All-fiber integrated saturable absorber-tunable wavelength filter for Q-switching laser in both C- and L-bands

Abstract

We proposed and experimentally demonstrated combining a nonlinear optic saturable absorber and a wideband-tunable spectral filter in a single graphene oxide (GO) film deposited fiber optic device. The GO film was prepared on the cleaved facet of an optical fiber applying two sequential processes: the electrical deposition to make a thick GO film using an arc fusion splicer, followed by the laser pulse drilling to form a multi-layered GO film. The GO deposited fiber facet and a pristine fiber facet formed an asymmetric Fabry-Perot interferometer (FPI), whose spectral response was flexibly controlled by adjusting the air gap between them. An all-fiber ring laser cavity was built using the proposed device as a tunable saturable absorber along with erbium-doped fiber as a gain medium in the L-band. Stable Q-switching laser pulse trains were successfully generated, whose pulse duration was in the order of a few microseconds and its peak wavelength was tunable over 40nm from 1564 to 1604nm covering both C-and L-bands. At a certain condition, we also obtained Q-switching pulses simultaneously lasing at the double wavelengths, 1573.3 and 1586.7nm. Detailed device fabrication processes and laser characteristics are described to elucidate the high potential of 2-dimensional material films in nonlinear optics.

Saturable absorption and its consequent effects in bistable erbium-doped fiber ring laser

“…The width of the bistable region is dependent on the feedback wavelength as reported earlier [8,9,11,12] . We demonstrate this feature by setting the wavelength filter in the cavity at different wavelengths, and measuring the laser output power as a function of input pump power when the EDF length in the EDFRL remains fixed.…”

“…wavelength tunability [6] and bistability [7,8] in continuouswave (CW) operation, as well as Q-switching [9,10] and mode-locking [11,12] in pulsed operation. One of the key physical processes for some of these effects is the saturable absorption in EDF.…”

Nanometer-Thin Stacks of MXenes (Ti3C2Tx and Ta4C3Tx) for Applications as Nonlinear Photonic Devices

“…The Z -scan measurement results confirm that Ti 3 C 2 T x and Ta 4 C 3 T x SAs possess fascinating saturable absorption behaviors at the 1 μm spectral region, which can be ascribed to the plasmon-enhanced ground state absorption . In particular, relatively low saturable intensity and high modulation depth in contrast to graphene-based SAs are favorable parameters of an SA element with a view to deliver laser pulses with ultrashort pulse durations and high repetition frequencies. − The imperfect fitting results may be attributed to the uneven distribution of MXene samples on the substrate surface, which can be improved by selecting better LPE and spin-coating parameters.…”

Generation of Q-switched and mode-locked pulses based on PbS/CdS saturable absorbers in an Er-doped fiber laser

“…[1][2][3][4] Two practical approaches to generate laser pulses are Q-switching and mode-locking methods, where saturable absorbers (SAs) are critical in determining the duration and power of laser pulses. [5][6][7][8] Although there are commercially available SAs, e.g., semiconductor saturable absorber mirrors (SESAMs), they are often expensive and offer suboptimal performance. On the other hand, artificial SAs have been used extensively to generate ultrafast laser pulses.…”