The WG3040 is a benchtop stabilized laser source engineered for high-stability optical power output in optical device production testing and laboratory calibration. Built on closed-loop power locking and constant-temperature optical path control, it delivers 0.05dB/h output stability with power adjustable from −10 to +5dBm in 0.1dB steps—giving test engineers a repeatable reference source for insertion loss, return loss, and wavelength-dependent loss measurements. Selectable wavelengths cover 850/1310/1490/1550nm communication windows, with FC/PC single-mode connectors standard. An integrated VFL (visual fault locator) enables quick fiber link fault isolation without an external tool. USB, RS232, and LAN interfaces with SCPI command compatibility allow the WG3040 to be sequenced alongside power meters, optical switches, and attenuators in a fully automated multi-channel test platform. The front-panel LCD and keys support standalone operation, while the 205×205×100mm compact chassis and continuous-duty design suit production floors and lab benches alike. The WG3040 is purpose-built for optical splitter/coupler/WDM batch inspection, 400G/800G module loss and PDL testing, fiber Bragg grating and silicon photonics device calibration, and automated test system integration—wherever a stable, programmable reference source is the starting point of the measurement chain.