We demonstrate an ultra-fast athermal continuous wavelength-swept III-V-on-SOI MOSCAP DFB laser with a mode-hop-free-tuning up to 10 GHz in less than 2 ns. We also propose a new method to linearize the frequency response without any pre-distortion or active feedback in the gain’s current injection ramp. Instead, we polarize the III-V gain Section under direct current injection, and we drive the hybrid MOSCAP waveguide with an AC voltage signal. By optimizing its driving frequency, we demonstrate an ultra-fast athermal triangular-shaped time-varying frequency tuning with a speed of $4\times 10 ^{4}$ PHz/s and a laser’s frequency excursion of 4 GHz.

The integration of active devices such as lasers, modulators or photodetectors on silicon photonics platforms has enabled the development of efficient, performant, low-cost and scalable high-speed integrated transceivers for optical communications. In this invited contribution, we will review the most relevant work in the field so far and we will present our recent progress on high-speed integrated transceivers for silicon photonics. The most relevant figures of merit for integrated lasers and electro-absorption modulators for high-speed optical communications will be discussed, as well as our vision for future developments.

We demonstrate externally modulated widely tunable lasers co-integrated with semiconductor optical amplifiers (SOAs) heterogeneously integrated on silicon. The widely tunable laser enables continuous single-mode operation over a tuning range of approximately 40 nm, with a side-mode suppression ratio (SMSR) of at least 50 dB and an average waveguide-coupled optical power of 5 mW. The integrated electro-absorption modulator (EAM) exhibits an extinction ratio (ER) of 16 dB when reversed biased at -2 V. The bit-error-rate (BER) measurements conducted across the available optical bandwidth (15 nm) showcase error-free transmission at 32 Gbps using non-return-to-zero (NRZ) signals for the majority of wavelengths in a back-to-back (B2B) configuration. Additionally, transmission measurements over distances of up to 10 km through a standard single-mode fiber (SSMF) have been successfully demonstrated. Dynamic extinction ratio (DER) values exceeding 4.5 dB are achieved for all wavelengths. Open-eye diagrams were measured up to 56 Gbps. These results demonstrate that this compact mono-epitaxial externally modulated tunable laser with integrated optical amplification can be a cost-effective transmitter solution for dense wavelength division multiplexing (DWDM) metropolitan and access networks.

