Showing papers on "Injection locking published in 2008"
TL;DR: In this article, the authors have shown that fundamental oscillation up to 2.3 THz and an output power of 60 µW at 1 THz are theoretically expected by improving the structures of the RTD and the antenna.
Abstract: Resonant tunneling diodes (RTDs) have the potential for use as compact and coherent terahertz (THz) sources operating at room temperature. In this paper, sub-THz and THz oscillators with RTDs integrated on planar circuits are described. Fundamental oscillation up to 0.65 THz and harmonic oscillation up to 1.02 THz were obtained at room temperature in our recent study. Limiting factors for oscillation frequency and output power are theoretically analyzed including tunneling and transit-time effects and parasitic elements. Oscillation frequency and its dependence on RTD size are in good agreement with the measured results. Based on this result, it is shown that fundamental oscillation up to 2.3 THz and an output power of 60 µW at 1 THz are theoretically expected by improving the structures of the RTD and the antenna. Voltage-controlled oscillation, which is useful for the precise control of frequency, is observed in the RTD oscillators. Coherent power combining in an array configuration to achieve high output power as well as mutual injection locking between the array elements are also described.
313 citations
TL;DR: In this paper, the authors derived closed-form solutions to the relaxation oscillation (resonance) frequency and damping term, as well as the low-frequency damping terms, and discussed design rules for maximizing resonance frequency and broadband performance.
Abstract: The modulation response of injection-locked lasers has been carefully analyzed, theoretically and experimentally, with a focus on the strong optical injection regime. We derive closed-form solutions to the relaxation oscillation (resonance) frequency and damping term, as well as the low-frequency damping term, and discuss design rules for maximizing resonance frequency and broadband performance. A phasor model is described in order to better explain the enhancement of the resonance frequency. Experimental curves match closely to theory. Record resonance frequency of 72 GHz and broadband results are shown.
143 citations
TL;DR: A sub-harmonic injection-locked tripler multiplies a 20-GHz differential input to 60-GHz quadrature (I/Q) output signals and Regenerative peaking is also used to optimize the gain/bandwidth performance of the 50-Omega output buffers.
Abstract: A sub-harmonic injection-locked tripler multiplies a 20-GHz differential input to 60-GHz quadrature (I/Q) output signals. The tripler consists of a two-stage ring oscillator driven by a single-stage polyphase input filter and 50-Omega I and Q-signal output buffers. Each gain stage incorporates a hard limiter to triple the input frequency for injection locking and a negative resistance cell with two positive feedback loops to increase gain. Regenerative peaking is also used to optimize the gain/bandwidth performance of the 50-Omega output buffers. Fabricated in 90-nm CMOS, the tripler has a free-running frequency of 60.6 GHz. From a 0-dBm RF source, the measured output lock range is 56.5-64.5 GHz, and the measured phase noise penalty is 9.2 plusmn 1 dB with respect to a 20.2-GHz input. The 0.3 times 0.3 mm2 tripler (including passives) consumes 9.6 mW, while the output buffers consume 14.2 mW, all from a 1-V supply.
138 citations
TL;DR: This work uses a generalized Adler's equation for large injections to analyze the operation of injection-locked ring oscillators and derive expressions for the input lock range, and discovers that injection in the correct progressive phases greatly widens the lock range.
Abstract: Injection-locked oscillators divide at very high frequencies and consume low power. They are not widely deployed in commercial products because they operate over small, often unpredictable, ranges of input frequencies. Ring oscillators as dividers are interesting because they are compact, and capable of a multi-phase output, including quadrature phases. Using a generalized Adler's equation for large injections, we analyze the operation of injection-locked ring oscillators and derive expressions for the input lock range. We discover that injection in the correct progressive phases greatly widens the lock range; all that is needed is the right delay cell circuit, and the injection input in one or two phases. As proof of concept, divide-by-two and six prototypes are built. The measured lock range spans DC to 1.5 the free-running frequency, the highest reported to date.
128 citations
19 May 2008
TL;DR: In this paper, the authors describe two recent types of opto-electronic oscillators: a long-fiber optical oscillator and a low-noise 10 GHz compact oscillator.
