Technology explainer
How a Waveguide-Integrated Photodiode Receives Optical Data
A concise guide to how a chip guides modulated light into a semiconductor junction, converts photons into charge and recovers a data signal.
An optical receiver turns changes in light intensity into an electrical data stream. Integrating the detector with a waveguide keeps that conversion on the same photonic platform.
Guiding the signal
A waveguide confines light and carries it across a chip. The detector is placed where its semiconductor can absorb part of the guided optical field.
Generating charge
Absorbed photons create electron-hole pairs. An electric field across a p-i-n junction separates those carriers and drives current through the contacts. The changing current follows the encoded light signal.
Key measurements
Bandwidth indicates how rapidly the detector responds to small changes. Data rate measures performance in a particular communications test. Responsivity relates electrical current to optical power, while external quantum efficiency compares collected carriers with incident photons.
System limits
A detector alone is not a complete receiver. Couplers, amplifiers, packaging, thermal control and signal processing affect sensitivity, energy use and error rate.
First appeared in
A WSe2 Photodiode Received Visible-Light Data at 10 Gbit/s
