Free-running Phase Noise Research Articles

5-GHz Injection-Locked Delay Cell With 10–25 ns Adjustable Group Delay in SiGe BiCMOS

This paper presents an on-chip delay line (DL) unit with an adjustable group delay (GD) between 10 and 25 ns. This active DL is designed based on an injection locked voltage-controlled oscillator (ILVCO) topology, with operation frequency of 5 GHz. Analog GD tuning is achieved through the control voltage of the VCO and the power of the injected signal. The free running phase noise (PN) of the DL at 100 kHz and 10 MHz offsets are -98 and -140 dBc/Hz, respectively, and the DL PN follows the PN of the injected signal in the locked mode. The DL was implemented in a 130-nm SiGe BiCMOS platform, and consumes 1.26 mm2 of silicon area. The power dissipation of the VCO core and buffer stage are 1.68 and 17.7 mW, respectively. To the authors best knowledge, the proposed DL achieves one of the highest GDs among the integrated DL cells.

Ultralow Noise Optical Frequency Combs

The invention of optical frequency combs (OFCs) based on femtosecond (fs) mode-locked lasers has merged laser based spectroscopy with fs-laser technology. OFCs have triggered quantum leaps of advancement in photonics, physics, astronomy, and engineering, while also lending themselves to applications in medical and environmental fields. The key feature of OFCs is their ultrahigh frequency and time resolution. In this review, we introduce the concept behind OFCs and their sources, with a focus on stability and phase-noise performance. We conclude with a discussion of recent progress of a monolithic OFC, which provides ultralow free-running phase noise and an unprecedented frequency stability of 1 part in ${10^{19}}$ at a 1 s gate time.

A 42 mW 200 fs-Jitter 60 GHz Sub-Sampling PLL in 40 nm CMOS

A 60 GHz sub-sampling PLL implemented in 40 nm CMOS is presented in this paper. The sub-sampling phase detector (SSPD) runs at 30 GHz after an inductively-peaked static divide-by-two. Thanks to the lower frequency of operation, the effect of non-zero sampling aperture of the switch is minimized. A dummy divider of the quadrature PLL is utilized for the sub-sampling loop to avoid extra loading in the 60 GHz path. A 53.8–63.3 GHz QVCO uses super-harmonic coupling at 120 GHz for relaxed headroom at a 0.9 V supply and achieves a free-running phase noise down to ${-}$ 94.5 dBc/Hz at 1 MHz offset. The millimeter-wave sub-sampling PLL achieves an RMS jitter, integrated from 1 kHz to 100 MHz, of 200 fs at a power consumption of 42 mW, compared to 210 fs for the PFD/CP PLL at 75 mW. Reference spurs in both modes are below ${-}$ 40 dBc.

Phase-noise measurement using two inter-injection-locked microwave oscillators

Phase noise in two mutually coupled oscillators is analyzed by the describing function method, and the after-lock phase noise of the oscillators is calculated in terms of their free-running phase noise. A new phase-noise measurement technique based on inter-injection locking of two similar oscillators is proposed. Experimental results are presented, which confirm the theory. It is shown that in the case of zero phase of coupling coefficient, the system is in the optimum state where the only required parameter for the measurement is the locking bandwidth. In this optimum state, as far as the locking bandwidth is measured correctly, imperfections such as the frequency drift, parameters discrepancy, and nonlinear susceptance of the oscillators have no serious effect on the measurement accuracy. The proposed method is compared to the conventional ones.

A Ka-band MMIC oscillator utilizing a labyrinthine PBG resonator

A Ka-band monolithic microwave integrated circuit (MMIC) oscillator was implemented by using a coplanar waveguide photonic bandgap (PBG) resonator and a 0.1-/spl mu/m GaAs pseudomorphic high electron mobility transistor. A coplanar labyrinthine one-dimensional PBG resonator was used for reduction in MMIC size. The fabricated MMIC oscillator had an output power of 6.5dBm at 30.3GHz and a free-running phase noise of -80dBc/Hz at 100-kHz offset.

Low Phase Noise, InGaP/GaAs HBT VCO MMIC for Millimeter-Wave Applications

A fully integrated voltage controlled oscillator (VCO) MMIC for millimeter-wave applications has been designed and implemented in InGaP/GaAs heterojunction bipolar transistor (HBT) technology. To achieve a fully integrated VCO, a base-emitter diode is employed as the tuning varactor, and microstrip lines are employed for the transmission lines. The fabricated VCO MMIC chip size is 0.86 mm x 1.34 mm and delivers an output power of 5.1 dBm at 28.7 GHz and a free-running phase noise of -118 dBc/Hz at 1 MHz offset. The dc current consumption is only 20 mA.

Phase-noise properties of an ytterbium-doped fiber amplifier for the Laser Interferometer Space Antenna

Phase noise is a critical issue for the sensitivity of the interferometric gravitational-wave detector Laser Interferometer Space Antenna that requires laser sources with 1 W of output power. A low-power seed laser with a subsequent fiber amplifier is in discussion, and we report on spectrally resolved phase-noise measurements of an ytterbium-doped fiber amplifier emitting 1 W of output power from 10 mW of seed power. Phase-noise measurements for Fourier frequencies from 10(-4) Hz to 100 kHz show 60 rad/Hz0.5 at 10(-4) Hz and 0.2 mrad/Hz0.5 at 1 kHz. This measured excess phase noise is orders of magnitude below the free-running phase noise of nonplanar ring oscillators.

Analysis of Coupled Phase-Locked Loops With Independent Oscillators for Beam Control Active Phased Arrays

Phase dynamics and phase noise of N coupled phase-locked loops (PLLs) with N independent oscillators are analyzed. The phase noise of coupled PLLs with independent oscillators is analyzed by using the signal flow graph and Mason's gain rules. The near-carrier phase noise of PLL elements in the array can be reduced to 1/N that of a single independent (without coupling) VCO of the PLL element, and return to its free-running phase noise far from the carrier frequency, provided the coupling network is reciprocal, the feedback loop gain of the PLL elements is large, and the phase detector and amplifier noise are neglected. The phase dynamics and noise improvement of coupled PLL arrays are verified by using two coupled PLLs with independent GaAs MESFET oscillators operating at X-band.

Simple K-band MMIC VCO utilizing a miniaturized hairpin resonator and a three-terminal p-HEMT varactor with low phase noise and high output power properties

Presents a fully monolithic K-band MMIC voltage-controlled oscillator (VCO) implemented by using a 0.25 /spl mu/m AlGaAs/InGaAs pseudomorphic HEMT (p-HEMT) technology. The use of a half-wavelength miniaturized hairpin-shaped resonator and a three-terminal p-HEMT varactor was effective in reducing the chip size and simplifying fabrication processes of the microwave MMIC VCO without impairing the performance of the circuit. The VCO provides a typical output power of 11.5 dBm at 20.8 GHz and a free-running phase noise of -82 dBc/Hz at 100 kHz offset and -95 dBc/Hz at 1 MHz offset. It also shows a tuning range of 70 MHz with little reduction in output power and high yield properties. The chip size of the MMIC VCO is 1.5 /spl times/ 2.0 mm/sup 2/.