Overview of radiation induced point defects in silica-based optical fibers

In this topical review, the recent progress on radiation-hardened fiber-based technologies is detailed, focusing on examples for space applications. In the first part of the review, we introduce the operational principles of the various fiber-based technologies considered for use in radiation environments: passive optical fibers for data links, diagnostics, active optical fibers for amplifiers and laser sources as well as the different classes of point and distributed fiber sensors: gyroscopes, Bragg gratings, Rayleigh, Raman or Brillouin-based distributed sensors. Second, we describe the state of the art regarding our knowledge of radiation effects on the performance of these devices, from the microscopic effects observed in the amorphous silica glass used to design fiber cores and cladding, to the macroscopic response of fiber-based devices and systems. Third, we present the recent advances regarding the hardening (improvement of the radiation tolerance) of these technologies acting on the material, device or system levels. From the review, the potential of fiber-based technologies for operation in radiation environments is demonstrated and the future challenges to be overcome in the coming years are presented.

https://iopscience.iop.org/article/10.1088/2040-8986/aad271/pdf

Recent advances in radiation-hardened fiber-based technologies for space applications

A comparison of the losses induced in step index multimode, graded index multimode and single mode fibers by pulsed radiation exposure has been made among 12 laboratories over a period of 5 years. The recoveries of the incremental attenuations from 10{sup -9} to 10{sup 1} s are reported. Although a standard set of measurement parameters was attempted, differences between the laboratories are evident; possible origins for these are discussed. 18 refs., 18 figs., 7 tabs.

Interlaboratory comparison of radiation-induced attenuation in optical fibers. Part 3: Transient exposures

Over the last years, fiber optic sensors have been increasingly applied for applications in environments with a high level of radiation as an alternative to electrical sensors, due to their: high immunity, high multiplexing and long-distance monitoring capability. In order to assess the feasibility of their use, investigations on optical materials and fiber optic sensors have been focusing on their response depending on radiation type, absorbed dose, dose rate, temperature and so on. In this context, this paper presents a comprehensive review of the results achieved over the last twenty years concerning the irradiation of in-fiber Long Period Gratings (LPGs). The topic is approached from the point of view of the optical engineers engaged in the design, development and testing of these devices, by focusing the attention on the fiber type, grating fabrication technique and properties, irradiation parameters and performed analysis. The aim is to provide a detailed review concerning the state of the art and to outline the future research trends.

Radiation Effects on Long Period Fiber Gratings: A Review.

More and more satellites are populating the sky nowadays in the Low Earth orbits (LEO). Most of the targeted applications are related to broadband and narrowband communications, Earth observation, synthetic aperture radar, and internet-of-Things (IoT) connectivity. In addition to these targeted applications, there is yet-to-be-harnessed potential for LEO and positioning, navigation, and timing (PNT) systems, or what is nowadays referred to as LEO-PNT. No commercial LEO-PNT solutions currently exist and there is no unified research on LEO-PNT concepts. Our survey aims to fill the gaps in knowledge regarding what a LEO-PNT system entails, its technical design steps and challenges, what physical layer parameters are viable solutions, what tools can be used for a LEO-PNT design (e.g., optimisation steps, hardware and software simulators, etc.), the existing models of wireless channels for satellite-to-ground and ground-to-satellite propagation, and the commercial prospects of a future LEO-PNT system. A comprehensive and multidisciplinary survey is provided by a team of authors with complementary expertise in wireless communications, signal processing, navigation and tracking, physics, machine learning, Earth observation, remote sensing, digital economy, and business models.

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Position, Navigation, and Timing (PNT) Through Low Earth Orbit (LEO) Satellites: A Survey on Current Status, Challenges, and Opportunities

Airbus Defence and Space developed with its partners iXBlue and CILAS an engineering breadboard (EBB) model of optical communication chain able to manage nonreturn to zero (NRZ) on-off-keying (OOK) and differential phase shift keying (DPSK) modulations at 10 Gb/s and 25 Gb/s. The EBB includes a digital processing unit (DPU), an optical transceiver (Tx/Rx) and a 5 W-optical booster. It uses wavelength division multiplexing (WDM) technology to increase the total data rate. This is a first step towards the development of an engineering model (EM) that will be developed in 20202021. This paper reports a part of measurements performed on the EBB, particularly the performance of NRZ-OOK and NRZ-DPSK modulations for 3 × 25 Gb/s channels. Measurements reveal that non-linear effects start to appear inside the 5 W-booster. Because of its constant envelope during bit time, NRZ-DPSK signal is less sensitive to power modulation-related non-linear effects than NRZ-OOK The average sensitivity of the NRZ-OOK and NRZ-DPSK links at 25 Gb/s are respectively −36.8 dBm and −40.2 dBm for bit error ratio (BER) at 10−3.

Assessment of the Performance of DPSK and OOK Modulations at 25 Gb/s for Satellite-Based Optical Communications

A radiation resistant optical fiber used in a broadband source is presented. Both ASE source and Fiber Optical Gyroscope (FOG) commonly used in space missions, suffer from failures and degradation after long term exposure to radiative environment. The aim of this article is to present the results of our investigation on fiber and ASE source architecture in order to design a Radiation Resistant Erbium Doped Fiber that offers long term stability of the gyroscope performances.

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10564/105642V/Radiation-resistant-erbium-doped-fiber-for-ASE-source-and-fiber/10.1117/12.2309167.pdf

Jean-Jacques Bonnefois

Papers

Recent advances in radiation-hardened fiber-based technologies for space applications

Assessment of the Performance of DPSK and OOK Modulations at 25 Gb/s for Satellite-Based Optical Communications

Radiation resistant erbium doped fiber for ASE source and fiber gyroscope application

A new compact fiber optic gyroscope for a better line of sight management