Contact
Quote
Support
Laser
communication
in space
Mastering the full value chain of fiber lasers key components
In space, the standard transmission solutions using RF technology are limited to a data-rate of hundreds Mbit/s, at best. The need for high-speed communications, reaching the range of hundreds of Gbit/s creates an opportunity that can be addressed by photonics-based solutions. The added advantages of photonics solutions in space are also reliability, even under harsh environment, scalability (modulations schemes, numbers of optical channels, …) as well as smaller payload that reduces satellite consumption.
Laser Communication Terminal
Free-space optical communication has been implemented between satellites since the 90’s using directly modulated high power laser diodes at 820 nm to 850 nm. The emergence of fiber lasers in the near infrared and the availability of LiNbO3 modulators in this band have made possible space optical links (LEO to GEO to Ground Stations) using more efficient modulation formats and offering improved data rates and BER.
The laser terminal is designed to be installed aboard a geostationary satellite (GEO). The point of this GEO relay is to constantly transmit the data collected from the emitter, located on low-orbiting satellites (LEO – Low Earth Orbit). Orbiting at a low altitude, these LEO satellites must wait to pass over a station located on the ground to transfer the data collected.
In some cases, they are required to wait several hours before being able to transfer data, which can be detrimental – hence the idea to install data relays in geostationary orbit. Once the LEO satellite is visible to the relay satellite, a high-speed optic communication is established for the transmission of data packets.
Then, at nearly 36 000 km from Earth, the relay satellites, permanently positioned above the relay antennas of an optical ground station (OGS), can proceed with the transfer of the collected data, aided by radiofrequency waves.
From components to transceivers and receivers modules
Exail has been involved in several EU projects to prove the ability of its components to address the need of space communications. One of them was the Feeder Optical Links for Constellation (FOLC) project, started in 2017. Funded by ESA, supported by the French CNES, and with Airbus Defence and Space as a partner, it aimed at building the telecommunication devices for future satellites constellations. It includes the links between satellites in low Earth orbit (LEO <> LEO), the links between LEO satellites and a GEO satellite, and the links between LEO/GEO satellites and Earth. The complete telecommunications network has the goal to reach data transmission rates higher than 1 Tb/s.
The ready-to-flight optical transceiver developed within the FOLC project was delivered to Airbus Defense & Space in 2023, and launched onboard the satellite and Optical Ground Station of the TELEO demonstrator. The optical transceiver is made of a compact optical channel emitter that integrates Exail’s LiNbO3 modulator and radio frequency amplifier. Several optical channel emitters can be multiplexed and the reception channel integrates the proprietary low-noise optical fiber.
Our range of products for the space industry
Example of Flight Model Modulator
LiNbO3 electro-optical modulator components for high-speed space communication
In the last decade, Exail has already been involved in more than 20 projects, for which the company has supplied more than 200 modulators for different flying users worldwide, either for big players or space agencies, and for LEO or GEO satellites, but also onboard the ISS. 850 nm, 1064 nm and 1550 nm amplitude modulator and phase modulator were supplied, as Breadboard, Engineering, Qualification and Flight models.
The main modulator specifications and environmental operating conditions are given below in the table. These values refer to the FM operating conditions, knowing that more stringent and higher values on the test conditions are applied to the Qualified Models during the qualification phases.
