Fibre Optic Cables Revision

Advantages of Fibre Optic Cables

• Smaller in size and weight, non-conductive, higher security, and higher bandwidth compared to copper cables.

Structure of Fibre Optic Cables

• Consist of a silica glass core with a cladding having a lower refractive index.

Immunity to Electromagnetic Interference (EMI)

• Fibre optic cables are immune to EMI.

Coupling in Fibre Optic Cables

• Two connected fibre optic cable ends are parallel but not quite touching, known as end-to-end coupling.

Disadvantages of Fibre Optic Cables

• End terminals are susceptible to environmental contamination.

Light Used in Fibre Optic Systems

• Infrared light is used in fibre optic systems.

Data Transmission in Fibre Optic Systems

• Fibre optic data is sent by modulating the intensity of a laser beam.

High Intensity Radio Frequency (HIRF) Prevention

• HIRF is prevented from entering a fibre optic cable by using an opto-isolator coupling.

Continuity Checking in Fibre Optic Cables

• Continuity of a fibre optic cable is checked by using a calibrated light source and an opto-power meter.

Fibre Optic Data Bus

• A fibre optic data bus used on an aircraft can transmit on several channels at the same time.

Light Propagation in Fibre Optic Cables

• Light travels along a fibre optic cable by reflection.

Main Disadvantage of Fibre Optic Data Bus

• The main disadvantage of a fibre optic data bus is that it is expensive to install.

Types of Fibre Optic Connectors

• A typical fibre optic connector is a coupling type with a lens fitted.

Optoelectronic Devices

• A laser diode is an optoelectronic device.

Advantages of Single Mode Fibre Optic Cables

• Single mode fibre optic cables have a larger bandwidth compared to ordinary wire.

Fibre Optic Light Sources

• A fibre optic light source is normally a laser or LED.

Identification of Fibre Optic Cables on Aircraft

• The fibre optic cable can be identified on aircraft by its purple jacket colour.

Types of Fibre Optic Cable Connectors

• For a fibre optic cable connector that is not regularly disconnected, a butt type connector is used.

Maintenance Problems with Fibre Optics

• Kinking and contamination of connectors are associated with fibre optic maintenance.

Fibre Optic Data Bus Transmission

• A fibre optic data bus can transmit several messages simultaneously.

Connection of Fibre Optic Cables to LRU

• A fiberoptic cable to LRU connector should be connected very carefully to ensure alignment and reduce light loss.

Single Mode Fibre Optic Cables

• In a single mode fibre optic cable, the diameter of the cable is dependent on the wavelength of the light used.

Laser Diodes

• A semiconductor that emits photons and releases electrons when stimulated by photons is called a laser diode.

Fibre Optic Star Connection

• A fibre optic star connection provides direct point-to-point services to units on dedicated lines emanating from the central hub.

Passive Sensors in Fibre Optics

• Passive sensors in fibre optics require no power and do not process signals.

Optical Fibre Losses

• Optical fibre losses are due to absorption, scattering, and reflection.

Cone of Acceptance

• The cone of acceptance is measured between the longitudinal axis of the core and the outer angle.

Fibre Optic Cable Signal Separation

• Signals in fibre optic cables are separated by active optic filters.

Fibre Optic Connector Design

• Most fibre optic connectors are designed so that they cannot be over-tightened.

Light Transmission in Fibre Optic Cables

• Light transmission in a fibre optic cable is due to repeated internal reflection.

Fibre Optic Cable Joining

• The name given to the joining of two fibre optic cables by aligning them carefully and bringing them into close proximity of each other is end to end.

Fibre Optic System Reliability

• Fibre optic systems can transmit data in both directions at the same time.

Fibre Optic Cable Types

• For high bandwidth high-speed fibre optic transmission, single mode cables are used.

ILD vs LED

• The advantage of an ILD over an LED when used as a light source in fibre optics is a lower frequency range.

Speed of Light in Fibre Optic Fibres

• The speed of light in a fibre optic fibre is never greater than the speed of light in free space.

Angle of Incidence in Fibre Optic Cables

• The angle of incidence of a beam of light in a fibre optic cable is approximately half that of the cone of acceptance.

Angle of Acceptance in Fibre Optic Cables

• The angle of acceptance in an optical fibre is equal to the cone of acceptance.

Fibre Optic Cable Loss Value

• The loss value of the cable is shown by the curve on the TDR screen.

Aircraft Fibre Optics

• Common aircraft fibreoptics use modulating intensity on direct read.

Attenuation in Fibre Optics

• The main cause of attenuation in fibre optics is poor termination.

Laser Diode vs LED

• The advantage of a laser diode over an LED is a narrower bandwidth.

Type A Fibre Optic Connector

• A type A fibre optic connector is used for connections not regularly disconnected.