Characterization and Lifetesting of Laser Diodes

Diode lasers are compact and efficient sources of optical power but often suffer from noncircular
beam profiles and multiple spatial modes, both of which are non-ideal for many applications.
This research focuses on developing, characterizing, and testing diode lasers fabricated with a
process that allows for single spatial mode circular beam lasers, with the goal of demonstrating
their potential for large-scale production in industry.

Present work involves evaluating diode lasers fabricated at Notre Dame by
measuring their pulsed L-I-V (light output power L vs. current I vs. voltage V) characteristic
curves, assessing how their performance has changed over time. To measure the quality of the
lasers under continuous wave (CW) operation, lasers are bonded to aluminum nitride
submounts soldered atop copper tungsten c-block heatsinks to enhance heat dissipation.
Additional efforts include singulating newer laser bars into individual die for subsequent
packaging and testing.

A 10-channel long-term reliability test bed is also being developed to monitor and log the output
power for up to 10 diode lasers during CW operation for hundreds to potentially several
thousands of hours, with the aim to compare in-lab fabricated lasers against commercially
available devices. Measurements gained from this would validate the fabrication process and
support broader industrial adoption.