Publications

Here are listed the latest Publications from Almae Technologies

Room temperature inductively coupled plasma etching of InP with Cl2 mixtures using SiO2 and photoresist masks26/04/2024Abstract: We report the results of a study on the inductively coupled plasma (ICP) etching of InP at room temperature using Cl2 mixtures (Cl2/N2/H2). The impact of different process parameters, including the RF power, the ICP power, the ion-to-neutral ratio, and the chamber pressure, on the etched profile was investigated. The etch rate, selectivity, and anisotropy of the profile were depicted for each etching recipe. Two types of masks, such as SiO2 and AZ5214 photoresist, were used in this study. The etched InP feature showed a very smooth surface (rms as low as 0.5 nm) and a relatively fast etch rate of about 450 nm/min with both masks. By adjusting the etch process and depending on the used mask, we tuned the anisotropy from about 19° to 60°. A selectivity of around 4:1 and 1:1 was obtained with SiO2 and photoresist masks, respectively. These results demonstrate how altering the ICP process parameters could affect the etching characteristics and profile. Published in: Journal of Vacuum Science & Technology BRead more here [...] Read more...
Extremely High-Power Laser-Modulators with Integrated Amplifier Section (EML-SOAs)27/02/2024Abstract: We present an EML-SOA targeting highest modulated power. The SOA section is designed to maximise saturation power, in order to reach high power while still operating in SOA linear regime. We demonstrate for 1342 nm 50 GPON a record 15.2 dBm modulated power Published in: European Conference on Optical Communication (ECOC), 2023 [...] Read more...
Towards passive hybridization of high-power and high-speed InP transmitters27/02/2024Abstract: We present a versatile InP technology, applied for lasers, laser-modulators and semiconductor optical amplifiers, particularly adapted for hybrid integration with silicon photonics. In particular we show examples of passive hybridization of high power lasers for silicon photonics modulators, 100Gb/s PAM4 laser-modulators with fiber for datacom, and reflective SOAs in tunable external cavity lasers. Published in: European Conference on Integrated Optics (ECIO), Milan, Italie (invited paper), 2022 [...] Read more...
Record High Power 13dBm Electro-Absorption Modulated Laser for 50G-PON27/02/2024Abstract: We present a 50Gb/s electro-absorption modulated laser emitting at 1342-1358nm and optimised to provide high output power and efficient modulator extinction. With a record modulated output power of >13dBm (ex-facet) and a 6dB dynamic extinction ratio it can serve for 50G-PON as unamplified transmitter. Published in: European Conference on Optical Communication (ECOC), Basel, Switzerland, pages1-4, 2022Read more at https://ieeexplore.ieee.org/ [...] Read more...
32dB of Optical Budget with DSP-free real time experimentation up to 50Gbit/s NRZ using O-band DFB-EAM and SOA-PIN for Higher Speed PONs07/06/2021We achieve 32.3dB of optical budget and 45km reach transmission in real time with an O-band EAM-DFB and SOA-PIN for 50Gbit/s NRZ standards. A DSP-free transmission was demonstrated with a semi-cooled transmitter.Published in: 2021 Optical Fiber Communications Conference and Exhibition (OFC) Read more at https://ieeexplore.ieee.org/  [...] Read more...
Achieving high budget classes in the downstream link of 50G-PON02/06/2021Abstract: With 50G passive optical networks (PONs) currently being standardized, we review the challenges of meeting the high loss budgets required in such high speed fiber access networks. Simulations of the 50 Gb/s link performance show the impact of critical parameters when using 25G-class avalanche photodiode receivers with digital signal processing. We describe how a 1342 nm electro-absorption modulated laser, with an external semiconductor optical amplifier, enables an E2-class, 20 km, downstream link for ITU-T, 50G-PON to be demonstrated. Using a 25G-class receiver and real-time equalization, a link budget of 35.6 dB was measured. With more powerful equalization performed offline, an increase in the link budget to 38.2 dB is also demonstrated. Published in: Journal of Optical Communications and Networking ( Volume: 13, Issue: 8, August 2021) Read more at https://ieeexplore.ieee.org/ [...] Read more...
First Demonstration of an E2 Class Downstream Link for 50Gb/s PON at 1342nm05/03/2021Abstract: A 1342nm EML with an external SOA has enabled the 20km, 50Gb/s downstream link for ITU-T, 50G-PON to be demonstrated for the first time. Using a 25G-class receiver and real-time equalisation, an OMA sensitivity of −24dBm and a link budget of 35.6dB were measured. Published in: 2020 European Conference on Optical Communications (ECOC) Read more at https://ieeexplore.ieee.org/ [...] Read more...
