Optical interconnects essentially involve converting electrical signals into optical signals, transmitting them through optical fiber, and then converting the optical signals back into electrical signals at the receiving end. The structure appears simple, but in practical applications, the most challenging part is stably generating the optical signal.
The core device for generating optical signals is the laser.
For high-speed 1310nm and 1550nm optical modules used in AI data centers, the EMLs serving as light sources and numerous continuous-wave lasers are actually built on InP platforms. More precisely, these devices are manufactured by growing epitaxial layers on InP substrates.
On the receiving end, certain InGaAs-based photodetectors and specific long-distance, high-performance receiver structures also rely on the InP ecosystem. In silicon photonics transceivers, Ge-on-Si photodiodes are the currently commercialized platform. However, at the transmit side—where optical signal generation is actually required—InP remains in a structural bottleneck position.