Layer 1 - Fiber Optics
Fiber Optics uses light (visible and non-visble) to transmit communication signels
All Fiber optic cables are made up of sever important compmen
- Core: is ushally made up of very thin crystal clear glass or platic that allows light to pass through. Think of the core as a guide to help ensure the light passes through to the other side.
- Cladding: is ushally made up of ### which has a high index of refraction, meaning when light its the cladding at the right angle is it reflected (refracted) back into the core. Think of the cladding as bumpers on a bowling lane, making sure the light (bowling ball) stays inside the core, with as little loss as possible.
- Shielding, Buffer, Jackets: these are all names for protective shells that encased the cladding, many times there a multiple stands of fiber incased of several protective layers making 1 Fiber Optic cable with at time 100’s of fiber optic strands.
Single Mode and Multi-mode
Single Mode Fiber (SMF)
Has a very narrow core only allowing a “single mode” of light to propagate, and goes longer distances.
Typically has a core of 8-10 microns
Often has a Yellow cable color
Multi-Mode Fiber (MMF)
Has a wider core allow “multiple modes” of light to pass through and goes a shorter distances.
Two Core Sizes and Three Types
OM1 has a core size of 62.5 mircons and often has a orange cable color.
OM2 has a core size of 50 mircos and a calbe
OM3 also has a core size of 50 mircos and the often has a Aqua colored cable. OM3 is “laser optimized” made to be used for 10 Gbps connectors.
Light Soruces and Price
The reason there are differnet types of comes down to requirements. Differnt Optical transmitters used differnt lights sorces with different properites.
- LED light sorurces run at a wave length of 850nm (nano meters) LED light soruce diffuse light quickly and need a larger core to accept the light. This is why many MMF runs with LED light sources and at a wave length of 850nm.
- Laser light sources run at a wave length of about 1600nm
Fiber Connectors
- ST
- SC
- LC
Form Factors
GBIC
SPF
SPF+
Q40G
WDM