The field of Silicon Photonics has experienced a solid and continuous progress over the last few years, gaining in technological maturity, design tools, and new methods [1]. The deployment of low-cost, compact, and power-efficient photonic circuits with a high wafer yield and robustness stands as one of the fundamental pillars that sustain such progress [2]. Presently, photonic circuit technology has diversified its number of available platforms. Despite the fact that indium phosphide (InP) [3] and silicon-on-insulator (SOI) platforms are still considered as the workhorses of integrated photonics in terms of maturity and deployment of active (InP) and passive (SOI) components, other alternatives such as germanium-on-silicon [4], silicon nitride-on-insulator [2] or hybrid solutions combining different functional materials with Si are gaining momentum [5]. A representative example is the heterogeneous III-V/Si platform [6], which has been used to develop compact photonic circuits with on-chip gain. Contrarily to the hybrid integration, the III-V-on-Si heterogeneous integration avoids the constraints of chip-to-chip alignment while enabling the simultaneous integration of hundreds of III-V gain chips in a scalable fashion. Still, the integration methods of such III-V materials on silicon need to be improved to attain the maturity level of the monolithic III-V platform, which benefits from a complete palette of technological solutions not yet available in the III-V-on-Si heterogeneous integration. More recently, an advanced heterogeneous scheme based on wafer-seed-bonding and epitaxial regrowth has emerged [7]–[9]. The ambition is to create a generic integration scheme combining the best offered by the III-V and the Si-photonics platforms. The regrowth capability gives access to the large epitaxial toolkit available in the conventional InP monolithic platform, where several epitaxial steps are often implemented [10][11]. To cite some of them, the epitaxial regrowth of III-V materials to bury III-V lasers bonded onto silicon are object of intense research nowadays to overcome the thermally inefficient buried oxide [12]. In this paper, we will review the advances on III-V-on-Si heterogeneous integration through the implementation of several key demonstrators and building blocks for silicon photonics, including on-chip semiconductor optical amplifiers, lasers and electro-absorption modulators. We will discuss the progress and benefits of the direct seed bonding and regrowth as well as new device designs to improve the performance. References: [1] D. Thomson et al. , “Roadmap on silicon photonics,” J. Opt. , vol. 18, no. 7, p. 73003, 2016, doi: 10.1088/2040-8978/18/7/073003. [2] S. Y. Siew et al. , “Review of Silicon Photonics Technology and Platform Development,” Journal of Lightwave Technology , vol. 39, no. 13. Institute of Electrical and Electronics Engineers Inc., pp. 4374–4389, Jul. 01, 2021, doi: 10.1109/JLT.2021.3066203. [3] M. Smit, K. Williams, and J. Van Der Tol, “Past, present, and future of InP-based photonic integration,” APL Photonics , vol. 4, no. 5, May 2019, doi: 10.1063/1.5087862. [4] J. Chrétien et al. , “GeSn Lasers Covering a Wide Wavelength Range Thanks to Uniaxial Tensile Strain,” ACS Photonics , vol. 6, no. 10, pp. 2462–2469, Oct. 2019, doi: 10.1021/acsphotonics.9b00712. [5] S. Lin et al. , “Efficient, tunable flip-chip-integrated III-V/Si hybrid external-cavity laser array,” Opt. Express , vol. 24, no. 19, p. 21454, Sep. 2016, doi: 10.1364/oe.24.021454. [6] D. Liang and J. E. Bowers, “Recent Progress in Heterogeneous III-V-on-Silicon Photonic Integration,” Light Adv. Manuf. , vol. 2, no. 1, pp. 1–25, 2021, doi: 10.37188/lam.2021.005. [7] K. Takeda, S. Matsuo, T. Fujii, K. Hasebe, T. Sato, and T. Kakitsuka, “Epitaxial growth of InP to bury directly bonded thin active layer on SiO2/Si substrate for fabricating distributed feedback lasers on silicon,” IET Optoelectron. , vol. 9, no. 4, pp. 151–157, 2015, doi: 10.1049/iet-opt.2014.0138. [8] C. Besancon et al. , “AlGaInAs Multi-quantum Well Lasers On Silicon-on-insulator Photonic Integrated Circuits Based On InP-seed-bonding And Epitaxial Regrowth,” Appl. Sci. , vol. 12, no. 1, Jan. 2022, doi: 10.3390/app12010263. [9] Y. Hi et al. , “Electrically-Pumped 1.31 μm MQW Lasers by Direct Epitaxy on Wafer-Bonded InP-on-SOI Substrate,” in Proceedings of 2018 IEEE Photonics Conference (IPC) , 2018, pp. 1–2. [10] V. Rustichelli et al. , “Monolithic integration of buried-heterostructures in a generic integrated photonic foundry process,” IEEE J. Sel. Top. Quantum Electron. , vol. 25, no. 5, Sep. 2019, doi: 10.1109/JSTQE.2019.2927576. [11] F. Lemaître et al. , “96 nm Extended Range Laser Source Using Selective Area Growth,” in European Conference on Optical Communication, ECOC , 2018, doi: 10.1109/ECOC.2018.8535218. [12] C. Besancon et al. , “AlGaInAs Multi-Quantum Well Laser on Silicon Achieved byDirect-Bonding and MOVPE Semi-Insulating Buried Heterostructure Regrowth,” in Compound Semiconductor Week 2023 , Jan. 2023, vol. 12, no. 1, doi: 10.3390/app12010263.

We demonstrate rapid wavelength measurements with response times under 200 ns using a silicon photonic wavemeter. With this new capability, we show tracking of a DFB laser's wavelength during fast ramps and short bursts, for possible use in LiDAR, sensing, imaging, or optical communication applications.

