Frequency locking in beam-steering high power lasers

980 nm high power semiconductor lasers are prone to beam steering, which makes them less reliable as pumping sources for Er³⁺-doped optical fibers. This steering phenomenon has been attributed to the interference between the first-order and fundamental lasing lateral waveguide modes, which can both emerge in high power lasers due to carrier-induced effects, even in carefully designed single mode ridge structures. Here we present a theoretical explanation of how frequency locking, an integral part of the beam steering theory, occurs in high power lasers. The results obtained are consistent with all known experimental observations, both previously reported and newly obtained for this report