Congratulations to Dr. Radha Nagarajan for receiving the David Richarson medal at OFC 2024! March 26, 2024 Dr. Nagarajan at OFC 2024

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) March 22, 2024 IEE

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…

Conjoined 'racetracks' make new optical device possible December 8, 2023 Race track
John Bowers received the IEEE Nishizawa Medal for contributions to photonic integrated circuit technologies. November 28, 2023 IEEE Nishizawa Medal for Prof. Bowers
2023 IPC Tutorial by Prof. John Bowers November 14, 2023 IPC tutorial

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 15 Year Anniversary November 3, 2023 IEE15

IEE's 15 Year Anniversary! Celebrating Innovations!

The UC Santa Barbara Nanofab: An Innovation Center October 22, 2023 Highly capable nanofab facilities at UCSB fueling both academic and industrial technology advancements

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…

We are cited in Nobel Prize Chemistry on Quantum Dot this year! October 8, 2023 Ref68 in Nobel Prize Chemistry 2023

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!

Going Vertical to Advance PICs September 15, 2023 3d integration

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.”

3D PIC Integration without an Isolator published in Nature August 5, 2023 3D photonic integration

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…

Broadband quantum dot frequency modulated comb laser published in Light:Science&Application July 25, 2023 QD frequency modulated comb laser

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…

Design rules for the integration template for monolithic on-chip light sources published in Advanced Functional Materials July 8, 2023 Diffusion driven QD morphology anisotropy

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…

Stable Low Noise, AlGaAsOI Dark Pulse Comb Source June 12, 2023 Stable Low Noise, AlGaAsOI Dark Pulse Comb Source
Heterogeneous 780 nm narrowlinewidth tunable laser June 9, 2023 Heterogeneous 780 nm narrowlinewidth tunable laser
Congratulations to Chen on winning the Tingye Li Innovation Prize June 9, 2023 news image
QD Laser Integrated on Silicon Carbide May 15, 2023 QD Laser Integrated on Silicon Carbide
E-band laser integrated with S-C-L band lasers on Si April 24, 2023 E-band laser integrated with S-C-L band lasers on Si
Quantum limited coherence of dark pulses March 31, 2023 Quantum limited coherence of dark pulses
Adjustable SiN zero-dispersion microcombs February 15, 2023 Adjustable SiN zero-dispersion microcombs
Review of on-chip laser technology published in eLight January 4, 2023 Review of on-chip laser technology published in eLight
An integrated DWDM and mode multiplexed transmission system designed at Stanford December 22, 2022 Title
1 Hz Integrated Linewidth Laser on Si October 28, 2022 1 Hz Integrated Linewidth Laser on Si
First growth of quantum dot lasers in channels on 300 mm SOI substrates published in Light Science and Applications October 14, 2022 First growth of quantum dot lasers in channels on 300 mm SOI substrates published in Light Science and Applications
New paper in Nature on High temperature (185C) Shorter Wavelength Lasers (< 1um) on SiN/SiO2/Si September 28, 2022 New paper in Nature on High temperature (185C) Shorter Wavelength Lasers (< 1um) on SiN/SiO2/Si
Pockels Laser on Si September 12, 2022 Pockels Laser on Si
New paper in Nature Electronics on 4K Magneto-optic modulators September 8, 2022 New paper in Nature Electronics on 4K Magneto-optic modulators
Review of Comb Technologies Published in Nature Photonics September 8, 2022 Review of Comb Technologies Published in Nature Photonics
A comprehensive summary of recent heterogeneous photonic integration on silicon August 22, 2022 A comprehensive summary of recent heterogeneous photonic integration on silicon
New Nature paper on AlGaAsOI high-Q resonators used in 2 Tbps systems August 22, 2022 New Nature paper on AlGaAsOI high-Q resonators used in 2 Tbps systems
New summary of QD technology in IEEE Nanotechnology Magazine August 22, 2022 see article here
Our paper on reflection sensitivity of Quantum Dot lasers was chosen as "Best Paper of 2019 in Photonics Technology Letters September 21, 2021 Title
Congrats to Bob Herrick on publishing a new book! September 21, 2021 Cover

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.

On the front page of Google news! The first commercially scalable integrated laser and microcomb on a single chip. July 9, 2021 Microchip

See the article here

Science paper on the key DODOS seedling (integrating laser and > combs) July 9, 2021 a

Available online here.

This overview of the Future of Silicon Photonics and Electronics was just published in APL Perspectives June 4, 2021 .


Congratulations to Yating on winning the Tingye Li Innovation Prize May 19, 2021 y

We are so proud of you!

Here's the link to read the article.

A New Review Paper on QD Lasers and SOAs Published in IEEE Nanotechnology Magazine May 5, 2021 .
UCSB Technology Management's New Venture Fair! April 27, 2021 pic

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 Spread the word!

See it here!