We present a III-V/SOI platform using wafer-bonding which allows integration of lasers. We demonstrated new lasers leveraging innovations this platform provides: nanosecond wavelength tuning laser, 10GHz-frequency continuous tuning DFB laser and a new few mode-locking laser.

We demonstrate a silicon photonic wavemeter with high accuracy for broadband measurements over a large temperature range of 20-60˚C. The integrated wavemeter reaches a mean error of 11 pm over an 80 nm span.

We demonstrate an athermal silicon photonic wavemeter with high accuracy for broadband measurements over the temperature range 20-70°C. The integrated wavemeter has an average accuracy of 7.9 pm (<1 GHz) across the C-band.

Heterogeneous integration of III-V materials on silicon photonics circuits has emerged as an attractive approach to demonstrate compact lasers that address a wide range of applications ranging from short distance data communication to long distance optical transmission. Directly modulated III-V-on-SOI lasers (DML) with high bandwidths such as distributed feedback (DFB) lasers are particularly well suited for those applications that require high optical power and stable single-mode performance [1].

We review our work on integrated lasers for optical communications. An InP-based multilayer stack containing Al-based quantum wells with optical gain in the telecom window is bonded onto a silicon-on-insulator wafer with patterned photonic circuits and cavities. Ring-based widely tunable lasers and narrow linewidth DFB lasers are demonstrated.

Fiber Bragg Grating (FBG) sensors offer multiple benefits in comparison with electronic sensors due to their compactness, electromagnetic immunity as well as their resistance to harsh environments and their multiplexing capabilities. Structural Health Monitoring (SHM) is one of the various potential industrial applications that could take full advantage of those sensors. However, there is a need for a low size, weight, power and cost interrogation unit for certain application areas such as aerospace or aeronautics. That is the reason why recent efforts have been made to use integrated components and circuits for interrogation of FBGs. Among different techniques, interrogation with a swept laser source is of high interest since it has a high multiplexing capability and could reach a high level of integration using other integrated components such as photodetectors, grating couplers or directional couplers to form a compact interrogation unit. In this paper, we present characterization results of a fully-packaged hybrid III-V on silicon tunable laser diode operating in the C and L bands. Wavelength maps are produced and analyzed and modulation of emitted wavelength is discussed. Preliminary results corresponding to a moderate frequency (10-Hz sweep rate) were obtained and FBG reflection spectra acquired with a broadband source (BBS) and a swept laser diode are compared. Finally, we discuss potential design improvements in order to reach high scan rates (> 10 kHz) and a large tuning range.

In this work we will review our latest advancements on the development of widely tunable lasers using an heterogeneous integrated technology that combines an InP-based photonic platform containing Al-based multiple quantum wells with silicon photonic integrated circuits defined on a SOI platform.

We demonstrate stable operation of a multimode DFB laser-based on a 1D photonic crystal cavity. The laser signal comprises three modes spaced by similar to 28 GHz with linewidths below 135 kHz. Under mode-locking operation, the laser beat tone is narrowed down to 20 kHz. (C) 2022 The Author(s)

Heterogeneous integration of III-V on silicon lasers eliminates some constraints of chip-to-chip alignment, but the optical coupling between the two media remains of importance for repeatable performances. First, we present a processing enhancement of the bonding oxide thickness uniformity across the wafer, improving the cross-section reproducibility. Next optimized tapering of the III-V/Si waveguides, offering a design agnostic to the number of quantum wells, will be shown. Finally, the yield of III-V on Silicon tunable lasers was evaluated by mean of wafer level measurements, using a yield oriented tuning of each cavity, so that lasers characteristics can be fairly compared.

