Hybrid photonic integration combines complementary advantages of different material platforms, offering superior performance and flexibility compared with monolithic approaches. This applies in particular to multi-chip concepts, where components can be individually optimized and tested. The assembly of such systems, however, requires expensive high-precision alignment and adaptation of optical mode profiles. We show that these challenges can be overcome by in situ printing of facet-attached beam-shaping elements. Our approach allows precise adaptation of vastly dissimilar mode profiles and permits alignment tolerances compatible with cost-efficient passive assembly techniques. We demonstrate a selection of beam-shaping elements at chip and fibre facets, achieving coupling efficiencies of up to 88% between edge-emitting lasers and single-mode fibres. We also realize printed free-form mirrors that simultaneously adapt beam shape and propagation direction, and we explore multi-lens systems for beam expansion. The concept paves the way to automated assembly of photonic multi-chip systems with unprecedented performance and versatility. By exploiting two-photon laser lithography for in situ printing of facet-attached beam-shaping elements, hybrid photonic integration can now be realized, opening opportunities for the automated assembly of photonic multi-chip systems with unprecedented performance and versatility.

In situ 3D nanoprinting of free-form coupling elements for hybrid photonic integration

Provided are a semiconductor device, which can facilitate a salicide process and can prevent a gate from being damaged due to misalign, and a method of manufacturing of the semiconductor device. The method includes forming a first insulation layer pattern on a substrate having a gate pattern and a source/drain region formed at both sides of the gate pattern, the first insulation layer pattern having an exposed portion of the source/drain region, forming a silicide layer on the exposed source/drain region, forming a second insulation layer on the entire surface of the substrate to cover the first insulation layer pattern and the silicide layer, and forming a contact hole in the second insulation layer to expose the silicide layer.

Semiconductor devices and methods of manufacturing the same

Increasing the modulation speed of semiconductor lasers has attracted much attention from the viewpoint of both physics and the applications of lasers. Here we propose a membrane distributed reflector laser on a low-refractive-index and high-thermal-conductivity silicon carbide substrate that overcomes the modulation bandwidth limit. The laser features a high modulation efficiency because of its large optical confinement in the active region and small differential gain reduction at a high injection current density. We achieve a 42 GHz relaxation oscillation frequency by using a laser with a 50-μm-long active region. The cavity, designed to have a short photon lifetime, suppresses the damping effect while keeping the threshold carrier density low, resulting in a 60 GHz intrinsic 3 dB bandwidth (f3dB). By employing the photon–photon resonance at 95 GHz due to optical feedback from an integrated output waveguide, we achieve an f3dB of 108 GHz and demonstrate 256 Gbit s−1 four-level pulse-amplitude modulations with a 475 fJ bit−1 energy cost of the direct-current electrical input. Directly modulated membrane distributed reflector lasers are fabricated on a silicon carbide platform. The 3 dB bandwidth, four-level pulse-amplitude modulation speed and operating energy for transmitting one bit are 108 GHz, 256 Gbit s−1 and 475 fJ, respectively.

Directly modulated membrane lasers with 108 GHz bandwidth on a high-thermal-conductivity silicon carbide substrate

This paper describes the wide temperature range operation of an electroabsorption modulator (EAM) integrated with DFB laser diodes (LDs) (EML) designed to reduce the power consumption and size of optical transmitters. We optimized the multiquantum wells (MQWs) for LD and EAM separately to realize uncooled operation. We employed a conduction band offset (?Ec) of around 250 meV for the LD and 150 meV for the EAM. The number of well layers was set at 6 for the LD and 12 for the EAM, respectively. We fabricated the EML using a butt-joint (BJ) process to allow us to design the LD and the EAM independently. We introduced a ridge waveguide structure for the LD and EAM waveguides, and designed the width of the LD and EAM mesa to achieve a high optical coupling efficiency between the LD and the EAM. We then used the 200-? m-long EAM for 10-Gb/s operation and the 150- ?m-long EAM for 40-Gb/s operation, and thus obtained a dynamic extinction ratio of over 9 dB at 10 Gb/s from -25 °C to 100 °C and of 8.2 dB at 40 Gb/s from -15 to 80°C. We achieved a power penalty of less than 2 dB after an 80-km single-mode fiber (SMF) transmission at 10 Gb/s and a 2-km SMF transmission at 40 Gb/s over a wide temperature range. These results confirm the suitability of this EML with a BJ structure for use as a 10-Gb/s or 40-Gb/s uncooled light source.

