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A lumped-electrode-type EA-DFB with a short-length modulator packaged by using an ultra-short wiring technique achieved bandwidth over 60-GHz in a wide-temperature range, and 100-Gbaud NRZ eye opening up to 80°C was demonstrated for the first time.

Growing volume of data transmission in data centers requires large capacity optical communication networks. High-speed optical devices and their packaging technology have become important not only in realizing high speed optical communication but also from the view point of size and cost reduction. In this presentation, our high-speed optical devices and our approach to their packaging technology are reported.

Technologies for high-density integration of optical and electrical components are indispensable for next-generation optical transceivers whose capacity will exceed 400 Gbps. 3-D vertical integration technology with high optical coupling efficiency between a single mode fiber (SMF) array and lens-integrated surface emitting laser (LISEL) array using micro electro mechanical system (MEMS)-based movable micro-mirrors can meet this requirement. Light emitted from the LISEL is reflected at the micro-mirror and coupled to the SMF. Since the micro-mirror can steer the beam emitted from the LISEL to the SMF, the coupling efficiency that depends on the alignment accuracy between the LISEL and SMF is adjustable. After the alignment is completed, the position of the micro-mirror is fixed to keep high coupling efficiency. An optical sub-assembly (OSA) incorporating the LISEL, micro-mirror, and SMF array was fabricated using surface mount technology. All optical components were passively aligned, and the positions of micro-mirrors were adjusted to make a precise optical coupling to the SMFs as a post alignment. To confirm the effectiveness of this post-alignment system, the characteristics of the optical coupling to the SMF array were measured. It was found that the position of the reflected beam could be controlled to sub-micro-meter accuracy.

A movable micro-mirror array is proposed for high-density multi-channel single-mode optical sub-assembly. Adjustable optical-coupling loss of over 2dB was confirmed from experiments of 4-ch array optical-coupling between DFB lasers and single-mode fibers using the micro-mirrors.

We proposed a perfectly facet-free surface-emitting 1.3-μm DFB laser toward cost-effective light source, and confirmed the same performances as the usual DFB lasers and an on-wafer measurement.

A simple and practical method for integrating a DFB laser and a silicon photonics platform without additional optical components such as lenses and an isolator is proposed. Optical-coupling and feedback-tolerance characteristics arc experimentally measured.

40-Gb/s (4-ch x 10-Gb/s) operation of a 1.3-µm lens-integrated surface-emitting laser diode array was demonstrated by a CMOS shunt driver. Clearly opened eyes at 10-Gb/s were obtained for 4 channel simultaneous operation at 95°C.

A lens-integrated surface-emitting laser array has been developed for an optical module compliant with Parallel Single-mode 4-lane Multi-Source Agreement (PSM4 MSA) for 100GbE applications. High-efficiency optical coupling to SMF with two-lens configuration and uncooled 25-Gb/s operation over all four-channels were demonstrated.

A high-speed opto-electronic printed circuit board (OEPCB) composed of a polymer waveguide and an optical module is conceptually proposed and prototyped. The fabricated OEPCB prototype provides highly efficient optical coupling characteristics (> -1 dB) and large optical-coupling tolerance (> +/-15 μm). It demonstrated 25-Gbit/s high-speed optical-signal transmission through a 10-cm-long multi-mode polymer waveguide. This performance result indicates that the OEPCB is suitable for next-generation high-speed and high-density chip-to-chip optical interconnection.

40-Gb/s/ch direct modulation of multi-wavelength 1.3-μm surface-emitting laser array is demonstrated. Fabricated laser array consisting of four-channel DFB stripes with modified gratings, 45° mirror, and integrated lens, exhibited clear 40-Gb/s eye openings over all four channels.

A hybrid integration of a surface emitting DFB lasers and a fully integrated transceiver CMOS chip was proposed for compact 100-Gb/s transceivers of optical backplanes and datacenter optical links.

