Ando Optical Co., Ltd. AQ2140 Digital Multimeter

The Ando AQ2140 Optical Multimeter from Ando Optical Co., Ltd. is a modular mainframe for fiber‑optic measurement that combines an optical power meter, a stabilized light source, and, with the appropriate sensor modules, a loss‑test set or return‑loss measurement system. Interchangeable sensor units let you tailor the instrument to your task, and the system covers a wavelength range of 700 to 1870 nm with sensor accuracies around ±2.5%. In operation, the AQ2140 can graph measurement data and plot results directly to a plotter, facilitating immediate visualization of light‑level performance. The model is listed as discontinued by Yokogawa, with production ending on September 1, 2006, and documentation and listings continue to reflect its legacy as a modular optical test platform. Related variants exist in the AQ2140 family, including model AQ2141, which expands configuration options for multiple measurement channels.