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Optica is pleased to announce that Dr. Radhakrishnan Nagarajan, Marvell, USA has been selected as the 2024 recipient of the David Richardson Medal. Nagarajan is honored for the successful manufacturing and commercialization of InP and Si-based photonic integrated circuits for use as optical interconnects with a wide range of applications…

UC Santa Barbara’s Institute for Energy Efficiency (IEE) is a world leader in developing breakthrough technologies that substantially save energy while advancing the standard of living worldwide. IEE’s award-winning research has been the foundation for numerous energy-saving innovations including bright and energy-saving white light LED lighting, more energy-efficient data-center communications and interconnects, and software that reduces energy usage in buildings worldwide. Researchers are…

Prof. John Bowers' tutorial on heterogenous integration for data center and sensing applications at 2023 IEEE Photonics Society Conference! Please check out the slides below.

IEE's 15 Year Anniversary! Celebrating Innovations!

The UC Santa Barbara Nanofabrication Facility (Nanofab) is a state-of-the-art cleanroom with more than $60 million in equipment. The Nanofab combines world-class cleanrooms with its expert staff to enable students, faculty, and members from industry design and build impactful nano- and micro-scale technologies. Due to the facility's track record of enabling cutting-edge technology, UCSB and the Nanofab will play a pivotal role in one of the eight national innovation hubs that were…

Our review paper was cited in the Nobel Prize in Chemistry 2023 when they briefly discussed epitaxial dots used in semiconductor lasers as light emitters for optical communication in Reference 68!

ECE Prof. John Bowers and his lab researchers have spent several decades advancing photonic integrated circuits (PICs) – and now, with Caltech and Anello photonic colleagues, they have achieved a significant breakthrough. Bowers and the researchers' work appears in the August 3 issue of the journal NATURE, in an article titled “3D integration enables ultralow-noise isolator-free lasers in silicon photonics.”

Photonic integrated circuits are widely used in applications such as telecommunications and data-centre interconnects. However, in optical systems such as microwave synthesizers, optical gyroscopes and atomic clocks, photonic integrated circuits are still considered inferior solutions despite their advantages in size, weight, power consumption and cost. Such high-precision and highly coherent applications favour ultralow-noise laser sources to be integrated with other photonic components in…

Frequency-modulated (FM) laser combs, which offer a quasi-continuous-wave output and a flat-topped optical spectrum, are emerging as a promising solution for wavelength-division multiplexing applications, precision metrology, and ultrafast optical ranging. The generation of FM combs relies on spatial hole burning, group velocity dispersion, Kerr nonlinearity, and four-wave mixing (FWM). While FM combs have been widely observed in quantum cascade Fabry-Perot (FP) lasers, the requirement for a…

Integrating quantum dot (QD) gain elements onto Si photonic platforms via direct epitaxial growth is the ultimate solution for realizing on-chip light sources. Tremendous improvements in device performance and reliability have been demonstrated in devices grown on planar Si substrates in the last few years. Recently, electrically pumped QD lasers deposited in narrow oxide pockets in a butt-coupled configuration and on-chip coupling have been realized on patterned Si photonic wafers. However…

Congratulations to Bob Herrick on publishing a new book on Reliability of Semiconductor Lasers. We wrote a chapter on QD laser on silicon reliability in the book.

See the article here

Available online here.
 

Link

We are so proud of you!
 

Here's the link to read the article.

After 7 months of researching, prototyping, and validating their businesses, 13 Teams will participate in UCSB Technology Management's New Venture Fair -- the first of two culminating events as part of our Annual New Venture Competition. The event is FREE and open to the public. Register today at www.newventure.live. Spread the word!

See it here!

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Link to slides

We demonstrate the first tunable single wavelength quantum dot (QD) laser directly grown on Si. A simple, integrable architecture is implemented without involving re-growth steps or sub-wavelength grating lithography. 16 nm tuning range was achieved with over 45 dB SMSR and output powers exceeding 2.7 mW per tuning wavelength. The choice of QD gain material promotes high lasing efficiency in the presence of defects introduced by lattice-…

Read more here.

The very best of Santa Barbara, filmed by Christopher Helkey, watch here.

A Quantum Leap
UC Santa Barbara is selected as the site of the nation’s first NSF-funded Quantum Foundry, a center for the development of materials and devices for quantum information-based technologies

View the complete news release at: …

Pushing the Data Capacity Limit with Lasers on Silicon

Congrats to Yating and Justin on the publication of a chapter on Quantum Dot Microcavities in the new Elsevier book, "Future of Silicon Photonics", volume 101 of Semimetals:
https://www.sciencedirect.com/science/article/pii/S0080878419300092

 UC ranked #1 in the world in patents in 2018!

two papers from our group are selected as the top 10 cited articles on Integrated Optics published in 2018

In 2020, the laser will celebrate its 60th anniversary. Here Photonics Media presents a timeline of some of the more notable scientific accomplishments related to light amplification by stimulated emission of radiation (laser). An interactive version of the laser timeline is also available, as well as a primer on laser basics detailing how lasers work.