Versatile Externally Modulated Lasers Technology for Multiple Telecommunication Applications07/10/2020Abstract: This paper presents our technological approach for Externally Modulated Lasers (EMLs), based on Semi-Insulating Buried Heterostructure (SIBH) waveguide. We use Gas Source Molecular Beam Epitaxy (GSMBE) to grow the Phosphorus-based multi-quantum wells for both laser and modulator sections with butt-joint integration. The same GSMBE grows the p-doped InP claddings with low-diffusion Be dopant, leading to an accurate control of doping profiles, ensuring very steep modulator extinction curves. We present the main EML design rules and compromises, then apply them to different EMLs aiming at major telecom and datacom applications. After presenting characteristics of the standard 10 Gb/s C-band EML, we propose a 10 Gb/s EML at 1577 nm for next generation access networks, with a record high 10.5 dBm facet modulated power. Then we present high-speed EMLs up to 56 GBaud for datacenter interconnections, both in O- and C-band, aiming at very low peak-to-peak modulation voltage (< 1.2 V), high facet modulated power (> 4.4 dBm), and compatible with uncooled operation (20 to 70 °C). These results confirm the efficiency and versatility of this technological platform for EMLs in a broad range of applications. Published in: IEEE Journal of Selected Topics in Quantum Electronics ( Volume: 27, Issue: 3, May-June 2021)Read more at https://ieeexplore.ieee.org/ [...] Read more...
Uncooled 1.55µm Electro-Absorption Modulated Laser at 28Gb/s with high power and low Vpp for datacom26/09/2019Abstract: We present an uncooled 28Gb/s 1.55µm electro-absorption modulated laser, based on semi-insulating buried heterostructure waveguide technology. With only 0.9V peak-to-peak voltage, dynamic extinction ratio of more than 3.5dB, and facet average output power above 5dBm are demonstrated over the temperature range from 20 to 70°C. Published in: 45th European Conference on Optical Communication (ECOC 2019)   [...] Read more...
Hybrid III–V/Silicon Technology for Laser Integration on a 200-mm Fully CMOS-Compatible Silicon Photonics Platform11/03/2019Abstract: In this paper, we present the hybrid III-V/Si photonic platform developed in CEA-LETI. The overall integration is done in a fully CMOS compatible 200-mm technology, scalable to 300-mm wafers, leveraging the large-scale integration capabilities of silicon photonics. III-V material is integrated on top of a mature silicon photonic front-end wafer through direct molecular bonding enabling the monolithic integration of light sources. DFB and distributed Bragg reflector (DBR) laser reference designs are used as test vehicles for the process validation. A modular approach is used in order to minimize the impact on the already qualified silicon-based devices. Collective III-V die bonding is proposed in this platform. CMOS compatible metallizations are used to form ohmic contact on n-InP and P-InGaAs leading to contact resistivity in the range of 10 -6 Ω·cm 2 . A planarized two-metal-level BEOL is used to connect the device, leading to a drastic reduction of series resistance. Finally, the functionality of both types of lasers is demonstrated with SMSR up to 50 dB and maximum output power of 5 mW. Published in: IEEE Journal of Selected Topics in Quantum Electronics ( Volume: 25 , Issue: 5 , Sept.-Oct. 2019 ) Read more at https://ieeexplore.ieee.org/ [...] Read more...
1.3µm SI-BH Electro-Absorption Modulated Laser Operating at 56Gbauds/s with 8.4dB Dynamic Extinction Ratio27/09/2018  Abstract: We present a 56Gbaud/s 13μm electro-absorption modulated laser, based on semi-insulated buried waveguide technology. A dynamic extinction ratio of 8.4dB, with 1. 8dBm fiber coupled average power, and 112Gb/s PAM4 transmission, with a BER=10 -3 , are demonstrated. Published in: 2018 European Conference on Optical Communication (ECOC) Read more at ieeexplore.ieee.org [...] Read more...
Record 6dBm electroabsorption modulated laser for 10Gb/s and 25Gb/s high power budget access networks23/03/2017  Abstract: We present an electro-absorption modulated laser with 6dBm modulated power leading to record power budget NRZ transmissions at 1.55μm: 37dB at 10Gb/s over 50km and 30dB at 28Gb/s over 10km with a pre-amplified photodiode. Published in: 2017 Optical Fiber Communications Conference and Exhibition (OFC) Read more at ieeexplore.ieee.org [...] Read more...