Abstract: This paper describes two recent types of opto-electronic oscillators. The first is a long fiber opto-electronic oscillator, utilizing a high power laser with long delay, and consisting of low noise components. This oscillator generates a stable 10 GHz signal with phase noise of -163 dBc/Hz at 6 kHz offset from the carrier. The second is a low noise 10 GHz compact opto-electronic oscillator. This latter oscillator consists of coupled optical and microwave loops utilizing a short fiber. We also report on an automatic ultra-low noise floor measurement system, designed and built to measure the phase noise of the above (and other) oscillators. This delay line cross-correlation measurement system utilizes microwave-photonic links, eliminating the need for a second oscillator. This system provides quick and reliable measurement of the oscillator under test.
117 citations
TL;DR: In this paper, the authors proposed a dual-injection-locking technique to enhance the locking range of resonator-based frequency dividers, which achieved a frequency coverage from 35.7 to 54.9 GHz.
Abstract: This paper presents the dual-injection-locking technique to enhance the locking range of resonator-based frequency dividers. By fully utilizing the voltage and current injection of the input signal, the divider locking range is extended significantly. The 0.8-mW dual-injection-locked frequency divider was developed in 90-nm digital CMOS technology. The total chip size is 0.77 mm times 0.5 mm. Without any varactor or inductor tuning, the input signal frequency coverage of the divider is from 35.7 to 54.9 GHz. Combined with the excellent locking range and sub-milliwatt power consumption, the figure-of-merit of this work surpasses those of the previous resonator-based dividers by more than one order.
106 citations
TL;DR: A phase-domain macromodel is deduced which is able to capture high-order synchronization effects and the expressions derived for synchronization-regions are very general since they apply to any oscillator topology.
Abstract: This paper presents a novel approach to the analysis of oscillator injection locking due to weak external signals. From the intuitive concept of impulse-sensitivity function, a phase-domain macromodel is deduced which is able to capture high-order synchronization effects. Novel closed-form expressions for the synchronization regions are thus presented. The proposed phase-domain macromodel and the expressions derived for synchronization-regions are very general since they apply to any oscillator topology.
90 citations
TL;DR: The simple and elegant round-trip time-of-flight measurement concept introduced in this paper enables innovative localization and navigation systems.
Abstract: In this paper, the novel principle of the switched injection-locked oscillator is introduced. It is shown that the concept is ideally suited for transponder and secondary radar systems with outstanding performance. A switched injection-locked oscillator transponder can produce an approximately phase coherent high-power response to an interrogating signal and, consequently, allows for long-range transponder systems and precise distance measurement between the reader and transponder. The simple and elegant round-trip time-of-flight measurement concept introduced in this paper enables innovative localization and navigation systems. Furthermore, it can be applied in numerous areas such as sensor networks, RF identification and localization, ubiquitous computing, location sensitive billing, context dependent information services, or tracking and guiding.
84 citations
TL;DR: In this article, a K-and V-band differential subharmonic injection-locked frequency triplers (ILFTs) are proposed, and models for the injection-locking range and the output phase noise are developed.
Abstract: K- and V-band CMOS differential subharmonic injection-locked frequency triplers (ILFTs) are proposed, analyzed, and designed. Based on the proposed ILFT structure, models for the injection-locking range and the output phase noise are developed. A K-band ILFT is designed and fabricated using 0.18-m standard CMOS technology. The measured injection-locking range is 1092 MHz with a dc power consumption of 0.45 mW and an input injection power of 4 dBm. The harmonic rejection ratios are 22.65, 30.58, 29.29, 40.35 dBc for the first, second, fourth, and fifth harmonics, respectively. The total injection-locking range of the -band ILFT can achieve 3915 MHz when the varactors are used and the dc power consumption is increased to 2.95 mW. A -band ILFT is also designed and fabricated using 0.13-m standard CMOS technology. The measured injection-locking range is 1422 MHz with 1.86-mW dc power consumption and 6-dBm input injection power. The injection-locking range of the proposed ILFT is similar to the tuning range of a conventional varactor-tuned bulk-CMOS voltage-controlled oscillator (VCO). Moreover, the proposed ILFT has a greater output power and a lower dc power consumption level than a VCO. As a result, it is feasible to use the proposed ILFT in low-power millimeter-wave synthesizers.
81 citations
TL;DR: A 20-Gb/s clock and data recovery circuit incorporates injection-locking technique to achieve high-speed operation with low power dissipation and a frequency-monitoring mechanism is employed to ensure a close matching between the VCO natural frequency and data rate.
