Improvement of the lateral-mode discrimination of broad-area diode lasers with a profiled reflectivity output facet

Abstract

The emission of a broad-area laser always contains several lateral modes (along the junction plane) even at low drive levels. To increase the discrimination against high-order lateral modes, we developed simple techniques for depositing a profiled thin layer of SiO on the output facet of a broad-area laser that has a 75-μm-wide injection current stripe. The profiled coating provided a nearly Gaussian reflectivity in the lateral direction (parallel to the junction plane). The resolved near-field spectra of the uncoated and coated lasers have been compared. The maximum output power in the single-lateral-mode regime was pushed to 25 mW with the profiled coating, compared with a corresponding power of less than 1 mW before deposition. Experimental results have confirmed the behavior predicted by our numerical simulations. This method is scalable to higher-power lasers.

Generalised multiple-lateral-mode rate equation modelling of lasers with selective quantum-well intermixing for improved beam quality

“…instabilities, as has been demonstrated in work carried out on tapered structures including master oscillators-power amplifiers (Donnelly et al 1998;Selmic et al 2002), cavity spoiling features (Donnelly et al 1998;Selmic et al 2002), laterally profiled facets Stryckman et al (1996), patterned contacts Salet et al (1998), unstable resonators Tilton et al (1991), and angled DFB structures Lang et al (1998). However, these techniques largely rely on the use of low-fabrication-tolerance elements reducing the yields, so alternative designs for stable high-power lasers attract considerable interest, with selective quantum well intermixing proposed as an attractive method Kowalski (2005).…”

Дискриминация Поперечных Мод В Торцевых Полупроводниковых Лазерах С Пространственной Модуляцией Отражения Выходных Зеркал

“…Это создает принципиальную возможность дифференцированного изменения внешних оптических потерь для мод разного порядка при использовании лазерного зеркала с поверхностно неоднородным коэффициентом отражения [4]. Технологии напыления тонких пленок через маску позволяют создавать на лазерных зеркалах элементы с характерными размерами в десятки микрон, что было использовано в работе [5] для пространственной модуляции коэффициента отражения лазеров с широким полоском (broad-area laser), в работе [6] -для полоска 25 мкм. Альтернативным подходом является прецизионное травление лазерных зеркал или покрытий зеркал, например, фокусированным ионным пучком (ФИП) (focused ion beam, FIB) [7].…”

Coherent beam combining of high power broad-area laser diode array with near diffraction limited beam quality and high power conversion efficiency

“…Applying low anti-reflection (AR) coating to a BALD and employing external optical feedback to a BALD can limit the number of transverse modes. A variety of external feedback designs can limit the number of transverse modes of BALD and improve the beam quality [26][27][28][29][30][31][32][33][34][35][36][37][38]. The off-axis optical feedback was introduced to enhance one transverse mode and significantly increase beam quality of BALD [33,34,36,38].…”