shell text Flashcards
what is the equation to determine the lenth of a light pulse
what is the temperature equation
temperature standard deviation will increase with _____ even if the standard deviation of the Raman signals are constant.
Except for certain special quality control tests, the _______ signal is usually filtered and suppressed.
what is Tref and T0
what is a graded index
red shift is a _____ in wavelength and blue shift is a ______ in wavelength
When that pulse enters the fiber, it is said to be _____
what are the accuracy and resolution definitions and differences
If the sensitivity is known, the observed temperature
log is made up sum of three components:
what is Snell’s Law
The Raman signal is the signal used for evaluation of temperature. It is sufficiently strong and has a unique temperature dependence. Its wavelength is also shifted substantially (about ____/Nm) from the main Rayleigh peak,
thereby allowing the dominant Rayleigh and Brillouin peaks to be filtered out
The refractive index of the core is approximately
___% greater than the cladding thereby
assuring the containment of the laser light pulse
within the core.
why do most DTS measurements use multimode fiber
what does water do to fiber
What is the equation to determine window size required to achieve a one meter length resolution along the fiber
Laser pulses are directed to the fiber line by
means of a directional coupler. The fiber optic line then passes through a(n) ______ before going into the fiber
______ laser pulses and smaller time
windows are required to better detect short length high temperature nanomalies.
Those waves associated with the lattice vibrations show up as _____ lines or peaks on the backscatter spectrum.
the stokes and antistokes signals signal on the backscatter vary because
Total internal reflection is based on what law
what is the equation for overstuff of the fiber caused by its own weight
what is the refractive index
a DTS system’s resolution should be stated in terms of fiber ____ and _____.
what is the Beer-Lambert law
what is the equation for overstuff
what is the sampling resolution
what is optical overstuff
what are the x and y axis for a typical Optical Time Domain Reflectometry (OTDR) graph
Resolution can be expressed as ______
of the temperature measurement
If the velocity of light in the fiber is v, a ____can be opened at some time t to capture that backscattered light.
what are two definitions of spacial resolution
For singlemode fiber, longer distances requires ____ and _____
The main backscattered wave is at the wavelength of the
launched wave and is called the ____ peak or band. This is by far the _____ signal returned.
how is the speed of light in a fiber determined
During backscattering, the energized lattice and molecules then give off light having wavelengths at _______ the incident wave.
This light pulse is, in effect, a travelling ____ moving through the fiber line and relaying back temperature information
how is differential loss determined in a DTS wrap back
how long is the lightpulse to measure the fiber
the weakest of the backscattered waves, resulting from molecular and atomic vibrations, are the ____Bands
laser pulses are directed to the fiber line by
means of a _________.
Optical Time Domain Reflectometry (OTDR) is used to access what and with what type of wave
what is the equation for the energy of the returning Ramen backscatter
what is cone of acceptance
