Multi-wavelength selective crossbar switch.

Area of Science:

• Photonics
• Optical Communications
• Data Center Technology

Background:

• Scalable data centers require efficient interconnects for electronic packet switches.
• Existing solutions face challenges in latency, cost, and complexity.
• Multi-wavelength switching offers a path to higher bandwidth and connectivity.

Purpose of the Study:

• To demonstrate an 8x4 multi-wavelength selective ring resonator based crossbar switch matrix.
• To enable dynamic assignment of wavelength channels for port-port connections.
• To reduce latency, cost, and complexity in scalable data center interconnects.

Main Methods:

• Implementation of an 8x4 crossbar switch matrix using silicon photonics foundry technology.
• Utilizing multi-wavelength selective ring resonators for dynamic channel assignment.
• Thermal tuning of ring resonators controlled by a custom 64-channel DAC driver.

Main Results:

• Achieved an insertion loss of 0.8 dB per unit cell with 32 dB out-of-band rejection.
• Demonstrated low standard deviations in losses (2 dB), resonant wavelength (0.33 nm), and tuning efficiency (0.01 nm/mW).
• Data transmission experiments at 40 Gbps showed negligible penalty from crosstalk.

Conclusions:

• The developed switch provides near full connectivity with dynamic wavelength assignment.
• The silicon photonics switch significantly reduces latency, cost, and complexity.
• The technology is suitable for interconnecting electronic packet switches in scalable data centers.