A wavelength-tunable laser is a powerful tool as light source for sensing and its research and development has been studied so far. In order to obtain a new tunable laser the authors have developed a tunable Er3+-doped fiber laser in Littman/Metcalf configuration, and incorporating a Galvano mirror, scanning of the lasing wavelength is demonstrated. For the emission range that a semiconductor-based light source hardly covers, a tunable Tm3+-Ho3+ fluoride fiber laser is also demonstrated.
A novel Dual-frequency Doppler LiDAR (DFDL) is presented where the dual-frequency light source is generated by using external optical feedback (EOF) effect in a laser diode (LD). By operating a LD at period-one (P1) state and choosing suitable LD related parameters, a dual-frequency light source can be achieved. Such a dual-frequency source has advantages of the minimum part-count scheme, low cost in implementation, and ease in optical alignment. Theory and system design are presented for the proposed DFDL for velocity measurement with high measurement resolution. The proposed design has a potential contribution to the Light Detection And Ranging (LiDAR) in practical engineering applications.
8 kHz linewidth, 50 mW output, full C-band wavelength tunable DFB LD array with self-optical feedback
