This paper presents results of a microscopic photoluminescence (&mgr;‐PL) characterization of strained InAs0.5P0.5/InGaAsP multiquantum well (MQW) crystals with a series of well numbers (n=2–14). This method is useful in detecting misfit dislocations in the crystals, especially at the initial stage of their generation. The &mgr;‐PL intensity profile measurements of a laser diode (LD) cavity shows the intensity, being mainly influenced by the [01¯1]‐directed misfit dislocations, is closely correlated to the threshold current of the LD. ©1995 American Institute of Physics.