Page 196 - Photonics Essentials an introduction with experiments

Direct Modulation of Laser Diodes

190 Advanced Topics

Problems and Exercises
8.1. Using a sequence in time of energy band diagrams for a direct
band gap semiconductor, show how application to a laser diode of
an electrical pulse that is shorter than the recombination time
will lead to band filling, and once recombination begins, why the
wavelength of emission modulates from shorter toward longer
wavelengths.
8.2. Develop a set of design curves for turn-on delay using the follow-
ing parameters:
r = 10 –10 sec

J 1 = 0.9 J th
J 2 = 1.1 J th , 5 J th , 10 J th , 20 J th
8.2. Repeat for J 1 = 0.1 and 0.5 J th . Plot your results. Comment on the
optimum practical conditions for obtaining a negligible turn-on
time for the laser.

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