Design and Fabrication of 10-/40-Gb/s, Uncooled Electroabsorption Modulator Integrated DFB Laser With Butt-Joint Structure

To reduce the ever-increasing energy consumption in datacenters, one of the effective approaches is to increase the ambient temperature, thus lowering the energy consumed in the cooling systems. However, this entails more stringent requirements for the reliability and durability of the optoelectronic components. Herein, we fabricate and demonstrate silicon-polymer hybrid modulators which support ultra-fast single-lane data rates up to 200 gigabits per second, and meanwhile feature excellent reliability with an exceptional signal fidelity retained at extremely-high ambient temperatures up to 110 °C and even after long-term exposure to high temperatures. This is achieved by taking advantage of the high electro-optic (EO) activities (in-device n3r33 = 1021 pm V−1), low dielectric constant, low propagation loss (α, 0.22 dB mm−1), and ultra-high glass transition temperature (Tg, 172 °C) of the developed side-chain EO polymers. The presented modulator simultaneously fulfils the requirements of bandwidth, EO efficiency, and thermal stability for EO modulators. It could provide ultra-fast and reliable interconnects for energy-hungry and harsh-environment applications such as datacentres, 5G/B5G, autonomous driving, and aviation systems, effectively addressing the energy consumption issue for the next-generation optical communication. Information and communication datacentres require a large amount of energy for their cooling systems, which could be decreased by working at higher temperatures. Here, the authors introduce a silicon-polymer hybrid modulator that maintains high data rates for long periods at high temperatures that could be used under such conditions, to reduce energy consumption.

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High-temperature-resistant silicon-polymer hybrid modulator operating at up to 200 Gbit s-1 for energy-efficient datacentres and harsh-environment applications.

A 1.3- μ m directly modulated distributed feedback laser was newly developed by adopting an asymmetric corrugation pitch modulated grating structure and an InGaAlAs multiquantum well active layer with both a high optical confinement factor and a high differential gain. A low threshold current and a large saturation current in light-current characteristics at high temperature were obtained and a high 3-dB bandwidth and a high relaxation oscillation frequency in electro-optical characteristics were also achieved over a wide temperature range. As a result, clear back-to-back eye openings were achieved for 26-Gbaud PAM4 (53-Gb/s) operation from 25 to 95 °C with large outer extinction ratio and sufficiently small transmission dispersion eye closure quaternary. Furthermore, 53-Gbaud PAM4 (106-Gb/s) operation from 25 to 80 °C was successfully demonstrated for both back-to-back and after 10-km single mode fiber transmission. These excellent characteristics make our DFB laser a promising cost-effective and compact transceiver with low power consumption for next-generation 400GbE applications.

Wide-Temperature-Range (25–80 °C) 53-Gbaud PAM4 (106-Gb/s) Operation of 1.3- μ m Directly Modulated DFB Lasers for 10-km Transmission

Uncooled 1300-nm range 4-channel 25-Gbps EA/DFB lasers that support CWDM scheme for 100-Gbps Ethernet has been realized. A wide temperature ranged 12-km transmission with over 9.6-dB dynamic extinction ratio was demonstrated for the first time.

Uncooled CWDM 25-Gbps EA/DFB Lasers for Cost-Effective 100-Gbps Ethernet Transceiver over 10-km SMF Transmission

Uncooled 10-Gbit/s, 80- km SMF transmission was demonstrated for the first time using a 1.55-μm InGaAlAs EA/DFB laser. A power penalty below 2-dB was achieved over a wide temperature range from 15°C to 95°C.

Wide temperature (15°C to 95°C), 80-km SMF transmission of a 1.55-μm, 10-Gbit/s InGaAlAs electroabsorption modulator integrated DFB laser

We developed a high-bandwidth 1.3- μ m uncooled electro-absorption modulator-integrated distributed-feedback laser and demonstrated uncooled 53-GBd four-level pulse amplitude modulation (PAM4) operation with low drive voltage for the first time. Specifically, 53-GBd PAM4 operation with the drive voltage of 0.9 V pp from 20 to 85 °C was achieved. The extinction ratio of more than 4.9 dB and transmission dispersion eye closure quaternary of less than 2.3 dB were obtained from 20 to 85 °C in the 53 GBd-PAM4 operation.

Uncooled Operation of 53-GBd PAM4 (106-Gb/s) EA/DFB Lasers With Extremely Low Drive Voltage With 0.9 V pp

Newly developed lumped-electrode (LE) EA-DFB lasers demonstrated 224-Gb/s PAM4 uncooled operation with 2-km transmission. Its average output power and TDECQ from 20 to 80°C are respectively more than 6 dBm and less than 2.8 dB.

Kazuhiko Naoe

Papers

Wide-Temperature-Range (25–80 °C) 53-Gbaud PAM4 (106-Gb/s) Operation of 1.3- μ m Directly Modulated DFB Lasers for 10-km Transmission

Uncooled CWDM 25-Gbps EA/DFB Lasers for Cost-Effective 100-Gbps Ethernet Transceiver over 10-km SMF Transmission

Wide temperature (15°C to 95°C), 80-km SMF transmission of a 1.55-μm, 10-Gbit/s InGaAlAs electroabsorption modulator integrated DFB laser

Uncooled Operation of 53-GBd PAM4 (106-Gb/s) EA/DFB Lasers With Extremely Low Drive Voltage With 0.9 V pp

224-Gb/s PAM4 Uncooled Operation of Lumped-electrode EA-DFB Lasers with 2-km Transmission for 800GbE Application