Innovative Use of Optical Fiber

for Radio Frequencies

MicroComp Nordic AB

Topics of presentation

MicroComp Nordic AB

RF Radio over Fiber

Applications

Introduction to the ”black box”

Examples of real products

Fiber Optic Transmission

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VIRTUAL BLACK BOX

RF In RF Out

` Optical

Tx Long Distance Optical Fiber RF In RF Out

INSIDE THE VIRTUAL BLACK BOX

Optical

Rx

RF In RF Out Long Distance Optical Fiber

(Up to Several Kilometers)

JUST APPLY THE VOLTAGE AND IT IS READY TO USE

Optical

Tx Optical

Rx

Typical: +12V = 100mA

-12V

+5V

+12V

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Fiber Optic Transmission

Basically a Transmission Line.

Optical Carrier is Amplitude Modulated (AM).

Single Fiber can carry multiple color wavelengths also bi-directional.

Direct modulated Laser or Mach Zender modulated Laser

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Fiber Optic Transmission

Fiber Loss: 0.4dB/km loss over fiber (koax 6m at 500MHz M100 cable)

Wavelengths: 1270nm (most common 1550nm) to 1650nm

Fiber Type: Single Mode Fiber (SMF-28)

Allows for very high frequency transmission over long distance

Example: Loss of a 40GHz RF signal over 2km = 1dB (approx)

Very secure medium and virtually immune to EMI/RFI

Low weight on fiber cables, typical 1 to 8 deferens against RF cable

Low Price per unit length

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Radio RF over Fiber

Local Remote

Tx 1550nm

Rx 1310nm

Rx 1550nm

Tx 1310nm

1310nm 1310nm

1550nm 1550nm

RF In (Transmit)

RF Out (Transmit)

RF In (Receive)

RF Out (Receive)

Single Fiber

Different color wavelengths can be combined on one fiber, Separate for each Transmitter

Superb isolation in Mux/DeMux typical >85dB

Different color wavelengths can be combined to transmit multi-channels with superb isolation on one fiber typical >65dB

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Applications

FIBER OPTIC LINK

Remoting of ground based surveillance and tracking antennas.

Optical fiber is a secure medium

Good dynamic range

Link status can be monitored

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Applications cont Delay line for radar applications

Optical delay lines provide large time delays at wide bandwidth

For 1550 resp 1310nm 1m of fiber gives 4.897388ns delay resp 4.895720ns delay

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Applications cont

FIBER

OPTIC

TX

FIBER

OPTIC

RX

IF OUT

FIBER

OPTIC

RX

IF OUT

OPTICAL ELECTRICALELECTRICAL

Local Oscillator Remoting

Allows oscillator to be located away from hostile environments, i.e. aircrafts wings, ship masts, antenna towers etc.

Optical fiber is lightweight, provides lightning isolation and reduces EMI problems.

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Applications cont

Delay line for phased array antennas

Switched optical True Time Delays provide wideband beam forming

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Applications cont Antenna Towers

Replacing or eliminating copper coax and or waveguide

Waveguide spool 2.7m

May eliminate frequency conversion mounted on tower

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Performance

9.7ns, 122ms and 244 Microseconds Delay using a broad banded direct modulated link @ 10GHz.

10GHz Sine Wave @ 2m

“Back to back”

10GHz Sine Wave @ 25km 10GHz Sine Wave @ 50km

9.7 nanosecond delay 122 microsecond delay

244 microsecond delay

Thank You

Se us in the tent.