Contents I. Introduction
High power high brightness type-I GaSb-based quantum well lasers are needed in the 2-3.5 spectral range for numerous applications. In order to reach high power, generally broad area (BA) devices are fabricated [1]–[2]. However, the broad area geometry will lead to degraded lateral beam quality mainly due to filamentation within a FP cavity. Since good beam quality is required for beam combining to reach even higher power levels and high brightness, it is necessary to maintain a single lateral mode and limit filamentation in BA diode lasers. A handful of approaches have been applied over the years to achieve high power without loss of beam quality [3]–[5], but they generally add complexity to the fabrication process. A relatively new approach that promises to achieve high beam quality with minimal power loss is the angled cavity [6]–[8]. An angled cavity, as shown in Figure 1, looks similar to a regular FP cavity except that the waveguide is tilted slightly from the facet normal. With a high degree of mode discrimination, the fundamental mode with a zigzag propagation in the cavity can be the only lasing mode. Moreover, the zigzag light path have been proven to be sufficient to suppress filamentation in broad area diode lasers [6]. So far, no attempt has been made to implement angled cavity design in diode lasers emitting in the ~3 wavelength range. In this work, we demonstrated angled cavity diode lasers at 3 wavelength range.
