Noise Analysis of Photonic Modulator Neurons
This work addresses noise management in neuromorphic photonics hardware, which is crucial for scalable analog neural networks, but it is incremental as it builds on prior transduction methods.
The paper analyzed noise propagation in modulator-based photonic neuron circuits, finding that modulator nonlinearity can suppress noise, and identified trade-offs between signal-to-noise ratios and power consumption, with active transimpedance amplifiers helping for conventional modulators but passive circuits sufficing for efficient ones.
Neuromorphic photonics relies on efficiently emulating analog neural networks at high speeds. Prior work showed that transducing signals from the optical to the electrical domain and back with transimpedance gain was an efficient approach to implementing analog photonic neurons and scalable networks. Here, we examine modulator-based photonic neuron circuits with passive and active transimpedance gains, with special attention to the sources of noise propagation. We find that a modulator nonlinear transfer function can suppress noise, which is necessary to avoid noise propagation in hardware neural networks. In addition, while efficient modulators can reduce power for an individual neuron, signal-to-noise ratios must be traded off with power consumption at a system level. Active transimpedance amplifiers may help relax this tradeoff for conventional p-n junction silicon photonic modulators, but a passive transimpedance circuit is sufficient when very efficient modulators (i.e. low C and low V-pi) are employed.