Facet Cooling in High-Power InGaAs/AlGaAs Lasers

Abstract

Several factors limit the reliable output power of a semiconductor laser under CW operation, such as carrier leakage, thermal effects, and catastrophic optical mirror damage (COMD). Ever higher operating powers may be possible if the COMD can be avoided. Despite exotic facet engineering and progress in non-absorbing mirrors, the temperature rise at the facets puts a strain on the long-term reliability of these diodes. Although thermoelectrically isolating the heat source away from the facets with non-injected windows helps lower the facet temperature, data suggests the farther the heat source is from the facets, the lower the temperature. In this letter, we show that longer non-injected sections lead to cooler windows and biasing this section to transparency eliminates the optical loss. We report on the facet temperature reduction that reaches below the bulk temperature in high power InGaAs/AlGaAs lasers under QCW operation with electrically isolated and biased windows. Acting as transparent optical interconnects, biased sections connect the active cavity to the facets. This approach can be applied to a wide range of semiconductor lasers to improve device reliability as well as enabling the monolithic integration of lasers in photonic integrated circuits.

48W continuous-wave output power with high efficiency from a single emitter laser diode at 915nm

“…Along with the rapid development of fiber lasers, high power and PCE have become more critical to provide a cost-effective laser diode. To increase the output power [9,10] and power conversion efficiency [11], epitaxial design methods [12][13][14][15], epitaxial growth technologies [16,17], facet reliability against COMD [18][19][20][21], and passivation technologies [8,22,23] have been greatly improved. Increasing the reliable output power and PCE are always fundamental pursuits in research and practical applications.…”

Multisection waveguide method for facet temperature reduction and improved reliability of high-power laser diodes

“…This study uses a multi-section waveguide method shown in Figure 1 to effectively isolate laser heat load from the output facet, which dramatically reduces facet temperature even below the laser cavity temperature developed in our previous work [17,18]. We fabricated and carried out detailed characterization of the devices, studied their optimum working conditions (i.e., identical output power with much lower facet temperature than the standard LDs), and revealed elimination of COMD in LDs.…”

From Two- to Three-Dimensional Model of Heat Flow in Edge-Emitting Laser: Theory, Experiment and Numerical Tools

“…The unwavering interest in this subject can be explained by expectations of obtaining greater and greater optical powers. Thus, the researchers design very sophisticated techniques of facet temperature reduction [9,10], investigate degradation mechanisms [11] or look for more efficient cooling systems [12].…”