Fiber-optic cable (optical fiber) is a network cable used to carry the light signals along a transparent medium and consists of different parts:
1- Core:
2- Cladding layer: glass with lower refractive index
Due to the lower refractive index of the outer layer (cladding) compared to the inner layer (core), light signal does not enter the cladding and reflects into the core back. Therefore, under the radiated angle, light signal travels along the cable.
Note1: This light is near infrared wavelength (850 to 1500 nm).
Note2: Light reflection takes place when the angle of incidence for light is greater than critical angle.
3- Protective layer:
Fiber-optic cable types (ISO/IEC 11801):
1- SMF (Single mode fiber): Typically two fibers, diameter of 8.3 to 10 um (microns), wavelength of 1310 or 1550 nm
2- MMF (Multi mode fiber): Typically two fibers, diameter of 50 to 100 um, wavelength of 850 or 1300 nm
Multi mode cables are manufactured in OM1, OM2, OM3, OM4 and OM5 types.
3- POF (Plastic optical fiber): Similar to multimode
Note3: Transmission rate in single mode is up to 50 times more than multi-mode.
Fiber optic system components:
Note4: Converting of electronic pulse to light pulse means translation of 1 and 0 to ON and OFF.
So using light pulses in fiber-optic cables instead of electronic pulses in copper cables brings us a lot of advantages and some disadvantages as well. Below some of them can be enumerated:
Advantages:
Disadvantages:
Note5: Type designation code for fiber-optic cables according to VdS shows the exact specification of cables.
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