Broadband and low loss capability of photonics has led to an ever-increasing interest in its use for the generation, processing, control and distribution of microwave and millimeter-wave signals for applications such as broadband wireless access networks, sensor networks, radar, satellite communitarians, instrumentation and warfare systems. In this tutorial, techniques developed in the last few years in microwave photonics are reviewed with an emphasis on the systems architectures for photonic generation and processing of microwave signals, photonic true-time delay beamforming, radio-over-fiber systems, and photonic analog-to-digital conversion. Challenges in system implementation for practical applications and new areas of research in microwave photonics are also discussed.

Microwave Photonics

Microwave photonics is an area that studies the generation, processing, control and transmission of microwave signals by means of photonics. In this paper, microwave photonics techniques developed in the past few years will be reviewed, with an emphasis on system architectures for microwave applications.

http://ieeexplore.ieee.org/iel5/6305327/6320324/06320333.pdf

Microwave photonics

* The only book describing applications of nonlinear fiber optics * Two new chapters on the latest developments: highly nonlinear fibers and quantum applications* Coverage of biomedical applications* Problems provided at the end of each chapterThe development of new highly nonlinear fibers - referred to as microstructured fibers, holey fibers and photonic crystal fibers - is the next generation technology for all-optical signal processing and biomedical applications. This new edition has been thoroughly updated to incorporate these key technology developments.The book presents sound coverage of the fundamentals of lightwave technology, along with material on pulse compression techniques and rare-earth-doped fiber amplifiers and lasers. The extensively revised chapters include information on fiber-optic communication systems and the ultrafast signal processing techniques that make use of nonlinear phenomena in optical fibers.New material focuses on the applications of highly nonlinear fibers in areas ranging from wavelength laser tuning and nonlinear spectroscopy to biomedical imaging and frequency metrology. Technologies such as quantum cryptography, quantum computing, and quantum communications are also covered in a new chapter.This book will be an ideal reference for: RD scientists involved with research on fiber amplifiers and lasers; graduate students and researchers working in the fields of optical communications and quantum information. * The only book on how to develop nonlinear fiber optic applications* Two new chapters on the latest developments; Highly Nonlinear Fibers and Quantum Applications* Coverage of biomedical applications

Applications of nonlinear fiber optics

Microwave measurement refers to the acquisition of parameters of a microwave signal or the identification of properties of an object via microwave-based approaches. Thanks to the broad bandwidth and high speed provided by modern photonics, microwave measurement in the optical domain can provide better performance in terms of bandwidth and speed which may not be achievable using traditional, even state-of-the-art electronics. In this tutorial, techniques for photonics-based broadband and high-speed microwave measurement are discussed with an emphasis on the system architectures for microwave signal parameter measurement and object property identification. Emerging technologies in this area and possible future research directions are also discussed.

Photonics-Based Broadband Microwave Measurement

We propose theoretically and experimentally demonstrate an optical architecture for flexible Ultra-Wideband pulse generation. It is based on an N-tap reconfigurable microwave photonic filter fed by a laser array by using phase inversion in a Mach-Zehnder modulator. The proposed system permits a full reconfigurability of photonic microwave filter and therefore high-order UWB pulses can be generated to successfully satisfy the FCC regulation. Moreover, the photonic UWB pulse generator is adaptable to different pulse modulation formats since the amplitude, polarity and time delay of generated pulses can be controlled with a reconfiguration time up to tens of nanoseconds.

Optical UWB pulse generator using an N tap microwave photonic filter and phase inversion adaptable to different pulse modulation formats.

We theoretically analyzed and experimentally demonstrated a novel 4- to 40-GHz frequency quadrupler for radio-over- fiber systems. By using an optical carrier suppression modulation scheme in two cascaded intensity modulators, four-fold microwave or millimeter wave signals are optically generated without the need for an optical and electrical notch filter to remove the residual carrier components. Moreover, the limitation of high drive voltage is greatly reduced through tandem intensity modulation with pi/2 phase shift between two driving signals.

A Photonic Microwave Frequency Quadrupler Using Two Cascaded Intensity Modulators With Repetitious Optical Carrier Suppression

Optical methods for different type ultra-wideband (UWB) pulse generation based on cross-polarization modulation (CPM) are proposed and demonstrated in this paper. Two polarity-reverse pulses can be obtained by CPM and birefringence time delay to form a monocycle pulse. A semiconductor optical amplifier (SOA) is placed after the monocycle pulse process for doublet pulse generation. These two kinds of pulses can be employed in single-band impulse radio UWB (IR-UWB) systems. Two kinds of multi-band UWB pulses can be generated based on monocycle pulse train with proper apodization profiles, realized by hybrid photonic microwave filter and synchronous polarization modulation respectively. Experimental results show that these pulses can be used in multi-band UWB (MB-UWB) over fiber systems.

Methods for Ultra-Wideband Pulse Generation Based on Optical Cross-Polarization Modulation

A millimeter-wave signal with sextuple-frequency multiplication of a microwave source is obtained with two cascaded optical modulators, which are driven by the same microwave source with phase deviation of π/2 introduced by an electrical phase shifter. Without any optical filter, a wideband continuously tunable millimeter-wave signal is easily generated.

Photonic generation of a millimeter-wave signal based on sextuple-frequency multiplication.

A novel method of optical generation millimeter-wave (mm-wave) signals employing two cascaded optical modulators and four-wave-mixing effect in semiconductor optical amplifiers is proposed. This approach is capable of generating signals of four times, eight times, and 12 times microwave source frequency with high spectral purity and stability. A mm-wave of 42 GHz (12times fundamental) with a 3-dB linewidth less than 30 Hz and a phase noise less than 83 dBc/Hz at 10-kHz offset is obtained.

Millimeter-Wave Signal Generation Using Two Cascaded Optical Modulators and FWM Effect in Semiconductor Optical Amplifier

In this paper, novel approaches for millimeter-wave signal generation using double-sideband suppressed-carrier modulation and four-wave mixing are proposed and demonstrated. The millimeter-wave signal is generated at a photodetector by beating the optical sidebands, which are gained from intensity modulation and after semiconductor optical amplifiers. In the proposed methods, the generated millimeter-wave signal has a frequency that is double, quadruple, sextuple, 12 times, or even 18 times higher than the microwave drive signal. And, it has quite good gain flatness with extremely high-spectral-purity and stability. The phase noise performance of the generated millimeter wave is investigated. The 3-dB linewidth of the millimeter wave has no broadening after propagating through 20-km standard single-mode fiber.

Tianliang Wang

Papers

A Photonic Microwave Frequency Quadrupler Using Two Cascaded Intensity Modulators With Repetitious Optical Carrier Suppression

Methods for Ultra-Wideband Pulse Generation Based on Optical Cross-Polarization Modulation

Photonic generation of a millimeter-wave signal based on sextuple-frequency multiplication.

Millimeter-Wave Signal Generation Using Two Cascaded Optical Modulators and FWM Effect in Semiconductor Optical Amplifier

High-Spectral-Purity Millimeter-Wave Signal Optical Generation