光纤通信复习题(含答案).docVIP

1.Make a choice（共十题 每题1分）10p (1).Which of the following dispersion (色散)dose not exist in single-mode optical fiber? （ D ） A .material dispersion B.waveguide（波导） dispersion C.polarization-mode （偏振）dispersion D.intermodal（联合） dispersion (2).The unit （单位）of the fiber attenuation coefficient （衰减系数）is (C) A. dB B. dBm C. dB/km D. dBm/km (3).the bands of Optical fiber communication is (B) A.0.01um-0.39um B. 0.8um-2.0um  C.0.39um-0.79um D.100um-1000um (4).If the optical input power of a Optical amplifier is 10mW，and the optical output power is 100mW as well ,then its output gain level is (A) A.10dB B.20dB C.30dB D.40dB ()In order to make sure of the system BER（比特误差率） conditions , if the minimum optical input power of the receiver is 1 uW, the sensitivity of the receiver must be (A) A.－30dBm B.－40dBm C.－20dBm D.－43dBm ()The principal （主要）light sources used for fiber optical communications applications are ：（D） A.OA、LD B.PIN、APD C.PD、LED D.LD、LED ()laser（激光） action is the result of three key process，which one of the following is not be included？（D） A.photon absorption B.spontaneous emission（自发发射） C.stimulated emission （受激发射） D.compound radiation（复合发射） (8) A single mode fiber usually has a core diameter （芯径）of A. A. 10m B. 62.5nm C. 125nm D. 50mm (9)To make sure that the APD photo-detector works properly, a sufficiently D is applied across the p-n junction. A. high forward-bias voltage（高的前置偏压） B. low forward-bias voltage C. low reverse-bias voltage （低的反相偏压） D. high reverse-bias voltage (10) When DFA fiber amplifier uses as light Repeaters（中继器）, its main effect is B. A. amplifying and regenerating the signal B. regenerating the signal C. amplifying the signal D. reducing the signal noise (11) In graded-index