The Yokogawa AQ6370E is a Benchtop Optical Spectrum Analyzer (OSA) designed for high-precision analysis of optical signals in the Telecom C-band and L-band. It covers a wavelength range from 1200 to 1650 nm, making it an essential tool for the development, manufacturing, and maintenance of components and systems for modern optical communication networks, such as DWDM (Dense Wavelength Division Multiplexing).