Working principle
Due to the different structures of QSFP+ DAC and QSFP+ AOC, the working principles of the two are different. Both passive and active QSFP+ DACs can use copper cables for signal transmission. Passive QSFP+ DACs can be directly transmitted without signal conditioning. Active QSFP+ DACs have built-in driver chips to amplify and transmit signals. QSFP+ AOC completes signal transmission through optical fiber, and it can only convert electrical signals to optical signals and then to electrical signals with the help of an external power supply.
Transmission distance
It can be seen from the above that QSFP+ AOC active optical cables transmit signals through optical fibers, while QSFP+ DAC high-speed cables transmit signals through copper cables. Therefore, the transmission capacity of QSFP+ AOC active optical cables is higher than that of QSFP+ DAC high-speed cables. Strong, the maximum transmission distance is about 100 meters. At the same time, QSFP+AOC has a smaller bending radius and more flexible wiring.
Cost
From the structural point of view, QSFP+ DAC has a simple structure and few components, and its cost is usually lower than QSFP+ AOC.
How to choose 40G QSFP+ DAC? Or 40G QSFP+ AOC?
Different application scenarios have different requirements. How to choose between the two needs to be determined according to the actual situation, such as budget and transmission distance.
For a transmission link of less than 10 meters, it is recommended to choose a passive DAC high-speed cable considering the cost. Although QSFP+ AOC can also be used, from a cost perspective, a reliable passive DAC high-speed cable is better select. For a transmission link of 10 to 100 meters, 40G QSFP+ AOC is more appropriate.
But if the distance of the transmission link exceeds 100 meters, it is not recommended that you choose QSFP+ DAC and QSFP+ AOC, but consider the combination of optical modules and fiber jumpers. When the distance of the transmission link reaches 100 meters or 150 meters, you can choose the 40GBASE-SR4 QSFP+ optical module and OM3 or OM4 fiber jumper to combine; when the distance of the transmission link reaches 10 kilometers, choose the 40GBAESE-LR4 QSFP+ optical module Combine with single-mode fiber.
