Subluminal and superluminal propagation in Er3+ doped fiber Bragg grating

Group velocity control in Dy3+-doped fiber Bragg grating

“…This three-level system is similar the Ref. [20], Therefore, we get the spectral transmission coefficient t of the grating and the group delay g  of the grating expresses as:…”

Theoretical model for superluminal and slow light in erbium-doped optical fibers: enhancement of the frequency response by pump modulation

“…Superluminal and slow-light propagation are two very interesting phenomena that have been observed and measured in various material systems [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Moreover, from an applications perspective, the active control of the group velocity of light can be a key issue in the development of new technologies for optical communications, such as optical buffers for all-optical routing, optical memories, and optical signal processing [20][21][22][23][24][25][26][27].…”