Table 1. Various photonic integration platforms.

PIC technology	Silicon PIC	GaAs PIC	InP PIC	Silica PIC
Leveraging technologies	Leverages Silicon CMOS industry	Leverages GaAs HBT industry	Leverages InP HBT industry	No electronics industry
Photonic–electronic integration	‘Silicon CMOS photonics’	‘GaAs OEIC’	‘InP OEIC’	Independent
Waveguide confinement	Strong confinement, Si/SiO2	Medium confinement GaAs/AlGaAs	Medium confinement InP/InGaAsP	Weak confinement GeO2, and so on doping
Typical MFD	<0.5 micron confinement	>2 micron confinement	>2 micron confinement	>5 micron confinement
Optical gain and optical modulation	No gain, no Pockel’s effect	Efficient gain, strong Pockel’s effect	Efficient gain, strong Pockel’s effect	No gain, no Pockel’s effect
Wafer size	⩾300 mm wafers	⩾200 mm wafers	⩾100 mm wafers	⩾200 mm wafers

Abbreviations: CMOS, complementary metal-oxide-semiconductor; HBT, heterojunction bipolar transistor; PIC, photonic integrated circuits.