Abstract
The scientific community has been exploring new concepts as a result of the usage of optical fibers as absolute measurement sensors. While cross-sensitivity is a common issue with optical fiber sensors, this issue has been mitigated by simultaneous measurement techniques. But when it comes to absolute measurements, these methods have some limitations. The white light interferometer, which offers a superb solution for a range of applications, especially for absolute temperature measurement, is one of the most often used methods for absolute measurements.

Abstract
CubeSats are becoming an alternative challenge for space exploration. Research in the technology and applicability of these small platforms has received an increasing interest in the last years. They represent an emergent technological market (CAGR growth of 37.91 % in the 2017-2021 period), while a variety of fields like meteorology, climatic research, transportation safety, or navigation is resorting to this technology. As more complex CubeSats missions are defined, a natural increase in the mission power demand occurs. In a scarce-resource environment like the space, this demands the development of new ways of harvesting spacecraft electrical energy. An alternative to traditional energy harvesting systems composed of solar panels and batteries is Wireless Energy Transfer (WET). It originates in the electromagnetic transfer, proven to have two important limitations: high power efficiency decrease at distances bigger than coil size and the need of mobile parts. A new approach is proposed as a solution to these limitations: the possibility of mounting on a 3U CubeSat photo-thermoelectric generator array devices that can convert photon energy to electrical energy via thermal gradient generation. For creating the thermal gradient, a long-range laser source targets cells from each array forming the hybrid photo-thermoelectric plasmonic system (HPTP). Two possible scenarios are presented in terms of mission requirements and analysis: a controlled pulsed large-range laser source located on Earth, in the case of Earth-orbiting missions, or on a hub system, in a deep-space mission. For Earth, Mars and Jupiter, a simulation of the total energy produced by solar panels and the HPTP system is presented to illustrate the potential use of the WiPTherm technology. In each of the scenarios, key measures of effectiveness will be analysed to overcome potential CubeSat and constituent subsystems overheat, by comparison with nominal component and shield temperature profiles in both eclipse and illuminated cases when the HPTP system is not used. Pointing budget accuracy and jitter for targeting the HPTP generator cells and required laser link budget for a planned energy transfer efficiency of up to 10 % of the source power are other challenges covered in the presentation, apart from research topics from a multidisciplinary group covering nanomaterials science, optics, photonics, and CubeSats power systems engineering. Copyright

Abstract
Given the fact that CubeSats are becoming an alternative for accessible, reduced-risk development for space applications within an emergent technological market and that the power demand of these type of nanosatellites is increasing due to the complexity of the defined missions, an alternative solution to traditional energy harvesting systems (i.e., solar panels and batteries) is proposed within the WiPTherm project. Being a high-risk category (FET-Future and Emerging Technologies) project within the H2020 European funding scheme, it aims to provide a Wireless Energy Transfer solution via a photo-thermoelectric plasmonic (HPTP) generator array device that can convert photonic energy to electrical energy via thermal gradient. In order to create it, a long-range, continuous-wave (CW) laser source targets the cells of the HPTP generator, forming, as such, the photo-thermoelectric plasmonic system. Two possible scenarios were taken into account and presented in terms of mission requirements: the laser source charging the satellite from Earth, or a laser system mounted onto a master satellite charging a CubeSat orbiting Mars/Jupiter, within the context of a deep space mission. The development of such Wireless Energy Transfer (WET) system implies an improvement of the current technology in different research fields, among them: nanomaterials, photonics, electronics, and space systems. For the success of the project, all of them shall be developed considering the different interfaces as well as the assembly principles, to be compatible with the support structure: a 3U CubeSat. From the Assembly, Integration and Verification (AIV) plan point of view, a testing philosophy involving different models is presented: an STM of the complete 3U CubeSat for the development of higher-fidelity tests when evaluating both structural and thermal HPTP baseplate capabilities; an Engineering Model, where all the subsystems will be assembled on the CubeSat platform and all its functionalities tested; development models for all spacecraft subsystems that are new developments and are not off the shelf: HPTP, the CubeSat electrical module and the laser generator. As a conclusion, this work presents the concept beyond the technology herein purposed, its applicability, and, from the systems engineering point of view, the challenges faced on the AIV plan. © 2022 International Astronautical Federation, IAF. All rights reserved.

Abstract
This work proposes a signal processing algorithm to analyse the optical signal from a Low Coherence Interferometric (LCI) system. The system uses a Mach-Zehnder (MZ) interferometer to interrogate a Fabry-Perot cavity, working as an optical sensor. This algorithm is based on the correlation and convolution operations, which allows the signal to be reconstructed based on itself, as well as, on the linearization of the signal phase, allowing the non-linearities of the actuator incorporated on the MZ interferometer to be compensated. The results show a noise reduction of 30 dB in the signal acquired. As a result, a reduction of 8.2 dB in the uncertainty of the measurement of the physical measurand is achieved. It is also demonstrated that the phase linearization made it possible to obtain a coefficient of determination (namely, R-squared) higher than 0.999.

Abstract
The aim of this work is to introduce a novel digital signal processing method for data acquired using low coherence interferometry (LCI) with a 1-kHz actuator oscillation frequency. Convolution and correlation operations are employed as efficient filters, reducing computational complexity for multilayer filtering. An envelope filtering technique is developed to address discrepancies in peak signal determination caused by nonlinear actuator motion. Additionally, a phase linearization method is presented to normalize the peak position relative to the actuator signal. Experimental results demonstrate a significant signal-to-noise ratio (SNR) improvement of 50 dB. Long-term measurements reveal an 11-dB noise reduction for frequencies below 1 mHz. This research enables LCI implementation at sampling rates of at least 1 kHz and expands its applicability to extreme measurement conditions.

Abstract
This paper presents a new type of phase-shifted Fiber Bragg Grating (FBG): the sliced-FBG (SFBG). The fabrication process involves cutting a standard FBG inside its grating region. As a result, the last grating pitch is shorter than the others. The optical output signal consists of the overlap between the FBG reflection and the reflection at the fiber-cleaved tip. This new fiber optic device has been studied as a vibration sensor, allowing for the characterization of this sensor in the frequency range of 150 Hz to 70 kHz. How the phase shift in the FBG can be controlled by changing the length of the last pitch is also shown. This device can be used as a filter and a sensing element. As a sensing element, we will demonstrate its application as a vibration sensor that can be utilized in various applications, particularly in monitoring mechanical structures.