Dynamic all-optical tuning of transverse resonant cavity modes in photonic bandgap fibers

Abstract

Photonic bandgap fibers for transverse illumination containing half-wavelength microcavities have recently been designed and fabricated. We report on the fabrication and characterization of an all-optical tunable microcavity fiber. The fiber is made by incorporating a photorefractive material inside a Fabry-Perot cavity structure with a quality factor Q >200 operating at 1.5 microm. Under short-wavelength transverse external illumination, a 2 nm reversible shift of the cavity resonant mode is achieved. Dynamic all-optical tuning is reported at frequencies up to 400 Hz. Experimental results are compared with simulations based on the amplitude and kinetics of the transient photodarkening effect measured in situ in thin films.

All-Optical Broadband Variable Optical Attenuator Based on an ${\rm As}_{2}{\rm Se}_{3}$ Microwire

“…The response time measured in these experiments was τ c = 140 μs for a 500 Hz modulation frequency. Fitting of the signal with the stretched exponential function (1) yields a dispersion parameter β = 0.86, which agrees well with those previously reported for transient photodarkening effects in ChG glassy films [9], [14]. Further measurements at different powers for the bandgap light showed that the characteristic time decreases with increasing power, which is also consistent with transient photodarkening effects [11], [12].…”

“…Photodarkening in particular has proven useful for tuning resonances in photonic bandgap fibers [14], and we have further shown that this effect in As 2 Se 3 microwires could lead to develop all-optical broadband fiber attenuators.…”

“…The stretched exponential function has been widely used to describe the kinetics of changes in amorphous semiconductors, and has been confirmed as a good representation for photodarkening and other photoinduced phenomena in chalcogenide thin films [10]- [14]. Experimental studies have shown that photodarkening is a wavelength dependent effect; in particular, α max has been reported to decrease with increasing wavelength [11], [12].…”

Hybrid polymer photonic crystal fiber with integrated chalcogenide glass nanofilms

“…It has been demonstrated that the Kerr effect can provide an efficient way to control ultrafast optical component with intensity434445. However, it should be noticed that the photosensitivity of chalcogenide glasses is an additional effect, which might also contribute to the change in resonance wavelength46. For that reason, further experiments using silica PCFs were performed in order to verify that the observed shift of the bands is due to the Kerr effect of the high index chalcogenide glass (see supplementary Figs.…”

Piezoelectric Multimaterial Fibers

“…Enabling electricallymodulated fibres could pave the way for unprecedented technological capabilities including sensitive pressure and flow measurements in capillary blood vessels, low-cost large-scale fabricto-fabric communications, in vivo endovascular imaging and acoustic microscopy inside acoustically-opaque organs, and minimally-perturbative sparse sensor meshes for large-area studies of pressure/velocity fields in fluid flows. Previous approaches to realizing timedependent variations in fibers focused on refractive index modulation [3][4][5], non-linear optical mechanisms in silica glass fibers [6][7][8], and electroactively modulated polymer fibers [9]. However, the inert nature of traditional glassy fiber materials has limited these approaches to short fiber lengths, simple geometries, and high driving fields.…”