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The third-order optical nonlinearity in optical waveguides has found applications in optical switching, optical wavelength conversion, optical frequency comb generation, and ultrafast optical signal processing. The development of an…

Optics · Physics 2020-05-05 Yaojing Zhang , Zhenzhou Cheng , Yifei Yao , Hon Ki Tsang

A waveform channel is considered where the transmitted signal is corrupted by Wiener phase noise and additive white Gaussian noise (AWGN). A discrete-time channel model is introduced that is based on a multi-sample receiver. Tight lower…

Information Theory · Computer Science 2013-03-28 Hassan Ghozlan , Gerhard Kramer

Ground-based spectrometers have been developed to measure the concentration, velocity, and temperature of ozone in the mesosphere and lower thermosphere (MLT) using low-cost satellite television electronics to observe the 11.072 GHz…

Instrumentation and Methods for Astrophysics · Physics 2015-08-18 O. B. Alam , A. E. E. Rogers

The terahertz (THz) band radio access with larger available bandwidth is anticipated to provide higher capacities for next-generation wireless communication systems. However, higher path loss at THz frequencies significantly limits the…

Signal Processing · Electrical Eng. & Systems 2023-09-01 Hasan Nayir , Erhan Karakoca , Ali Görçin , Khalid Qaraqe

The Terahertz band holds a promise to enable both super-accurate sensing and ultra-fast communication. However, challenges arise that severe Doppler effects call for a waveform with high Doppler robustness while severe propagation path loss…

Signal Processing · Electrical Eng. & Systems 2025-02-26 Meilin Li , Chong Han , Shi Jin

In multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems, representing the whole channel only based on partial subchannels will significantly reduce the channel acquisition overhead. For such a…

Signal Processing · Electrical Eng. & Systems 2024-01-09 Zirui Chen , Zhaoyang Zhang , Zhaohui Yang , Lei Liu

Despite recent progress in nonlinear optics in wavelength-scale resonators, there are still open questions on the possibility of parametric oscillation in such resonators. We present a general approach to predict the behavior and estimate…

Optics · Physics 2021-02-22 Saman Jahani , Arkadev Roy , Alireza Marandi

High-density communication through optical fiber is made possible by Wavelength Division Multiplexing, which is the simultaneous transmission of many discrete signals at different optical frequencies. Vast quantities of data may be…

Optics · Physics 2020-02-19 Paul Fisher , Matteo Villa , Francesco Lenzini , Mirko Lobino

Microwave Kinetic Inductance Detectors (MKIDs) are the most attractive radiation detectors for far-infrared and sub-mm astronomy: They combine ultimate sensitivity with the possibility to create very large detector arrays, in excess of 10…

Instrumentation and Methods for Astrophysics · Physics 2016-04-04 Joris van Rantwijk , Martin Grim , Dennis van Loon , Stephen Yates , Andrey Baryshev , Jochem Baselmans

Multiple Mach-Zehnder interferometers are constructed using fiber-Bragg grating couplers, y-branches, silicon waveguides, and/or broadband splitters in silicon on insulator strip waveguides to test the effect of variation in waveguide…

Optics · Physics 2025-07-03 Cael Warner

A system using a non-linear multi-swept sine wave system is described which employs a multi-channel, multi-swept orthogonal waves, to separate channels and make multiple, simultaneous online/offline CO2 measurements. An analytic expression…

Atmospheric and Oceanic Physics · Physics 2013-04-30 Joel F. Campbell

Near-field imaging experiments exist both in optics and microwaves with often different methods and theoretical supports. For millimeter waves or THz waves, techniques from both fields can be merged to identify materials at the micron scale…

Instrumentation and Detectors · Physics 2021-01-29 Laurent Chusseau , Thibaut Auriac , Jérémy Raoult

The integration density of photonic integrated circuits has been limited by light coupling between waveguides. Traditional approaches to layout the waveguide with high density are based on refractive index engineering to suppress the light…

Recent spectroscopic observations by sensitive radio telescopes require accurate molecular spectral line frequencies to identify molecular species in a forest of lines detected. To measure rest frequencies of molecular spectral lines in the…

Instrumentation and Methods for Astrophysics · Physics 2021-01-27 Yoshimasa Watanabe , Yutaro Chiba , Takeshi Sakai , Akemi Tamanai , Rikako Suzuki , Nami Sakai

This letter presents a dual quadrature phasemeter, an implementation of a phase-locked loop designed to track the phase of homodyne and heterodyne inter-satellite laser links. The dual quadrature phasemeters use dual quadrature optical…

Optics · Physics 2024-10-30 Callum S. Sambridge , Kirk McKenzie

The OH molecule, found abundantly in the Milky Way, has four transitions at the ground state rotational level(J = 3/2) at cm wavelengths. These are E1 transitions between the F+ and F- hyperfine levels of the Lambda doublet of the J=3/2…

Astrophysics of Galaxies · Physics 2010-07-05 Visweshwar Ram Marthi , Jayaram N. Chengalur

In astronomy or biological imaging, refractive index inhomogeneities of e.g. atmosphere or tissues induce optical aberrations which degrade the desired information hidden behind the medium. A standard approach consists in measuring these…

Optics · Physics 2023-06-01 Tengfei Wu , Marc Guillon , Gilles Tessier , Pascal Berto

Coplanar waveguide resonators are central to the thriving field of circuit quantum electrodynamics. Recently, we have demonstrated the generation of a broadband microwave-frequency comb spectrum using a superconducting quantum interference…

High power and low phase noise oscillators at terahertz frequencies are required for several burgeoning scientific and technological applications, including radioastronomy, imaging, molecular spectroscopy, radar, and wireless…

A periodically poled lithium niobate (PPLN) waveguide-based single-pixel up-conversion infrared spectrometer was demonstrated. Sum-frequency generation between a 1.5 micrometer band scanning pump laser and a 1.3 micrometer band signal…

Instrumentation and Detectors · Physics 2009-11-13 Qiang Zhang , Carsten Langrock , M. M. Fejer , Yoshihisa Yamamoto