Photonics Society at UCSB
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  • Home
  • Members
    • Alumni
  • Calendar
  • Events
    • Lectures >
      • Industry Perspective Lectures
      • IPS Lectures
      • Student Lectures
      • Alumni Lectures
      • OSA Lectures
    • Outreach Events
    • Women in Photonics Week >
      • WIPW 2019
      • WiPW 2018
      • WiPW 2017
      • WiPW 2016
    • Light Science Workshop >
      • Light Science 2018
      • Light Science 2017
    • Day of Light >
      • Day of Light 2019
      • 2015 Symposium
    • Banquet >
      • Banquet 2024
      • Banquet 2022
      • Banquet 2019
      • Banquet 2016
      • Banquet 2014
    • QIS >
      • QIS 2024
      • QIS 2023
      • QIS2022
      • QIS2021
    • Social Events
    • Sign-up for Student Talks
  • Education
    • Education Home
    • After-School Science >
      • Light-Pipes: Controlling Light
      • DIY Holograms
      • Color Mixing
      • LaserComm
      • Fluorescence
    • Classes
    • Outreach Events
    • Outreach Kits 2020
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Heterogeneous Photonics for Next-generation Optoelectronics and Analog Processors

11/11/2019

 
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Dr. Volker J. Sorger

Associate Professor
ECE Dept. - George Washington University


Volker J. Sorger is an Associate Professor in the Department of Electrical and Computer Engineering, and the leader of the Integrated Nanophotonics lab at the George Washington University. He received his PhD from the University of California Berkeley and MS from UT Austin. His research focuses on integrated photonics and plasmonics, and analog information processing such as programmable photonic circuits and neuromorphic computing. His work was recognized by Presidential Early Career Award for Scientists and Engineers (PECASE), the Emil Wolf prize from the Optical Society of America, the AFOSR Young Investigator (YIP) award, the Hegarty Innovation prize, the National Academy of Sciences paper-of-the-year award, and both the Early Career and Outstanding Research awards at GWU. He is the editor-in-chief of the Nanophotonics and the OSA division chair for Optoelectronics-and-Photonics. He serves at the boards of OSA and SPIE, and is a senior member of IEEE, OSA & SPIE. Further details at sorger.seas.gwu.edu.

Thurs. Nov 14, 2019 | 12:00 - 1:00 pm | ESB 2001
Photonic technologies are at the forefront of the ongoing 4th industrial revolution of digitalization supporting applications such as virtual reality, autonomous vehicles, and electronic warfare. The development of integrated photonics in recent years enabled functional devices and circuits through miniaturization. However, fundamental challenges such as the weak light-matter integration can limited silicon and III-Vbased devices to millimeter-scale footprints demanding about one million photons-per-bit. Overcoming these challenges, in the first part of this talk I will show how nanoscale photonics together with heterogeneous integration of emerging materials into foundry-based photonic chips enables strong nonlinearity, which we use to demonstrate attojoule and compact optoelectronics. Here I will discuss our recent devices demonstrating ITO-based MZI modulators, 2D-material excitonic photodetectors, and exotic epsilon-near-zero modes empowering record-efficient phase shifters for applications in data-comm, LiDAR, and photonic neural networks (NN). Further, I will show that the usually parasitic Kramers-Kronig relations of altering the optical index can be synergistically exploited delivering new modulator operations. With Moore’s law and Dennard scaling now being limited by fundamental physics, the trend in processor heterogeneity suggests the possibility for special-purpose photonic processors such as NNs or RF-signal & image filtering. Here unique opportunities exist, for example, given by algorithmic parallelism of analog computing enabling non-iterative O(1) processors, thus opening prospects for distributed nonvan Neumann architectures. In the second part of this talk, I will share our latest work on analog photonic processors to include a) a feed-forward fully-connected NN, b) mirror symmetry perception via coincidence detection of spiking NNs, c) a Fourier-optics based convolutional processor with 1 PMAC/s throughputs at nanosecond-short delays for real-time processing, d) a photonic residue arithmetic adder, and e) meshbased reconfigurable photonic & metatronic PDE solvers. In summary, heterogeneous photonics connects the worlds of electronics and optics, thus enabling new classes of efficient optoelectronics and analog processors by employing the distinctive properties of light.
Pizza will be provided!

