单项选择题

Why are the 1300 nm and 1550 nm regions of the fiber spectrum primarily used for optical communications?（）

A. They are both regions of lowest loss.
B. They are both regions of low reflections.
C. They are both regions of low index of refraction.
D. They are both regions of low chromatic dispersion.
E. They are both regions of low Polarization Mode Dispersion (PMD).

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热门试题

单项选择题What is an advantage of an externally modulated laser over a directly modulated laser?（）

A. lower cost
B. higher chirp
C. easier to manufacture
D. higher dispersion tolerance
E. higher optical signal-to-noise ratio

单项选择题What is the difference between the transmitted power and the sensitivity of the receiver?（）

A. OSNR
B. dispersion
C. attenuation
D. power budget
E. amplifier spacing
F. four wave mixing

多项选择题Which three technologies are used to reduce chromatic dispersion accumulation in fiber-optic transmission systems? （）(Choose three.)

A. PIN photodiodes
B. zero-chirped lasers
C. Erbium-doped fiber amplifiers
D. dispersion compensating fiber
E. dispersion compensating Bragg grating

单项选择题What is the phenomenon called where different wavelengths of light travel at different speeds?（）

A.OSNR
B.dispersion
C.light skew
D.attenuation

单项选择题A 2.5 Gb s (OC-48 or STM-16) optical signal with a dispersion tolerance of 1200 ps nm goes through fiber with 18ps nm*km of dispersion. How many 15216-DCU-350 equivalents are needed for enough compensation after traveling 100 km?（）

A.none
B.one
C.two
D.three
E.four