Excited-state absorption in erbium-doped silica fiber with simultaneous excitation at 977 and 1531 nm

Abstract

We report a study of the excited-state absorption ͑ESA͒ in erbium-doped silica fiber ͑EDF͒ pumped at 977 nm, when the fiber is simultaneously excited by signal radiation at 1531 nm. We show, both experimentally and theoretically, that ESA efficiency at 977 nm gets strongly enhanced only in the presence of signal power. Experimentally, this conclusion is supported through the detection of upconversion emission, a "fingerprint" of the ESA process, and through the measurements of the EDF nonlinear transmission coefficient for the pump wavelength, which is sensitive to the ESA value. It is shown that the experimental data are precisely modeled with an advanced five-level Er 3+ model developed for the EDF.

Fiber laser switched by a long period grating interferometer as an intra-cavity loss modulator

“…2, the laser threshold is near 7 mW and the output laser power reaches 5 mW for a pump of 250 mW. Such low laser efficiency is explained by comparatively high intra-cavity loss due to numerous fiber splices, FRM and the interferometer internal loss, and presence of excited state absorption observed in erbium-doped fibers at both pump and laser wavelength [25].…”

The use of nonlinear dynamics of erbium-doped fiber laser at pump modulation for intra-cavity sensing

“…The EDFL cavity had relatively high overall loss composed of (i) the attenuator loss, (ii) the loss owing to a number of splices, (iii) the loss in the WDM and FRM ( $ 3.4 dB, one-pass), and (iv) the loss originated from Er 3 + excited-state absorption (ESA) immanent to any silica EDF [31,32]. An EDF length was chosen to be $ 6.3 m, providing gain sufficient to overcome the overall cavity loss and to allow lasing; for the same purpose, we used highly reflective FBG and FRM couplers in the EDFL scheme.…”

Study of upconversion in PCFs with high erbium concentration

“…According to the usual five energy-level scheme for the erbium ion 14 , the rate equations for this system, that describe the temporal evolution of the population densities of the levels, i n , can be written: …”