Continuously Tunable Time Delay Using an Optically Pumped Linear Chirped Fiber Bragg Grating

Simultaneous Multi-Channel Microwave Photonic Signal Processing

“…While the use of superimposed gratings in a Sagnac interferometer offers greater simplicity in terms of implementation, it cannot provide the same capability as the AWGSI, especially in terms of generating waveforms with very different central frequencies. Moreover, by using tunable chirped BGs, e.g., through pump tuning [35], the AWGSI offers the possibility to generate multiple waveforms, with independent tuning of the central frequency and RF chirp rate.…”

“…Thus, measuring the power spectral density around the probe using an optical spectrum analyzer (OSA) (which gives the squared magnitude of the Fourier transform of the field of the signal being measured) will correspond effectively to the RF spectrum of the signal under test, i.e., the OSA measurement gives |E s (t)| interferometer offers greater simplicity in terms of implementation, it cannot provide the same capability as the AWGSI, especially in terms of generating waveforms with very different central frequencies. Moreover, by using tunable chirped BGs, e.g., through pump tuning [35], the AWGSI offers the possibility to generate multiple waveforms, with independent tuning of the central frequency and RF chirp rate. Several factors will limit the number of waveforms that can be generated simultaneously.…”

Continuously Tunable Slow and Fast Light by Using an Optically Pumped Tilted Fiber Bragg Grating Written in an Erbium/Ytterbium Co-Doped Fiber

“…Thanks to the high absorption of an Er/Yb co-doped fiber, the refractive index of the fiber is changed [17]. In [15], we have shown that by pumping an FBG written in an Er/Yb co-doped fiber, the refractive index along the FBG changes correspondingly to the pumping profile,…”

“…Recently, we proposed a method to tune a LCFBG by optical pumping. The LCFBG was written in an erbium/ytterbium (Er/Yb) co-doped fiber [15], by optically pumping the LCFBG, the group delay response is changed which leads to the change of the time delay. A continuously tunable time delay of 200 ps for a 7.8-GHz Gaussian pulse was experimentally achieved.…”

Continuously tunable chirped microwave waveform generation using an optically pumped linear chirped fiber Bragg grating

“…Therefore, the absolute value of the dispersion of the LCFBG is decreased due to the optical pumping. By tuning the injection current to the pump LD, the dispersion of the LCFBG can be continuously tuned [13]. In arm I, the ultrashort optical pulse is temporally stretched and spectrally dispersed by passing through the LCFBG.…”