Photonic Integration for RF Photonics Systems

7/24/2019

 
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Dr. Paul Morton
Founder, C.E.O., C.T.O.
Morton Photonics Inc.
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Wednesday, July 31 | 12:00pm | ESB 2001
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Photonic Integration for RF Photonics Systems Photonic integration on the Silicon Photonics platform, together with heterogeneous integration to include other materials, provides an ideal platform for the development of complex photonic integrated circuit (PIC) devices. This talk will describe the requirements for basic RF Photonics systems, including low noise lasers, linear modulators, low loss optical processing elements, and high power photodetectors, followed by descriptions of devices and PICs that Morton Photonics is developing for these functions.

The talk will describe how a high performance PIC including arrays of these devices can be utilized for the processing of a phased array sensor to provide Multiple-Channel Simultaneous RF Beamforming, and describe potential commercial markets for these technologies, including automotive LIDAR systems, analog photonic links and RF Beamforming for 5G systems

Refreshments Provided!
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Dr. Paul Morton introduces his talk about RF Photonic Systems

Student Lecture Series: June 7th 2019

6/5/2019

 
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Matthew Wong
DenBaars group
Materials Dept, UCSB

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High Efficiency III-Nitride Mirco-Light-Emitting Diodes for Display Applications

Micro-light-emitting diodes (µLEDs) with high energy efficiency are desired for a variety of display applications, including virtual reality (VR) and augmented reality (AR) near-eye displays. Although outstanding performances in different display aspects have been demonstrated with InGaN µLEDs, there are several challenges for commercialization. In this talk, two main issues, namely size-dependent efficiency and mass transfer of µLEDs, will be addressed and some promising solutions will be discussed.
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Takako Hirokawa
Schow group
ECE Dept, UCSB

Energy Efficiency Analysis of Coherent Links for
Datacenters

We propose that coherent optical communication can offer energy-efficient operation in datacenters. Analysis and simulations determine optimal operating points for the laser and local oscillator (LO) and compare trade-offs in Silicon (Si) and Indium Phosphide (InP) Mach-Zehnder Modulators (MZMs) to reach pJ/b scale efficiency.
Friday, June 7th | 12:00pm | Elings 1605

Santa Barbara Photonics Banquet

5/24/2019

 
The 3rd Santa Barbara Photonics Banquet took place on:
Tuesday June 4th, 6pm at Corwin Pavilion @ UCSB

See the event page for more info:

SB Photonics Banquet 2019

Student Lecture Series: May 31st 2019

5/22/2019

 
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Kristina Davis
Mazin group
Physics Dept, UCSB

Coherent Differential Imaging Techniques for MKID Detectors

The field of direct imaging of exoplanetary systems allows astronomers to gain both photometric and spectroscopic analysis of these exoplanetary systems. I will present a technique I call Heterodyne Optical Phase Probe (HOPP) that measures the phase change of an incoming heterodyne signal incident on the kinetic inductance detector array as the deformable mirror is actuated. By measuring the phase response, we can improve our models of the DM surface shape under a variety of optical conditions, and have a better calibration of how to scale the offset positions we feed the DM when performing speckle nulling.

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Chris Zollner
Nakamura group
Materials Dept, UCSB

MOCVD growth of AlN on SiC substrates for deep-UV optoelectronics: an inside the box approach

MOCVD growth of high-quality GaN on sapphire substrates is vital to today's blue LED industry, but the same methods cannot be applied to AlN/sapphire which is needed for deep-UV optoelectronics. We have developed a novel approach to MOCVD growth of AlN on SiC with quality comparable to industrial GaN/sapphire, and demonstrated UV-LEDs emitting at 280nm.
Friday, May 31st | 12:00 pm | Elings 1605

Fluency Lighting: The Path of a Startup

5/13/2019

 
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​Dr. Kristin Denault
Fluency Founder & CEO
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Friday, May 17th | 12:00 pm | ESB 2001
Fluency Lighting Technologies is an early stage start-up company developing technology out of UC Santa Barbara. At Fluency, we are creating next-generation bright and narrow-beam light sources for highly efficient illumination, using laser technology and materials design. Our focus is the development of low-cost, optical platforms that convert laser diode emission into high-quality white light in various light levels, beam angles, and color temperatures, designed for customer-driven metrics, in applications where energy-saving LED technology is not used because of the limited light output from an LED.
Refreshments will be provided
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Dr. Denault begins her talk about the work done in lighting technology at her company, Fluency.

