Photonic microwave true time delays for phased array antennas using a 49  GHz FSR integrated optical micro-comb source [Invited]

Xu, Xingyuan; Wu, Jiayang; Nguyen, Thach G.; Moein, Tania; Chu, Sai T.; Little, Brent E.; Morandotti, Roberto; Mitchell, Arnan; Moss, David J.

doi:10.1364/prj.6.000b30

Cited by 221 publications

(157 citation statements)

References 61 publications

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“…The transversal structure, similar to the concept of finite impulse response digital filters, is a fundamental tool for photonic RF signal processing. With the proper design of the tap weights, any transfer function can be arbitrarily realized for different signal processing functions such as bandpass filters, differentiators and Hilbert transformers [23][24][25][26][27][28][29][30][31][32][33][34].…”

Section: Rf Transversal Signal Processorsmentioning

confidence: 99%

“…In addition, for photonic RF channelizers, with a given bandwidth for each wavelength channel, the total operation bandwidth (i.e., the maximum bandwidth of the input RF signal that can be processed) will depend on the number of wavelengths, and thus can be greatly enhanced with microcombs. Based on these advantages, a wide range of RF applications have been demonstrated, such as optical true time delays [23][24][25], transversal filters [25][26][27], signal processors [28,29], channelizers [30,31] and others [32][33][34]. Here, we review the recent advances of RF signal processing functions made possible through the use of microcombs, highlighting their potential and future possibilities.…”

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confidence: 99%

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Microcomb-Based Photonic RF Signal Processing

Tan

et al. 2019

IEEE Photon. Technol. Lett.

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Microcombs are powerful tools as sources of multiple wavelength channels for photonic RF signal processing. They offer a compact device footprint, large numbers of wavelengths, and wide Nyquist bands. Here, we review recent progress on microcomb-based photonic RF signal processors, including true time delays, reconfigurable filters, Hilbert transformers, differentiators, and channelizers. The strong potential of optical micro-combs for RF photonics applications in terms of functions and integrability is also discussed.Index Terms-Microwave photonics, micro-ring resonators. I. INTRODUCTIONHOTONIC RF techniques have attracted great interest during the past two decades since they offer ultra-high RF bandwidths, low transmission loss and strong immunity to electromagnetic interference. They have found wide applications ranging from radar systems to communications [1-5]. Among the many useful photonic RF techniques, optical frequency combs are one of the most fundamental and powerful tools due to their ability to provide multiple wavelength channels that can greatly increase the capacity of communications systems and allow the broadcast of RF spectra for advanced signal processing functions. However, traditional approaches for frequency comb generation, including those based on discrete laser arrays or electro-optic (EO) modulation, [6-9] all face limitations, such as their bulky size and large cost brought about by laser arrays and RF sources, or a limited free spectral range (FSR) of the comb lines that in turn yields a limited Nyquist zone for the RF system.Kerr optical frequency combs [10-22], or "microcombs", that originated from the optical parametric oscillation in monolithic micro-ring resonators (MRRs), offer distinct advantages over traditional multi-wavelength sources for RF applications, such as the potential to provide a much higher number of wavelengths, an ultra-large FSR, as well as greatly reduced footprint and complexity. In particular, for RF transversal functions, the number of wavelengths dictates the available channel number of RF time delays, and thus with microcombs, the performance of RF beamforming systems and filters can be greatly enhanced in terms of the angular resolution and quality factor, respectively. In addition, for photonic RF channelizers, with a given bandwidth for each wavelength channel, the total operation bandwidth (i.e., the maximum bandwidth of the input RF signal that can be processed) will depend on the number of wavelengths, and thus can be greatly enhanced with microcombs. Based on these advantages, a wide range of RF applications have been demonstrated, such as optical true time delays [23][24][25], transversal filters [25][26][27], signal processors [28,29], channelizers [30,31] and others [32][33][34]. Here, we review the recent advances of RF signal processing functions made possible through the use of microcombs, highlighting their potential and future possibilities.

