Presentacion YAO

8/21/2019 Presentacion YAO

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Microwave Photonics

Jianping Yao

Microwave Photonics Research Laboratory

School of Information Technology and EngineeringUniversity of Ottawa

Outline

Introduction to Microwave Photonics

Bragg gratings for Microwave Photonics applications

Optically controlled phased array antennas

All-optical microwave signal processing

Photonic generation of microwave, mm-wave and THz

Radio over fiber and UWB (Ultra-WideBand) over fiber

Photonics ADC

Conclusions

OThH1.pdf

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978-1-55752-855-1/08/$25.00 2008 IEEE


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Microwave photonics is an interdisciplinary area that studies the

interaction between microwave and optical signals for microwaveand millimeter-wave signal generation, distribution, controland

processingby means of photonics.

The broadband and low loss capability of photonics (optical fiber)

has led to great interest in their use to generate, distribute, control

and process microwave and millimeter-wave signals. Application

areas include


All-optical processing of microwave signals (filtering, mixing, etc)

Low phase-noise microwave, mm-wave and THz generation Radio over fiber and UWB over fiber

Photonic ADC


Outline


Bragg gratings for Microwave Photonics applications




Radio over fiber and UWB (ultra-wideband) over fiber

Photonics ADC

Conclusions

OThH1.pdf

OFC/NFOEC


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Fiber Bragg gratings for Microwave-Photonics

Applications

oeffn =2

0

Fiber Bragg gratings forMicrowave-Photonics Applications

1

5

4

3

2

TLS PC EOM

RF

PD

12

3

TLS PC EOM

RF

PD

51

1 ~

5

0

Uniform Fiber ragg Grating

2 eff on =

Chirped fiber grating based delay line

Uniform fiber grating based delay line

mi

n ma

x

mi

n ma

x

Chirped Fiber ragg Grating

mi2 =effn max2 =effn

OThH1.pdf

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Outline

Introduction to Microwave Photonics Bragg gratings for Microwave Photonics applications





Photonics ADC

Conclusions

Phased-Array Antenna using True Time Delay (TTD)

Phased Array Antenna System based on phase shifters

Phased Array Antenna System based on TTD

2

3

4

2

3

4

0

30

6090

120

150

180

-30

-60-90

-120

-

150

1800

30

6090

120

150

-30

-60-90

-120

-150

Example of

beam squintwith electrical

phase shift

technique

Example of beam

squint-free pattern with

true-time delay

OThH1.pdf

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Optically Controlled Phased Array Beamforming

Difficulty: to write the FBGs with very small spacing, especially for the first delay line.

4

3

1

TLS - tunable laser source, PC - polarization controller, EOM -electrooptic

modulator, FBG - fiber Bragg grating, PD - photodetector

H. Zmuda, R. A. Soref, P. Payson, S. Johns, and E. N. Toughlian, Photonic beamformer for phased array

antennas using a fiber grating prism, IEEE Photon. Technol. Lett., vol. 9, pp. 241243, Feb. 1997.

Wideband true-time-delay unit for phased arrayantenna using discrete-chirped fiber Bragg grating prism

The beam-pointing direction is determined by the grating

spacing difference and is independent of the microwave

frequency.

Y. Liu, J. P. Yao and J. Yang, "Wideband true-time-delay unit for phased array antenna using discrete-chirped

fiber Bragg grating prism," Optics Communications, vol. 207, pp. 177-187, June 2002.

OThH1.pdf

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Y. Liu and J. P. Yao "Wideband true time-delay beamformer employing a tunable chirped fiber grating prism," OSA Applied Optics,

vol. 42, no. 13, pp. 2273-2277, May 2003.

Wideband true time-delay beamformer

employing a tunable chirped fiber grating prism

y = -13.714x + 21297

R2= 0.999

y = -18.801x + 29198

R2= 0.9989

y = -24.052x + 37347

R2= 0.9956

y = -29.417x + 45682

R2= 0.9961

-150

-100

-50

0

50

100

150

1548 1550 1552 1554 1556 1558

Wavele ngth (nm)

Timedelay(ps)

Experimental time delay measurements of the tunable fiber

grating delay lines at the microwave frequency of 10 GHz.Experimental setup of the tunable chirped fiber grating prism

beamformer for a 4-element wideband phased array antenna system.

Y. Liu, J. P. Yao, X. Dong and J. Yang, "Tunable chirpingof a fibre Bragg grating without center wavelength shift

using simply supported beam," Optical Engineering vol.

41, pp. 740 - 741, April 2002.

The difficulty in implementing this system is the fabrication of the 4chirped gratings. The chirped gratings were fabricated using our

grating tuning techniques: chirped gratings can be obtained from

uniform gratings.

J. P. Yao, J. Yang and Y. Liu, "Continuous true-time-delay beamforming employing a multiwavelength tunable fiber laser

source," IEEE Photonics Technology Letters, vol. 14, no.5, pp. 687 -689, May 2002.

Continuous true-time-delay beamformingemploying a multiwavelength tunable fiber laser source

Tunable TTD beamformer configuration

Multiwavelength spacing tuning

Multiwavelength spacing tunable laser

Time delays versus increased

wavelength spacing.

OThH1.pdf

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Y. Liu, J. Yang and J. P. Yao, "Continuous true-time-delay beamforming for phased array antenna using a tunable chirped fiber

grating delay line," IEEE Photonics Technology Letters, vol. 14, no. 8, pp. 1172 -1174, August 2002.

