1. 1 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Photonic microwave signal processing Jianping Yao Microwave Photonics Research Laboratory School of Information Technology and Engineering University of Ottawa, Canada

2. 2 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Outline Introduction Photonic BANDPASS microwave filter based on polarization modulation in a polarization modulator Photonic BANDPASS microwave filter based on an MZM and an tunable optical polarizer Photonic BANDPASS microwave filter based on phase modulation to intensity modulation (PM-IM) conversion Photonic BANDPASS microwave filter with complex coefficients Conclusion

3. 3 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" All-Optical Microwave Signal Processing Digital signal processing - speed is limited. Advantages of all-optical microwave filters: Wideband, eliminate bottlenecks (electrical sampling rate < few GHz) Low loss (fiber distribution of radio signals) Tunability and reconfigurability Immune to electromagnetic interference (EMI) Finite Impulse Response (FIR) Filter Optical Delay Line FIR Filter

4. 4 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Fiber Bragg gratings for Microwave-Photonics Applications

5. 5 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Fiber Bragg gratings for Microwave-Photonics Applications Chirped fiber grating based delay line Uniform fiber grating based delay line

6. 6 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Fiber Bragg grating based all- optical microwave filter Implementation of an optical microwave filter using uniform FBGs Incoherent source: to avoid optical interference

7. 7 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Fiber Bragg grating based all- optical microwave filter Implementation of an optical microwave filter using a chirped FBG: by tuning the wavelength spacing, a tunable time delay leading to a tunable FSR (free spectral range) is realized. The powers from the LDs could be controlled to apply a proper windowing to the filter to reduce filter sidelobes.

8. 8 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" All-optical microwave filter 4-tap Lowpass Filter with All- positive Coefficients [1 1 1 1]. 4-tap Bandpass Filter with Negative Coefficients [1 -1 1 -1]. PROBLEM: The implementation an optical microwave filter based on incoherent detection leads to the optical coefficients all positive – an all- positive coefficient microwave delay line filter can function as a low pass filter only.

9. 9 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Outline Introduction Photonic BANDPASS microwave filter based on polarization modulation in a polarization modulator Photonic BANDPASS microwave filter based on an MZM and an tunable optical polarizer Photonic BANDPASS microwave filter based on phase modulation to intensity modulation (PM-IM) conversion Photonic BANDPASS microwave filter with complex coefficients Conclusion

10. 10 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Polarization Modulation (XPolM) in a Polarization Modulator (PolM) J. P. Yao and Q. Wang, "Photonic microwave bandpass filter with negative coefficients using a polarization modulator," IEEE Photonics Technology Letters, vol. 19, no. 9, pp. 644-646, May 2007. Photonic bandpass microwave filter based on polarization modulation in a polarization modulator

11. 11 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Experimental Results (1) The generation of two complementary microwave signals based on PolM. Frequency responses of the two- tap microwave bandpass filter with one negative coefficient. FSR = 17.5 GHz (HiBi fiber = 42 m)

12. 12 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Frequency responses of the four-tap microwave bandpass filter. (a) The frequency response with coefficients [1 -1 1 -1]. Experimental Results (2) Optical path length: The time delay:

13. 13 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Outline Introduction Photonic BANDPASS microwave filter based on polarization modulation in a polarization modulator Photonic BANDPASS microwave filter based on an MZM and an tunable optical polarizer Photonic BANDPASS microwave filter based on phase modulation to intensity modulation (PM-IM) conversion Photonic BANDPASS microwave filter with complex coefficients Conclusion

14. 14 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Negative tap photonic microwave filter based on a Mach-Zehnder modulator and a tunable optical polarizer a1, a2 and a3 can be adjusted by adjusting the bias and the direction of the optical polarizer: the filter can be reconfigured to have positive or negative coefficient. Frequency response of the microwave filter with coefficients of (1 1) and (1 -1). Q. Wang, J. P. Yao, and J. D. Bull, "Negative Tap Photonic Microwave Filter based on a Mach-Zehnder Modulator and a Tunable Optical Polarizer," submitted to IEEE Photonics Technology Letters

15. 15 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Negative tap photonic microwave filter based on a Mach-Zehnder modulator and a tunable optical polarizer: For UWB impulse generation The first-order derivative of a Gaussian pulse  Gaussian monocycle (suitable for UWB impulse radio). The first-order derivative can be approximated by a first-order difference Gaussian monocycle pulse generation using the photonic microwave filter with coefficients of (1 -1); (a) the generated monocycle; (b) the spectrum.

