SKSO Assignment : OPTICAL SOURCES

  1. An engineer has two  Ga(1-x)Al(x)As LEDs: one has band gap energy of 1.540 eV and the other has x = 0.01. find :
    a. Al fraction (x) and emission wavelength of LED1
    b. Eg and emission wavelength of LED2
    answer :
    a. Eg = 1,424 + 1.266X + 0.266X^2
    1.540 = 1.424 + 1.266X+0.266X^2
    X = 0.09
    LED1 = Ga(0.91)Al(0.09)As
    Emission Wavelength :

    skso

    b.  Eg = 1.424 + 1.266X + 0.266X^2            = 1.424 + 1.266(0.015) + 0.266(0.015)^2
    = 1.4430 eV
    skso

  2. A double heterojunction InGaAsP LED emitting at a peak wavelength of 1310 nm has radiative and nonradiative recombination time of 25 and 90 ns, respectively. The drive current is 35 mA.
    a Find the internal quantum efficiency and the internal power level.
    b. If the refractive index of the light source material is n = 3,5, find the power emitted from the device.

    Asnwer :
    a. skso
    skso
    b. power emitted from device (Po) = n^2 = 3.5×3.5=12.25W

  3. a GaAl As laser diode has a cavity length which has an effective absorption coeffient of 10 cm-1. For the uncoated facets the reflectives are 0.32
    a. What is the optional gain at the lasing threshold?
    b.If one end of the laser is coated with a dielectric reflector so that its reflectivityis now 90%, what is the optical gain at the lasing threshold?
    c. If the internal quantum efficiency is 0,65, what is the external quantum effiency is cases (a) and (b)?
    answer :
    a. skso
    bskso
    c.  untuk kasus a skso untuk kasus b skso
  4. belum selesai … nyusul 🙂