[4] Wang Wei, Zhai Teng, Wang Hao, et al. Distributed feedback semiconductor laser with double-trench ridge waveguide structure[J]. Acta Photonica Sinica, 2017, 46(6): 158-163.
[6] Spiessberger S, Schiemangk M, Wicht A, et al. Narrow linewidth DFB lasers emitting near a wavelength of 1 064 nm[J]. J. Lightwave Technol., 2010, 28(17): 2611-2616.