Optical Generation Of Microwave Signals Research Articles

Multi-gigabit X-band transmitter for satellite communication using the optical phase-locked loop.

Optical generation of microwave signals using photonic techniques offers benefits of frequency agility, ease of frequency scaling, and reduced hardware complexity. We demonstrate the generation and detection of QPSK modulated with symbol rates up to 5 GBaud at carrier frequencies of 8-12 GHz through optical heterodyning of two-phase-locked lasers. The received data is demodulated through appropriate post-processing to correct for the phase noise and IQ imbalance. The approach is scalable to mmWave and THz communication.

Continuous optical generation of microwave signals for fountain clocks.

For the optical generation of ultrastable microwave signals for fountain clocks, we developed a setup based on a cavity stabilized laser and a commercial frequency comb. The robust system, in operation since 2020, is locked to a 100MHz output frequency of a hydrogen maser and provides an ultrastable 9.6GHz signal for the interrogation of atoms in two cesium fountain clocks, acting as primary frequency standards. Measurements reveal that the system provides a phase noise level that enables quantum projection noise limited fountain frequency instabilities at the low 10-14(τ/s)-1/2 level. At the same time, it offers largely maintenance-free operation.

Simplified optical generation of microwave signal based on polarization multiplexing using an optical phase modulator

AbstractA new method to generate microwave signal with frequency doubled of the RF signal using an optical phase modulator by simply adjusting the polarization angle of the polarizer without any optical filters is experimentally proposed. The optical carrier is 19 dB lower than the 2 first‐order sidebands, which is better than the traditional optical carrier suppression double sideband modulation scheme. After detected by a high speed photodiode, a high spectrum purity 28 GHz microwave signal is generated easily. In addition, as pure optical carrier can also be recovered easily, the proposed scheme is cost‐effective and may be useful for the radio over fiber system with wavelength reuse.

Optical generation of microwave signal using fiber Bragg gating‐based double‐ring fiber laser assisted by saturable absorber

AbstractWe propose and demonstrate a simple approach to optical generation of microwave signal by exploiting a uniform fiber Bragg gating (FBG)‐based double‐ring laser and a saturable absorber.Parallel arranged uniform FBGs have a wavelength spacing corresponding to the microwave signal. A piece of unpumped polarization‐maintaining erbium‐doped fiber (EBF) serves as a saturable absorber, ensuring the dual‐wavelength single longitudinal mode operation. Stable dual‐wavelength single longitudinal mode lasers are obtained in the experiment. A microwave signal at 28.38 GHz is successfully generated by beating the dual‐wavelength single longitudinal mode lasers. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2478‐2481, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26303

Compact Optical Generation of Microwave Signals Using a Monolithic Quantum Dot Passively Mode-Locked Laser

Microwave signal generation from the saturable absorber of a monolithic quantum dot passively mode-locked laser is presented. We observe a differential efficiency of 33% that measures the optical-to-RF power conversion. An optimum extraction efficiency of the saturable absorber of about 86% is also found. To assess the stability of the device, the mode-locking operation regime of the quantum dot device is analyzed and compared to the quantum well system. Our findings confirm that quantum dot mode-locked lasers are suitable candidates for the optical generation of RF signals in a compact and efficient semiconductor device.

Optical generation of microwave signal for FMCW radar applications

AbstractAn optically shifted oscillator has been designed in integrated technology and tested in order to use as a signal generator for frequency modulated continuous wave radar applications. Simulation and measurement results demonstrate a 200 MHz microwave frequency tuning range when the applied optical power varies from 0 to 100 mW at a wavelength of 800 nm. Illumination is applied on a photoconductive switch inserted within the circuit to achieve a quasi‐linear oscillation frequency shift with a linear variation of optical power. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 690–693, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24146

Optical generation of microwave signals using SSB-based frequency-doubling scheme

A novel method for optical generation of microwave signals is demonstrated using a dual-electrode Mach-Zehnder modulator followed by a dual-input modulator. This method, without any optical filters, has all the advantages of Mach-Zehnder-based frequency-doubling techniques, and it is especially useful for applications that require accurate control of signal phase.

Optical generation of microwave signals using a directly modulated semiconductor laser under modulated light injection

AbstractWe have experimentally demonstrated a new optical microwave signal generation scheme using semiconductor lasers in a master–slave configuration, in which both lasers are directly modulated. The sidebands of the slave laser are locked to those of the master laser by the simple control of the applied modulation power. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 369–370, 2001.

A traveling fringes photodetector for microwave signals

We report a novel straightforward theoretical analysis and improved high frequency experimental performances of a new type resonant photodetector. A large detection volume is provided by a synchronous drift of photogenerated carriers with a moving interference pattern in a photoconductor. It appears to be suitable for optical generation of microwave signals at high power levels. Performances as a function of applied electric field, photoconductive material characteristic, fringe period, and optical power level are analyzed. Experimental results using a GaAs photoconductive layer are presented at frequency f=1.6 GHz.

Photodetector for microwave signals based on the synchronous drift of photogenerated carriers with a moving interference pattern

We present the principle of a new photodetector based on the synchronous drift in a semiconductor of photogenerated carriers with a moving interference pattern. It provides a large detection volume which could be suitable for the optical generation of microwave signals. A theoretical analysis is detailed and followed by an experimental demonstration in a MBE grown GaAs layer illuminated with a moving interference pattern. We study the evolution of the detected signal at frequency f=1.6 GHz as a function of applied electric field, carrier lifetime, and fringe period.

Generation and control of microwave signals by optical techniques

Optical techniques for microwave signal generation and optical control of microwave devices are described. Optical generation of microwave signals to 35 GHz and above by coherent heterodyne was carried out by FM sideband injection locking of laser diodes and by offset frequency phase locking of solid state lasers. Applications of optically generated microwave signals including optical control of phased array radar and photodetector characterisation are discussed. Optical injection locking, phase control, and phase locking of microwave oscillators are also presented.