See picture below. Is it? ;)

https://www.laserfocusworld.com/fiber-optics/article/14074687/optics-will-be-indispensable-for-5g-networks

‘Pluggables’ to upgrade the network

While 5G hardware will not reach directly into the network core, it will bring a flood of data traffic that will require major expansion of transmission capacity. Growth in the fiber transmission system will be divided between datacenters and the external fiber network, says Bill Gartner, senior vice president/general manager of Cisco’s Optical Systems and Optics Group. Fiber is plentiful inside datacenters, and transmission distances are short: no more than 10 km, and often shorter. “Every router or switch port has its own dedicated fiber; if a new switch or router is added, additional fiber is added to terminate the new ports,” says Gartner. This will require increasing port densities and large-scale deployment of new high-speed optics.

Advances in silicon integrated circuits have steadily decreased the cost per bit for electronics, but the cost per bit of optics has not decreased as rapidly, says Gartner. Thus, as the bit rate increases, the cost of the optics becomes a larger portion of the hardware cost. Optics account for 10% of the hardware cost in a 10 Gbit/s datacenter network, but he says that at current rates, the optics will exceed half the hardware cost when data rates reach 400 Gbit.

Cisco’s approach to control optics costs is to push development of “pluggable” optics, which are standardized modules packaging optics and electronics to convert signals between optical and electronic form (see Fig. 2). One end of the module is an electronic module that plugs into the electrical interface on the router, while the other is an optical connector connecting to the output fiber. Modules generate optical signals in formats that optimize performance over specific distances, such as 500 m or 2 km. Datacenter transmission is limited to about 10 km, so the pluggables use direct detection of ones and zeros rather than coherent transmission to limit costs.FIGURE 2. Cisco pluggable modules convert signals from electronic form into optical form, with one end accepting electrical input and delivering optical output. The photo shows the modules with and without their covers.(Courtesy of Cisco)