256 research outputs found
New opportunities for integrated microwave photonics
Recent advances in photonic integration have propelled microwave photonic technologies to new heights. The ability to interface hybrid material platforms to enhance light-matter interactions has led to the developments of ultra-small and high-bandwidth electro-optic modulators, frequency synthesizers with the lowest noise, and chip signal processors with orders-of-magnitude enhanced spectral resolution. On the other hand, the maturity of high-volume semiconductor processing has finally enabled the complete integration of light sources, modulators, and detectors in a single microwave photonic processor chip and has ushered the creation of a complex signal processor with multi-functionality and reconfigurability similar to their electronic counterparts. Here we review these recent advances and discuss the impact of these new frontiers for short and long term applications in communications and information processing. We also take a look at the future perspectives in the intersection of integrated microwave photonics with other fields including quantum and neuromorphic photonics
On-Chip Analog Circuit Design Using Built-In Self-Test and an Integrated Multi-Dimensional Optimization Platform
Nowadays, the rapid development of system-on-chip (SoC) market introduces
tremendous complexity into the integrated circuit (IC) design. Meanwhile, the IC
fabrication process is scaling down to allow higher density of integration but makes
the chips more sensitive to the process-voltage-temperature (PVT) variations. A
successful IC product not only imposes great pressure on the IC designers, who have
to handle wider variations and enforce more design margins, but also challenges the
test procedure, leading to more check points and longer test time. To relax the
designers’ burden and reduce the cost of testing, it is valuable to make the IC chips
able to test and tune itself to some extent.
In this dissertation, a fully integrated in-situ design validation and optimization
(VO) hardware for analog circuits is proposed. It implements in-situ built-in self-test
(BIST) techniques for analog circuits. Based on the data collected from BIST,
the error between the measured and the desired performance of the target circuit is
evaluated using a cost function. A digital multi-dimensional optimization engine is
implemented to adaptively adjust the analog circuit parameters, seeking the minimum
value of the cost function and achieving the desired performance. To verify
this concept, study cases of a 2nd/4th active-RC band-pass filter (BPF) and a 2nd
order Gm-C BPF, as well as all BIST and optimization blocks, are adopted on-chip.
Apart from the VO system, several improved BIST techniques are also proposed
in this dissertation. A single-tone sinusoidal waveform generator based on a finite-impulse-response (FIR) architecture, which utilizes an optimization algorithm to
enhance its spur free dynamic range (SFDR), is proposed. It achieves an SFDR of
59 to 70 dBc from 150 to 850 MHz after the optimization procedure. A low-distortion
current-steering two-tone sinusoidal signal synthesizer based on a mixing-FIR architecture is also proposed. The two-tone synthesizer extends the FIR architecture to
two stages and implements an up-conversion mixer to generate the two tones, achieving better than -68 dBc IM3 below 480 MHz LO frequency without calibration.
Moreover, an on-chip RF receiver linearity BIST methodology for continuous and
discrete-time hybrid baseband chain is proposed. The proposed receiver chain
implements a charge-domain FIR filter to notch the two excitation signals but expose
the third order intermodulation (IM3) tones. It simplifies the linearity measurement
procedure–using a power detector is enough to analyze the receiver’s linearity.
Finally, a low cost fully digital built-in analog tester for linear-time-invariant
(LTI) analog blocks is proposed. It adopts a time-to-digital converter (TDC) to
measure the delays corresponded to a ramp excitation signal and is able to estimate
the pole or zero locations of a low-pass LTI system
Integrated radio frequency synthetizers for wireless applications
This thesis consists of six publications and an overview of the research topic, which is also a summary of the work. The research described in this thesis concentrates on the design of phase-locked loop radio frequency synthesizers for wireless applications. In particular, the focus is on the implementation of the prescaler, the phase detector, and the chargepump.
This work reviews the requirements set for the frequency synthesizer by the wireless standards, and how these requirements are derived from the system specifications. These requirements apply to both integer-N and fractional-N synthesizers. The work also introduces the special considerations related to the design of fractional-N phase-locked loops. Finally, implementation alternatives for the different building blocks of the synthesizer are reviewed.
The presented work introduces new topologies for the phase detector and the chargepump, and improved topologies for high speed CMOS prescalers. The experimental results show that the presented topologies can be successfully used in both integer-N and fractional-N synthesizers with state-of-the-art performance.
The last part of this work discusses the additional considerations that surface when the synthesizer is integrated into a larger system chip. It is shown experimentally that the synthesizer can be successfully integrated into a complex transceiver IC without sacrificing the performance of the synthesizer or the transceiver.reviewe
Optical frequency comb technology for ultra-broadband radio-frequency photonics
The outstanding phase-noise performance of optical frequency combs has led to
a revolution in optical synthesis and metrology, covering a myriad of
applications, from molecular spectroscopy to laser ranging and optical
communications. However, the ideal characteristics of an optical frequency comb
are application dependent. In this review, the different techniques for the
generation and processing of high-repetition-rate (>10 GHz) optical frequency
combs with technologies compatible with optical communication equipment are
covered. Particular emphasis is put on the benefits and prospects of this
technology in the general field of radio-frequency photonics, including
applications in high-performance microwave photonic filtering, ultra-broadband
coherent communications, and radio-frequency arbitrary waveform generation.Comment: to appear in Laser and Photonics Review
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