[開課學院]: 資電學院
[開課系所]: 電機系
[課程名稱]: 光電工程
[老師名稱]: 田春林 老師
[開課學期]: 982
[類型]: 98-2期末考
1. Consider a InGaAsP-InP laser diode which has an opticalcavity of
length 250 microns. The peak radiation is at 1550nm and the
refractive index of InGaAsP is 4. The optical gain bandwidth
(as measured between half intensity points) will normally depend
on the pumping current(diode current) but for this problem assume
that it is 2nm. (24%)
(a) What is the mode integer m of the peak radiation?
(b) What is the separation between the modes of the cavity?
(c) How many modes are there in the cavity?
(d) What determines the angular divergence of the laser beam emerging
from the optical cavity?
2. Suppose that a particular family house in a sunny geographic location
over a year consumes a daily average electrical power of 500W. If the
annual average solar intensity incident per day is about 6kW.h.m^-2,
and a photovoltaic device that converts solar energy to electrical
to electrical energy has an efficiency of 15%, what is the required
device area? (12%)
3. A solar cell under an illumination of 100Wm^-2 has a short circuit
current Isc of 50mA and an open circuit output voitage Voc, of 0.55V.
What are the short circuit current and open circuitvoltage when the
light intensity is halved? (16%)
4. (a)Calculate and compare the thickness of quarter-wave plates made
from calcite, quartz and LiNbO3 crystals all operating at a
wavelength of λ～590nm. What is your conclusion? (12%)
(b)Assuming little relative change in the indices, what are the
thicknesses at double the wavelength? (12%)
5. Suppose that a linearly polarized light is passed through a polarizer
placed with its transmission axis at angle π/4(45°) to the incoming
optical field. Suppose now that we "rotationally modulate" the
transmission axis of the polarizer by small amounts Φ about π/4(45°).
(a) Show that the change in the transmission intensity is
△I α -Φ+2/3Φ^3-....
(正比)
where Φ is in radians. (12%)
(b) What is the extent of change (in degrees) in Φ so that the second
term is only 1% of the first term? (12%)
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◆ From: 122.117.10.38
※ 編輯: R16 來自: 122.117.10.38 (07/03 16:26)