(Solved): 13.6 A double-heterostructure laser diode is used as a Fabry-Perot-type optical amplifier. When bia ...
13.6 A double-heterostructure laser diode is used as a Fabry-Perot-type optical amplifier. When biased at the operating point it has a gain coefficient of 50cm−1, a loss coefficient of 4cm−1 and a confinement factor of 0.9 . The length between Fabry-Perot endfaces is 350μm and the reflectivities of the endfaces are both 33%. (a) What is the overall gain of this optical amplifier? (b) If the reflectivities of both endfaces are made very small so that the device acts as a traveling wave amplifier, but the current through the device is kept to be the same as in (a), what is the overall gain?