Mid-infrared laser sources are of great interest for various applications, including light detection and ranging, spectroscopy, communication, trace-gas detection, and medical sensing. Silicon photonics is a promising platform that enables these applications to be integrated on a single chip with low cost and compact size. Silicon-based high-power lasers have been demonstrated at 1.55 μm wavelength, while in the 2 μm region, to the best of our knowledge, high-power, high-efficiency, and monolithic light sources have been minimally investigated. In this Letter, we report on high-power CMOS-compatible thulium-doped distributed feedback and distributed Bragg reflector lasers with single-mode output powers up to 267 and 387 mW, and slope efficiencies of 14% and 23%, respectively. More than 70 dB side-mode suppression ratio is achieved for both lasers. This work extends the applicability of silicon photonic microsystems in the 2 μm region.

To meet the increasing demand for data communication bandwidth and overcome the limits of electrical interconnects, silicon photonic technology has been extensively studied, with various photonics devices and optical links being demonstrated. All of the optical data links previously demonstrated have used either heterogeneously integrated lasers or external laser sources. This work presents the first silicon photonic data link using a monolithic rare-earth-ion-doped laser, a silicon microdisk modulator, and a germanium photodetector integrated on a single chip. The fabrication is CMOS compatible, demonstrating data transmission as a proof-of-concept at kHz speed level, and potential data rate of more than 1 Gbps. This work provides a solution for the monolithic integration of laser sources on the silicon photonic platform, which is fully compatible with the CMOS fabrication line, and has potential applications such as free-space communication and integrated LIDAR.

A key challenge for silicon photonic systems is the development of compact on-chip light sources. Thulium-doped fiber and waveguide lasers have recently generated interest for their highly efficient emission around 1.8 µm, a wavelength range also of growing interest to silicon-chip based systems. Here, we report on highly compact and low-threshold thulium-doped microcavity lasers integrated with silicon-compatible silicon nitride bus waveguides. The 200-µmdiameter thulium microlasers are enabled by a novel high quality-factor (Q-factor) design, which includes two silicon nitride layers and a silicon dioxide trench filled with thulium-doped aluminum oxide. Similar, passive (undoped) microcavity structures exhibit Q-factors as high as 5.7 × 10 5 at 1550 nm. We show lasing around 1.8-1.9 µm in aluminum oxide microcavities doped with 2.5 × 10 20 cm −3 thulium concentration and under resonant pumping around 1.6 µm. At optimized microcavity-waveguide gap, we observe laser thresholds as low as 773 µW and slope efficiencies as high as 23.5%. The entire fabrication process, including back-end deposition of the gain medium, is silicon-compatible and allows for co-integration with other silicon-based photonic devices for applications such as communications and sensing.

No abstract

Erbium-doped lasers provide high power, narrow linewidth and thermally stable emission in the important 1.5-µm eye-safe and telecommunications band. By integrating such lasers on a chip we can realize cost-effective, compact and highly robust devices compared to fiber-based platforms. Furthermore, using a silicon-compatible fabrication approach allows for co-integration with silicon electronic/photonic devices and will open new applications for compact microsystems. The presentation will cover our work on silicon-based erbium-doped aluminum oxide lasers (Al2O3:Er3+). Al2O3:Er3+  has recently received significant attention because of its broad emission, reduced clustering, and higher index, thus potential for more compact devices, compared to Er-doped silica. This has led to numerous demonstrations of amplification and lasing on chips using Al2O3:Er3+ as monolithic gain medium. As an important step towards silicon compatibility and exploiting wafer-scale lithography methods for high resolution cavity features, we have developed a silicon nitride-based Al2O3:Er3+ platform. Using such an approach, we have demonstrated a number of on-chip lasers, including distributed feedback, distributed Bragg reflector and microcavity devices. The talk will cover critical materials and design considerations towards realizing high performance lasers, including the influence of ion-ion clustering in the Al2O3 host, nanoscale film-thickness non-uniformities, and cavity Q factor optimization.