Abstract: A 20-Gb/s clock and data recovery circuit incorporates injection-locking technique to achieve high-speed operation with low power dissipation. The circuit creates spectral line at the frequency of data rate and injection-locks two cascaded LC oscillators. A frequency-monitoring mechanism is employed to ensure a close matching between the VCO natural frequency and data rate. Fabricated in 90-nm CMOS technology, this circuit achieves a bit error rate of less than 10-9 in both continuous (PRBS of 231-1) and burst modes while consuming 175 mW from a 1.5-V supply.
78 citations
TL;DR: In this paper, an analytical formulation of the phase noise behavior of injection-locked oscillators and analog frequency dividers has been obtained, which allows a better understanding of the shape of the output phase-noise spectrum of these circuits.
Abstract: In-depth investigation of the phase-noise behavior of injection-locked oscillators and analog frequency dividers is presented. An analytical formulation has been obtained, which allows a better understanding of the shape of the output phase-noise spectrum of these circuits. The simplicity of this formulation is also helpful for circuit design. Approximate expressions for the corner frequencies of the spectrum are determined, identifying the most influential magnitudes and deriving design criteria. In particular, a technique has been developed to shift the frequency of the first corner of the phase-noise spectrum, up to which the output phase noise follows the input one. The expressions for the corner frequencies can be introduced in either in-house or commercial harmonic-balance software, thus allowing an agile design, as no separate phase-noise analysis is required. The validity of the analytical techniques is verified with the conversion-matrix approach and with measurements using two field-effect-transistor-based circuits: a 4.9-GHz injection-locked oscillator and a frequency divider by 2 with 9.8-GHz input frequency.
TL;DR: In this paper, the first experimental invetigation of the polarization mode switching dynamics and injection-wavelength-dependent polarization-mode bistability of a 1.5m wavelength single-mode vertical-cavity surface-emitting laser (VCSELs) under external laser beam injection was reported.
Abstract: We report the first experimental invetigation of the polarization-mode switching dynamics and injection-wavelength-dependent polarization-mode bistability of a 1.5-m wavelength single-mode vertical-cavity surface-emitting lasers (VCSELs) under external laser beam injection. An injection beam with polarization orthogonal to that of the stand-alone VCSEL caused polarization-mode instability and switching of the VCSEL output. By varying the optical injection detuning for fixed injection power observation was made of a novel form of polarization bistability which will have applications in a new type of all-optical flip-flop and signal processing scheme.
TL;DR: In this paper, the authors investigated both analytically and numerically the switching, locking and stability properties of a bistable semiconductor ring laser subject to an external optical injection.
Abstract: We investigate both analytically and numerically the switching, locking and stability properties of a bistable semiconductor ring laser subject to an external optical injection. Minimum optical power required for the injected signal at certain frequency to switch the lasing direction of a bistable semiconductor ring laser from its initially lasing direction to initially nonlasing direction is determined. Locking to the injected signal and stability of the switched laser are investigated to give an area of reliable switching operation. Correspondingly, numerical simulation has been carried out to find successful switching and stable locking region with variable injection power and frequency, and is compared with the analytical results. The region obtained from simulation coincides well with the intersection of switching, locking and stable locking regions. The relation between switching speed and parameters of injected source is also studied numerically.
TL;DR: In this article, the authors evaluated the performance of Fabry-Perot laser emitting at 1570 nm without an absorbing section for microwave signal generation and demonstrated a phase noise reduction of more than 15 dB in the low-frequency range.
Abstract: Quantum dash active region Fabry-Perot lasers emitting at 1570 nm without an absorbing section have been evaluated as an optical source for microwave signal generation. These devices self-pulsate at 39.9 GHz with a mode-beating spectral linewidth as narrow as 10 kHz. Integration of these devices into an Opto-Electronic Oscillator has been performed, demonstrating a phase noise reduction of more than 15 dB in the low-frequency range. Moreover, the measured phase noise spectrum is well explained by a rate equation model taking into account the feedback loop.
TL;DR: In this paper, a 60 GHz 0.13mum CMOS divide-by-three frequency divider with regenerative injection-locked technique is proposed to achieve divide-and-three function at millimeter-wave frequency.