Congratulations to Warren Jin and collaborators at UCSB and Caltech for publishing "Hertz-linewidth semiconductor lasers using CMOS-ready ultra-high-Q microresonators" in Nature Photonics. Coupling a high Q resonator to a DFB laser using self injection l February 18, 2021 .
Congrats to Travis for a featured article in APL Photonics on self injection locked octave spanning combs! February 18, 2021 .
AlGaAsOI Resonators generate 1000x higher entangled photon generation rate February 16, 2021 .
OSA Webinar February 11, 2021 .
Two new frequency combs could boost telecoms and molecular fingerprinting July 8, 2020 1


An new way to simply generate low noise solitons with injection locked lasers and resonators was just published in Nature June 23, 2020 2
An important paper on limits to linewidths in widely tunable lasers has just been published June 23, 2020 1
Plenary Talk at CLEO May 14, 2020 2


Link to slides

Link to movie



Hot Topic Talk at CLEO on New Nonlinear Platform May 12, 2020 5


Link to slides


Integration of semiconductor lasers with low loss Si3N4 waveguides results in very low linewidths (<1 kHz) and great temperature stability (10 pm/C). March 2, 2020 Image2
Tutorial on narrow linewidth tunable semiconductor lasers using Si/III-V heterogeneous integration February 1, 2020 Image
Congrats to Yating and group for demonstration the first tunable single wavelength quantum dot (QD) laser directly grown on Si. October 24, 2019  tunable single wavelength quantum dot (QD) laser directly grown on Si

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-…

Congratulations to Dr. Archie Holmes on being selected as Executive Vice Chancellor for the University of Texas System! September 30, 2019 a


Read more here.


Beautiful Santa Barbara September 29, 2019 Rainbow Arch

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

NSF names UC Santa Barbara home to its first Quantum Foundry, a center for developing materials and devices for quantum information-based technologies September 27, 2019 ucsb

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 September 27, 2019 123

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 September 27, 2019 1

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:

UC ranked #1 in the world in patents in 2018! September 26, 2019 58

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

Congratulations Mike, Yating, Songtao and everyone for 2 of the top 10 articles which are from our group. September 20, 2019 the first demonstration of direct-modulation of 1.3 μm InAs/GaAs QD microring laser grown on on-axis (001) substrate

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

A history of the laser: 1960 to 2019 June 7, 2019 John Bowers and Brian Koch is mentioned in the article

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.

New linearized ring modulator June 6, 2019 Schematic of a conventional RF over fiber link.

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…

UC ranked #1 in the world in patents in 2018 June 4, 2019 Top 100 Worldwide Universities Granted US Utility Patents in 2018

"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…

A paper on 500 Hz linewidth DBR lasers on silicon just published in Optica. May 29, 2019 Schematic of the E-DBR laser, with SEM images of the transitions between the various sections of the laser. (b) A ring resonator is in- corporated in the cavity to form the RAE-DBR laser.

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)…

Looking for 2 postdocs experienced in optoelectronics and photonic integrated circuits! May 16, 2019 Bowers Group 2017

Please email your CV and a cover letter to Professor John Bowers at and cc 

Honorable mention for the Corning Student Paper Competition March 20, 2019 Duanni Huang

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.

New Quantum Cascade Laser paper selected as the cover of Photonics March 15, 2019 Cover of Photonics

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…

New Paper on GaAs SHG Chosen as Editor's Pick at APL Photonics March 15, 2019 Schematic structure of the ring resonator with a pulley coupler.

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…

High Performance Photonic Integrated Circuits on Silicon March 12, 2019 (a) A two-level folded Clos data center utilizing electronic spine and ToR switches of a radix of , with an added layer of , - wavelength, optical WDM circuit switches. paths. (b) A realization of the WDM switch employing two interconnected WDM crossbar switches.

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…

The AIM Photonics Silicon foundry was used to build this 8x4multi-wavelength selective ring resonator based crossbar switch matrix February 12, 2019 Layout of a 8x4,L=2 switch (d) Die Shot of the switch with I/O marked

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-…

A mode locked quantum dot laser was used to transmit 4.1 Tbps of data on 64 lines spaced at 20 GHz. January 25, 2019 Optical spectrum and corresponding optical linewidth of each mode within 10 dB

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…

Arrays of DFB QCLs emitting at 4.7 μmwavelength are coupled to AWGs on the same chip in this new paper in Photonics January 24, 2019 (a) Top-view schematic of the QCL array and arrayed waveguide grating (AWG). Mirrors are defined under the red III-V QCL ridges for both the distributed feedback (DFB) and distributed Bragg-reflection (DBR) type lasers. (b) Micrograph of a multi-spectral DFB laser, showing the individual lasers on the left and the AWG combiner on the right.

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…

Congratulations to Tony and Paolo for this invited paper on integrated isolators and circulators. August 9, 2018 The transmission spectra of the isolator at 1549.5 nm for 40 mA of applied current showing 25 dB of optical isolation.

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…

Congratulations to Alan Liu on the publication of this analysis of alternative approaches to high levels of optical integration August 3, 2018 Alan Liu

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.