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Section: Rf Transversal Signal Processorsmentioning

confidence: 99%

mentioning

confidence: 99%

Microcomb-Based Photonic RF Signal Processing

Tan

et al. 2019

IEEE Photon. Technol. Lett.

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160

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“…Diverse platforms have been developed for microcomb generation [47] such as silica, magnesium fluoride, silicon nitride, and doped silica glass. The MRRs used in the experiments reviewed here were fabricated using CMOS compatible fabrication processes, with Q factors of over 1.2 million and radii of ~592 μm and ~135 μm, corresponding to FSRs of ~0.4 nm (~49 GHz) and ~1.6 nm (~200 GHz), respectively [118,127].…”

Section: Integrated Kerr Microcombsmentioning

confidence: 99%

Photonic RF spectral filters based on transversal filters with Kerr microcombs of varying free spectral ranges

Moss¹,

Tan²,

Xu³

et al. 2020

Preprint

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Integrated Kerr microcombs are emerging as a powerful tool as sources of multiple wavelength channels for photonic RF and microwave signal processing mainly in the context of transversal filters. They offer a compact device footprint, very high versatility, large numbers of wavelengths, and wide Nyquist bands. Here, we review recent progress on Kerr microcomb-based photonic RF and microwave reconfigurable filters, based both on transversal filter methods and on RF to optical bandwidth scaling. We compare and contrast results achieved with wide comb spacing combs (200GHz) with more finely spaced (49GHz) microcombs. The strong potential of optical micro-combs for RF photonics applications in terms of functions and integrability is also discussed. Index Terms-Microwave photonics, micro-ring resonators.

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“…The Kerr coefficient of GO is on the order of 10 -15~1 0 -14 m 2 /W [33,34], which is slightly lower than that of graphene (~10 -13 m 2 /W) [36,37], but still orders of magnitude higher than that of high-index doped silica glass (~10 -19 m 2 /W) and silica (~10 -20 m 2 /W) [25]. The waveguides were fabricated via CMOS compatible processes [38][39][40]. First, high-index doped silica glass films (n = ~1.60 at 1550 nm) were deposited using standard plasma enhanced chemical vapour deposition (PECVD), then patterned using deep UV photo-lithography and etched via reactive ion etching (RIE) to form waveguides with exceptionally low surface roughness.…”

Section: Introductionmentioning

confidence: 99%

Enhanced four-wave mixing in hybrid integrated waveguides with graphene oxide

Yang

et al. 2019

2D Photonic Materials and Devices II

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Enhanced four-wave mixing in hybrid integrated waveguides with graphene oxide," Proc. ABSTRACTOwing to the ease of preparation as well as the tunability of its material properties, graphene oxide (GO) has become a rising star of the graphene family. In our previous work, we found that GO has an ultra-high Kerr nonlinear optical response -several orders of magnitude higher than that of silica and even silicon. Moreover, as compared with graphene, GO has much lower linear loss as well as nonlinear loss (two photon absorption (TPA)), arising from its large bandgap (2.4~3.1 eV) being more than double the photon energy in the telecommunications band. Here, we experimentally demonstrate enhanced four-wave mixing (FWM) in hybrid integrated waveguides coated with GO films. Owing to strong mode overlap between the integrated waveguides and the high Kerr nonlinearity GO films as well as low linear and nonlinear loss, we demonstrate significant enhancement in the FWM efficiency. We achieve up to ~9.5-dB enhancement in the conversion efficiency for a 1.5-cm-long waveguide with 2 layers of GO. We perform FWM measurements at different pump powers, wavelength detuning, GO film lengths and numbers of layers. The experimental results verify the effectiveness of introducing GO films into integrated photonic devices in order to enhance the performance of nonlinear optical processes.

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Photonic microwave true time delays for phased array antennas using a 49 GHz FSR integrated optical micro-comb source [Invited]

Cited by 221 publications

References 61 publications

Microcomb-Based Photonic RF Signal Processing

Microcomb-Based Photonic RF Signal Processing

Photonic RF spectral filters based on transversal filters with Kerr microcombs of varying free spectral ranges

Enhanced four-wave mixing in hybrid integrated waveguides with graphene oxide

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