 requires high capacity, high speed, and high security. It also provides terrestrial, underwater, and space/air coverage for communication. The vital components of VLC, quantum com- munication and LiFi systems are optical components, for example, lasers, LEDs, optical modulators, optical amplifiers, optical detectors, optical filters, and optical multiplexers. Currently, indium phosphide (InP) optics and silicon photonics technolo- gies are employed to meet the requirement of VLC communication. The integrated photonic technology provides compact, high bandwidth, low power consumption platforms for the VLC system. A photonic circuit must be securely packaged and integrated with an external laser source. Silicon photonics technology combined with graphene materials will be able to perform different various optical operations such as switching, logic, routing, memory, and optical signal processing in 6G all-optical communication in the future. In designing amplifiers and lasers, heterogenous inte- gration of InP is used on a silicon wafer. Because just one PIC technology is used, heterogeneous integration of InP-Photonics on silicon platforms minimizes optical Role of Photonics for Future 6G coupling losses and provides high-performance connections. Silicon photonics is driving an unprecedented technological shift in the optical network business, from discrete components to integrated chips. The silicon nitride (SiN) substrate can be utilized to make elements with minimum losses and wider fabrication constraints, and also improve thermal stability as mentioned in [24, 26-29]. 10.3.2 PHOTONIC MODULATOR Direct detection or coherent detection DWDM transceivers are used for different channel bit rates. Coherent detection is more efficient than direct detection because coherent detection provides a higher bit rate. For less complexity and low-cost inten- sity modulation-based channels, direct detection is used. Coherent detection is based on dual polarisation QPSK or dual polarisation 16-QAM [26-29]. Silicon-based Mach Z