Abstract—Silicon photonics offer a low-cost platform for large- scale RF system integration. Spur-free dynamic range (SFDR) for analog and RF photonic components is limited by electri- cal and optical characteristics of the p- and n- junction used to produce plasma dispersion. We propose a silicon ring modula- tor and demonstrate design conditions that balance the phase change between the DC Kerr and plasma dispersion effects to produce a broadband, linear electro-optical conversion. A…

"The National Academy of Inventors and the Intellectual Property Owners Association have announced their seventh annual report on trends within academic patenting. The Top 100 Worldwide Universities Granted U.S. Utility Patents in 2018 has been announced by the National Academy of Inventors (NAI) and the Intellectual Property Owners Association (IPO). The report is created using data from the U.S. Patent and Trademark Office (USPTO), and it highlights the vital role patents play in…

We demonstrate a fully integrated extended distributed Bragg reflector (DBR) laser with ∼1 kHz linewidth and over 37 mW output power, as well as a ring-assisted DBR laser with less than 500 Hz linewidth. The extended DBR lasers are fabricated by heterogeneously integrating III-V material on Si as a gain section plus a 15 mm long, low-kappa Bragg grating reflector in an ultralow-loss silicon waveguide. The low waveguide loss (0.16 dB/cm) and long Bragg grating with narrow bandwidth (2.9 GHz)…

Please email your CV and a cover letter to Professor John Bowers at bowers@ece.ucsb.edu and cc bowers-admin@ece.ucsb.edu. 

Sub-kHz linewidth Extended-DBR lasers heterogeneously integrated on silicon by D. Huang, M. A. Tran, J. Guo, J. Peters, T. Komljenovic, A. Malik, P. A. Morton, J. E. Bowers. 

We demonstrate single-mode E-DBR lasers with 1kHz linewidth and >37mW output power, and ring-assisted E-DBR lasers with 500Hz linewidth, by heterogeneously integrating III-V gain material with a 15mm long ultra-low loss silicon waveguide-based Bragg reflector.

Abstract: Multi-spectral midwave-infrared (mid-IR) lasers are demonstrated by directly bonding quantum cascade epitaxial gain layers to silicon-on-insulator (SOI) waveguides with arrayed waveguide grating (AWG) multiplexers. Arrays of distributed feedback (DFB) and distributed Bragg-reflection (DBR) quantum cascade lasers (QCLs) emitting at 4.7 μm wavelength are coupled to AWGs on the same chip. Low-loss spectral beam combining allows for brightness scaling by coupling the light generated by…

In this contribution, we demonstrate the first integrated gallium arsenide (GaAs) ring resonator for second harmonic generation (SHG) on a GaAs-on-insulator platform. Such resonators exhibit high nonlinear optical coefficients, a strong optical confinement, and intrinsic quality factors exceeding 2.6 Å~ 105, which makes them very attractive for nonlinear optical applications. The fabricated resonators exhibit a great potential for frequency conversion: when 61 μW of pump power at 2 μm…

A new invited review paper on heterogeneous integration of III-V semiconductor photonics combined with silicon foundry technology has just been published in IEEE Journal of Selected Topics in Quantum Electronics.

"Heterogeneous integration of III-V semiconductor photonics combined with silicon foundry technology enables low-cost, high-performance photonic integrated circuits. Highly reliable lasers using epitaxial deposition of quantum dot lasers, with <2 mA threshold and lifetime…

Here we demonstrate an 8x4 multi-wavelength selective ring resonator based crossbar switch matrix implemented in a 220-nm silicon photonics foundry for interconnecting electronic packet switches in scalable data centers. This switch design can dynamically assign up to two wavelength channels for any port-port connection, providing almost full connectivity with significant reduction in latency, cost and complexity. The switch unit cell insertion loss was measured at 0.8 dB, with an out-of-…

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), which can fulfill the rapidly increasing bandwidth and lower energy per bit requirements. We present here, for the first time to our knowledge, a low-noise high-channel-count 20 GHz passively mode-locked quantum dot laser grown on a complementary metal-oxide-semiconductor…

