Optech 1.6T OSFP Close Top Passive Direct Attach Copper (DAC) Twinax Cable

As AI clusters and next-gen Ethernet/InfiniBand fabrics move toward 1.6T, customers need short-reach interconnects that are low latency, power-efficient, and cost-optimized—especially inside racks and between adjacent racks. The Optech 1.6T OSFP Close Top Passive DAC Twinax Cable is designed for these high-density environments, delivering reliable electrical connectivity without the complexity of optical modules.

What Is a 1.6T OSFP Passive DAC Twinax Cable?

A passive DAC is a copper twinax cable assembly with OSFP connectors on both ends. “Passive” means it contains no signal retiming or amplification (no DSP/retimer), keeping latency and power near zero on the cable itself. It’s best suited for short distances where channel loss remains within the system’s electrical budget.

1.6T typically refers to a link built on eight electrical lanes, supporting next-generation switch and NIC connectivity for AI/HPC and large-scale data center networks.

Why “Close Top” Matters in High-Density Racks

OSFP systems are built for performance and thermal headroom. A close top OSFP DAC design helps in deployments where airflow control and mechanical robustness are priorities:

• Improved airflow management in dense switch/NIC cages

• Better dust protection and reduced contamination risk at the connector interface

• Mechanical stability for frequent plug/unplug operations in lab and production environments

(Exact benefits depend on chassis cage design and airflow direction, but close top designs are widely preferred in many high-density builds.)

Key Advantages of Optech 1.6T OSFP Passive DAC

1) Ultra-Low Latency

Because the cable is passive (no active electronics), it adds minimal latency, making it ideal for GPU-to-GPU communication where microseconds matter.

2) Lowest Power per Port

Passive DAC consumes no additional power like optical transceivers or active copper options, helping reduce rack power and cooling load.

3) Cost-Effective Short-Reach Scaling

For top-of-rack and end-of-row architectures, passive DAC is often the most economical way to scale high-speed ports—especially when multiplied across hundreds or thousands of links.

4) Simple Deployment & Operations

• No fiber polarity planning

• No optical cleaning routines

• Straightforward cable management for short runs
  This shortens installation time and reduces operational complexity.

5) Built for Data Center Reliability

Optech focuses on production-grade assembly and verification to support stable performance in demanding environments, including AI fabrics running sustained, high-utilization traffic.

Common Application Scenarios

A) Switch-to-NIC (Leaf Switch ↔ AI Server NIC)

Use cases include connecting 1.6T OSFP switch ports to next-generation server NICs (or breakout architectures where applicable). Passive DAC is typically used when the distance is short and the channel budget allows.

B) In-Rack and Adjacent-Rack Links

• AI servers to top-of-rack switch

• Neighbor rack cross-connects (when within passive reach)
  Ideal for high-density GPU pods where minimizing cost and power is critical.

C) HPC / AI Fabrics with Tight Latency Requirements

Whether your fabric is Ethernet (RoCE) or InfiniBand-based, passive DAC is a strong fit for latency-sensitive, short-reach links inside compute blocks.

What to Specify When Quoting a 1.6T OSFP Passive DAC

To ensure the right build, buyers typically confirm:

• Cable length (passive DAC is generally for short reach; exact max length depends on platform/channel budget)

• Wire gauge (AWG) options based on flexibility vs. loss requirements

• Operating environment (airflow direction, port density, bend radius constraints)

• Compatibility targets (switch/NIC platform families, EEPROM/cable ID requirements)

Why Optech

Optech supports data center and AI connectivity with a broad portfolio of optical transceivers and cable solutions—helping customers deploy high-speed networks with consistent quality, stable supply, and engineering-focused support.