AOC (Active Optical Cable) is an Optical fiber with a module at both ends, which is equivalent to the integration of line and module.
AOC is now being used extensively by many customers because it is cheaper than two modules and one fiber. From a technical point of view, what is the difference between AOC and module + fiber? AOC is the same as the optical module, which is still optical driven and contains many core components. Their differences are mainly due to the difficulty of the process. For optical module, because the opposite end situation may be very different, so it needs to adapt to different conditions, high requirements for the laser, high complexity of manual operation when the internal device coupling. AOC, because the opposite end is fixed, so there is no need to consider various situations, low requirements for the laser, peripheral supporting devices are relatively simple, manual operation is also simple, which can reduce some costs, which is why the price of AOC is lower than two modules + a fiber. But since none of the most expensive core components were omitted, the difference in cost is not very significant (note: cost does not equal selling price).
Of course, even if the same manufacturer, their light module with AOC in chip package, may have different coupling way, which is why the same manufacturer of optical modules and AOC in the same third party equipment performance may also have different reasons, but on the whole, because is light, so the difference is not too big.
