Time resolved studies of catastrophic optical mirror damage in red-emitting laser diodes

Abstract

We have observed the changing light intensity during catastrophic optical mirror damage (COMD) on the timescale of tens of nanoseconds using red-emitting AlGaInP quantum well based laser diodes. Using as-cleaved facets and this material system, which is susceptible to COMD, we recorded the drop in light intensity and the area of damage to the facet, as a function of current, for single, high current pulses. We found that in the current range up to 40 A, the total COMD process up to the drop of light intensity to nonlasing levels takes place on a timescale of hundreds of nanoseconds, approaching a limiting value of 200 ns, and that the measured area of facet damage showed a clear increase with drive current. Using a straightforward thermal model, we propose an explanation for the limiting time at high currents and the relationship between the time to COMD and the area of damaged facet material.

Mechanisms and fast kinetics of the catastrophic optical damage (COD) in GaAs‐based diode lasers

“…In other cases, even careful SEM inspection does not reveal any surface alteration [77], whereas electroluminescence patterns reveal darkened areas not far behind the seemingly unaffected facet. If COD signatures are visible at the facet, there is typically a correlation between P COD and the observed surface damage, i. e., the higher P COD the more extended the damage pattern at the facet [86,87].…”

“…Elliott et al [86] have performed a set of COD experiments by applying single rectangular current pulses. The changing light intensity during COD of the red-emitting QW based diode lasers was analyzed on a timescale of tens of nanoseconds.…”

Transient thermal characteristics related to catastrophic optical damage in high power AlGaAs/GaAs laser diodes

“…Very recently, the dynamics of the COD process under continuous wave operation has been analyzed in redemitting high-power diode lasers by means of combined real-time thermal and optical near-field imaging with cameras, and COD is time-resolved analyzed in singlepulse excitation [10,11]. Additionally, Elliott et al has proposed an explanation for the limiting time at high current and the relationship between the time to COD and the area of damaged facet material using a straightforward thermal model [12].…”

“…The measured temperature at the melting spot is about 95 and 94 8C which are the average temporarily values within a single frame (1 ms integration time) including the COD occurrence. As known, the total COD process up to the drop of light intensity to nonlasing levels takes place on a timescale of hundreds of nanoseconds [12]. Therefore, the measured temperature using the infrared thermography has an underestimation due to the temporal averaging and limited spatial resolution.…”

“…The results indicate that the increase of total thermal resistance comes mainly from that increase of chip. The total COD process up to the drop of light intensity to nonlasing levels takes place on a timescale of hundreds of nanoseconds, approaching a limiting value of 200 ns [12], which results in facet melting followed by re-solidification of the local molten area moving into the laser cavity [20]. Consequently, after COD, when LD is operated under constant electrical power, more electrical power transform into the dissipated thermal power (P diss ) than before COD due to the enhancement of nonradiative recombination, which lead to the temperature rise of active layer (DT) increasing accordingly.…”