Fast, Widely Tunable MEMS-VCSELs for Imaging, Metrology, and Spectroscopy

5/13/2019

 
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​Dr. Vijaysekhar Jayaraman
Founder
​Praevium Research
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Thursday, May 16th | 12:00 pm | Elings 1601
In recent years, widely tunable micro-electro-mechanical systems vertical cavity surface-emitting lasers (MEMS-VCSELs) have found commercial application in swept source optical coherence tomography medical imaging and also show considerable promise in metrology and spectroscopy. These devices exhibit fractional tuning ranges of >11% of the center wavelength, wavelength tuning repetition rates over full tuning range of >1MHz, and clean single-mode operation. These properties, in conjunction with small size and wafer scale fabrication and testing, promise an economical optical source that can impact sensing applications from the visible to the mid-infrared.
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I. Grulkowski, et al. Biomedical Optics Express 2012
Refreshments will be provided
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Dr. Jayaraman begins his talk about different applications for MEMS-Tunable VCSELs

History and Key Development in GaN Based Photonics and Electronics at UCSB

5/13/2019

 
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​Dr. Steven DenBaars
Mitsubishi Distinguished Professor 
Materials Distinguished Professor
Electrical & Computer Engineering

Wednesday, May 15th | 12:00 pm | ESB 1001
In this talk I will highlight the history of GaN research at UCSB, and some of the key breakthroughs and technologies developed by the faculty, students and staff.  Starting with one MOCVD system, UCSB Faculty were the first University world-wide to achieve a blue GaN Laser in 1996. In 2000, Prof. Shuji Nakamura joined the Faculty and along with Prof. DenBaars, Prof. Speck and Prof. Mishra co-founded the Solid State Lighting and Energy Electronics Center (SSLEEC), which has now become one of the largest academic GaN based Photonic and Electronic research centers in the world. SSLEEC has played a key role in developing numerous breakthroughs, some of which have led to the realization of high-efficiency Solid-State Lighting, which the Dept. of Energy estimates will save the equivalent annual electrical output of about fifty 1,000-megawatt power plants. 

​Looking into the future we see next generation GaN Laser Diode based solid state lighting as impacting high brightness specialty lighting. We have demonstrated laser based white lighting with luminous efficacies of 87 lm/watt, and over 1000 lumens from a single emitter.  In addition, tunnel junctions have been employed to achieve vertical cavity surface emitting lasers (VCSELs) in the blue spectral region. Blue and green lasers and Micro-LEDs based on GaN materials are expected to enable new full color projections displays for cinema, office and augmented reality (AR) applications.

Refreshments will be provided

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Dr. DenBaars begins his talk about GaN photonics and electronics developments made at UCSB
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Dr. DenBaars' talk filled the room with lots of interested students.

The Perils of Conventional Thinking

5/8/2019

 
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Dr. Chris Cole

Finisar
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Thursday, May 9th | 12:00 pm | Elings 1601
Chris will discuss next-generation optical interfaces for large scale datacenters, including Intensity Modulated Direct Detection and Coherent technologies at 100, 200, 400 and 800 Gb/s rates. He will show several examples of how applying insights gained from previously successful applications can lead to flawed conclusions about different applications. If he is persuasive, students will no longer trust what they are taught by their professors and other experts.
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Refreshments Provided.
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Dr. Cole outlines his discussion of Telecom and different modulation formats in the data center

Student Lecture Series: May 3rd 2019

5/2/2019

 
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Yating Wan
Bowers group
​ECE Dept, UCSB
Low Threshold 1.55 um Quantum Dash Microring Lasers 
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We report the first room-temperature-continuous-wave (CW) operation of electrically-injected InAs quantum-dash microring lasers emitting at 1.55 µm telecom window. The microrings sustain CW lasing up to 55°C, while the lowest threshold current density is 528 A/cm2 .

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Lei Wang
Klamkin group
​ECE Dept, UCSB
Quantum dot devices on silicon grown by MOCVD 
Direct heteroepitaxy of III-V quantum dots (QDs) is promising for achieving a monolithic laser source for silicon photonics. QDs are believed to be less sensitive to defects than quantum wells, and also offer desirable characteristics for high temperature operation and reduced sensitivity to reflection, because of the 3D carrier confinement of individual QDs. In this talk, I will introduce my research on growth of aluminium-free InAs/GaAs quantum dot laser structure on CMOS-compatible (001) by MOCVD, and some initial fabrication works for both electrically and optically devices. 
Friday, May 3 | 12:00pm | Elings 1605
Pizza will be provided!

