16.2 Equipment: Instrument Box and Fiber

Several organizations manufacture and / or operate DTS equipment on a service basis for the E&P industry. The optic fibers are mass-manufactured by a number of companies with a variety of materials and designs for different applications. The 'Instrument Boxes' comprise a laser light source, an oven which provides a reference temperature, and photo-electric sensors which capture the backscattered light, along with digital circuitry which both controls the laser transmission and analyses the frequency and intensity of the backscatter. Instrument boxes and fibers can readily be interchanged.

The transmission characteristics of optic fibers are dependent upon several factors in addition to temperature, which include their construction, physical deformation and chemical, particularly aqueous, contamination. For these reasons, calibrations of the equipment are routinely necessary to monitor the transmission characteristics.