Comments on "Compact first-order polarization mode dispersion compensator based on birefringent crystals"

In 2004, with the title quoted above, Yang Chang-Xi, Li Shi-Guang, Miao Hou-Xun, Tian Yu, Zhang Er-Yao, and Jin Guo-Fang published an article in Chinese Physics Letters (CPL), vol.21 p.326 (2004). Regrettably, the technical contents of this paper are substantially the same as those of a paper published in the Journal of Lightwave Technology (JLT) in 2003 (Yan et al., vol.21, no.7, p.1676) and an OFC postdeadline paper, which was presented and published in 2002. However, the authors (Yang et al.) did not reference any of the earlier publications. Yao and Yan compares the journal papers in this commentary.