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Photonics-Electronics Convergence Laboratory

Optical packet switching technology
- Hybrid Optoelectronic Packet Router -


Optical Packet switching enables the transfer of packet signals in the optical domain on a packet-by-packet basis. In conventional electronic routers, all input optical packets are converted into electrical signals that are subsequently stored in a memory. The stored signals then undergo switching to reach the intended output ports while being handled as low-speed signals, and finally the switched signals are reassembled into the high-speed packets. This process leads to high power consumption and large latency.
To resolve these issues, we have been undergoing research for the hybrid optoelectronic packet router (HOPR) that aims to optimally combine optical and electrical technologies based on novel optical and optoelectronic devices developed in our labs.


Optical/Optoelectronic/Electronic device technologies for 100-Gbps optical packet

Optical devices
Broadcast-&-Select Optical Switch, Tunable Transmitter, Burst-mode EDFA
Optoelectronic devices
Serial-to-Parallel Converter, Parallel-to-Serial Converter, Optical Clock Pulse Train Generator
Electronic devices
Burst-mode APD-TIA, Latch Clock Generator

Optical packet processing technologies with high speed operation, low power consumption and low latency

Optical label processor
Performing label processing while keeping the payload in the optical domain
Optical switch
Data rate and format-free packet switching for a wide range of wavelengths
Shared buffer
Highly functional shared buffer based on optoelectronic interfaces and CMOS memory

Hybrid optoelectronic packet router technologies enabled by novel router architecture

Power efficiency
reducing power consumption by utilizing novel optical technologies
Low Latency
Adopting the cut-through switching method together with a shared buffer
High functionality
QoS, Forward error correction, Conversion between 10GbE and 100Gbps optical packets



An optical packet switched network can maximize the efficiency of the link bandwidth utilization through the deployment of statistical multiplexing. The network is also attractive for the reduction of power consumption and latency by adopting flexible traffic engineering on a packet-by-packet basis and novel optical technologies. These advantages are particularly beneficial in the networks with a high variation of traffic. In this regard, we have been researching the technologies necessary for realizing future networks for data centers, cloud computing and metro NW, as well as access aggregation NW and optical mobile NW.

Fig.2 Data center network with Torus topology

  • Fig.2 Data center network with Torus topology
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: avalanche photodiode and transimpedance amplifier
: complementary metal-oxide semiconductor
: erbium-doped fiber amplifier
: electro-absorption modulator
: field programmable gate array
: hybrid optoelectronic packet router
: optically clocked transistor array
: optical clock pulse-train generator
: quality of service
: serial-to-parallel converter, parallel-to-serial converter
Tx, Rx
: transmitter, receiver
: top of rack
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