The MS9780A is a diffraction-grating spectrum analyzer for analyzing optical spectra in the 600 to 1750 nm wavelength band. Its input section has been redesigned to support fibers with core diameters of 50/62.5 um. The input section of the MS9780A can be used to measure the spectra of LDs and LEDs. In addition to uses such as measurement of LD and LED spectra, it has functions for measuring the transmission characteristics of passive elements such as optical isolators, as well as the NF/Gain of optical fiber amplifier systems. In addition to its basic features, the superior stability and reliability of the diffraction-grating (patent pending) capability easily passes the severe specifications required for the precise measurement of WDM communications methods, particularly in the 1.55 um band. The MS9780A is calibrated automatically by inputting the reference light for the wavelength (option). Features -70 dB dynamic range -90 dBm guaranteed optical reception sensitivity Tracking with tunable laser source Optical pulse measurement Full range of WDM application functions Wavelength range 600 to 1750 nm Wavelength Accuracy ±0.05 nm (1550 ±20 nm, resolution: 0.07 to 0.2 nm, after calibration with wavelength reference light source option) Resolution 0.07nm(min., SM Fiber) Level measurement range (attenuator: off)-90 to +10 dBm (1250 to 1600 nm) (attenuator: on)-65 to +20 dBm (1100 to 1650 nm) Dimensions and mass 320(W) x 177(H) x 350(D)mm, less than 16.5 kg