Congratulations to Yating and team for selection as cover article and Editor's Choice on this article just published on low threshold, high speed quantum dot ring lasers. July 26, 2018 Illustration of one fabricated microring laser

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…

Congratulations to Daehwan Jung for winning Best Paper Award at OECC 2018! July 15, 2018 Dr. Daehwan Jung at OECC 2018

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 Wins SEMI Award at SEMICON West for Process and Integration July 11, 2018 Dr. Thomas Liljeberg, senior director of R&D for Intel Silicon Photonics.

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.

We are using p-modulation doping to reduce the linewidth enhancement factor in Quantum Dot lasers. This is important for narrower linewidth lasers, lower chirping lasers and reduced reflection sensitivity lasers. June 21, 2018 The aH-factor as a function of temperature for p-doped (red) and undoped (blue) QD lasers. The linear curve-fittings (dashed lines) are the guide to the eye only.

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…

Achieving Unprecedented Frequency Control in Miniature Lasers April 25, 2018 Under the DODOS program, researchers from NIST, University of California at Santa Barbara, and the California Institute of Technology have made significant progress advancing chip-based integrated photonics and nonlinear optics to miniaturize optical synthesizer components. Combining a pair of frequency combs, several miniature lasers, and other compact optoelectronic components, the researchers were able to replicate the capabilities of a tabletop-sized optical frequency synthesizer on four microchips.

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…

The importance of reducing threading dislocation density on laser lifetime is detailed in this paper. April 16, 2018 Extrapolated quantum dot laser lifetime versus the threading dislocation density. Lasers from Ref. 8 were aged at 30 C. The dashed line is a linear fit.

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…

A first for single-section QDML lasers on Si April 2, 2018 Front from the left: Arthur C. Gossard and John E. Bowers, back from the left: Daehwan Jung, Songtao Liu and Justin C. Norman

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.

An invited summary of the prospects for quantum dot photonic integrated circuits has just been published. March 27, 2018 device lifetime (either extrapolated or measured) for lasers on Si operating in the continuous wave mode. The distinction is noted between historical results on miscut Si substrates and recent results on CMOS compatible on-axis (001) Si.

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…

A new review paper on the exciting technology and applications of thin film LiNbO3 has just been published March 19, 2018 Schematically overview of a LNOI integrated optical chip

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…

A new paper on high performance 2 micron arrayed waveguide gratings has just been published. February 27, 2018 (a) Cross-section SEM of a single-mode Si waveguide. Micrographs (b) of an AWG and (c) of an AWG-ring.

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…

Reducing dislocations in gallium arsenide on silicon templates January 23, 2018 Room-temperature PL spectra of GaAs PL samples grown on native GaAs, and three different GaAs/GaP/Si templates.

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.

Chao Xiang demonstrated a novel scissors design with widely tunable delays and large dynamic range. The device and performance are shown below: January 22, 2018 Layout of a 40 microresonator TTD device.

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…

An important paper on Epitaxial Quantum Dot lasers on silicon has just been published. December 18, 2017 Record high injection efficiency: 87% 

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.
Congratulations to Chong Zhang for an Invited Paper on the highest capacity transceiver on Si. December 12, 2017 2.56 Tbps Network on Chip

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…

Congratulations to Tony and Paolo for demonstrating broadband integrated MZI optical isolators with 100 nm tuning, which covers the entire S + C telecom bands. November 21, 2017 Paolo Pintus and Tong (Duanni) Huang

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…

Congratulations to Tin for demonstrating a novel idea to make a very stable arbitrary microwave frequency generator! November 20, 2017 Tin Komljenovic

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…

Congratulations to Justin Norman for winning Best Student Paper award at the 2017 IEEE International Photonics Conference October 24, 2017 Justin Norman

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.

Congratulations to Alex Spott and colleagues for a postdeadline paper at the 2017 IEEE International Photonics Conference on the first Interband Cascade Laser on Silicon. October 12, 2017 Alexander Spott

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.

High efficiency low threshold current 1.3 μm InAs quantum dot lasers on on-axis (001) GaP/Si September 27, 2017 High efficiency low threshold current 1.3 μm InAs quantum dot lasers on on-axis (001) GaP/Si

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.

1.3 μm submilliamp threshold quantum dot micro-lasers on Si August 1, 2017 Optica August 2017 cover

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.

Looking for Postdocs (immediately) and Graduate Students for Admission in Fall 2018 July 1, 2017 Bowers Group 2017

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.

Semiconductor Today article on Quantum Dot Laser and Photodetector Integration June 30, 2017 Semiconductor Today

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, 1928-2017 June 29, 2017 Gordon Kino

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.

The Revolution Has Just Begun: Q&A with John Bowers January 8, 2017 Image of Dr. Bowers

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 awarded 2017 IEEE Photonics Award August 3, 2016 Image of Dr. Bowers and Dr. Komljenovic

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. 

Best Chapter April 13, 2016 UCSB’s student chapter of IEEE’s Photonics Society, with faculty advisor John Bowers (top left)

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…