Multi-spectral midwave-infrared (mid-IR) lasers are demonstrated by directly bonding quantum cascade epitaxial gain layers to silicon-on-insulator (SOI) waveguides with arrayed waveguide grating (AWG) multiplexers. Arrays of distributed feedback (DFB) and distributed Bragg-reflection (DBR) quantum cascade lasers (QCLs) emitting at 4.7 μmwavelength are coupled to AWGs on the same chip. Low-loss spectral beam combining allows for brightness scaling by coupling the light generated by multiple…

Optical isolators and circulators are extremely valuable components to have in photonic integrated circuits, but their integration with lasers poses significant design and fabrication challenges. These challenges largely stem from the incompatibility of magnetooptic material with the silicon or III-V platforms commonly used today for photonic integration. Heterogeneous integration using wafer bonding can overcome many of these challenges, and provides a promising path towards integrating…

We present a brief overview of the various leading platforms for photonic integration. Subsequently, we consider the possibility of a photonic integrated circuit platform utilizing epitaxially grown III–V material on silicon—without the need for wafer bonding, or an externally coupled laser. Finally, a technoeconomic analysis contrasting the aforementioned platforms will be presented.

Microring lasers feature ultralow thresholds and inherent wavelength-division multiplexing functionalities, offering an attractive approach to miniaturizing photonics in a compact area. Here, we present static and dynamic properties of microring quantum dot lasers grown directly on exact (001) GaP/Si. Effectively, a single-mode operation was observed at 1.3 μm with modes at spectrally distant locations. High temperature stability with T 0∼103 K has been achieved with a low threshold of 3 mA…

1.3 μm InAs quantum dot lasers on Si show a CW threshold current of 4.8 mA and extrapolated lifetimes of ten million hours at 35 °C and ~65,000 hours at 60 °C.

Intel has won SEMI’s 2018 Award for the Americas. SEMI honored the celebrated chipmaker for pioneering process and integration breakthroughs that enabled the first high-volume Integrated Silicon Photonics Transceiver. The award was presented yesterday at SEMICON West 2018.

This work reports on the ultra-low linewidth enhancement factor (aH-factor) of semiconductor quantum dot lasers epitaxially grown on silicon. Owing to the low density of threading dislocations and resultant high gain, an aH value of 0.13 that is rather independent of the temperature range (288 K–308 K) is measured. Above the laser threshold, the linewidth enhancement factor does not increase extensively with the bias current which is very promising for the realization of future integrated…

Only a few decades ago, finding a particular channel on the radio or television meant dialing a knob by hand, making small tweaks and adjustments to hone in on the right signal. Of course, we now take such fine tuning for granted, simply pressing a button to achieve the same effect. This convenience is enabled by radio frequency synthesis, the generation of accurate signal frequencies from a single reference oscillator. The need for better radar in World War II drove the development of radio…

We investigate the impact of threading dislocation density on the reliability of 1.3 lm InAs quantum dot lasers epitaxially grown on Si. A reduction in the threading dislocation density from 2.8108 cm2 to 7.3106 cm2 has improved the laser lifetime by about five orders of magnitude when aged continuous-wave near room temperature (35 C). We have achieved extrapolated lifetimes (time to double initial threshold) more than 10 106 h. An accelerated laser aging test at an elevated temperature (60…

The first single-section quantum dot mode-locked laser directly grown on a CMOS-compatible silicon substrate has been produced by researchers in the US. Their achievement could open the door to much lower complexity, cheaper laser sources for future large-scale silicon photonic integrated circuits.

Direct epitaxial integration of III-V materials on Si offers substantial manufacturing cost and scalability advantages over heterogeneous integration. The challenge is that epitaxial growth introduces high densities of crystalline defects that limit device performance and lifetime. Quantum dot lasers, amplifiers, modulators, and photodetectors epitaxially grown on Si are showing promise for achieving low-cost, scalable integration with silicon photonics. The unique electrical confinement…

Lithium niobate on insulator (LNOI) technology is revolutionizing the lithium niobate industry, enabling higher performance, lower cost and entirely new devices and applications. The availability of LNOI wafers has sparked significant interest in the platform for integrated optical applications, as LNOI offers the attractive material properties of lithium niobate, while also offering the stronger optical confinement and a high optical element integration density that has driven the success…

Low-loss arrayed waveguide gratings (AWGs) are demonstrated at a 2.0-μm wavelength. These devices promote rapidly developing photonic applications, supported by the recent development of mid-infrared lasers integrated on silicon (Si). Multi-spectral photonic integrated circuits at 2.0-μm are envisioned since the AWGs are fabricated with the 500-nm-thick Si-on-insulator platform compatible with recently demonstrated lasers and semiconductor optical amplifiers on Si. Characterization with the…

University of California Santa Barbara (UCSB) in the USA has been working to optimize gallium arsenide (GaAs) molecular beam epitaxy (MBE) on gallium phosphide on silicon (GaP/Si) [Daehwan Jung et al, J. Appl. Phys., vol122, p225703, 2017]. Normally, growth of GaAs on Si uses off-axis substrates in efforts to avoid anti-phase domains. On-axis silicon is preferred for compatibility with CMOS processing foundries. The lattice mismatch between GaAs and Si is ~4%, leading to dislocations.

