Passive fibers - opposite to active fibers, having an additional laser active dopant (like fiber amplifiers). Passive fiber optics have a very wide range of applications, including areas like optical fiber communications (sending data through fiber-optic links and networks), illumination (fiber-optic lighting), fiber optic sensors and so on. The core components of passive fiber is always the optical fiber, which may be packaged into a fiber optic cable, or sometimes a fiber bundle. Fiber patch cables are often equipped with fiber connectors, and there are various other kinds of fiber tools and accessories such as strippers, cleavers and splicers.

Passive optical network (PON), does not include electrically powered switching equipment and instead uses optical splitters to separate and collect optical signals as they move through the network. A passive optical network shares fiber optic strands for portions of the network. Powered equipment is required only at the source and receiving ends of the signal.

Passive optical networks have some distinct advantages. PON takes advantage of wavelength division multiplexing (WDM), using one wavelength for downstream traffic and another for upstream traffic on a single non-zero dispersion-shifted fiber (ITU-T G.652). BPON, EPON, GEPON, and GPON have the same basic wavelength plan and use the 1,490 nanometer (nm) wavelength for downstream traffic and 1,310nm wavelength for upstream traffic. 1,550nm is reserved for optional overlay services, typically RF (analog) video. PONs are efficient, in that each fiber optic strand can serve up to 32 users. PONs have a low building cost relative to active optical networks along with lower maintenance costs. Because there are few moving or electrical parts, there's simply less that can go wrong in a PON.

Passive optical networks are also inevitable with some disadvantages. They have less range than an active optical network, meaning subscribers must be geographically closer to the central source of the data. PONs also make it difficult to isolate a failure when they occur. Also, because the bandwidth in a PON is not dedicated to individual subscribers, data transmission speed may slow down during peak usage times in an effect known as latency. Latency quickly degrades services such as audio and video, which need a smooth rate to maintain quality.

Common passive optical components include branching devices such as WDMs, isolators, circulators, and filters. These broad variety of passive optical components applications include multichannel transmission, distribution, optical taps for monitoring, pump combiners for fiber amplifiers, bit-rate limiters, optical connects, route diversity, polarization diversity, interferometers, and coherent communication. And fiber optics like fiber optic cables, fiber optic patch cords, fiber pigtails are widely used to make a fiber optic link between other optical devices.