Quantum Photonics Using 2D Materials

4/21/2019

 
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​Dr. Vinod Menon
Professor of Physics
City University of New York

Friday April 26th | 12:00 pm | Elings 1605
Two-dimensional Van der Waals materials have emerged as a very attractive class of optoelectronic material due to the unprecedented strength in its interaction with light. In this talk I will discuss approaches to realize quantum photonic devices by integrating these 2D materials with microcavities, and metamaterials. I will first discuss the formation of strongly coupled half-light half-matter quasiparticles (microcavity polaritons) and their optical and electrical control in the 2D transition metal dichacogenide (TMD) systems. Prospects of realizing condensation and few photon nonlinear switches using Rydberg states in TMDs will also be discussed. Following this, I will discuss the broadband enhancement of light-matter interaction in these 2D materials using photonic hypercrystals and chiral metasurfaces. Finally, I will talk about room temperature single photon emission from hexagonal boron nitride and the prospects of developing deterministic quantum emitters using them through strain engineering. The realization of room temperature single photon emitters and few photon
nonlinear switches using 2D materials presents an attractive direction for robust next generation quantum photonic technologies.
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Refreshments Provided!
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Dr. Menon describes the different categories of 2D materials and identifies Van der Waals materials

Low voltage SiGe avalanche photodiodes for low energy high speed optical links

4/21/2019

 
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​Dr. Zhihong Huang
HP Labs 

Tuesday, April 23rd | 12:00 pm | Elings 1601
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Today zettabytes of data are generated and nearly doubled every two years. The conventional microprocessor is reaching its physical limitation and cannot keep up with the exponential growth in rich data. This leads to the increased demands on memory systems due to their frequent access patterns between microprocessors and memories. High speed, low energy and high sensitive optical data links are desirable for data transmission between multicores, microprocessors and memories in the new data center and high performance computer architectures. I am going to talk about the silicon photonics efforts in developing low energy high speed optical links in Hewlett Packard Labs, including the development of low voltage SiGe avalanche photodiodes, as well as photonic links.

Refreshments Provided!
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Dr. Zhihong Huang introduces her talk about silicon APDs developed at HP Labs.

Applications of Optoelectronics in Facebook Hyperscale Datacenters

4/7/2019

 
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Dr. Katharine Schmidtke
Optical Technology Strategy
Facebook

Monday, April 15 | 12:00pm | Elings 1605
From subsea fiber cables to short-reach switch interconnects, opto-electronics is a key technology for hyperscale data center networks. As performance requirements increase, photonics moves deeper into the network replacing copper for shorter distances. The next move for photonics is to distances of less than 3m for in-rack applications. This talk will describe how the scale of data-bandwidth growth has challenged what is possible with traditional networks and where the next opportunities for innovation lie.
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Refreshments Provided!

Think small: developing color centers in crystals for nanoscale optical sensors of fields and forces

4/7/2019

 
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​Dr. Claire McLellan
Department of Material Science and Engineering
Stanford University

Friday, April 12 | 12:00pm | Elings 1605
From mapping inter-cellular mechanical interactions in the immune system to imaging magnetic phenomena in condensed matter systems, there is a growing need for noninvasive sensors with high spatial resolution. Color centers in crystals such as alkaline-earth upconverting nanoparticles (UCNPs) and the nitrogenvacancy (NV) center in diamond are an exciting class of sensors for highresolution imaging because of their optical readout, nanoscale size, and robust hosts. The first part of this talk will discuss UCNPs for mechanical force sensing in biological applications. UCNPs consist of a ceramic host doped with lanthanides (Yb3+ and Er3+). They operate by absorbing low energy infrared photons and emitting higher energy visible photons. Mechanical forces cause a change in the crystal symmetry and spacing of the dopant atoms, which results in a change of emission intensity and color. We have recently detected 27 nN forces with our UCNPs, a requisite for detecting inter-cellular forces in the immune system. The second half of this talk will discuss using the NV center in diamond as a magnetic force sensor. Through careful materials science studies in the Jayich lab, we created NV ensembles approaching the NV dipolar interaction limit of sensitivity. Using these NV ensembles, we imaged magnetic structure in CoTiSb.
Refreshments provided!
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Dr. McLellan explains that the up-conversion wavelength of nanoparticles depends on the pressure exerted. This effect allows the particles to be used as nano-scale forces sensors.