Continuous true-time-delay beamforming for phased array

antenna using a tunable chirped fiber grating delay line

Time delay response when the

chirped FBG is tunedTunable TTD beamformer configuration

Applications

1. Radar 2. Broadband wireless access networks

BS

Radio over fiber system

OThH1.pdf

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Outline

Introduction to Microwave Photonics Bragg gratings for Microwave Photonics applications





Photonics ADC

Conclusions

All-Optical Microwave Signal Processing

Digital signal processing - speed is limited.

Advantages of all-optical microwave filters:

Wideband

Low loss

Light weight

Immune to electromagnetic interference (EMI)

Finite Impulse Response (FIR) Filter Optical Delay Line FIR Filter

][][][][][1

0

nxnhknxkhnyN

k

==

=

8 GHz 16 GHz2 GHz

-10 dB

-50 dB

-40 dB

-30 dB

-20 dB

Frequency response of an all-optical

microwave filter

OThH1.pdf

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Optical Delay Line Microwave Filter

Limitation of an Optical Delay Line FIR Filter

Incoherent detection All-positive coefficients Low-pass filters only

Fr

equency

Response

(dB)

Fr

equency

Response

(dB)

4-tap Lowpass Filter with

All-positive Coefficients [1 1 1 1]4-tap Bandpass Filter with

Negative Coefficients [1 -1 1 -1]


OThH1.pdf

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BroadbandOptical

Source

Modulator

RF

T

R1 R2 R3 R4 Rn

1 2 3 4 n

OutputPD

Optical

Source

Modulator

RF Input RF Output

b1

b0

T-

1x2Coupler

Photonic microwave filter using a FBG-based tapped delay line.

1.S. Sales, J. Capmany, J. Marti, and D. Pastor, Experimental demonstration of fiber-optic delay line filters with

negative coefficients, Electron. Lett., vol. 31, pp. 1095-1096, Jul. 1995.

Photonic microwave filter with negative coefficients using differential detection


J. Capmany, D. Pastor, A. Martinez, B. Ortega, and S. Sales,

Microwave photonics filter with negative coefficients based on

phase inversion in an electro-optic modulator, Opt. Lett., vol. 28,

pp. 1415-1417, Aug. 2003.

Optical Microwave Filter: differential detection

OThH1.pdf

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All-optical microwave bandpass filter with negativecoefficients based on PM-IM conversion

LD 1

LD 2

EOPM

RFInput

PD

RFOutput

2x1Coupler

AWG

LCFBG 1 (-)

LCFBG 2 (+)

F. Zeng, J. Wang, and J. P. Yao, "All-opticalmicrowave bandpass filter with negative

coefficients based on a phase modulator and

linearly chirped fiber Bragg gratings," Opt. Lett.,

vol. 30, no. 17, pp. 2203-2205, Sep. 2005.

J. Wang, F. Zeng, and J. P. Yao, "All-optical

microwave bandpass filter with negativecoefficients based on PM-IM conversion," IEEE

Photon. Technol. Lett., vol. 17, no.10, pp. 2176-

2178, Oct. 2005.

Group

Delay

Group

Delay

0

DC

t

t

0

After

Photodetector

Directly detected by a photodetector

After

Dispersive Device

0

+0

0

t

Amplitude

0>

=

D

010

GHz) periodic sequence of optical pulses with timing jitter

significantly below that of electronic circuitry.

2. The sampling process can be made to be highly linear with

negligible back-coupling between optical sampling pulsesand the electrical signal being sampled.

R S

( )x t

( )Sx nT ( )Sq nT

( )SnT

An Electrooptic Analog-to-Digital Converter

The first photonic ADC was proposed in 1975 by Taylor using Mach-

Zehnder interferometer

H. F. Taylor, An electrooptic analog-to-digital converter, Proc. IEEE. vol. 63, no. 10, pp. 1524-1525, Oct. 1975.

OThH1.pdf

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Advantages:

1. Linear in complexity:

each additional bit of

resolution requires anaddition MZ

interferometer.

2. Decoupling of the

analog sampled signal

from the optical

sampling signal.

Drawback:

A limitation of this

approach is that each

additional bit of

resolution

requires a doubling of

the length of the MZmodulator.

A photonic ADC scheme using Mach-Zehndermodulators with identical half-wave voltages

A 4-channel ADC using four MZMs with identical half-

wave voltages.

111

0

110

0

1000

000

0

000

1

0011

011

1

111

1

1110

intensity(au)

comparator

output

quantized

s()

The operation of the 4-channel photonic ADC. (a) The transfer

functions of the four MZMs; (b) The linear binary code at the

outputs of the comparators; (c) Quantized value (solid) v.s. theinput phase modulation (dotted).

Experimental results. (a) The measured 8 waveformscorresponding to 8 bias phase shifts; (b) The digitized signal

(solid) and the fitted sinusoidal signal (dashed).

H. Chi and J. P. Yao, A photonic analog-to-digital

conversion scheme using Mach-Zehnder modulators with

identical half-wave voltages, Optics Express, submitted.

OThH1.pdf

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Conclusions

Microwave photonics has compelling benefits for many current

applications (mm-wave and THz generation, broadbandtunable signal processors, etc).

Microwave photonics has great potential for next generation

broadband wireless access networks.

Transparent to the modulation format

Microwave photonics will also find important applications in

wireless sensor networks (transmission of sensing data for

environmental, medical, traffic surveillance, defense and

homeland security applications)

Acknowledgements Students and post-doctoral fellows in the Microwave

Photonics Research Laboratory, University of Ottawa

NSERC

Canada Foundation for Innovation (CFI)

Ontario Innovation Trust (OIT)

National Capital Institute for Telecommunications (NCIT)

Canadian Institute for Photonics Innovation (CIPI)

OThH1.pdf

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