Which three technologies are used to reduce chromatic dispersion accumulation in fiber-optic transmission systems？（）

单项选择题Whyarethe1300nmand1550nmregionsofthefiberspectrumprimarilyusedforopticalcommunications？（）

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）.

多项选择题Whatthreeincombinationarefactorsthatcancausefour-wavemixinginfiber-opticcables？（）

A. low optical powe
B. high optical power
C. few optical channels
D. many optical channels
E. low chromatic dispersion
F. high chromatic dispersion
G. too much power differential in the optical channels

单项选择题Given the formula： （Fiber Attenuation * Km） + （Splice Attenuation * # of Splices） + （Connector Attenuation * # of Connectors） + （Optical Fiber or OADM） + Buffer（Fiber aging）） With regard to SONET SDH optical calculations，  what will the given formula provide？（）

A. fiber loss
B. OSNR level
C. post amplification
D. index of reflection
E. index of refraction
F. power post amplification budget

单项选择题Click the Exhibit button.  Which type of multiplexer is shown in the exhibit？（）

A. Thin Film filter
B. Fiber Bragg Grating
C. Arrayed Wave Guide
D. Erbium fiber amplifier

多项选择题Whatarethreefactorsthatlimitthemaximumdistanceofanamplifiedopticalsignalwithoutregeneration？（）

A. fiber dispersion
B. signal attenuation
C. transmitter power
D. amplifier bandwidth
E. receiver dispersion tolerance