Photonics OBFN in Selex SI

Photonic Technologies for Spaceborn
Beam Forming Networks
Optical Beam Forming Networks
in Selex SI
Luigi Pierno
ESA- ESTEC 21° November 2008
Outline
Architectures for Optical BFN and routing for M-AESA
COTS and critical optical components for OBFN
R&D activities in Selex SI
Conclusion
ESA ESTEC
21° November 2008
OBFN advantages in antenna
Advantages of OBFN in Terrestrial, Naval,
Airborne and Spaceborn M-AESA antennas
•Low weight , size , EMC typical of fiber optics
•True Time Delay (squint free) approach
•Wide bandwidth (>30 GHz ) of optical analogue or digital
transmission (for Multi Role Antenna)
•Smart Antenna (dynamic routing among functions, low loss remoting
of components)
•Optical Beamforming architecture applies to analogue and digital
radar front end (Digital MF Radar)
ESA ESTEC
21° November 2008
Architectures for OBFN:
Wavelength Domain Multiplexing
AOTF
a( a)
PD
Mod
2
Sub
Array
(a)
1
PD
AWG
AOTF
b( b)
PD
Mod
MWL
1
Sub
Array
(b)
Mod
2,…. N
AWG
1
2,…. N
1
2,….
N
1
2
AOTF
M( M)
PD
Mod
Sub
Array
(M)
N
Wavelength
Fiber Optic Delay
Based on ElectroOptical or AcoustoOptical Tunable Filters
ESA ESTEC
21° November 2008
Architectures for OBFN:
Time Domain Multiplexing for COSMO like antenna
OA
RF Input (1)
Opt.
Source
1x10
RF Input (2)
Opt.
Source
1x10
RF Input (3)
RF Input (4)
Opt.
Source
1x10
Opt.
Source
1x10
Splitting Network
Switch Matrix 4x 1
TTD
Switch Matrix 4x 1
TTD
Switch Matrix 4x 1
TTD
Switch Matrix 4x 1
TTD
Switch Matrix 4x 1
TTD
System on a chip
40:10
TDM Architecture for multifunctional COSMO like
antenna (Transmit mode)
Ref: 28th Antenna Workshop on Space Antenna Systems and Technologies
DIGITAL OPTICAL SWITCHES IN TTD FOR SPACE ACTIVE ANTENNAS
ESA ESTEC Mauro Varasi, Luigi Pierno, Massimiliano Dispenza, Roberta Buttiglione, Fulvia Verzegnassi
21° November 2008
OBFN advantages in COSMO like antenna
Parameter
Proposed TTD
TTD modules
40
TTD required
15
N° of bits
5 bits
(0,47 = 1 bit)
Rec. speed
< 10 nsec
Optical Losses
18dB
Volume
12 x 12 x 2 cm3
Power consumtion
1mW
HighSpeed of reconfigurability of Optical
Beam Forming Network due to the
Electrooptical drive of the devices
z
H sin
<10g
Cross Talk Extinction
30dB
z
c
2N
High degree of integration
for satellite payload
EFE
DIVIDER
Mass
Step
Suitalble
T/R MODULES
efe
Optical Extinction
Negligible
Optical Crosstalk (single
TTD)
60 dB
1:4 div.
1:4 div.
Tile Divider
1:8 div.
1:8 div.
Panel Divider
Panel Divider
1:2 div.
1:2 div.
1:3 div.
1:2 div.
1:2 div.
1:3 div.
ANTENNA DIVIDER
ESA ESTEC
21° November 2008
Tile Divider
TDL
DISTRIBUTION NETWORK
ANTENNA DIVIDER
CALIBRATION NETWORK
Architectures for OBFN: EWOCS(*) project
Demonstrator Architecture for Receive operation
1
Wing-Mounted
Sub-Module
2
8
9
16
Antenna array
Apodising Filters
Wideband LNA
Optical
modulator
16 fibre PM ribbon cable
(10 metre)
Fuselage
Sub-Module
DOS Fine Time
Delay Trimming
modules
8 fibre SM ribbon cable
(10 metre)
OBFN1
OBFN2
RF
Combiner
Lasers
optical
source
ESA ESTEC
21° November 2008
Beam 1
Beam 2
Beam 3
Beam 4
Beam
outputs
(*) EDA project in partnership with BAE Systems
Photonics components for OBFN: EWOCS
Fuselage Module & Wing-Mounted Module
Based on Selex SI Modulators
ESA ESTEC
21° November 2008
Performance of OBFN: EWOCS project
-30dBm
Maximum Signal
45dB Dynamic
Range
-75dBm Minimum
Detectable RF Signal
6dB Minimum
Signal-to-Noise
Ratio
20dB Minimum
Signal-to-third order
Intermodulation
Product
-50dBm
Maximum Third Order
Intermodulation Product
6-18GHz frequency coverage
4GHz instantaneous bandwidth
16 antenna elements (in a linear array)
Angular coverage/TTD array: ±45o azimuth, ±45o elevation
Adjacent beam crossover: 3 - 8 dB below beam peak
Next adjacent beam crossover = 20 dB below beam peak and greater than the
highest sidelobe
ESA ESTEC
21° November 2008
Maximum
noise level
Optical Routing and Beamforming Architecture
MORSE (*) Project Objectives
Optical MIR
BFN
Optical MIR
EW Rx
BFN
Optical MIR
ESA ESTEC
21° November 2008
Radar Rx
Comms Rx
BFN
Optical MIR
(*) EDA project in partnership
with BAE Systems, SAAB
Optical Routing Switch
Multifunctional Antenna (S&T, Comms, Synthetic Aperture Radar for
Imaging, ….)
