Active Optical Cable (AOC) – Rising Star of Telecommunications & Datacom Transceiver Markets

Updated on Feb 26, 2021 by

As data rates rise and data center clusters grow in size, copper cable technology is getting stretched to its limits. Active optical cable (AOC) assemblies were invented to replace copper technology in data centers and high performance computing (HPC) applications in virtue of its stability and flexibility. In the era of the optical network, AOC cable captures a major chunk of high-speed optical inter-connectivity market on a global level.

Active optical cable assemblies

Active Optical Cable AOC Wiki

Active optical cable (AOC) can be defined as an optical fiber jumper cable terminated with optical transceivers on both ends. It uses electrical-to-optical conversion on the cable ends to improve speed and distance performance of the cable without sacrificing compatibility with standard electrical interfaces. To understand the structure of AOC cable, the following figure depicts the detailed structure:

Active Optical Cable AOC Wiki

Active optical cables incorporate active electrical and optical components to boost and receive signal via optical fiber. They are becoming one of the most popular cabling solutions in the data center. In the modern market, a variety of AOC cables have been launched for 10G/40G/100G applications, including 10G SFP+ AOC, 25G SFP28 AOC, 40G QSFP+ AOC, 56G QSFP+ AOC, 40G QSFP+ to 4x SFP+ breakout AOC, 40G QSFP+ to 8x LC breakout AOC, 100G QSFP28 AOC, 100G QSFP28 to 4x SFP28 breakout AOC and 120G CXP AOC, etc. These AOC optics are commonly used for short-range multi-lane data communication and interconnect applications between two devices, such as rack-to-rack, shelf-to-shelf interconnect, storage, hubs, switches, routers, servers, etc.

Why Use Active Optical Cable (AOC) Rather Than DAC or Fiber Transceiver?

For 10/40/100G transmission, there are many choices to meet the increasing needs for speed and performance. Why on earth do we need to choose active optical cable? The following part will demonstrate the potential advantages of AOC cable by comparing it with DAC cable and fiber optical transceiver.
AOC VS DAC VS Fiber Transceiver

From the chart, we can conclude that:

1. The lower weight and smaller bend radius of AOCs enable simpler cable management in high-density deployments.

2. The thinner AOC cables frees up a lot of space for increased air flow that is better helping to balance generated heat in crowded systems.

3. AOCs have great advantages over DACs especially when transmission distance reaches above 15 meters.

4. Optical fiber in AOC has considerable dielectricity, thus its EMI resistance level is considerably high.

5. AOC is a cost-effective and flexible short-reach (≤100m) direct-attach option in the interconnect system.

6. Since the connectors of AOC are factory pre-terminated, it is less affected by the repeating plug during daily use. It has also been proved that AOC has better reliability than that of transceivers.

How Are AOC Cables Used in Data Centers?

AOC cables are far superior in performance and their advantages are undeniable. When making plans for 10G/25G at the server and 40G/100G in the switching fabrics, multiple hyper-scale data center operators have completely shifted from using cooper cables to AOC cables. AOCs provide a cost-effective means to connect top-of-row (ToR) switches to end-of-row aggregation switches. Additionally, AOCs are also used to connect ToR switch with storage subsystems at reaches greater than DAC limits of 3-7 meters. The following three scenarios show the specific applications.

Scenario 1: One AOC cable can be used to connect two switches directly.

10G SFP+ to SFP+ AOC cable connectivity

Scenario 2: The breakout AOC cable can offer a highly cost-effective way to connect within racks and across adjacent racks. The following figure shows 40GbE QSFP+ to 4 x SFP+ AOC cable connecting to a 40G QSFP+ port switch on one end, and to four 10G SFP+ ports switch on the other end.

40GbE QSFP+ to 4 x SFP+ AOC cable connectivity

Scenario 3: For the long haul transmission between the two switches, a suitable solution is suggested to use single-mode patch cable, OEO converters and AOC cables, which can provide seamless integration of different fiber types by converting multimode fiber to single-mode fiber.

AOC cables long haul transmission

What to Consider When Buying AOC cable?

Similar to buying other fiber optics, there are many details to consider when choosing AOC cables:

AOC Cable Data Rate

AOC cables are designed for data rates including 10Gb/s, 25Gb/s, 40Gb/s, 100Gb/s and 120Gb/s, which accelerate storage, data, and high-performance computing connectivity. In the AOC market, data center managers seem to appreciate the affordability of a plug-and-play, high-bandwidth 40G link that AOC offers.

AOC Cable Length

AOC cables are designed to bypass the bulk and distance limitations of copper. AOC cable assemblies are typically used in data centers for 1- 100m link length. As for how to make the final decision about the cable length, it depends on your specific situation. Too long or too short, it is susceptible to manage the cabling.

AOC Cable Reliability

Another issue to consider when choosing an AOC is reliability. As data rates increase and customers become less tolerant of errors and failure, the reliability of all equipment becomes more critical. The tiny electronics embedded in the transceiver carry a potential for failure. It is a wise action to choose an AOC vendor that can show testing confirming its product’s reliability.

AOC Cable Price & Vendor

On the flip side, which brand should we choose for the AOC cables? Cisco, Juniper, HP, etc. are the most common brands, however products of these brands can only be applied in the corresponding switches, and the price of original pieces are super high. From an economic standpoint, many IT technicians are more inclined to a decent alternative to third-party optics.

AOC Market

While many brands of AOCs are available on the market, all are not alike. As data rates increase, concern over power consumption and heat generation will increase. Low-power AOC cable assemblies will become more and more important as data center operators strive to lower carbon footprint and energy costs.

FS.com Active Optical Cable Assemblies

FS.com goes further than other third-party vendors, we use the same software codes as the original vendor for major-brands optics, and our generic transceivers can be compatible with almost all the brands. All compatibility is strictly tested and controlled. More importantly, you can customize your AOC cables in accordance with your needs. The following offers FS.com active optical cable assemblies solution:

Type Description Price
10G SFP+ AOC Cable 1m (3ft) Cisco SFP-10G-AOC1M Active Optical Cable $ 42.00
25G SFP28 AOC Cable 1m Cisco SFP28-25G-AOC1M Active Optical Cable $ 220.00
40G QSFP+ AOC Cable 1m Cisco QSFP-H40G-AOC1M Active Optical Cable $ 120.00
40G QSFP+ to 4xSFP+ AOC Cable 1m Cisco QSFP-4X10G-AOC1M Active Optical Cable $ 190.00
40G QSFP+ to 8xLC AOC Cable 5m (16ft) Cisco QSFP-8LC-AOC5M Active Optical Cable $ 140.00
100G QSFP28 AOC Cable 1m Cisco QSFP-100G-AOC1M Active Optical Cable $ 480.00
100G QSFP28 to 4x SFP28 AOC Cable 1m (3ft) Cisco QSFP-4SFP25G-AOC1M Active Optical Cable $ 720.00

For more information about FS AOC cable, please contact us via sales@fs.com.

Related Article: Use High Speed Direct Attach Cable for Data Center Interconnection

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