Uncooled 25-Gb/s operation of a multi-wavelength 1.3-µm surface-emitting-laser array was demonstrated. This array–consisting of four distributed-feedback (DFB) active stripes, 45° mirrors and integrated lenses–exhibited 25-Gb/s operation up to 85°C over all channels.

Uncooled 25-Gb/s transmission of a 1.3-µm surface-emitting laser is demonstrated. A fabricated laser, which consists of an InGaAlAs-MQW DFB active stripe and surface-mountable structure, exhibited clear 25-Gb/s eye openings after 2-km SMF transmission up to 85°C.

Four-channel 25-Gb/s direct modulation of a 1.3-µm surface-emitting laser array with a surface mountable device structure was demonstrated. The fabricated laser array, which consists of InGaAlAs-MQW DFB stripes, exhibited a total output of 100 Gb/s with collimated optical outputs.

Recent progress in developing 1.3-um InGaAlAs-MQW directly modulated lasers is reported. Uncooled 25-Gbps operations over a wide temperature range were demonstrated. Clear eye opening up to 100 °C % was successfully obtained.

Recent advances in integrated photonic devices for next-generation Ethernet are described. In particular, 1.3-µm-range uncooled photonic devices (namely, electroabsorption modulator integrated lasers, directly modulated lasers, and lens integrated devices) are focused on. A key technology for uncooled operation is an InGaAlAs multiple quantum well (MQW), which produces a strong electron confinement. The electroabsorption modulator integrated lasers, which incorporated an InGaAlAs-MQW absorption layer, exhibit uncooled 25.8-Gbit/s and 43-Gbit/s single-mode fiber 10-km transmissions. The 1.3-µm directly modulated laser, which consists of an InGaAlAs MQW distributed feedback (DFB) active stripe, exhibits uncooled direct modulation at 25 Gbit/s. To improve the optical coupling of the directly modulated laser, we developed a lens-integrated surface-emitting laser, which incorporates an InGaAlAs DFB active stripe. This lens-integrated laser exhibits 25-Gbit/s direct modulation up to 100°C. Furthermore, the lens-integrated photodiode exhibited high speed (35 GHz), high responsivity (0.8 A/W), and large alignment tolerance (26 µm) for direct coupling to a single-mode fiber. These photonic devices have demonstrated their potential for implementation in cost-effective 100-Gbit/s and 40-Gbit/s Ethernet.

We describe an aspheric-microlens-integrated high-performance PIN photodiode, which exhibits high speed (35 GHz), high responsivity (0.8 A/W), and large alignment tolerance (26 µm) for direct coupling to a flat-ended standard single-mode fiber.

Circular, narrow beam emission of a lens-integrated surface-emitting laser operated at 1.3-µm wavelength was demonstrated. The laser consists of a distributed feedback laser cavity monolithically integrated with an etched 45° total reflection mirror and an etched InP lens. The profile of the etched InP lens was estimated to be a highly symmetrical parabolic shape that is ideal for the collimation of a Gaussian beam. A fabricated lens-integrated surface-emitting laser exhibited a circular, narrow far-field pattern with full-width at half-maximums of 3.9° × 3.5°. A highly efficient direct coupling to a single-mode fiber with a coupling efficiency of − 2.7 dB was also confirmed.

High-performance GalnNAs/GaAs triple quantum well (TQW) edge-emitting lasers were demonstrated. Al-free molecular beam epitaxy (MBE) is effective to prevent any Al impurity or contamination, which had appeared in previous GalnNAs materials, leading to a significant improvement in the photoluminescence intensity. By using this growth method, we have successfully grown highly-strained GalnNAs/GaAs TQW lasers that exhibit a record low threshold current of 4.4 mA at 25degC and a 40-Gbit/s direct modulation at 5degC. These results indicate that GalnNAs lasers are good candidates for future high-frequency operation cost-effective light sources.

We experimentally demonstrated that a record-low threshold current of 4.3 mA is achieved in long-wavelength, 1.29 μm, GaInNAs-TQW RWG lasers. Moreover, 40-Gb/s direct modulation of the laser is confirmedat 5°C.