7 Frequently Asked Questions About 200G Active Optical Cables (AOCs)

1. What Are the Benefits of Using 200G AOCs?

  • To address the need for high-density, high-speed networking solutions
  • To support a variety of next-generation of Ethernet applications
  • The 200G AOCs are crucial to enable hyperscale data centers, service providers and enterprises to meet growing bandwidth demands
  • Backward plug compatible with existing 100G-based systems and flexible port bandwidth for system design

2. What 200G AOCs Are Available on the Market?

Currently, there are only a few suppliers of 200G AOCs on the market, for example, the Gigalight company — a leader in the AOC industry. Gigalight offers a full range of 200G AOCs in both QSFP-DD and QSFP56 form-factors. The Gigalight 200G AOC product line includes 200G QSFP-DD AOC, 200G QSFP-DD to 2x 100G QSFP28 AOC, 200G QSFP-DD to 4x 50G QSFP28 AOC, 200G QSFP56 AOC, 200G QSFP56 to 2x 100G QSFP56 AOC, 200G QSFP56 to 4x 50G SFP56 AOC. All of these cable assemblies are compliant to IEEE standards and industry Multi-Source Agreements (MSAs).

Table 1: The Maximum Data Rates of Gigalight 200G AOCs

Note:

The QSFP-DD stands for a “Quad Small Form-factor Pluggable–Double Density”. The QSFP-DD connector also has 8 electrical lanes similar to the QSFP form-factor, but the second row of electrical contacts has been added to the QSFP connector in order to increase the number of high-speed electrical lanes from 4 (in a QSFP) to 8 (in a QSFP-DD).

The QSFP56 stands for “Quad Small Form-factor Pluggable 56 (’56′ refers to the max data rate 56Gb/s each electrical interface can handle)”. The QSFP56 form-factor is a solution for 200G applications. It’s a pluggable form-factor that has the same size as QSFP.

3. Can QSFP56 AOC Support QSFP-DD AOC Ports or Can QSFP-DD AOC Support QSFP56 AOC Ports?

Yes. The QSFP56 is a pluggable form-factor that has the same size as QSFP. The QSFP-DD assemblies are backward compatible with existing QSFP, so your 200G QSFP56 AOC can be used in the 200G QSFP-DD AOC system ports. Your 200G QSFP-DD AOC also can be used in the 200G QSFP56 AOC system ports.

4. What Is the Maximum Distance of 200G AOCs?

For Gigalight’s 200G AOCs, a max length of 100m is supported for both QSFP-DD AOCs and QSFP56 AOCs using OM4 MMF.

Table 2: The Maximum Distances of Gigalight 200G AOCs

5. What Industry Standards Are Associated with 200G AOCs?

The QSFP-DD series AOCs are compliant with the QSFP-DD MSA while the QSFP56 series AOCs are compliant with the QSFP MSA.

6. What Is the Maximum Power Consumption of 200G AOCs?

The maximum power consumption of 200G QSFP-DD AOCs (based on NRZ) is 4w per end while that of 200G QSFP56 AOCs (based on PAM4) is 7w per end.

In general, higher power consumption levels are associated with higher data rates and longer reach.

7. Where Are 200G AOC Used?

The 200G AOCs are suitable for short distances and offer a cost-effective solution to connect within racks and across adjacent racks. While the 200G Direct Attach Cables (DAC) are a low-cost solution for 200GE high-speed interconnects within the reach up to 3 meters only, the 200G AOCs pick it up from there and can reach up to 100 meters. The 200G AOCs are widely used in High-Performance Computing (HPC) and recently became more popular in hyperscale data centers, enterprise and storage systems.

Originally article: 7 Frequently Asked Questions About 200G Active Optical Cables (AOCs)