Optics and Electronics Seminar

OSA/SPIE present "A revolution in high-performance computing driven by CMOS-integrated photonics"

Topic: 
A revolution in high-performance computing driven by CMOS-integrated photonics
Abstract / Description: 

Recent years have seen an explosive growth in bandwidth requirements at all levels of computing, from consumer-grade GPUs to datacenters and supercomputers. Consensus is growing that traditional interconnect development is reaching its limits. Electrical I/O is limited to line data rates of around 112 Gbps, given physical limits of copper and dielectrics losses, and noise. Proposed approaches to surpass this limit increasingly offer higher rates without providing any real benefit; bandwidth comes with degradation of power consumption, complexity, and cost. Furthermore, the 112 Gbps limit is achievable only over very short distances, constraining the architecture of computer systems.

Photonic I/O is the only viable, near-term path to increasing data rates, and to solving the problems of power consumption, bandwidth, and latency faced by electrical I/O. Its low latency and low propagation loss can enable new "disaggregated" computer architectures, with separate chips of memory and logic linked over larger distances for more efficient utilization.

Ayar labs is pursuing a photonic interconnect solution that involves an external multi-wavelength laser source, an integrated transceiver chip with photonics densely integrated along with CMOS circuits, along with advanced chip packaging and optical-fiber connectivity. The transceiver chip integrates electro-optic modulators and detectors with analog drivers, control logic, and SERDES, taking advantage of dense integration to reduce parasitics, power consumption, latency, and packaging costs. Micro-rings provide wavelength-division multiplexing of many channels needed to achieve high capacity per chip edge at low power consumption. This development comes at an exciting time: the emergence of a large-scale process for CMOS-compatible photonics along with and advanced packaging ecosystem is converging with an acute market need for bandwidth density.

Date and Time: 
Tuesday, February 11, 2020 - 4:15pm
Venue: 
Allen 101X

Special MSE Colloquium presents "Spatiotemporal Metaphotonics"

Topic: 
Spatiotemporal Metaphotonics
Abstract / Description: 

Materials are often used to manipulate waves. Metamaterials have provided far-reaching possibilities in achieving "extremes" in such wave-matter interaction. Various exciting functionalities have been achieved in exploiting metamaterials and metasurfaces in nanophotonics and nano-optics. We have been exploring how spatiotemporal metamaterials can give us new platforms in metaphotonics for exploiting waves to do certain useful functions for us. Several scenarios are being investigated in my group. As one scenario, we have been developing metastructure platforms that can perform analog computation such as solving integral and differential equations and inverting matrices with waves as waves interact with them. Such "metamaterial machines" can function as wave-based analog computing machines, suitable for micro- and nanoscale integration. Another scenario deals with 4-dimensional metamaterials, in which temporal variation of material parameters is added to the tools of spatial inhomogeneities for manipulating light-matter interaction with spatiotemporal platforms. The third category for metaphotonics is the concept of near-zero-index materials, structures and associated photonic doping that exhibit unique features in light-matter interaction, opening doors to exciting new wave-based and quantum optical features. In this talk, I will present some of our ongoing work on extreme and spatiotemporal material platforms for metaphotonics, and will forecast possible future research directions in these paradigms.

Date and Time: 
Tuesday, February 4, 2020 - 3:00pm to Wednesday, February 5, 2020 - 2:55pm
Venue: 
Durand 450

Q-Farm Quantum Seminar Series presents "Surprises from Time Crystals"

Topic: 
Surprises from Time Crystals
Abstract / Description: 

Time crystals are new states of matter that only exist in an out-of-equilibrium setting. I will review the state of this rapidly evolving field, focusing in particular on some of the remarkable properties of this phase, and the surprises coming out of its study. I will provide a detailed overview of existing experiments, with a view towards identifying the ingredients needed for an unambiguous observation of this phase in the future.

Date and Time: 
Wednesday, January 29, 2020 - 12:00pm to Thursday, January 30, 2020 - 11:55am
Venue: 
Hansen Physics & Astrophysics Building, 102/103

OSA/SPIE present "Writing and submitting your papers and How to become an editor"

Topic: 
Preparing your papers for submission+Becoming a journal editor
Abstract / Description: 

Rachel will talk you through the detailed information and guidelines on scientific paper preparation and submission. She will share with you some guidelines and tips for writing an abstract and a paper, as well as the submission, editorial and peer-review processes. Information about how to become an editor will also be provided.