Abstract: This paper presents the design and analysis of a 60-GHz 0.13-mum CMOS divide-by-three frequency divider (FD). The regenerative injection-locked technique is proposed to achieve divide-by-three function at millimeter-wave frequency. The novel level shifter is used to increase the overdrive voltage of the input switch of the loop divider such that the divider locking range and input sensitivity can be enhanced. The CMOS divide-by-three FD including the testing pads occupies the silicon area of 0.99 mm t 0.69 mm. Operated at 1.3 V, the CMOS divider consumes 13 mW of power. The measured locking range is 1.8 GHz around the input frequency of 59 GHz, and the phase noise of the output signal at 1-MHz offset is -131.36 dBc/Hz.
TL;DR: In this article, it was shown that the frequency and phase of a microtoroidal optomechanical oscillator can be locked to those of an electronic oscillator (or any other signal) that can modulate the optical input power and whose frequency is within the lock range.
Abstract: Injection locking of a radiation-pressure optomechanical oscillator is demonstrated through external modulation of the optical pump power near the optomechanical oscillation frequency. It is shown that the frequency and phase of a microtoroidal optomechanical oscillator can be locked to those of an electronic oscillator (or any other signal) that can modulate the optical input power and whose frequency is within the lock range.
TL;DR: A hysteresis loop of the output power in the uninjected mode as a function of the power injected in the long-wavelength primary mode is shown, which shows the co-existing steady states associated with the bistability.
Abstract: We study the injection locking bistability of a specially engineered two-color semiconductor Fabry-Perot laser. Oscillation in the uninjected primary mode leads to a bistability of single mode and two-color equilibria. With pulsed modulation of the injected power we demonstrate an all-optical memory element based on this bistability, where the uninjected primary mode is switched with 35 dB intensity contrast. Using experimental and theoretical analysis, we describe the associated bifurcation structure, which is not found in single mode systems with optical injection.
TL;DR: In this paper, a divide-by-3 CMOS injection-locked frequency divider (ILFDMOS) was proposed, which was realized with a double cross-coupled CMOS LC-tank oscillator with an injection MOS.
Abstract: This letter proposes a new divide-by-3 CMOS injection locked frequency divider (ILFDMOS. ) fabricated in a 0.18-mum CMOS process and describes the operation principle of the ILFD. The ILFD circuit is realized with a double cross-coupled CMOS LC-tank oscillator with an injection MOS. The self-oscillating voltage controlled oscillator is injection-locked by third-harmonic input to obtain the division order of three. Measurement results show that at the supply voltage of 1.8 V, the free-running frequency is from 1.62 to 1.89 GHz. At the incident power of 5 dBm, the locking range is from the incident frequency 4.85 to 5.7 GHz.
TL;DR: Numerical results show that if the laser subjected to strong injection serves as the receiver, chaos pass filtering of the system is similar to that of unidirectional coupled systems, and it is demonstrated that messages can be extracted successfully from either of the two transmission directions.
Abstract: Chaos synchronization and message transmission between two semiconductor lasers with extremely unsymmetrical bidirectional injections (EUBIs) are discussed. By using EUBIs, synchronization is realized through injection locking. Numerical results show that if the laser subjected to strong injection serves as the receiver, chaos pass filtering (CPF) of the system is similar to that of unidirectional coupled systems. Moreover, if the other laser serves as the receiver, a stronger CPF can be obtained. Finally, we demonstrate that messages can be extracted successfully from either of the two transmission directions of the system.
TL;DR: In this paper, the bistable behavior of a single transverse and polarization mode vertical-cavity surface-emitting laser (VCSEL) when subjected to orthogonal optical injection was investigated.
Abstract: In this paper, we report on an experimental investigation of the bistable behavior of a 1550 nm single transverse and polarization mode vertical-cavity surface-emitting laser (VCSEL) when subjected to orthogonal optical injection. As the master laser wavelength is scanned near the resonance wavelength of the depressed linearly polarized fundamental mode, and for a fixed injected power, the VCSEL exhibits two successive polarization switchings (PSs). Both PSs exhibit bistable regions in such a way that a pure-frequency-induced polarization bistability is found. The width of both bistable regions has been measured as a function of the injected power and for different values of the VCSEL current. While the injection power is lesser than a certain value, the hysteresis width fluctuates around a constant level. Further increase of the injection power leads to a smaller constant value of the hysteresis width. The value of that transition value is independent of the VCSEL current. Power-induced polarization bistability - by fixing the master laser wavelength - is found near the transition value. Clockwise and anticlockwise power-hysteresis cycles are observed for short and long master laser wavelengths, respectively.
