The Ando AQ6319 is an optical spectrum analyzer which can measure loss wavelength characteristics and propagation characteristics on optical fiber cables, optical filters and the like, in addition to spectral measurements on light sources such as LDs and LEDs. The measurement wavelength range is wide at 600 to 1700 nm, enabling optical spectrum analysis in the near infrared range. In addition to basic features such as high resolution, high sensitivity, high accuracy, wide dynamic range and superior linearity, the AQ6319 has a wide variety of functions such as program measurement functions and numerous data processing functions, including analysis functions and template functions. In terms of data output capabilities, the AQ6319 can provide screen hard copies through the internal high-speed printer or an external printer. In addition, waveforms and programs can be read from and written to the internal hard disk and floppy disk, or read/written through the LAN interface. The AQ6319 also includes GP-IB and RS-232C interfaces as standard features, enabling fully remote control. Lastly, the AQ6319 has an intuitive graphical user interface using a keyboard and mouse for user-friendly operation.