Leti, technology research institute

Thanks to its ultimate miniaturization stage and its best CMOS process compatibility, Silicon photonics is the key technology to address high volume markets.Photonic fiber links are currently used to transfer digital data. In a near future, integrated photonics will be used first inside computers and then inside core-processor chips, to solve the transmission bottleneck limits of electronics. Several other applications are addressed by silicon photonics: PIC (Photonic Integrated Circuits) sensors, RF analog applications (RF free space transmission, high optical performance fidelity), and PIC array technologies (including LIDAR).

Figuring among the global pioneers in Silicon photonics research, Leti has developed a specific technology toolbox to reach state-of-the-art performances.Leti’s packaging capabilities rely on 3D-integration building blocks for a variety of uses (e.g. hybridization of CMOS-electronic drivers with Si-photonics circuits), fiber-array attachment to the Si-photonics chip, and on-board packaging. Leti’s testing facilities are at the cutting edge of the technique, thanks to several automated on-wafer measurement probers, high-frequency and temperature test facilities (at wafer or packaged devices stages).

Silicon photonicS benefitS

leti technical background

Silicon photonicSleti’S Silicon photonicS-baSed SolutionS

Leti, technology research institute

Leti has developed active and passive integrated Silicon Photonic devices with state-of-the art performances: routing and WDM devices, Si-modulators, Ge-photo-detectors and III-V/Si lasers. Recently Leti set up a Photonics Design Kit using Mentor Graphics tools, devoted to easy standard components assembly in all-type devices.

Passive devices (1310 and 1550 nm bandwidth)Waveguides • Multimode rib : ≤ 0.5 dB/cm• Single mode : ≈ 2 dB/cmSurface injection coupler 1D&2D• 1D Insertion Loss : 2-3 dB• 2D Insertion Loss : 3.5-4 dBWDM Mux/Dmux (100G-LR4)• Insertion Loss : 3 dB (4 dB with

flattening)• Crosstalk : < -20 dB

Active devices (1310 nm bandwidth)ModulatorsPN junction-waveguide in Ring Resonating or Mach-Zehnder structures:• e.g.2 V.cm & -0.6dB/mm• 40GHz BW at -4V for 3mm longGe on Si photo detectors• Surface-illuminated or

Waveguide-coupled• Responsivity ~ 0.6 A/W• Dark current < 20nA @ 20°C;

< 1μA @100°C• Bandwidth up to 40GHzHeterogeneous III-V on Si - lasers• Tunable DBR, DFB, racetrack lasers• DFB @ 1310nm: P Si-wg up to

> 20mW@20°C, SMSR > 50dB• DBR @ 1550nm: P Si-wg up to

> 20mW@20°C, SMSR > 30dB

Leti clean room facilities offer a broad range of processes on 200mm & 300mm wafers:

• Amorphous Silicon, SiNx deposition;• Deep UV 193 nm lithography with 80nm resolution; • Dry etching with very low sidewall roughness -Silicon and

SiNx waveguides; • Germanium epitaxial growth on Silicon;• p-type and n-type ion implantation;• Direct bonding and processing of III-V-materials on

Silicon: wafer to wafer and die to wafer.

MPW (Multiple Project Wafer) prototyping: as a partner, thanks to the high Technology Maturity Level of our SOI -310 nm platform and the corresponding design rules, you can now use 200 mm Leti platform to prototype your own designs, through two European brokers: Europractice, CMP.

Supporting you from deSign to device prototyping, integrated circuitS and packaging SolutionS. Supporting you in Setting up your Supply chain.

device library fabrication platform

Integrated III-V laser1Laser spectral response Passive components

Leti, technology research institute

Hybridation of photonic and electronic ICsInterconnection between photonic ICs and dedicated electronic ICs (trans-impedance amplifiers, drivers…) is managed using copper micro-pillars and flip-chip bonding

Optical fiber attachment• Multichannel pigtailing of Si

photonics chips using active alignment of fiber V-groove arrays

• Flip-chip alignment of microlenses or silicon fiber holders (under developement)

Circuit designCircuits of any complexity can be designed, starting from passive and active components device building blocks issued from devices library, thanks to dedicated optoelectronic softwares.

For instance, exploiting packaging tools and partnerships for electronic IC development, Leti has designed, fabricated and tested modules in the 3 main application fields in photonic communications: long haul, Fiber-To-The-Home and data center.

Packaging tools

Several tests can be performed at the wafer level according to automated sequences (statistical tests on devices and circuits), or at the package level.

Leti facilities are at the cutting edge of technology:• 4 fully-automated on-wafer probers (fiber to fiber passive

optical measurements, up to 60 GHz Electronics/Optics, O/E and E/E measurements)

• Ambient temperature up to 90°C (heating chuck)• Up to 56 Gb/s Bit-Error-Rate measurements• OFDM and QAM up to 10 GBd• Pulse Amplitude Modulation (PAM) up to 32 GBd • Small signal analysis up to 67 GHz (O/E, E/O, E/E)

circuitS & moduleS teSting

PIC for FTTH network

Reflective modulator

4x25 Gbp/s photo-receiver (data center)

On wafer 25Gb Tx test PAM-4 eye diagram

Leti, technology research instituteCommissariat à l’énergie atomique et aux énergies alternatives Minatec Campus | 17 rue des Martyrs | 38054 Grenoble Cedex 9 | Francewww.leti.fr

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Leti

ABOUT LETI

Leti is a technology research institute at CEA Tech and a recognized global leader in miniaturization technologies enabling smart, energy-efficient and secure solutions.Committed to innovation, its teams create differentiating solutions for Leti’s industrial partners.

By pioneering new technologies, Leti enables innovative applicative solutions that ensure competitiveness in a wide range of markets. Leti tackles critical, current global issues such as the future of industry, clean and safe energies, health and wellness, safety & security…

Leti’s multidisciplinary teams deliver solid micro and nano technologies expertise, leveraging world-class pre-industrialization facilities.

For 50 years, the institute has been building long-term relationships with its industrial partners providing tailor-made solutions and a clear intellectual property policy.

intereSted in thiS technology?

Contact:Sylvie MenezoCorporate Business & Partnerships Development sylvie.menezo@cea.fr+33 684 822 764+33 438 780 451

A photonics device library is Leti-designed, and the devices are processed in Leti CMOS clean room facilities on 200 or 300 mm wafers.

As a partner, you can either build your solutions from the Leti components library, or manufacture your own designs on Leti’s process platform with a set of advanced CMOS processes.

As a partner, you can also evaluate your results with Leti’s photonics highly automated testing facilities.

how to work with leti?

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