InP/InGaAsP channeled-substrate buried-heterostructure lasers and broad area double heterostructure devices as back-face monitors.

An InP/InGaAsP laser/laser monitor hybrid structure which demonstrates the use of channeled-substrate buried-heterostructure lasers or broad area double heterostructure devices as "on-board" back-face monitors is presented. Devices with and without anti-reflection facet coatings are used as monitors. A linear relationship between photocurrent and light output from the laser is observed for all monitor types. Photocurrents of 2.2 to 17.6 microA/mW are obtained (at a monitor-laser separation of ~ 100 microns), comparable to our previous results on monolithically integrated laser/monitor structures. These sensitivities are in close agreement with those predicted assuming close to unity quantum efficiency in the junction region. Channeled- substrate buried heterostructure laser devices used as back- face monitors do not produce usable monitor currents, with sensitivities of less than 3MicroA/mW being obtained.