Date and Time: 
Wednesday, February 5, 2020 - 4:15pm
Venue: 
Spilker 232

OSA/SPIE present "Nanoscale Foundries: Electronics, Photonics, Ionics, Fluidics"

Topic: 
Nanoscale Foundries: Electronics, Photonics, Ionics, Fluidics
Abstract / Description: 

Modern silicon fabs routinely produce functional electrical components for a few dollars at part counts exceeding billions per year and a complexity rivaling the human genome. The productivity of these fabs is ensured by design rules that govern the structures that constitute these systems. These design rules govern the range of sizes and separations between various materials - from silicon to metals and dielectrics. However, the essential design rules do not dictate function. For example, MEMs structures have been realized in silicon without modification of the design rules (so called zero-change). Here, we show that the manufacturing infrastructure and design rules support a host of functions and applications beyond electronics - to include nanoscale photonics, ionics, and fluidics. We utilize open foundries (such as MOSIS) that support many users sharing the cost of fabrication. Our nanoscale photonics, ionics, and fluidics are realized next to the electronic circuits designed by small and large companies, students from around the world, and people who just like to tinker. They are the machine shops of the nano-era.

Date and Time: 
Thursday, January 30, 2020 - 4:00pm to Friday, January 31, 2020 - 3:55pm
Venue: 
Spilker 232

OSA/SPIE present "Gallium Nitride and its Transformation of the Lighting Industry"

Topic: 
Gallium Nitride and its Transformation of the Lighting Industry
Abstract / Description: 

The invention of the transistor in 1947 inspired research in semiconductor materials other than germanium and silicon, including compound III-V "direct-bandgap" semiconductors that could efficiently emit light. It was a student of transistor-inventor John Bardeen, Nick Holonyak, Jr., who explored alloy engineering aspects of these compounds that eventually led to the first demonstration of a practical visible-spectrum light emitting diode (LED) in 1962. Since then, several compound semiconductor materials systems have been developed for LEDs, the most important of which is the (Al,Ga,In)N system which demonstrated blue-emitting LEDs for the first time and for which the Nobel Prize in Physics was awarded in 2014. This rather unusual material system is now the backbone of solid-state lighting, which has transformed the flat-planel display industry, and has now penetrated about 50% of the traditional (i.e., incandescent, fluorescent, discharge) general lighting market, delivering enormous savings in energy consumption. This seminar will tell this story, including details of III-Nitride optoelectronic device physics, and look at what we might expect in the future for III-Nitride based photonic devices and their applications.

Date and Time: 
Thursday, January 23, 2020 - 4:00pm to Friday, January 24, 2020 - 3:55pm
Venue: 
Spilker 232

AP 483 Seminar Series presents "Photovoltaic Restoration of Sight in Retinal Degeneration"

Topic: 
Photovoltaic Restoration of Sight in Retinal Degeneration
Abstract / Description: 

Retinal degenerative diseases lead to blindness due to loss of the “image capturing” photoreceptors, while neurons in the “image-processing” inner retinal layers are relatively well-preserved. Information can be reintroduced into the visual system by photovoltaic subretinal implants, which convert incident light into electric current and stimulate the secondary retinal neurons.

 

To provide sufficient light intensity for photovoltaic stimulation while avoiding visual perception by remaining photoreceptors, images captured by a camera are projected onto the retina from augmented-reality glasses using pulsed near-infrared light. This design avoids the use of bulky electronics and wiring, thereby greatly reducing the surgical complexity and enabling scaling the number of photovoltaic pixels to thousands. Many features of the natural retinal signal processing are preserved in this approach, and spatial resolution matches the pixel pitch (so far 100 μm pixels in human patients, and 50 μm in rodents). For a broad acceptance of this technology by patients who lost central vision due to Age-Related Macular Degeneration, visual acuity should exceed 20/100, which requires pixels smaller than 25 μm. I will present a 3-dimensional electro-neural interface scalable to cellular dimensions and discuss the outlook and challenges for future developments.


 AP483 Optics and Electronics Seminar Series 2019-20 (Sponsored by Ginzton Laboratory, SPRC, Applied Physics, Physics, and HEPL).

Date and Time: 
Monday, February 24, 2020 - 4:15pm
Venue: 
Spilker 232

AP 483 Seminar Series presents "Taking the Humble FBG on a Voyage of Discovery from the Lab Bench to the Hospital and Beyond"

Topic: 
Taking the Humble FBG on a Voyage of Discovery from the Lab Bench to the Hospital and Beyond
Abstract / Description: 

Fiber Bragg gratings (FBGs) emerged almost magically in 1978. Since then, they have developed from being primarily of academic interest, to being one of the most versatile photonic components for both telecommunications and sensing. 