Advanced Optical Sources for Spectrally Efficient Photonic Systems

2/28/2019

 
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Prof. Liam Barry
Department of Electronic Engineering
Dublin City University

Monday March 11th, 11am, ESB 1001
Abstract
The continuing growth in demand for bandwidth (from residential and business users), necessitates significant research into new advanced technologies that will be employed in future broadband communication systems. Two specific technologies, becoming increasingly important for future photonic systems, are wavelength tunable lasers and optical frequency combs. Although these topics have been studied for over two decades their significance for the development of future ultra-high capacity photonic systems has only recently been fully understood. Wavelength tunable lasers are currently becoming the norm in optical communication systems because of their flexibility and ability to work on any wavelength. However, as their operating principles are different to standard single mode lasers they can effect how future systems will operate. For example as optical transmission systems move towards more coherent transmission (where the data is carried using both the intensity and phase of the optical carrier), the phase noise in these tunable lasers will become increasingly important. Optical frequency combs also have many applications for future photonics systems, and for telecommunications they can be used to obtain the highest spectral efficiency in optical transmission systems by employing the technology of optical frequency division multiplexing (OFDM), and also for generation of high frequency RF signals in future 5G networks. Wavelength tunable lasers and optical frequency combs are thus topics at the leading edge of current photonics systems research, and their detailed understanding promises new applications in all-optical signal processing, optical sensing and metrology, and specifically telecommunications. This talk will focus on the development and characterization of various wavelength tunable lasers and optical frequency combs, and then outline how these sources can be employed for developing optical transmission systems and networks which make the best use of available optical spectrum.

Biography
Liam Barry received his BE (Electronic Engineering) and MEngSc (Optical Communications) 
degrees from University College Dublin in 1991 and 1993 respectively. From February 1993 until January 1996 he was employed as a Research Engineer in the Optical Systems Department of
France Telecom's Research Laboratories (now known as Orange Labs) in Lannion, France, and as a result of this work he obtained his PhD Degree from the University of Rennes in France. In February 1996 he joined the Applied Optics Center in Auckland University, New Zealand, as a Research Fellow and in March 1998 he took up a lecturing position in the School of Electronic Engineering at Dublin City University, and established the Radio and Optical Communications Laboratory. From April 2006 until February 2010 he served as Director of The Rince Institute, an interdisciplinary research center with over 100 researchers. He is currently a Professor in the School of Electronic Engineering, a Principal Investigator for Science Foundation Ireland, and Director of the Radio and Optical Communications Laboratory. His main research interests are; all-optical signal processing, optical pulse generation and characterization, hybrid radio/fibre communication systems, wavelength tuneable lasers for reconfigurable optical networks, and optical performance monitoring. He has published over 200 articles in international peer reviewed journals, 250 papers in international peer reviewed conferences, and holds 10 patents in the area of optoelectronics. He has been a TPC member for the European Conference on Optical Communications (ECOC) since 2004, and a TPC member for the Optical Fibre Communication Conference (OFC) from 2007 to 2010, serving as Chair of the Optoelectronic Devices sub-committee for OFC 2010.
Refreshments provided!

Student Lecture Series: March 1st

2/26/2019

 
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Hector Andrade
Schow Group
​Electrical Engineering

​Monolithically-Integrated Photoreceiver with Cherry-Hooper TIA in BiCMOS Technology

In this talk, we report a monolithically-integrated photoreceiver with a pseudo-differential Cherry-Hooper trans-impedance amplifier (TIA) in a 250 nm BiCMOS process. High sensitivity 50 Gbps operation is demonstrated, and the TIA architecture is analyzed. 

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Songtao Liu
Bowers Group
​Electrical Engineering

A Low-noise High-channel-count 20 GHz Passively Mode Locked Quantum Dot Laser Grown on Si

Low cost, small footprint, highly efficient and mass producible on-chip wavelength-division-multiplexing (WDM) light sources are key components in future silicon electronic and photonic integrated circuits (EPICs). We present here, for the first time, a low noise high-channel-count 20 GHz passively mode locked quantum dot laser grown on CMOS compatible on-axis (001) silicon substrate. The laser demonstrates a wide mode locking regime in the O-band. The 3 dB optical bandwidth of the comb is 6.1 nm (containing 58 lines, with 80 lines within the 10 dB bandwidth). Utilizing 64 channels, an aggregate total transmission capacity of 4.1 terabits per second is realized by employing a 32 Gbaud Nyquist four-level pulse amplitude modulation format. The demonstrated performance makes the laser a compelling on-chip WDM source for multi-terabit/s optical interconnects in future large scale silicon EPICs.
12:00 PM Friday, March 1st in Elings 1605
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Pizza will be provided!