Abstract—We design, fabricate, and characterize ultra-low loss continuously tunable optical true time delay devices based on Si3N4 ring resonators in a side-coupled integrated spaced sequence of resonators (SCISSOR) structure. A large tunable delay range up to 3.4 ns is demonstrated using the Balanced SCISSOR delay tuning scheme, for a record loss of only 0.89 dB/ns of delay. By optimizing the coupler design a device delay bandwidth of over 10 GHz is achieved with over 0.5 ns maximum time…

Important advances: 

1. Record low threshold current density for growth on (100) Si: 198 A/cm^2 
2. Record low threshold current for any F-P laser grown on Si
3. Record high injection efficiency: 87%
4. Record long lifetime: More than 10 M hours at 35 C.

Silicon photonic integration is an enabling technology for power- and cost-effective optical interconnects in exascale performance computers and datacenters which require extremely low power consumption and dense integration for a higher interface bandwidth density. In this paper, we experimentally demonstrate a fully integrated optical transceiver network on a silicon substrate using heterogeneous integration. High performance on-chip lasers, modulators and photodetectors are enabled by…

We demonstrate integrated optical isolators with broadband behavior for the standard silicon-on-insulator platform. We achieve over 20 dB of optical isolation across 18 nm of optical bandwidth. The isolator is completely electrically controlled and does not require a permanent magnet. Furthermore, we demonstrate the ability to tune the central operating wavelength of the isolator across 100 nm, which covers the entire S + C telecom bands. These devices show promise for integration in optical…

We demonstrate a technique to precisely control and stabilize the beat frequency of a photonic microwave signal generator based on beating the optical signals of two lasers on a high-speed photodetector. The approach does not require high-speed electronic circuitry, but allows the control of the generated signal frequency up to hundreds of GHz. The demonstrated technique can readily be integrated on a chip-scale device using heterogeneous silicon platform, opening possibilities for…

We report 1300 nm continuous wave lasing on an on-axis GaP/Si (001) virtual substrate operating up to 60°C with record low threshold current of 27 mA. Ridge and broad area lasers were fabricated with seven layers of p-modulation doped quantum dots and as-cleaved facets.

We demonstrate the first interband cascade lasers heterogeneously integrated with silicon waveguides. The 3.6 μm wavelength lasers operate in pulsed mode at room temperature, with threshold currents as low as 394 mA.

As a result of record low threading dislocation densities, the threshold current and threshold current density have gone down in our Quantum Dot lasers, and we see record high wallplug efficiencies for any laser on silicon.

The cover of the latest issue of Optica shows the latest quantum dot microring lasers on silicon with record low lasing thresholds.  This is promising for next generation data center interconnects.

We are looking for two photonics students and two postdocs for design, fabrication and testing of photonic integrated circuits. Students should apply to the ECE or Materials departments for Fall 2018 admission. Postdocs should apply directly to Prof. Bowers.

UCSB and HKUST demonstrated the integration of quantum dot lasers and photodetectors on silicon substrates. An ultra-low dark current of 0.8 nA and an internal responsivity of 0.9 A/W were measured in the O band.

Gordon Kino was my PhD advisor and a great mentor and researcher.  He was my inspiration and model for a great professor. He will be missed by so many researchers across the world.

UCSB successfully demonstrated an electrically pumped hybrid silicon laser a decade ago. That advance has paved the way for the commercial production of high-bandwidth silicon photonic devices. Today, Bowers is leading UC Santa Barbara’s Institute for Energy Efficiency’s involvement in the AIM initiative and is a central figure in this exciting field. Photonics Spectra spoke with Bowers about AIM, his breakthrough work and the impact of integrated photonics on medicine, communications and…

John Bowers, Professor of Materials and of Electrical and Computer Engineering, has been awarded the 2017 IEEE Photonics Award in honor of his pioneering research in silicon photonics, including hybrid silicon lasers, photonic integrated circuits, and ultra low-loss waveguides.

Please click on the following link to read on. 

The UC Santa Barbara student chapter of the Institute of Electrical and Electronics Engineer’s Photonics Society has been named Chapter of the Year for 2016.

Established four years ago, the student organization of young engineers at UCSB is recognized for its effort in promoting professional growth and career development in the field of photonics. “This international award exemplifies the strength of our local photonics community and the hard work of our members to promote…