Stable Lateral Far Field of Highly Dense Arrays of Uncoupled Narrow Stripe Ridge Waveguide 1060 nm Lasers

In order to stabilize the lateral far-field profile of a broad area laser diode at high pump currents, the design of an asymmetric InGaAs/AlGaAs/GaAs laser heterostructure was developed. Lasers with an aperture formed by ten optically uncoupled ridge waveguides (each 6.5 μm wide) were developed on its basis. To maintain the single-mode operation of each ridge waveguide without coupling between emitters, a High Dense Microstripe Array (HDMSA, the pitch is 13.5 μm) and a Low Dense Microstripe Array (LDMSA, the pitch is 40 μm) were fabricated with a coupling parameter between adjacent lateral waveguides of 2·10 ⁻⁵ and 3·10 ⁻¹⁹ , respectively. The maximum optical output power was 5 W (HDMSA) in CW mode and 25 W (HDMSA) and 26 W (LDMSA) in pulsed mode (130ns/1kHz). It is shown that in both CW and pulsed modes, lasers of both designs provide a stable Gaussian-like distribution in the lateral far field (LFF) with a FWHM of 8–11 degrees for HDMSA and 6.5–10 degrees for LDMSA. It was found that the LFF broadens with a pump current in the range of low currents and stabilizes in the range of high currents for both designs. Studies of the near field in both operating modes at any pump currents showed no array modes and the uncoupling mode is maintained for ridge waveguide arrays.