An Optical Spectrum Analyzer (or OSA) is a precision instrument designed to measure and display the distribution of power of an optical source over a specified wavelength span. An OSA trace displays power in the vertical scale and the wavelength in the horizontal scale. The expanding field of optics related applications has created a vast variety of industries and organizations that require advanced optical spectral measurements for both R&D and manufacturing. These industries include telecommunications, consumer electronics, healthcare, life science/medical research, security, sensing, microscopy, and gas/chemical analysis, and environmental monitoring. Yokogawa (formerly Ando) is the global leader in optical spectrum analyzers, delivering high quality, cutting edge technology with dependability, performance and flexibility for over thirty years.