Performance
Operating wavelength | 800 nm | 1060 nm | 1550 nm |
|---|---|---|---|
Modulator types | Phase, amplitude, IQ | Phase, amplitude, IQ | Phase, amplitude, IQ |
Modulator bandwidth | Low frequencies up to 40 GHz | Low frequencies up to 40 GHz | Low frequencies up to 40 GHz |
Insertion loss/Phase modulators | 3.5 dB | 3 dB | 2.5 dB |
Insertion loss/amplitude modulators | 4.5 dB | 3.5 dB | 3.5 dB |
Amplitude modulator extinction ratio (ER) | >20 dB | >30 dB | >30 dB |
Polarisation Extinction Ratio (PER) | >20 dB | >20 dB | >20 dB |
Optical input signal | Up to 25 mW | Up to 300 mW | Up to 200 mW |
Environment
Operating temperature (full performances) | 0 °C to +70 °C | 0 °C to +70 °C | 0 °C to +70 °C |
|---|---|---|---|
Non operating temperature | -40 °C to 85 °C | -40 °C to 85 °C | -40 °C to 85 °C |
Vibration | 2.5 min/axis, 33.6 gRMS | 2.5 min/axis, 33.6 gRMS | 2.5 min/axis, 33.6 gRMS |
Shock (some type of packages sucessfully tested up to 2,000 g) | Level up to 1,000 g, 0.2 – 10 kHz | Level up to 1,000 g, 0.2 – 10 kHz | Level up to 1,000 g, 0.2 – 10 kHz |
Radiation | Gamma ray 352 Krad (Si) / Proton 1011 p/cm2 (60 Mev) | Gamma ray 352 Krad (Si) / Proton 1011 p/cm2 (60 Mev) | Gamma ray 352 Krad (Si) / Proton 1011 p/cm2 (60 Mev) |
Lifetime | Up to 15 years GEO | Up to 15 years GEO | Up to 15 years GEO |
Missions compatibility | GEO, EOR, MEO and LEO | GEO, EOR, MEO and LEO | GEO, EOR, MEO and LEO |
Mechanical Interface
Mass | 120 g | 120 g | 120 g |
|---|---|---|---|
Package size | 110 x 15 x 9.7 mm3 or customized design | 110 x 15 x 9.7 mm3 or customized design | 110 x 15 x 9.7 mm3 or customized design |
Fibers jacket | Ø1 mm PEEK tube | Ø1 mm PEEK tube | Ø1 mm PEEK tube |
Leveraging its extensive experience, Exail is now offering the space-grade LiNbO3 optical phase modulator within new standardized Commercial-off-the-shelf (COTS) product lines, under three different versions according to customer’s requirements in terms of qualification: Engineering Model, New Space Flight Model and Flight Model.
The product having already been submitted to a thorough qualification and having been embedded into satellites (TRL9), the COTS product line answers the current needs of the space industry, with the rise of New Space. They are cost-effective solutions with different levels of customizations possible according to each customer's requirements.
3 modulators for space
Low Noise Optical Amplifier
This Low Noise Optical Amplifier provides excellent optical performances specifically at very low input power either for single or multi-channel configuration for space applications with very low power consumption and light weight. Optical components selected in this amplifier are space qualified.
Space Grade Fibers
The need for new earth and universe observation satellites is becoming more and more important, with new challenges in this very hostile space environment where components are exposed to ionizing radiation. Longer missions, very distant satellites for deep space sensing, and new telecommunication demands necessitate stronger photonic devices and components to withstand ionizing radiation.
Exail has produced more than 20 flying navigation systems that are equipped with our fibers and components. We have developed a strong experience in the qualification of such devices in collaboration with end users.
Exail’s specialty fiber family includes high performance Polarization Maintaining Fibers that are specifically designed for integration into Fiber Optic Gyroscopes on or above the earth.
Integrated micro-optics assemblies for space applications
Exail offers fibered optical benches integrating within a compact and ultra-stable package a wide variety of optical functions such as power splitters, combiners, optical switches, frequency shifters… As a result, usual free-space optics set-ups are transformed into turn-key ultra-stable integrated subsystems. These modules feature remarkable stability and are able to operate at high power.
The exceptional alignment stability over an extended operating temperature range and the small footprint of Exail micro-optic modules were the triggering arguments to consider this enabling technology towards possible future space missions. To this date, Exail is working hand by hand with several space agencies to advance the TRL of this technology. The first tests of an under-space-like environment are extremely promising and the current TRL is 6. In particular, an excellent robustness with respect to shocks and vibrations have been witnessed.
