4 optics Flashcards
A concave mirror is used in
Headlights
A chromatic aberration
Spherical aberrations
Can be compensated by using a compound lenses
Incidents Ray’s further from the axis of intersect slightly closer to the lens to produced distorted image
A material with a gradually varying refractive under is said to have
Graded index
Graded index fibre cable - variable refractive index across its cross sectional area
A fibre optic cable is attenuated at 29 dB/metre. This is referring to?
Attenuated pulses have their sizes and shape restored by?
The figure allows for when calculating power again
Regenators- ( boost signal)
A parabolic mirror may be used to prevent
Spherical aberration
Attenuation is most often caused by
Absorption and scattering
Light in fibre optics is transmitted at
1.99 X 10 ( power of 5 ) m/s
200,000 kilometres per second
For light to travel down a fibre optic cable , it’s angle must be
Same or less than the done angle
Angle of reflection =
Angle of incidence
Illumination of one lumen per metre squared is one
The unit of luminous in the SI SYSTEM is
Lux
Candela
What does not require power?
What does require power in a fibre optics flight control system?
Passive sensor
Sensor and transmitter
In a multi mode fibre optics system?
Diameter is greater than the wave length
In refraction , SIN I/SIN R represents the
Refractive index
Lasers use which source of light?
Coherent
Fibre optics is used because
Optical fibres in communication
Greater bandwidth than electrical systems
Resistant to noise caused by stray electromagnetic signals
Refractive index
Speed of light / speed of light in the medium
Speed of light is
Miles / second =
M/s?
Km/s
186,000 miles/s
300,000,000 m/s
300,000 km/s
Speed of sound
M/s?
343m/s
Fibre optic receiver is a
Photodiode
The numerical aperture (NA) of a fibre is a measure of
Max cone angle of light rays to be reflected down the fibre
The power of a lens is measured in
Diopters
Range of core diameters for optical for optical fibres are
Thickness of a single mode fibre optic ?
50- 100 microns
5 micro meters
When light meets a glass / air boundary at an angle of incidence less than the critical angle?
Both reflection and refraction takes place
What does a passive filter achieve?
What does an active filter achieve?
Sorts out/ blocks certain wavelengths
Catch certain wavelengths and converts then to other wavelengths
