Laser communication in space


Photonics systems, sub-systems and components are found in an increasing number of applications of many high technology industry segments.
This remark applies particularly to space-embarked systems, which rely on the versatility and reliability of photonic systems to realize many of the critical functions needed to insure their safe and durable operation.
iXblue has a continuous presence in space across
 its Astrix products range of 3-axis fiber-optic gyroscopes (FOG). A privileged partnership between iXblue and 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 2 million hours in operation without incident. iXblue 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 iXblue 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.
The telecommunication and inter-satellites telecommunications are ones of these space applications where iXblue Photonics is today well involved. 

 

Laser Communication Terminal


The spatial activities of telecommunications for Earth observation programs high-definition images and videos currently in service necessitate the improvement of the retransmission back to Earth for high speed communications, as the classic solutions are no longer able to handle the increases in data volumes.
The solution to resolve this situation is based on the deployment of optic transmissions in space.
Optics and the modulation of light are therefore employed to assist with radiofrequency links, used heretofore in satellite transmissions.

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. 

 

space


Fig. 1: iXblue products in space and inter-satellite communication 

 

After 10 years of experience, iXblue Photonics was involved in more than 20 projects, for which we supply more than 200 modulators for different flying users worldwide, either for big players or space agencies, and for LEO or GEO satellites, or the ISS as well. We supply 850 nm, 1064 nm and 1550 nm amplitude modulator and phase modulator as Breadboard, Engineering, Qualification and Flight models (please refer to the Application Note Space grade modulators definitions).

SPACE MODULATOR

Fig. 2: Example of Flight Model Modulator

 

The main modulators specifications and environmental operating conditions are given here below in the table. These values refer to the FM operating conditions, knowing that more stringent and higher values on the tests conditions are applied to the Qualified Models during the qualification phases. 
 

PERFORMANCE    
Operating wavelength                                                           800 nm                  1060nm                  1550 nm
Modulator types                                                                                           Phase, Amplitude, IQ
Modulator bandwidth                                                                      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    
Non operating temperature                                                                       -40 °C to +85 °C    
Vibration                                                                                                     2,5 min/axis, 33,6 gRMS          
Shock*                                                                                                  Level up to 1 000 g, 0,2 - 10 kHz  
Radiation                                                                                                   Gamma ray 352 Krad (Si)        
                                                                                                                    Proton 1011 p/cm² (60 Mev)
Lifetime                                                                                                   Up to 15 years GEO
Missions compatibility                                                                       GEO. EOR. MEO and LEO 

*Some type of packages succesfully tested up to 2 000 g 
 

MECHANICAL INTERFACE
Mass                                                                                                                          120 g
Package size                                                                          110 x 15 x 9.7 mm3 or customised design 
Fibers jacket                                                                                           Ø 1 mm PEEK tube    

 Fig. 3: Operating conditions compliance table 

 

Space grade solutions: from components to transceivers and receivers modules


Last March 2021, for ICSO virtual conference, Dr Hervé Gouraud, Sales Manager for iXblue Photonics, 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.

 

In September 2019 in Noordwijk, in collaboration with ESA, the European Photonics Industry Consortium (EPIC) has organized a meeting on New Space. Key actors and manufacturers involved in the Space Activity were invited. Dr Jérôme Hauden, R&D Manager for iXblue Photonics in Besançon, shared iXblue products and background in space, and he introduced iXblue Photonics strategy and roadmap related to the photonic components being deployed for high-speed space communication. 

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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

The Laser Ranging Interferometer (LRI) instrument on the GRACE Follow-On mission was turned on in June 2018, four weeks after the launch. After a brief checkout, the instrument acquired lock immediately and measured the biased range of about 220 km between the two spacecraft over many days without interruption...

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

Airbus Defence and Space developed with its partners iXBlue and CILAS an engineering breadboard (EBB) model of optical communication chain able to manage non return 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.

International Conference on Space Optics

A. Mottet et al. (iXblue Photonics Besançon); D. Veyrié, O. Gilard (CNES)

ICSO
2018

This paper presents the technical solutions implemented with the support of the French Space Agency (CNES) to design and manufacture hermetic Lithium Niobate (LiNbO3: LN) modulators, in the framework of a Research & Technology (R&T) project [1]....

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

In collaboration with the French Space Agency (CNES), a reliability study of lithium niobate (LiNbO3) modulators manufactured by iXBlue PSD, SA (former Photline Technologies), was previously reported. This study included a complete evaluation program and did validate lithium niobate modulators technologies for space applications ([1], [2]).

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

NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft has embarked the MIT-LL's Lunar LasercomSpace Terminal (LLST) as a secondary payload andpart of the Lunar Laser Communications Demonstration (LLCD) experiment...

Application Notes

jeu 27/05/2021 - 14:00

Space grade Modulators definitions

jeu 27/05/2021 - 14:05

iXblue Photonics Space Products - Background - Strategy