Exail’s track record in Space
Exail has a continuous presence in space across its Astrix products range of 3-axis fiber-optic gyroscopes (FOG). A privileged partnership with Airbus Defence & Space has allowed the emergence of a new class of fiber-optic gyroscope instruments. The Astrix Series already equips more than 25 satellites on all types of orbits (LEO, MEO, GEO, Lagrangian point…) while counting more than 6 million hours in operation without incident. Exail has also developed a FOG-based Inertial Navigation System dedicated to launchers, used in Ariane 5 since 2020 and in Ariane 6. Our experience with Exail FOGs being deployed in space opened the way to supply space grade components, such as passive and doped fibers, as well as the electro optical phase and amplitude modulators.
The electro-optic Lithium Niobate (LiNbO3) have long standing proven record of use in many applications (for instance long-haul and radio over fiber communications) as well as Distributed Temperature Sensors (DTS) (where the modulators operate in harsh environmental conditions), and have been comprehensively and successfully qualified (e.g. Telcordia). The LiNbO3 modulators offer indeed a unique combination of performance that makes them prime candidates, not only to satisfy the optical system specifications, but also to meet the tough requirements of space operation. Today, many embarked space photonic systems use light modulators as a key component to achieve intensity or phase modulation of various light sources at different operating wavelengths.
Telecommunication and inter-satellites telecommunications are among these space applications where Exail is today well involved.
In March 2021, for ICSO virtual conference, Dr Hervé Gouraud, Exail Sales Manager, introduced the TRL9 space grade products portfolio: key fiber and electro-optical modulator components as well as sub-modules for high-speed space communication. These ten minutes talk describes briefly the already existing solution for space communication, as well as new modulation and receiver solution under development.
Trusted by
Publications
Laser ranging interferometry with sub-nm noise over 200 km between the GRACE Follow-On satellites
K. Abich et al. (Deutsches Zentrum fur Luft); Alexander Abramovici et al. (Jet Propulsion Lab. California Inst. of Technology), …
Physical Review Letters 123, 031101 – 2019
Laser ranging interferometry with sub-nm noise over 200 km between the GRACE Follow-On satellites
K. Abich et al. (Deutsches Zentrum fur Luft); Alexander Abramovici et al. (Jet Propulsion Lab. California Inst. of Technology), …
Assessment of the performance of DPSK and OOK modulations at 25 Gb/s for satellite-based optical communications
Thomas Anfray et al. (Airbus Defence and Space); Alexandre Mottet et al. (iXblue Photonics); Thomas Schmitt et al. (CILAS)
ICSOS – 2019
Assessment of the performance of DPSK and OOK modulations at 25 Gb/s for satellite-based optical communications
Thomas Anfray et al. (Airbus Defence and Space); Alexandre Mottet et al. (iXblue Photonics); Thomas Schmitt et al. (CILAS)
International Conference on Space Optics
A. Mottet et al. (iXblue Photonics Besançon); D. Veyrié, O. Gilard (CNES)
ICSO – 2018
International Conference on Space Optics
A. Mottet et al. (iXblue Photonics Besançon); D. Veyrié, O. Gilard (CNES)
Recent progress on the reliability and the hermeticity of space grade LiNbo3 modulators
H. Brahimi et al. (CNES); A. Mottet et al. (iXblue Photonics Besançon)
ISROS – 2016
Recent progress on the reliability and the hermeticity of space grade LiNbo3 modulators
H. Brahimi et al. (CNES); A. Mottet et al. (iXblue Photonics Besançon)
Lunar Optical Communications Link (LOCL) Demonstration between NASA’s LADEE Spacecraft and ESA’s Optical Ground Station
Igor Zayer et al. (European Space Agency, ESA-ESOC); Zoran Sodnik et al. (European Space Agency, ESA-ESTEC); Johan Rothman (CEA-Leti/LIR)
SpaceOps Conference – 2014
Lunar Optical Communications Link (LOCL) Demonstration between NASA’s LADEE Spacecraft and ESA’s Optical Ground Station
Igor Zayer et al. (European Space Agency, ESA-ESOC); Zoran Sodnik et al. (European Space Agency, ESA-ESTEC); Johan Rothman (CEA-Leti/LIR)
Downloads
381,42 Ko
(pdf)
1,78 Mo
(pdf)
3,41 Mo
(pdf)
4,55 Mo
(pdf)
4,60 Mo
(pdf)
