Performance analysis of long band passive optical network using amplifier spontaneous noise and fiber Bragg gratings

Long band (L-Band) passive optical networks (PONs) are attracting a lot of attention these days, thanks to rising capacity demands. Because of PONs requesting more and more channels, fault detection/monitoring is critical. Fault detection in the conventional band (C-Band) employing reflecting Fiber Bragg Gratings (FBGs) and a probe signal integrating an additional amplified spontaneous noise (ASEN) source has been frequently demonstrated. However, interference occurs when ASEN and transmitter signals are in the same wavelength band, and adding additional ASEN sources to the network raises the overall cost. So, in L-Band PONs, a cost-effective, low-complexity fault detection/monitoring system is required. Therefore, in this work, a fault detection/monitoring system for L-Band PON using C-Band ASEN from inline erbium doped fiber amplifier (EDFA) and dual purpose FBG, i.e. (1) ASEN reflection for fault monitoring and (2) dispersion compensation is proposed. A 4 × 10 Gbps L-Band PON is investigated over 40 km feeder fiber (FF) and 1 km drop fibers (DFs) that serve 32 optical network units (ONUs)/different input powers, dispersion values, and laser linewidths in terms of reflective power of FBGs, eye opening factor, and bit error rate (BER), respectively.

Recent Achievements on Grating Fabrications in Polymer Optical Fibers with Photosensitive Dopants: A Review

This review discusses recent achievements on grating fabrications in polymer optical fibers doped with photosensitive materials. First, different photosensitive dopants in polymer optical fibers (POFs) are summarized, and their refractive index change mechanisms are discussed. Then, several different doping methods to fabricate the photosensitive POFs are presented. Following that, the principles of gratings, including standard fiber Bragg gratings (FBGs), tilted fiber Bragg gratings (TFBGs), chirped fiber Bragg gratings (CFBGs), phase-shifted fiber Bragg gratings (PSFBGs), and long period fiber gratings (LPFGs), are reported. Finally, fabrications of different gratings based on photosensitive POFs in the last 20 years are reported. We present our article clearly and logically, so that it will be helpful for researchers to explore a broad perspective on this proposed topic. Overall, the content provides a comprehensive overview of photosensitive POF fabrications and grating inscriptions in photosensitive POFs, including previous breakthroughs and recent advancements.

Fiber Bragg Grating-Based Sensors and Systems

Today, no one doubts that fiber Bragg gratings (FBGs) have become the most used tool for measuring various physical parameters, the structural integrity of engineering systems, and the biological activity of living systems [...]

Medical Range Radiation Dosimeter Based on Polymer-Embedded Fiber Bragg Gratings

Fiber Bragg gratings (FBGs) are valuable dosimeters for doses up to 100 kilograys (kGy), but have hardly been used for the low-dose range of a few grays (Gy) required in medical radiation dosimetry. We report that embedding a doped silica fiber FBG in a polymer material allows a minimum detectable dose of 0.3 Gy for γ-radiation. Comparing the detector response for different doped silica fibers with various core doping, we obtain an independent response, in opposition to what is reported for high-dose range. We hypothesized that the sensor detection is based on the radio-induced thermal expansion of the surrounding polymer. Hence, we used a simple physical model based on the thermal and mechanical properties of the surrounding polymer and obtained good accordance between measured and calculated values for different compositions and thicknesses. We report that over the 4 embedding polymers tested, polyether ether ketone and polypropylene have respectively the lowest (0.056 pm/Gy) and largest sensitivity (0.087 pm/Gy). Such FBG-based dosimeters have the potential to be distributed along the fiber to allow multipoint detection while having a sub-millimeter size that could prove very useful for low-dose applications, in particular for radiotherapy dosimetry.