A 5 Gb/s 32-QAM data transmission over a hybrid standard single-mode fibre (SSMF) and free-space optics (FSO) link has been experimentally demonstrated in the 42 − 90 GHz range for 5G networks deployment. Four-wave mixing (FWM) nonlinear effect in a semiconductor optical amplifier (SOA) experienced by a carrier suppressed double sideband modulated signal has been employed to photonically generate millimetre wave (mmW) signals with reduced electronics bandwidth. Both simulation and experimental results have been shown to describe the error vector magnitude (EVM) performance of the system. Large operation bandwidth is shown in our experimental setup, where measured penalties for 42 and 66 GHz are below 1 dB whereas 90 GHz leads to 3 dB penalty at 12 % EVM threshold. Sensitivity has also been estimated for optical back-to-back (OB2B), after SSMF and hybrid link transmissions for different mmW frequencies.
FBG in polymer optical fibers (POFs) is a promising technology for a wide range of sensing applications due to a lower Young’s modulus and a large range of applying strain. Furthermore, POFs have several properties which make them attractive for biosensing applications such as nonbrittle nature, flexibility in bending and biocompatibility. Chirped Fiber Bragg gratings (CFBGs), which are characterized by a nonuniform modulation of the refractive index show a broad reflection spectrum, enabling shortlength distributed sensing. The combining benefits of POF and CFBGs is attractive for biomedical applications. Here, we present a novel method to obtain CFBG in POF with a postprocess uniform POF FBG by using resin.
We demonstrate a long period grating (LPG) inscription in microstructured polymer optical fibers (mPOFs) using a single 248 nm UV laser pulse of 15 ns duration for every inscription point using a point by point technique with total length of 25 mm. The fabrication time indicates shortening for a single coupling point (15 ns against 42 s reported in literature). A grating with 20 dB transmission dip has been fabrication by using two UV pulses for each coupling point. The device has been fabricated in mPOF with a core that has been doped with benzyl dimethyl ketal (BDK) for photosensitivity increase. The strain and temperature responses of the fabricated gratings under different conditions have been characterized in order to assess the viability for sensing applications. Better performance was achieved with suitable post annealing process of the gratings.
In this contribution we report on the fabrication of novel bandpass transmission filters based on PS-FBGs in microstructured polymer fibers at telecom wavelengths. The phase mask technique is employed to fabricate several superimposed gratings with slight different periods in order to form Moiré structures with a single or various π phase shifts along the device. Simulations and experimental results are included in order to demonstrate very narrowband transmission filters. Experimental characterization under strain and temperature variations is provided in a non-annealed fiber and time stability of the fabricated devices has been also measured under different pre-strain conditions.
We propose a new structure for sensing variations in the refraction index independent of fluctuations in temperature. The scope of applications is very wide and can be used to detect electromagnetic, biochemical and even radiation changes. Also, it can be applied to the telecommunications field.