16. 16 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Outline Introduction Photonic BANDPASS microwave filter based on polarization modulation in a polarization modulator Photonic BANDPASS microwave filter based on an MZM and an tunable optical polarizer Photonic BANDPASS microwave filter based on phase modulation to intensity modulation (PM-IM) conversion Photonic BANDPASS microwave filter with complex coefficients Conclusion

17. 17 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" BANDPASS microwave filter based on phase modulation to intensity modulation (PM-IM) conversion Filter configuration  opt  m  PM/IM conversion SMF  opt  m 

18. 18 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" F. Zeng and J. P. Yao, "All-optical bandpass microwave filter based on an electro-optic phase modulator," Optics Express, vol. 12, no. 16, pp. 3814-3819, August 2004. F. Zeng and J. P. Yao, "Investigation of phase modulator based all- optical bandpass filter," IEEE/OSA Journal of Lightwave Technology, vol. 23, no. 4, April 2005. Experimental Results

19. 19 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Photonic microwave bandpass filters implemented in a radio-over- fiber link Fig. 1 Block diagram of the proposed all-optical microwave bandpass filter. Insert: Linearly polarized light launch into the Hi-Bi fiber.. Frequency response of the filter with (a) one section of PM fiber (b) two sections of PM fiber with the azimuth angle 45 degrees. J. Wang, F. Zeng, and J. P. Yao, "All-optical microwave bandpass filters implemented in a radio-over-fiber link," IEEE Photonics Technology Letters, vol. 17, no. 8, pp. 1737-1739, August 2005.

20. 20 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Fig.1 Illustration of the recovered RF modulating signals that sustain a positive, zero or negative chromatic dispersion. Photonic microwave bandpass filter with negative coefficients based on a phase modulator and linearly chirped fiber Bragg gratings Fig. 2 System configuration of the proposed all-optical microwave bandpass filter with negative coefficients. F. Zeng, J. Wang, and J. P. Yao, "All-optical microwave bandpass filter with negative coefficients based on an electro-optic phase modulator and linearly chirped fiber Bragg gratings," Optics Letters, vol. 30, no. 17, pp. 2203-2205, September 2005. Fig. 5 Experimental results of the two-tap filter with one negative coefficient.

21. 21 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Photonic microwave bandpass filter with negative coefficients based on PM-IM conversion Fig. 1. Fundamental concept for the implementation of negative coefficients based on PM-IM conversion using an optical filter. (a) Intensity transfer function of an optical filter. (b) Illustration of the generation of RF modulating signals in counter-phase. Fig. 2. Block diagram of the proposed all-optical microwave bandpass filter. Fig. 4. Tunability of the true bandpass filter with negative coefficient. (a) Optical spectra of the two tunable laser sources. (b) Frequency response of the true bandpass filter. J. Wang, F. Zeng, and J. P. Yao, "All-optical microwave bandpass filters with negative coefficients based on PM-IM conversion," IEEE Photonics Technology Letters, vol. 17, no.10, October 2005

22. 22 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" All-optical microwave mixing and bandpass filtering in a radio-over-fiber link 25-km

23. 23 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" F. Zeng and J. P. Yao, "All-optical microwave mixing and bandpass filtering in a radio-over-fiber link," IEEE Photonics Technology Letters, vol. 17, no 4, April 2005 (a) (b) (c) (a) Filter frequency response, (b) mixing output without filtering, (c) mixing output with filtering. All-optical microwave mixing and bandpass filtering in a radio-over-fiber link

24. 24 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Outline Introduction Photonic BANDPASS microwave filter based on polarization modulation in a polarization Modulator Photonic BANDPASS microwave filter based on phase modulation to intensity modulation (PM-IM) conversion Photonic BANDPASS microwave filter with complex coefficients Conclusion

25. 25 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Photonic microwave filter with complex coefficients A two-tap microwave filter with one complex coefficient has a transfer function given The frequency response for different phase shift: The advantage: tuning of the passband without changing the FSR.

26. 26 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" A Tunable Photonic Microwave Filter with Complex Coefficient Using an Optical RF Phase Shifter Measured phase shift for different bias voltages. The phase shift is independent of the microwave frequency. Measured frequency response of the two-tap photonic microwave filter with one complex coefficient. Y. Yan, and J. P. Yao "A tunable photonic microwave filter with complex coefficient using an optical RF phase shifter," submitted to IEEE Photonics Technology Letters

27. 27 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Conclusion All-optical microwave signal processing has compelling benefits such as broad bandwidth, large tunability, which may not be realized with the current electronic signal processing techniques. Fiber-optic microwave signal processing is inherently compatible with fiber optic wireless systems: has great potential for next generation broadband wireless access networks. Other applications: Microwave systems, true time delay beamforming, UWB over fiber, sensor networks

28. 28 ISIS-IPHOBAC SUMMER SCHOOL, May 17-18, 2007, Budapest, Hungary "Broadband Architectures and Functions" Acknowledgements Contributions: Fei Zeng, Jun Wang, Qing Wang, Sebastien Blais, Yu Yan. The Natural Sciences and Engineering Research Council (NSERC) of Canada