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We present a novel photonic integrated circuit (PIC) that monolithically integrates a racetrack colliding-pulse mode-locked laser with a pulse-picking electro-absorption modulator and a semiconductor optical amplifier on Indium Phosphide. We present detailed characterization of this PIC that includes optical pulse characterization, phase noise and long term stability under passive and hybrid mode-locking conditions. Allan deviation measurements made on the optical pulse train from the PIC show a fractional frequency instability of $8\times 10 ^{-11}$ at 1 second and follow a 1/ $\tau $ trend. We also demonstrate repetition rate reduction from ~10 GHz to ~500 MHz with an extinction ratio of ~14.65 dB using an on-chip pulse-picking electro-absorption modulator.

A 305 GHz dissipative Kerr soliton is synchronized to a chip-scale 10GHz mode-locked laser through regenerative harmonic injection locking, the repetition rate stability of the mode-locked laser after synchronization is shown to be 10−9 at 100 ms.

We present an optical frequency division technique to transfer the timing stability of a stabilized Kerr Microresonator Soliton Frequency Comb (~305 GHz repetition rate) to a chip-scaled mode-locked laser (~10 GHz repetition rate).

A mmWave optical frequency comb with a repetition rate of ~300GHz is synchronized to a MLL with a repetition rate of ~10GHz via harmonic injection locking using

A mm-Wave frequency comb with 240GHz spacing is synchronized to a MLL-PIC using harmonic injection locking, this represent optical frequency division of 24x. The Allan Deviation on the repetition rate stability is 10-10 at 1s.

A novel injection locking architecture is demonstrated to simultaneously improve the axial mode linewidth and stabilize the repetition rate of a monolithically integrated mode-locked laser. First, linewidth reduction is demonstrated via multitone injection locking. Then, the passive mode-locked laser is used as a source to make a coupled optoelectronic oscillator, and its RF spectral characteristics are investigated for different optical delays. A novel combination of these two techniques is established by creating a coupled optoelectronic oscillator via multitone injection locking, using an intracavity element as photodetector to generate the feedback signal to a Mach-Zehnder modulator. Using this combination of methods, the axial mode linewidth is reduced by over 6000× to $\sim$ 100 kHz and the RF linewidth is reduced by a factor of 70 at $-$ 30 dBc, resulting in a 3 dB RF linewidth of 400 Hz. The improvement in RF phase noise at 200 kHz offset is $>$ 40 dB. Finally, the system is referenced to a RF synthesizer using a variable voltage phase-shifter and a PID controller. Allan deviation measurements show a resolution limited stability in the repetition rate of $10^{-10}$ at 1 second following a $1/\tau$ trend.

Miniaturization of frequency-comb sources could open a host of potential applications in spectroscopy, biomedical monitoring, astronomy, microwave signal generation, and distribution of precise time or frequency across networks. This review article places emphasis on an architecture with a semiconductor mode-locked laser at the heart of the system and subsequent supercontinuum generation and carrier-envelope offset detection and stabilization in nonlinear integrated optics.

We present an all-optical technique to divide millimeter-wave range (20–80GHz) optical frequency combs down to microwave regime (10GHz) using harmonic injection locking of a chip-scale MLL achieving a repetition rate stability of 10−10 at 1s.

A novel optical frequency division technique, called regenerative harmonic injection locking, is used to transfer the timing stability of an optical frequency comb with a repetition rate in the millimeter wave range ( ∼ 300 G H z ) to a chip-scale mode-locked laser with a ∼ 10 G H z repetition rate. By doing so, the 300 GHz optical frequency comb is optically divided by a factor of 30 × to 10 GHz. The stability of the mode-locked laser after regenerative harmonic injection locking is ∼ 10 − 12 at 1 s with a 1 / τ trend. To facilitate optical frequency division, a coupled opto-electronic oscillator is implemented to assist the injection locking process. This technique is exceptionally power efficient, as it uses less than 100 µ W of optical power to achieve stable locking.

We present the detailed science case, and brief descriptions of the telescope design, site, and first light instrument plans for a new ultra-wide field submillimeter observatory, CCAT-prime, that we are constructing at a 5600 m elevation site on Cerro Chajnantor in northern Chile. Our science goals are to study star and galaxy formation from the epoch of reionization to the present, investigate the growth of structure in the Universe, improve the precision of B-mode CMB measurements, and investigate the interstellar medium and star formation in the Galaxy and nearby galaxies through spectroscopic, polarimetric, and broadband surveys at wavelengths from 200 m to 2 mm. These goals are realized with our two first light instruments, a large field-of-view (FoV) bolometer-based imager called Prime-Cam (that has both camera and an imaging spectrometer modules), and a multi-beam submillimeter heterodyne spectrometer, CHAI. CCAT-prime will have very high surface accuracy and very low system emissivity, so that combined with its wide FoV at the unsurpassed CCAT site our telescope/instrumentation combination is ideally suited to pursue this science. The CCAT-prime telescope is being designed and built by Vertex Antennentechnik GmbH. We expect to achieve first light in the spring of 2021., Ground-based and Airborne Telescopes VII, June 10-15, 2018, Austin, USA, Series: Proceedings of SPIE; no. 10700