12 Dec 2008
TL;DR: A very small area 90-nm CMOS prototype synthesizes the frequencies of band group #6 with a hop time shorter than 4 ns and is supported by a thorough analysis that emphasizes the tradeoffs in the parameters of the proposed system.
Abstract: Sub-harmonic injection locking is employed to generate the fast-hopping carriers required in UWB systems for WiMedia . A very small area 90-nm CMOS prototype synthesizes the frequencies of band group #6 with a hop time shorter than 4 ns . It occupies 0.074 mm2 and draws 30 mA from a 1.2 V supply. Phase noise at 8.71 GHz is -112 dBc/Hz at 1 MHz offset. The design is supported by a thorough analysis that emphasizes the tradeoffs in the parameters of the proposed system.
TL;DR: It is found that a receiver subject to a feedback similar to that of the emitter shows better synchronization with the master laser when compared with a receiver without feedback (open-loop receiver).
Abstract: We study numerically the synchronization properties of two unidirectionally coupled semiconductor lasers subject to filtered optical feedback. By adding a perturbation (a message) to the output of the master laser, we show that mutual information allows distinguishing between chaotic synchronization (at low to moderate coupling strengths) and injection locking (at large coupling strength). We find that a receiver subject to a feedback similar to that of the emitter (closed-loop receiver) shows better synchronization with the master laser when compared with a receiver without feedback (open-loop receiver). Closed-loop receivers also show better capability to recover weak messages. The filter in the feedback loop allows reducing the bandwidth of the chaotic carrier, improves the synchronization with respect to the conventional feedback case, and requires less coupling strength with a minor loss in complexity.
TL;DR: Time-domain delay-based modeling of injection locking is used to describe injection-locking phenomena in nonharmonic oscillators and is further used to predict the injection- locking behavior of a single-ended CMOS inverter based ring oscillator.
Abstract: Time-domain delay-based modeling of injection locking is used to describe injection-locking phenomena in nonharmonic oscillators. The model is used to predict the locking bandwidth, and the locking dynamics of the locked oscillator. The model predictions are verified against simulations and measurements of a four-stage differential ring oscillator. The model is further used to predict the injection-locking behavior of a single-ended CMOS inverter based ring oscillator.
TL;DR: In this article, a detailed theoretical model and simulation results were presented for both amplitude and phase modulation of the master light before injection and the resulting 3-dB bandwidth was enhanced by up to three times, exceeding 50 GHz.
Abstract: In normal injection-locked semiconductor lasers, the modulation signals are applied to the slave laser. In this paper, we show that modulating the master light before injection exhibits distinctive modulation dynamics and frequency response. We first present a detailed theoretical model and simulation results. Experimentally, we have successfully demonstrated both master amplitude and master phase modulation. The resulting 3-dB bandwidths have been enhanced by up to three times, exceeding 50 GHz. The resonance frequency of the combined lasers is greater than 100 GHz.
TL;DR: In this article, an integrated transceiver design suitable for short range wireless applications, such as RFID or the transmission of data from medical sensors, is presented, which includes the transceiver, the integrated antenna, the phase-locked loop (PLL) loop filter and supply decoupling.
Abstract: An integrated transceiver design suitable for short range wireless applications, such as RFID or the transmission of data from medical sensors, is presented. Fabricated in a standard 0.13-m CMOS process, the test chips include the transceiver, the integrated antenna, the phase-locked loop (PLL) loop filter and supply decoupling. The transmitter and receiver consist of PLLs operated in both closed- and open-loop modes. Initially closed, the transmit PLL phase locks an RF voltage-controlled oscillator (VCO), the loop is subsequently opened and the VCO is modulated to yield an FM output signal that radiates directly from the tank inductor that doubles as the integrated antenna. The closed-loop receiver phase locks an RF VCO which, in open-loop mode, is injection locked to the incoming FM signal and the PLL components serve to demodulate the signal. Averaged transmit and receive power consumptions are less than 1.1 mW, enabling on-chip ultracapacitors to serve as the power source. When one chip communicates using the on-chip antenna to another chip connected to an off-chip patch antenna the communication range is 1.8 m at 5 kb/s. The communication range can be increased at the expense of the data rate, or by using off-chip antennas with both chips.
