Study on the Output Characteristics of External-cavity Tunable Diode Lasers

An external-cavity tunable diode laser (ECTDL) is designed, which is based on a classical Littman-Metcalf structure. The diode laser with a wide gain spectrum is served as the seed source of the internal cavity. Meanwhile, the external-cavity feedback unit is composed of a blazed grating and a tuned mirror. The experimental results of no mode-hopping, high side-mode suppression ratio (84.34dB) with tunable wavelength range of 1479.96∼1599.96nm are obtained. The effective cavity length of the designed external-cavity tunable diode laser is about 50mm, the maximum output power is 15.19dBm, and the minimum output spectral linewidth is 18.89kHz. The research is conductive to promoting the research of new ultra-high resolution spectral analysis systems and providing autonomous and controllable laser signal generation source.