Photon networks leverage light (photons) as the primary information carrier, offering advantages such as high speed, low latency, energy efficiency, and massive parallelism. These networks span multiple architectures and application contexts, from classical optical communications to photonic computing and neural networks.

Based on current research and industry sources, photon networks can be categorized as follows:


1. All-Photonics Networks (APNs)

Definition: Networks that replace conventional electronic switching and routing with fully photonic pathways, transmitting signals end-to-end via optical wavelengths.

Characteristics:

  • Ultra-low latency
  • High capacity (target: >1 Pbit/s per fiber)
  • Low power consumption
  • Enhanced flexibility using wavelength multiplexing and multicore fibers

Applications:
Data centers, telecommunication backbones, low-latency real-time services, immersive multimedia, remote healthcare, smart factories, precision agriculture.

Examples:

  • NTT IOWN All-Photonics Network
  • Open APN for disaggregated multi-vendor optical networking

Research:


2. Integrated Photonic Networks

Foundation: Incorporates Photonic Integrated Circuits (PICs) where multiple optical components (lasers, modulators, detectors) are integrated on a single chip.

Purpose: Reduce size, energy consumption, and increase speed for high-throughput data transmission.

Applications:
High-speed interconnects in computing, optical transceivers for data center networks, on-chip optical communication.

Research:


3. Quantum Optical or Quantum Photonic Networks

Definition: Use photons as quantum information carriers (qubits) for entanglement-based communication and quantum computing.

Key Example:
Quantum Optical Neural Networks (QONNs) and atom-cavity quantum optical systems enabling nonlinear all-optical computation.

Applications:
Secure communications (quantum key distribution), satellite-based real-time machine learning, quantum information processing.

Research:


4. Photonic Neural Networks (PNNs)

Function: Mimic artificial neural networks using photonic components to implement neurons and connections.

Types of Architectures:

  • Feedforward Neural Networks (FNNs)
  • Recurrent Neural Networks (RNNs)
  • Convolutional Neural Networks (CNNs)
  • Reservoir Computing (RC)
  • Spiking Neural Networks (SNNs)
  • Photonic Ising Machines (PIMs)
  • Optoelectronic Neural Networks (ONNs)

Advantages:
Ultrafast processing, high parallelism, low energy consumption, scalability to complex AI and image processing tasks.

Research:


5. Specialized Photonic Networks


6. Hybrid Photonics-Electronics Networks

Concept: Combines classical electronic processing with photonic transmission for intermediate scales where full photonic conversion is not yet practical.

Research:


7. Emerging Photonics Networks / Experimental Platforms


Summary

Photon networks can be broadly grouped into:

  • Telecommunications and data transfer networks: APN, WDM, POLAN, hybrid optics-electronics
  • Computational networks: PNNs, PIMs, ONNs, quantum optical networks
  • Specialized timing and sensing networks: Optical lattice clock networks, optoacoustic networks
  • Reconfigurable or emerging physical platforms: Plasmonics, polaritonics, programmable photonics

These networks represent a continuum from classical optical communication systems to cutting-edge quantum and neuromorphic photonic systems, distinguished by their degree of electronic integration, network topology, and information-processing capabilities.


Visual Taxonomy

Photon Networks
β”œβ”€β”€ All-Photonics Communication Networks
β”‚   β”œβ”€β”€ APN
β”‚   β”œβ”€β”€ WDM
β”‚   └── POLAN
β”œβ”€β”€ Integrated Photonic Networks / PICs
β”œβ”€β”€ Hybrid Photonic-Electronic Networks
β”œβ”€β”€ Photonic Neural Networks
β”‚   β”œβ”€β”€ FNN
β”‚   β”œβ”€β”€ CNN
β”‚   β”œβ”€β”€ RNN
β”‚   β”œβ”€β”€ SNN
β”‚   β”œβ”€β”€ PIM
β”‚   β”œβ”€β”€ ONN
β”‚   └── RC
β”œβ”€β”€ Quantum Photonic Networks
β”‚   β”œβ”€β”€ QONN
β”‚   └── Atom-cavity systems
β”œβ”€β”€ Timing and Sensing Networks
β”‚   β”œβ”€β”€ Optical Lattice Clocks
β”‚   └── Optoacoustic
└── Emerging / Reconfigurable Networks
    β”œβ”€β”€ Plasmonics
    β”œβ”€β”€ Polaritonics
    └── Programmable Photonics