In an era demanding ever-smaller, more efficient, and higher-performing light sources, particularly in the short-wave infrared (SWIR) spectrum crucial for telecom and advanced sensing, a quiet revolution is underway in integrated photonics. CoreOptics is at the forefront, pioneering a new generation of surface-emitting lasers at 1310nm that promise to overcome the limitations of traditional edge-emitting counterparts.
For years, integrating lasers onto photonic integrated circuits (PICs) has been a complex dance of alignment and interconnection. Now, CoreOptics is changing the steps with its innovative SWIR high-power Continuous Wave (CW) surface-emitting laser. The secret? Its inherent surface emission capability, tailor-made for direct flip-chip integration. This seemingly simple shift unlocks a cascade of benefits, streamlining manufacturing and paving the way for unprecedented integration efficiency.
Beyond the Edge: The Power of Surface Emission
The limitations of conventional edge-emitting lasers in integrated systems are becoming increasingly apparent. CoreOptics is embracing a different paradigm: Horizontal Cavity Surface Emitting Lasers (HCSELs). Imagine an edge-emitting laser cleverly engineered with a turning mirror, redirecting its light output perpendicular to the semiconductor wafer's surface. This ingenious design allows for packaging reminiscent of familiar Vertical Cavity Surface Emitting Lasers (VCSELs) or LEDs, but with distinct advantages.
HCSELs offer a compelling alternative, most notably enabling wafer-scale testing. This fundamental shift in manufacturing allows for rigorous quality control at an early stage, translating to lower production costs and significantly higher throughput.
But the benefits don't stop there. Surface emission inherently delivers:
• Superior Grating Coupling: Resulting in significantly better grating coupling efficiency into the PIC.
• Ultra-Compact Footprint: A crucial factor in the relentless drive towards miniaturization of integrated systems, allowing for denser and more powerful PICs.
• Untapped Potential: Opening doors to the creation of higher power and more complex integrated light sources, pushing the boundaries of what's possible on a chip.
CoreOptics' Innovation: SWIR Powerhouse
At the heart of CoreOptics' advancement lies its novel 1310nm (FP/DFB)high-power CW surface-emitting laser design. Leveraging advanced InP-based alloys and a meticulously optimized layered epitaxial structure, this laser is engineered for peak performance in the SWIR region.
Key to its integration prowess are its innovative design features, including:
• AR/HR Wafer-Level Coating: Enhancing optical performance and simplifying the manufacturing process.
• Etched Facet (Mirror) and 45-Degree Reflector: Precisely engineered for efficient light extraction and surface emission. These features streamline production and contribute directly to the laser's superior performance and seamless integration capabilities.
Flip the Chip, Transform the Integration
The true magic unfolds with direct flip-chip integration onto PICs. This technique involves attaching the laser die directly onto the PIC substrate, "face down." It's a seemingly small change with profound implications.
By embracing flip-chip bonding, CoreOptics is effectively bypassing the complexities of traditional wire bonding and intricate packaging steps, leading to a new era of integration efficiency characterized by:
• Lightning-Fast Electrical Paths: Shorter pathways translate directly to higher speed operation and pristine signal integrity – critical for high-bandwidth applications.
• Unprecedented Compactness: The elimination of bulky interconnects results in a significantly smaller overall footprint for the integrated laser-PIC module, paving the way for truly miniaturized devices.
• Pinpoint Optical Alignment: The direct and meticulously controlled bonding process ensures precise and stable optical grating coupling between the laser and the PIC waveguide, maximizing efficiency and reliability.
SWIR HCSELs: SWIR Horizontal Cavity Surface Emitting Lasers Credit: CoreOptics
Simplifying the package: Less is more
The elegance of flip-chip integration extends to packaging. By directly bonding the laser, CoreOptics is drastically reducing the need for intermediate components and connections for both electrical and optical interfacing. This simplification translates to:
• Fewer Interconnects, Higher Reliability: Eliminating potential points of failure leads to more robust and dependable integrated devices.
• Streamlined Assembly: The direct bonding process simplifies the manufacturing flow, potentially lowering assembly costs and boosting overall reliability.
• Smaller and Lighter Packages: A crucial advantage for applications where size and weight are at a premium, such as portable sensing devices and wearable technology.
A Spectrum of Possibilities: Applications Unleashed
The unique advantages of CoreOptics' integrated SWIR HCSEL laser solution are poised to revolutionize a wide array of applications, including:
• High-Speed Optical Communication: Enabling next-generation on-chip interconnects and ultra-compact silicon photonics transceivers.
• Advanced Sensing: Powering integrated LiDAR systems for autonomous vehicles and robotics, as well as compact gas sensing platforms.
• The Smart Revolution: Enabling under-display proximity sensing in smartphones and other consumer electronics.
• Miniature Analytical Instruments: Facilitating the development of compact spectroscopy devices for on-the-go analysis.
• Next-Gen Medical Diagnostics: Enabling the creation of sophisticated lab-on-a-chip devices for SWIR imaging and advanced biosensing.
Expanding the Horizon: 1460nm and Beyond
CoreOptics isn't stopping at 1310nm. