulated electrical signal is applied to the transmitter. The transmitter usually consists of LED and LD to convert the electrical signal to an optical signal. Further optical elements and color converter phosphor can be used to control the shape and color of the emitted light beam, respectively. The transmitter's capabilities are usually determined by its design. In VLC and SSL promising light source requires high energy conversion efficiency, large modulation bandwidth, high light output power, low operating voltage, small foot print and long lifetime. Practically, the low modulation response and low emitting intensity of LED are the drawbacks for the development of ultrahigh-speed VLC and high-quality SSL system. Blue gallium nitride (GaN) laser *Blue Laser Diode-Based Visible Light Communication and Solid-State Lighting DOI: http://dx.doi.org/10.5772/intechopen.100106*


## **Table 1.**

*Specification difference between LED and LD [11].*

diode (LD) and remote phosphor based generated white light can be used for both high-speed VLC and SSL simultaneously. The specification difference between LED and LD is shown in **Table 1**.