Dynamical Reconfigurability of the aperture
Wide bandwidth
Control
Linearity - Dynamic range
Scalability
Reliability
BFN
Comms Rx
Optical Routing and Beamforming Architecture
Morse Key features
Antenna architecture must enable dynamical reassign of portions of antenna
aperture while ensuring simultaneous operation of e-m functions
COM 1
Radar
S&T
Hi - Resol.
COM 4
COM 3
ESM
ESM
ESM
1
2
3
Example of 3 possible antenna apertures
ESA ESTEC
21° November 2008
COM 2
Optical Routing and Beamforming Architecture
Morse Key features
Alternative approaches to be employed for multiple functions to be implemented and
dynamically reassigned will be evaluated:
Space Multiplexing by Integrated Optical Switching Matrixes
Wavelength Division Multiplexing by tunable lasers/ filters, multiwavelength
lasers …
Control
Splitter
EDFA
Laser
Laser
Laser
ë3
2
ëë
1
WDM
Detector
Sub-array i
Modulator
Detector
WDM
TTD
Switch
ESA ESTEC
21° November 2008
Switch
S&T
Comms
SAR
Architectures for OBFN: Key approaches
Functionalities
Technical approach
Changing the physical path
True Time Delay Beam
Steering
M-AESA: Routing
among Functions
(also digital front end)
ESA ESTEC
21° November 2008
Critical Devices
Optical switches
Changing wavelenght in
dispersive media
Optical Tuneable filters
Multiwavelenght lasers
Space Domain Routing
Optical switches
Wavelenght Domain Routing
Tuneable filters
Multiple lasers + passive
filters
Photonic components for OBFN
Switchable True Time Delay Unit
Optical
Fibers
Integrated Optics TTD
high speed (10ns) for beam steering
Atten.
Elementary cell of the system
O p tic a l S w it c h e s
5 cm
To subarray
Fiber delays
6 cm
2 cm
Integrated delay
elements
0,7 cm
From RFin
DOS switch
ESA ESTEC
21° November 2008
0,2 cm
Photonics components for OBFN
Digital Optical Switches Reflection TTD
Lower Insertion Loss
More Stable operation
DOS integrated with time delay waveguide chip
More compact delay module
Minimum delay increment for 2 Bit Fine TTD: 0.1ps
Dielectric
buffer layer
Driving
Electrode
Adiabatic Y
Junction
EO active
area
True Time Delay for fixed beams : Fiber in Boards (BAE)
ESA ESTEC
21° November 2008
Components for OBFN and routing
Array of 1X4 MagnetoOptical Switches
for routing matrix in Space Multiplexing
(Speed 1 us, Optical Losses 1 dB)
1X8 DOS matrix from Selex SI
(Speed 10ns, Optical Losses 7 dB)
WDM mux for WDM based OBFN
(Optical Losses 1 dB)
ESA ESTEC
21° November 2008
R&D activities in Selex SI
R&D Projects:
PNRM 156: Optical Processing of Microwave Signals (2004)
EWOCS: Electronic Warfare Optically Controlled Subsystem (2006)
MORSE: Multifunction Optical Reconfigurable Scalable Equipment (Running
Project)
Main objectives
True Time Delay Optical Beam Forming Networks for Phased Array Radars
Optical Beam Forming and Optical Routing in Multifunction/Multirole AESA
Future Perspectives
Implementation in the routing network of the distribution of LO for RF signal
downconversion in antenna front end
Digital MF radar
ESA ESTEC
21° November 2008
Conclusion
Optical Beam Forming Networks have a big potential in the application to
M-AESA antennas in satellite payloads due to low weight , size EMC
compliance and wide BW
Prototypes of OBFN are based on COTS and on some integrated optics
components for improved dynamic range, speed of Beam steering and size,
weight
Research funded by Ministry of Defence in this field is going on in the
last 10 years for Terrestrial, Naval, Airborne, applications
The achieved solutions are reusable for the Satellite payload antenna and
also for future Digital front end Radars
Selex SI is still involved in activity with running project that addresses
OBFN and Optical Routing
ESA ESTEC
21° November 2008
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