The CCAT-prime telescope is a 6-meter aperture, crossed-Dragone telescope, designed for millimeter and sub-millimeter wavelength observations. It will be located at an altitude of 5600 meters, just below the summit of Cerro Chajnantor in the high Atacama region of Chile. The telescope's unobscured optics deliver a field of view of almost 8 degrees over a large, flat focal plane, enabling it to accommodate current and future instrumentation fielding >100k diffraction-limited beams for wavelengths less than a millimeter. The mount is a novel design with the aluminum-tiled mirrors nested inside the telescope structure. The elevation housing has an integrated shutter that can enclose the mirrors, protecting them from inclement weather. The telescope is designed to co-host multiple instruments over its nominal 15 year lifetime. It will be operated remotely, requiring minimum maintenance and on-site activities due to the harsh working conditions on the mountain. The design utilizes nickel-iron alloy (Invar) and carbon-fiber-reinforced polymer (CFRP) materials in the mirror support structure, achieving a relatively temperature-insensitive mount. We discuss requirements, specifications, critical design elements, and the expected performance of the CCAT-prime telescope. The telescope is being built by CCAT Observatory, Inc., a corporation formed by an international partnership of universities. More information about CCAT and the CCAT-prime telescope can be found at www.ccatobservatory.org., Event: SPIE Astronomical Telescope + Instrumentation, 2018, Austin, Texas, USA; Proceedings Volume 10700, Ground-based and Airborne Telescopes VII; 107005X (2018)

CCAT-prime will be a 6-meter aperture telescope operating from sub-mm to mm wavelengths, located at 5600 meters elevation on Cerro Chajnantor in the Atacama Desert in Chile. Its novel crossed-Dragone optical design will deliver a high throughput, wide field of view capable of illuminating much larger arrays of sub-mm and mm detectors than can existing telescopes. We present an overview of the motivation and design of Prime-Cam, a first-light instrument for CCAT-prime. Prime-Cam will house seven instrument modules in a 1.8 meter diameter cryostat, cooled by a dilution refrigerator. The optical elements will consist of silicon lenses, and the instrument modules can be individually optimized for particular science goals. The current design enables both broadband, dual-polarization measurements and narrow-band, Fabry-Perot spectroscopic imaging using multichroic transition-edge sensor (TES) bolometers operating between 190 and 450 GHz. It also includes broadband kinetic induction detectors (KIDs) operating at 860 GHz. This wide range of frequencies will allow excellent characterization and removal of galactic foregrounds, which will enable precision measurements of the sub-mm and mm sky. Prime-Cam will be used to constrain cosmology via the Sunyaev-Zeldovich effects, map the intensity of [CII] 158 $\mu$m emission from the Epoch of Reionization, measure Cosmic Microwave Background polarization and foregrounds, and characterize the star formation history over a wide range of redshifts. More information about CCAT-prime can be found at www.ccatobservatory.org., Comment: Presented at SPIE Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX, June 15th, 2018

Repetition rate stabilization of an injection locked chip-scale mode-locked laser and progress towards carrier envelope offset frequency stabilization using chalcogenide waveguides for supercontinuum generation and a bulk PPLN for second harmonic generation are presented.

We report the stabilization of a 10 GHz monolithic passively mode-locked laser using a novel combination of multitone injection locking and regenerative mode-locking via optoelectronic loop. Comb-teeth linewidths are narrowed by 4000x and repetition rate is stabilized to better than 10−10/τ at 1 second.

A novel method of regenerative mode-locking using multi-tone optical injection locking of a chip-scale CPM laser is demonstrated. This technique achieves simultaneous reduction in RF phase noise (8x) and narrows the longitudinal mode by 4,000x.

We present a novel racetrack colliding-pulse mode-locked laser with external pulse-picking and optical amplification monolithically integrated on InP. Optical pulses with FWHM of 2.36 ps are observed under hybrid mode-locking at 10 GHz repetition rate.

We calculate numerically the quantum capacitance of a nanocapacitor formed of oxide-silicon layers deposited alternately with their widths following a Cantor set structure. We show that this configuration brings about a nano-hybrid capacitor which allows a classical and quantum behavior depending on the Cantor generation. In addition, we propose an approximate equivalent circuit representation for the nano-hybrid capacitor.

We describe an upgrade to the Cosmic Background Imager instrument to increase its surface brightness sensitivity at small angular scales. The upgrade consisted of replacing the thirteen 0.9-m antennas with 1.4-m antennas incorporating a novel combination of design features, which provided excellent sidelobe and spillover performance for low manufacturing cost. Off-the-shelf spun primaries were used, and the secondary mirrors were oversized and shaped relative to a standard Cassegrain in order to provide an optimum compromise between aperture efficiency and low spillover lobes. Low-order distortions in the primary mirrors were compensated for by custom machining of the secondary mirrors. The secondaries were supported on a transparent dielectric foam cone to minimize scattering. The antennas were tested in the complete instrument, and the beam shape and spillover noise contributions were as expected. We demonstrate the performance of the telescope and the inter-calibration with the previous system using observations of the Sunyaev-Zel'dovich effect in the cluster Abell 1689. The enhanced instrument has been used to study the cosmic microwave background, the Sunyaev-Zel'dovich effect and diffuse Galactic emission.

