High Speed Travelling Wave Carrier Depletion Silicon Mach-Zehnder Modulator

Abstract: We present the first demonstration of a travelling wave carrier depletion Mach-Zehnder modulator impedance matched to 50 : This device has a bandwidth of 24 GHz and a halfwave voltage length product of 0.7 V-cm, placing it among the best in its class

Metropolitan quantum key distribution with silicon photonics

Photonic integrated circuits (PICs) provide a compact and stable platform for quantum photonics. Here we demonstrate a silicon photonics quantum key distribution (QKD) transmitter in the first high-speed polarization-based QKD field tests. The systems reach composable secret key rates of 950 kbps in a local test (on a 103.6-m fiber with a total emulated loss of 9.2 dB) and 106 kbps in an intercity metropolitan test (on a 43-km fiber with 16.4 dB loss). Our results represent the highest secret key generation rate for polarization-based QKD experiments at a standard telecom wavelength and demonstrate PICs as a promising, scalable resource for future formation of metropolitan quantum-secure communications networks

Low-power high-speed silicon microdisk modulators

Abstract: A novel silicon microdisk modulator with "error-free" ~3 femtojoule/bit modulation at 12.5Gbs has been demonstrated. Modulation with a 1 volt swing allows for compatibility with current and future digital logic CMOS electronics

An Apical PDZ Protein Anchors the Cystic Fibrosis Transmembrane Conductance Regulator to the Cytoskeleton

The function of the cystic fibrosis transmembrane conductance regulator (CFTR) as a Cl- channel in the apical membrane of epithelial cells is extensively documented. However, less is known about the molecular determinants of CFTR residence in the apical membrane, basal regulation of its Cl- channel activity, and its reported effects on the function of other transporters. These aspects of CFTR function likely require specific interactions between CFTR and unknown proteins in the apical compartment of epithelial cells. Here we report that CFTR interacts with the recently discovered protein, EBP50 (ERM-binding phosphoprotein 50). EBP50 is concentrated at the apical membrane in human airway epithelial cells, in vivo, and CFTR and EBP50 associate in in vitro binding assays. The CFTR-EBP50 interaction requires the COOH-terminal DTRL sequence of CFTR and utilizes either PDZ1 or PDZ2 of EBP50, although binding to PDZ1 is of greater affinity. Through formation of a complex, the interaction between CFTR and EBP50 may influence the stability and/or regulation of CFTR Cl- channel function in the cell membrane and provides a potential mechanism through which CFTR can affect the activity of other apical membrane proteins

Loss-of-function mutations in the X-linked biglycan gene cause a severe syndromic form of thoracic aortic aneurysms and dissections.

Thoracic aortic aneurysm and dissection (TAAD) is typically inherited in an autosomal dominant manner, but rare X-linked families have been described. So far, the only known X-linked gene is FLNA, which is associated with the periventricular nodular heterotopia type of Ehlers-Danlos syndrome. However, mutations in this gene explain only a small number of X-linked TAAD families. We performed targeted resequencing of 368 candidate genes in a cohort of 11 molecularly unexplained Marfan probands. Subsequently, Sanger sequencing of BGN in 360 male and 155 female molecularly unexplained TAAD probands was performed. We found five individuals with loss-of-function mutations in BGN encoding the small leucine-rich proteoglycan biglycan. The clinical phenotype is characterized by early-onset aortic aneurysm and dissection. Other recurrent findings include hypertelorism, pectus deformity, joint hypermobility, contractures, and mild skeletal dysplasia. Fluorescent staining revealed an increase in TGF-β signaling, evidenced by an increase in nuclear pSMAD2 in the aortic wall. Our results are in line with those of prior reports demonstrating that Bgn-deficient male BALB/cA mice die from aortic rupture. In conclusion, BGN gene defects in humans cause an X-linked syndromic form of severe TAAD that is associated with preservation of elastic fibers and increased TGF-β signaling.Genet Med 19 4, 386-395

Bounds on the k-dimension of Products of Special Posets

Trotter conjectured that dimP×Q≥dimP+dimQ−2 for all posets P and Q. To shed light on this, we study the k-dimension of products of finite orders. For k ∈ o(ln n), the value 2dimk(P)−dimk(P×P) is unbounded when P is an n-element antichain, and 2dim2(mP)−dim2(mP×mP) is unbounded when P is a fixed poset with unique maximum and minimum. For products of the “standard” orders S m and S n of dimensions m and n, dimk(Sm×Sn)=m+n−min{2,k−2} . For higher-order products of “standard” orders, dim2(∏ti=1Sni)=∑ni if each n i  ≥ t.Hertz FoundationUnited States. Dept. of Defense (National Defense Science and Engineering Program)United States. National Security Agency (Award H98230-06-1-0065)United States. National Security Agency (Award H98230-10-1-0363

Integrated optical phase locked loop

Abstract: A silicon photonics based integrated optical phase locked loop is utilized to synchronize a 10.2 GHz voltage controlled oscillator with a 509 MHz mode locked laser, achieving 32 fs integrated jitter over 300 kHz bandwidth

Athermal silicon optical add-drop multiplexers based on thermo-optic coefficient tuning of sol-gel material

Silicon photonics has gained interest for its potential to provide higher efficiency, bandwidth and reduced power consumption compared to electrical interconnects in datacenters and high performance computing environments. However, it is well known that silicon photonic devices suffer from temperature fluctuations due to silicon's high thermo-optic coefficient and therefore, temperature control in many applications is required. Here we present an athermal optical add-drop multiplexer fabricated from ring resonators. We used a sol-gel inorganic-organic hybrid material as an alternative to previously used materials such as polymers and titanium dioxide. In this work we studied the thermal curing parameters of the sol-gel and their effect on thermal wavelength shift of the rings. With this method, we were able to demonstrate a thermal shift down to -6.8 pm/% for transverse electric (TE) polarization in ring resonators with waveguide widths of 325 nm when the sol-gel was cured at 130 % for 10.5 hours. We also achieved thermal shifts below 1 pm/% for transverse magnetic (TM) polarization in the C band under different curing conditions. Curing time compared to curing temperature shows to be the most important factor to control sol-gel's thermo-optic value in order to obtain an athermal device in a wide temperature range. (C) 2017 Optical Society of AmericaNational Science Foundation (NSF) CIAN ERC [EEC-0812072]; Office of Naval Research (ONR) NECom MURIOpen access journal.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]