TL;DR: In this article, a monolithic optically injection-locked laser system on one chip was proposed, which is based on the availability of two modes in a ring laser (clockwise, and counter-clockwise).
Abstract: We propose a monolithic optically injection-locked laser system on one chip, without the use of an isolator. This system is based on the availability of two modes in a ring laser (clockwise, and counter-clockwise). In a ring laser whose operation is dominated by the counter-clockwise mode, the clockwise mode power is significantly reduced. Hence, the coupling between the master laser and the ring laser is highly unidirectional, due to the direction of the ring laser output. This monolithic injection locking system is predicted to exhibit a greatly enhanced resonance frequency and modulation bandwidth under ultrahigh injection locking conditions.
01 Jan 2008
TL;DR: In this paper, the authors present theoretical and experimental results and the physical origin of injection-locked laser with particular emphasis on its dynamic performance, and present new applications, techniques, and performance of injection locking in wavelength-division multiplexed systems and passive optical network applications.
Abstract: Publisher Summary Injection locking refers to a state when the frequency and phase of an oscillator, referred to as the slave oscillator, are locked through direct coupling or injection of another oscillator, referred to as the master oscillator. This chapter reviews theoretical and experimental results and the physical origin of injection-locked lasers with particular emphasis on its dynamic performance. Some performance improvements include ∼20-dB increase of both spur-free dynamic range (SFDR) and radio frequency (RF) link gain, one order of magnitude increase in resonance frequency, as well as ∼20-dB reduction in laser noise. A record-high modulation bandwidth of 66 GHz is attained by injection locking a 10-GHz vertical-cavity surface-emitting laser (VCSEL). These properties can lead to an increase of the transmission distance or bandwidth. New applications, techniques, and performance of injection locking in wavelength-division multiplexed systems are discussed for metropolitan area networks and passive optical network applications. The characteristics of a directly modulated laser can be fundamentally changed when it is locked to a master laser through coherent nonlinear interactions, resulting in superior device performance for various applications.
TL;DR: In this paper, a self-oscillating ILFD is realized with a cross-coupled CMOS LC-tank oscillator, and the injecticon is carried out through the bodies of cross- coupled transistors.
Abstract: This letter proposes a new CMOS injection locked frequency divider (ILFD) fabricated in a 0.35 mum CMOS process. The ILFD circuit is realized with a cross-coupled CMOS LC-tank oscillator, and the injecticon is carried out through the bodies of cross- coupled transistors. The self-oscillating ILFD is injection-locked by second-(third-) harmonic input to obtain the division order of two (three). Measurement results show that at the supply voltage of 1.5 V and at the incident power of 10 dBm, the locking range is from the incident frequency 6.94 to 8.41 GHz in the divide-by-3 mode and the operation range is from the incident frequency 4.56 to 5.59 GHz in the divide-by-2 mode.
04 May 2008
TL;DR: In this paper, a two-mode injection-locked Fabry-Perot laser using second-order sideband injection is investigated, which can be used for 60 GHz millimeter-wave generation in radio-over-fiber system.
Abstract: A scheme of two-mode injection-locked Fabry-Perot laser using second-order sideband injection is investigated, which can be used for 60 GHz millimeter-wave generation in radio-over-fiber system. Modulation response enhancement of Fabry-Perot lasers is also experimentally demonstrated.
TL;DR: Generated output signals are found to preserve not only the narrow linewidths of the selected individual modes but also the absolute frequency positions of the original comb over a wide spectral range.
Abstract: A precise way of optical frequency generation is demonstrated with direct use of the frequency comb of a mode-locked femtosecond laser. Only a single mode is extracted at a time on demand from the frequency comb through a composite filtering scheme and then amplified by means of optical injection locking with extremely low background noise. Generated output signals are found to preserve not only the narrow linewidths of the selected individual modes but also the absolute frequency positions of the original comb over a wide spectral range. These outstanding performances of optical frequency generation could find applications in high precision spectroscopy, frequency calibration, and length metrology.