In this paper we describe the status of an upgrading program that it is being carried out to modernize the front and back ends of the Southern 1.2-m mm-Wave Telescope to cover eciently the band from 86 to 115 GHz. On the one hand, the new front end will have a sideband-separating conguration to suppress the image band noise. This front end will use one low noise amplier and two Schottky diodes for down conversion. On the other hand, we are developing a modern digital spectrometer, based on the Recongurable Open Architecture Computing Hardware (ROACH), to ease the operation and improve the spectral resolution up to a factor of 4. Moreover, the spectrometer will include IF hybridization capabilities to avoid analog hybrids and, therefore, improve the sideband rejection ratio of the receiver.

The Q/U Imaging ExperimenT (QUIET) employs coherent receivers at 43GHz and 94GHz, operating on the Chajnantor plateau in the Atacama Desert in Chile, to measure the anisotropy in the polarization of the cosmic microwave background (CMB). QUIET primarily targets the B modes from primordial gravitational waves. The combination of these frequencies gives sensitivity to foreground contributions from diffuse Galactic synchrotron radiation. Between 2008 October and 2010 December, over 10,000hr of data were collected, first with the 19 element 43 GHz array (3458hr) and then with the 90 element 94 GHz array. Each array observes the same four fields, selected for low foregrounds, together covering ≈1000 deg2. This paper reports initial results from the 43 GHz receiver, which has an array sensitivity to CMB fluctuations of 69μK√s. The data were extensively studied with a large suite of null tests before the power spectra, determined with two independent pipelines, were examined. Analysis choices, including data selection, were modified until the null tests passed. Cross-correlating maps with different telescope pointings is used to eliminate a bias. This paper reports the EE, BB, and EB power spectra in the multipole range ℓ = 25-475. With the exception of the lowest multipole bin for one of the fields, where a polarized foreground, consistent with Galactic synchrotron radiation, is detected with 3σ significance, the E-mode spectrum is consistent with the ΛCDM model, confirming the only previous detection of the first acoustic peak. The B-mode spectrum is consistent with zero, leading to a measurement of the tensor-to-scalar ratio of r = 0.35+1.06 -0.87. The combination of a new time-stream "double-demodulation" technique, side-fed Dragonian optics, natural sky rotation, and frequent boresight rotation leads to the lowest level of systematic contamination in the B-mode power so far reported, below the level of r = 0.1. © 2011. The American Astronomical Society. All rights reserved.

The Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope provides an unprecedented opportunity to study gamma-ray blazars. To capitalize on this opportunity, beginning in late 2007, about a year before the start of LAT science operations, we began a large-scale, fast-cadence 15 GHz radio monitoring program with the 40-m telescope at the Owens Valley Radio Observatory (OVRO). This program began with the 1158 northern (declination>-20 deg) sources from the Candidate Gamma-ray Blazar Survey (CGRaBS) and now encompasses over 1500 sources, each observed twice per week with a ~4 mJy (minimum) and 3% (typical) uncertainty. Here, we describe this monitoring program and our methods, and present radio light curves from the first two years (2008 and 2009). As a first application, we combine these data with a novel measure of light curve variability amplitude, the intrinsic modulation index, through a likelihood analysis to examine the variability properties of subpopulations of our sample. We demonstrate that, with high significance (7-sigma), gamma-ray-loud blazars detected by the LAT during its first 11 months of operation vary with about a factor of two greater amplitude than do the gamma-ray-quiet blazars in our sample. We also find a significant (3-sigma) difference between variability amplitude in BL Lacertae objects and flat-spectrum radio quasars (FSRQs), with the former exhibiting larger variability amplitudes. Finally, low-redshift (z, 23 pages, 24 figures. Submitted to ApJS

We present the results of the flux density measurements at 4.85 GHz and 10.45 GHz of a sample of 5998 NVSS radio sources with the Effelsberg 100 m telescope. The initial motivation was the need to identify the NVSS radio sources that could potentially contribute significant contaminating flux in the frequency range at which the Cosmic Background Imager experiment operated. An efficient way to achieve this challenging goal has been to compute the high frequency flux density of those sources by extrapolating their radio spectrum. This is determined by the three-point spectral index measured on the basis of the NVSS entry at 1.4 GHz and the measurements at 4.85 GHz and 10.45 GHz carried out with the 100 m Effelsberg telescope. These measurements are important since the targeted sample probes the weak part of the flux density distribution, hence the decision to make the data available. We present the table with flux density measurements of 3434 sources that showed no confusion allowing reliable measurements, their detection rates, their spectral index distribution and an interpretation which explains satisfactorily the observed uncertainties., Comment: 13 pages, 9 figures, in press