The TSL-710 from Santec Corporation is a Tunable Laser for optical testing that operates from 1480 to 1640 nm. It has a high signal-to-noise ratio of over 90 dB/0.1nm, while still maintaining a high output power of over +10 dBm. This laser is an outstanding tool for testing next generation components for Dense Wavelength Division Multiplexing (DWDM) such as multi-input, high extinction ratio devices such as Wavelength Selective Switch (WSS). It has high wavelength accuracy of ±2 pm, high wavelength resolution of 0.1 pm, and narrow linewidth of under 100 kHz. The laser is designed to improve production inspection throughput by doubling the scan repetition rate over conventional lasers. It is suitable to be used as a local oscillator in coherent transmission, as well as a tool for interferometry and sensing applications. The TSL-710 is equipped with features such as fine-tuning and coherence control.