An optical spectrum analyzer (OSA) measures and displays the optical power distribution over a wavelength range. Yokogawa OSAs are recognized for leadership in wavelength resolution, close-in dynamic range, and stray-light suppression ratio (measurement dynamic range). For over 45 years, Yokogawa. VIAVI covers a broad range of OSA needs with many compact solutions. The COSA-4055 module offers the functionality and speed of an OSA in a handheld form factor at a fraction of. 📦 For purchasing, use the RP Photonics Buyer's Guide for optical spectrum analyzers. At Aumictech, we know OSAs inside and out.