The AQ4321D is a Tunable Laser Source with precise wavelength control in the 1520 to 1620 nm range. It has excellent basic performance such as high-speed sweep, high stability, and narrow linewidth. Resolution is 0.001 nm. Full remote control is available via IEEE-488 or RS232C interfaces. An internal hard drive and 3.5 inch floppy disk make test setups easy to store and recall. Additional features include a color LCD display with soft key menus for selecting functions and sub menus. Parameters may be changed via a numeric key pad or through a front panel RPG. An FC optical output connector is standard with SC or ST available optionally.