Hybrid Technology: Combining Photonic and Conventional Circuits

PICs are still a developing technology. Full photonic systems utilizing PICs almost exclusively with the complexity and infrastructure levels found in electronic devices like computers have yet to come to fruition. Although, some photonic-based systems are currently supplementing or replacing components in larger electronic systems to increase efficiency, rather than being used in a purely photonic system. This is analogous to how digital systems began to replace legacy analog components such as thermometers or rotary dial telephones in the second half of the 20th century before advancing into larger, more complex systems.

An example of this trend is seen in the telecommunications industry where high-speed information is transmitted along fiber optic waveguides (Figure 2). The information must ultimately be converted into digital signals for common electronic devices to process because common data networks and power infrastructures exist on electrical structures: not photonic structures. Because optical systems are more power efficient than electrical systems, PICs will likely continue replacing conventional ICs in a wide range of applications.

Figure 2: Photonic components have replaced many electronic components in telecommunications due to their high efficiency and speed

The development of silicon as a viable semiconductor substrate for photonic components is making the integration of PICs and ICs more feasible. PICs are typically fabricated on a variety of different and sometimes multiple layered substrates such as InP and GaAs. However, due to the ubiquity and abundance of silicon substrates for most ICs and electronics, the integration of PICs into existing devices will be much more convenient on silicon substrates. One example is the development of nanolaser diodes integrated into silicon microchips, which facilitates on-chip communications and data processing.