Practise

1、单选题：
"Optical fiber communication" refers to (   )‌
选项：
A: A communication mode in which radio waves are used as carriers and optical fibers are used as transmission media.
B: A communication mode in which optical waves are used as carriers and optical fibers are used as transmission media.
C: A communication mode in which optical waves are used as carriers and cables are used as transmission media.
D: A communication mode in which laser is used as carriers and optical fibers are used as transmission media.
答案: 【 A communication mode in which optical waves are used as carriers and optical fibers are used as transmission media.】

2、判断题：
The disadvantage of optical fiber communication is high transmission loss.‎
选项：
A: 正确
B: 错误
答案: 【 错误】

3、判断题：
The function of photodiodes is to convert optical signals into electrical signals.‌
选项：
A: 正确
B: 错误
答案: 【 正确】

4、判断题：
The first laser was a ruby laser.‍
选项：
A: 正确
B: 错误
答案: 【 错误】

5、判断题：
‍The laser commonly used in communication is semiconductor laser.​
选项：
A: 正确
B: 错误
答案: 【 正确】

Test 1

1、单选题：
‌The production material of optical fiber is (      )‍
选项：
A: Copper
B: Iron
C: Compound
D: Quartz
答案: 【 Quartz】

2、单选题：
‏The three wavelengths used in optical fiber communication are (   )‎
选项：
A: λ=0.85um，λ=1.20um，λ=1.80um
B: λ=0.80um，λ=1.51um，λ=1.80um
C: λ=0.85um，λ=1.31um，λ=1.55um
D: λ=0.85um，λ=1.20um，λ=1.80um
答案: 【 λ=0.85um，λ=1.31um，λ=1.55um】

3、单选题：
‌The function of the photodetector is (   )‏
选项：
A: Convert an optical signal into an electrical signal
B: Convert an electrical signal into an optical signal
C: Amplify electrical signal
D: Amplify optical signal
答案: 【 Convert an optical signal into an electrical signal】

4、单选题：
‍The spectrum of optical fiber communication belongs to (    )‎
选项：
A: Visible light
B: Ultraviolet light 
C: Infrared light
D: X-ray
答案: 【 Infrared light】

5、判断题：
‎Optical fiber can be connected directly without special tools.​
选项：
A: 正确
B: 错误
答案: 【 错误】

Practise

1、单选题：
‌Which kind of amplifier is amplified by the nonlinear effect in optical fiber?​‌​
选项：
A: EDFA
B: Raman fiber amplifier
C: PDFA
D: Semiconductor amplifier
答案: 【 Raman fiber amplifier】

2、多选题：
​Which are the characteristic parameters of optical wavelength division multiplexer?‎
选项：
A: Insertion loss
B: Wavelength isolation
C: Gain
D: Echo loss
答案: 【 Insertion loss;
Wavelength isolation;
Echo loss】

3、判断题：
‌Optical amplifiers can extend the transmission distance better than photoelectric repeaters.‍
选项：
A: 正确
B: 错误
答案: 【 正确】

4、判断题：
‌DWDM uses C and L band.‏
选项：
A: 正确
B: 错误
答案: 【 正确】

Test 2

1、单选题：
‎Which of the following is a dispersion-shifted single-mode fiber?‌
选项：
A: G.652
B: G.653