The K940DA5HN-70.00WN0N is a high-power fiber-coupled laser diode delivering 70W of Continuous Wave (CW) output power at a center wavelength of 940nm (±3nm). Engineered for fiber laser pumping, this compact module outputs through a high-brightness 105μm core fiber (0.22 NA) — delivering 70W of 940nm pump power in a tight beam profile ideally suited for coupling into small-core double-clad gain fibers and high-brightness fiber combiners. A defining characteristic of this laser diode is its exceptional 52% electrical-to-optical efficiency — the highest among all 940nm and 976nm modules in this product family. This record efficiency significantly reduces the thermal load per watt of optical output, enabling more compact cooling solutions and lower system operating costs in multi-pump fiber laser architectures. The low operating voltage of 11.2V typical (12.5V maximum) further simplifies power supply design for OEM integration. This module features a unique **1400–1600nm feedback isolation band** , unlike other modules in the lineup which isolate the 1020–1200nm range. This makes the K940DA5HN-70.00W particularly suited for pumping Er-doped or Tm-doped fiber systems operating in the 1400–1600nm signal window, where back-reflected signal light would otherwise damage the pump diode. The 6-pin package includes optional Thermistor (Rt, Pins 3 & 4) and Photodiode (PD, Pins 5 & 6) interfaces for closed-loop monitoring.