Starting a Company Successfully

2/13/2019

 
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Dr. Milton Chang
Engineer, Entrepreneur, and Author
​www.miltonchang.com

Thursday, Feb 28, 12 - 1 pm, ESB 1001
Key ingredients for a successful startup are the business idea, founder’s drive and ability, and adequate financial resources. The speaker will discuss practical ways and prescribe a career roadmap for a young person to succeed in entrepreneurship without taking undue risks.

Milton Chang is a serial entrepreneur and angel investor. He successfully built Newport and New Focus to IPO and also participated in incubating Aurrion, a local startup born in UCSB. He is an engineer graduated from the University of Illinois and Caltech and is currently a Trustee of Caltech. You can read the review of his book on starting and managing a startup Toward Entrepreneurship at www.miltonchang.com.
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Refreshments will be provided

The Physics and Applications of Coherently Coupled Photonic Crystal VCSEL Arrays

2/3/2019

 
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​Kent D. Choquette
Electrical and Computer Engineering
University of Illinois

[email protected]

​Friday, Feb 8, 1 – 2 pm, ESB 1001
More than a billion individual VCSELs were deployed before 2017 as optical sources within short-reach optical interconnects as well as for position sensing. In 2018, laser manufacturing began the era of 2D VCSEL arrays. As a result more than a billion new VCSELs were added in a single year to provide new functionality for consumer electronics products. In this talk I will report on the development of coherently coupled VCSEL arrays which may enable new VCSEL applications. I will discuss the physics of operation for antiguided photonic crystal VCSEL arrays, and will show their potential application for electronic beam steering and high speed digital data transmission.
Refreshments Provided!

Student Lecture Series: Jan 25th

1/21/2019

 
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Joseph Fridlander
Integrated Photonics Lab
​Electrical Engineering, UCS
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Photonic Integrated Transmitter for ​
​Space-Optical Communications

Abstract:  This talk provides an overview and demonstrates test results of a photonic integrated circuit transmitter for space optical communication utilizing an RZ-DPSK modulation format realized on an indium phosphide monolithic integration platform.
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Daniel Myers
Dr. James Speck’s
Group
​Materials, UCSB

Understanding the Limitations of LED Efficiency by Electron Emission Spectroscopy

Abstract:  The analysis of the energy distribution of electrons, emitted from the surface of an LED can provide an unambiguous measurement of efficiency loss mechanisms and transport phenomena. Previously this technique has been used to identify Auger recombination as the dominant efficiency loss mechanism for GaN LEDs operating at high current densities. My talk will focus on using this technique to improve the understanding of several other efficiency loss issues. Specifically, the loss of efficiency at elevated temperatures and the poor performance of long-wavelength (green) GaN LEDs.
Friday, Jan. 25th at 12:00 PM in ESB 1001
Pizza will be provided

Coherent Ising machine: a photonic Ising model solver based on degenerate optical parametric oscillator network

1/15/2019

 
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Dr. Hiroki Takesue
NTT Basic Research Laboratories
NTT Corporation
Friday, Jan 18, 12 – 1 pm, Elings 1605
As various systems and networks in our society grow larger and more complex, analysis and
optimization of such systems are becoming increasingly important. Such tasks are classified as combinatorial optimization problems, which are generally difficult to solve with current digital computers. It is well known that combinatorial optimization problems can be converted to ground-state-search problems of the Ising model, a theoretical model for the interacting spins. Recently, several approaches to find solutions to the Ising model using artificial spin systems have been studied intensively. A coherent Ising machine (CIM) is one of such systems in which degenerate optical parametric oscillators (DOPO) pulses are used as artificial spins. By using a long-distance (typically 1 km) fiber cavity that contains a phase sensitive amplifier based on a periodically poled lithium niobate waveguide, we can generate thousands of DOPO pulses multiplexed in time domain. Since a DOPO phase only takes either 0 or p at above threshold, we can stably express an Ising spin with a DOPO by allocating phase 0 (p) as spin up (down). The “spin-spin interaction” can be implemented by using a measurement-feedback scheme, with which we can effectively realize mutual injection of lights among thousands of DOPO pulses. The networked DOPOs are most likely to oscillate at a phase configuration that best stabilize the whole network, which gives the solution to the given Ising problem. Based on this scheme, we realized a CIM with all-to-all-coupled 2000 DOPO pulses, by which we could find good solutions to 2000-node combinatorial optimization problems in less than 100 microseconds. In the talk, I will describe the basic principle and the experimental details of the CIM, as well as our effort for finding its applications.
Refreshments Provided!
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