I was lucky enough to get introduced to photonics during the early years of discovery and experimentation with FBGs and ended up making FBG components for telecommunications. Jumping forward a few decades, I had moved away from telecommunications and had started to dabble with free space optical sensing. Then, during a chance meeting over a beer in Sydney, I was asked, rather naively, if it was possible to use optical fiber to monitor what goes on in the esophagus when we swallow. This set me off on an entirely new path and, pulling together some ideas from telecoms, and some basic mechanical engineering, my team ended up developing a range of sensors for monitoring pressure in the human digestive tract. 

Being able to detect swallowing disorders quickly led to monitoring in other regions of the gut, like the colon and small bowel, and, together with colleagues from Flinders Medical Center, we provided some details of the inner workings of the human gastrointestinal tract. Thus, the fiber optic catheter was born. This device kept me busy for almost 10 years, during which time we worked closely with clinical research groups to write a whole new chapter on how the gut works.

The next ‘Eureka’ moment came when we had to develop a temperature independent version of our sensor, initially for monitoring pressure beneath bandages. The very simple design that resulted worked well for sub-bandage measurements but has also become a key technology that has moved to applications in aerospace, pipeline monitoring, and mining.

When I started working in optics, I never thought I'd end up monitoring what makes your stomach growl when hungry, how air flows across an airplane wing, or detecting pressure transients in water pipes. 

During this talk I will explain how our basic transducers work and will then describe the applications they are now being applied to, demonstrating how the humble FBG has opened up the scope and reach of fiber-optic sensing.


 

AP483 Optics and Electronics Seminar Series 2019-20 (Sponsored by Ginzton Laboratory, SPRC, Applied Physics, Physics, and HEPL).

Date and Time: 
Monday, February 10, 2020 - 4:15pm
Venue: 
Spilker 232

AP 483 Seminar Series presents "Non-Hermitian Photonics: Optics at an Exceptional Point"

Topic: 
Non-Hermitian Photonics: Optics at an Exceptional Point
Abstract / Description: 

In recent years, non-Hermitian degeneracies, also known as exceptional points (EPs), have emerged as a new paradigm for engineering the response of optical systems. At such points, an N-dimensional space can be represented by a single eigenvalue and one eigenvector. As a result, these points are associated with abrupt phase transitions in parameter space. Among many different non-conservative photonic configurations, parity-time (PT) symmetric systems are of particular interest since they provide a powerful platform to explore, and consequently utilize, the physics of exceptional points in a systematic manner. In this talk, I will review some of our recent works in the area of non-Hermitian (mainly PT-symmetric) active photonics. For example, in a series of works, we have demonstrated how the generation and judicial utilization of these points in laser systems can result in unexpected dynamics, unusual linewidth behavior, and improved modal response. On the other hand, biasing a photonic system at an exceptional point can lead to orders of magnitude enhancement in sensitivity, an effect that may enable a new generation of ultrasensitive optical sensors on-chip. Non-Hermiticity can also be used as a means to promote or single out an edge mode in photonic topological insulator lattices. Rotation sensors play a crucial role in a diverse set of applications associated with navigation, positioning, and inertial sensing. Most optical gyroscopes rely on the Sagnac effect induced phase shift that scales linearly with the rotational velocity. In ring laser gyroscopes (RLGs), this shift manifests itself as a resonance splitting in the emission spectrum that can be detected as a beat frequency. The need for evermore precise RLGs has fueled research activities towards devising new approaches aimed to boost the sensitivity beyond what is dictated by geometrical constraints. In this respect, attempts have been made in the past to use either dispersive or nonlinear effects. Here, we propose a new scheme for ultrasensitive laser gyroscopes that utilizes the physics of exceptional points. By exploiting the properties of such non- Hermitian degeneracies, we show that the rotation-induced frequency splitting becomes proportional to the square root of the gyration speed, thus enhancing the sensitivity to low angular rotations by orders of magnitudes. We will then describe a possible modification of a standard RLG to support an exceptional point and measure the resulting enhanced sensitivity in the proposed system.


 

Date and Time: 
Monday, January 27, 2020 - 4:15pm
Venue: 
Spilker 232

AP 483 Seminar Series presents "Where Are We Heading: A Brief History and Future of Navigation"

Topic: 
Where Are We Heading: A Brief History and Future of Navigation
Abstract / Description: 

- tba -


 

AP483 Optics and Electronics Seminar Series 2019-20 (Sponsored by Ginzton Laboratory, SPRC, Applied Physics, Physics, and HEPL).

Date and Time: 
Monday, January 13, 2020 - 4:15pm
Venue: 
Spilker 232

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