The tremendous demand for low-cost, low-consumption and high-capacity optical transmitters in data centers challenges the current InP-photonics platform. The use of silicon (Si) photonics platform to fabricate photonic integrated circuits (PICs) is a promising approach for low-cost large-scale fabrication considering the CMOS-technology maturity and scalability. However, Si itself cannot provide an efficient emitting light source due to its indirect bandgap. Therefore, the integration of III-V semiconductors on Si wafers allows us to benefit from the III-V emitting properties combined with benefits offered by the Si photonics platform. Direct epitaxy of InP-based materials on 300 mm Si wafers is the most promising approach to reduce the costs. However, the differences between InP and Si in terms of lattice mismatch, thermal coefficients and polarity inducing defects are challenging issues to overcome. III-V/Si hetero-integration platform by wafer-bonding is the most mature integration scheme. However, no additional epitaxial regrowth steps are implemented after the bonding step. Considering the much larger epitaxial toolkit available in the conventional monolithic InP platform, where several epitaxial steps are often implemented, this represents a significant limitation. In this paper, we review an advanced integration scheme of AlGaInAs-based laser sources on Si wafers by bonding a thin InP seed on which further regrowth steps are implemented. A 3 µm-thick AlGaInAs-based MutiQuantum Wells (MQW) laser structure was grown onto on InP-SiO2/Si (InPoSi) wafer and compared to the same structure grown on InP wafer as a reference. The 400 ppm thermal strain on the structure grown on InPoSi, induced by the difference of coefficient of thermal expansion between InP and Si, was assessed at growth temperature. We also showed that this structure demonstrates laser performance similar to the ones obtained for the same structure grown on InP. Therefore, no material degradation was observed in spite of the thermal strain. Then, we developed the Selective Area Growth (SAG) technique to grow multi-wavelength laser sources from a single growth step on InPoSi. A 155 nm-wide spectral range from 1515 nm to 1670 nm was achieved. Furthermore, an AlGaInAs MQW-based laser source was successfully grown on InP-SOI wafers and efficiently coupled to Si-photonic DBR cavities. Altogether, the regrowth on InP-SOI wafers holds great promises to combine the best from the III-V monolithic platform combined with the possibilities offered by the Si photonics circuitry via efficient light-coupling.

We present our work on heterogeneously integrated widely tunable lasers for optical communications. We revisit the main design parameters and show how the performance of such devices can be boosted from design.

We demonstrate a heterogeneously integrated III-V-on-SOI distributed feedback laser with a low grating strength (κ < 40 cm-1) and a narrow linewidth of Δν = 118 kHz. The laser operates single mode with a side-mode suppression ratio over 45 dB, provides a single-sided waveguide-coupled output power of 22 mW (13.4 dBm) and has a wall-plug efficiency of 17%. The dynamic characteristics were also evaluated, obtaining an intrinsic 3 dB modulation bandwidth of 14 GHz and a photon lifetime of 8 ps. Large-signal intensity modulation using a 231-1 PRBS pattern length revealed open eye diagrams up to 25 Gb/s and a penalty on the dynamic extinction ratio lower than 1 dB after transmission over a 2 km standard single mode optical fiber.

Heterogeneously integrated III-V/Si lasers and semiconductor optical amplifiers (SOAs) are key devices for integrated photonics applications requiring miniaturized on-chip light sources, such as in optical communications, sensing, or spectroscopy. In this work, we present a widely tunable laser co-integrated with a semiconductor optical amplifier in a heterogeneous platform that combines AlGaInAs multiple quantum wells (MQWs) and InP-based materials with silicon-on-insulator (SOI) wafers containing photonic integrated circuits. The co-integrated device is compact, has a total device footprint of 0.5 mm2, a lasing current threshold of 10 mA, a selectable wavelength tuning range of 50 nm centered at λ = 1549 nm, a fiber-coupled output power of 10 mW, and a laser linewidth of ν = 259 KHz. The SOA provides an on-chip gain of 18 dB/mm. The total power consumption of the co-integrated devices remains below 0.5 W even for the most power demanding lasing wavelengths. Apart from the above-mentioned applications, the co-integration of compact widely tunable III-V/Si lasers with on-chip SOAs provides a step forward towards the development of highly efficient, portable, and low power systems for wavelength division multiplexed passive optical networks (WDM-PONs).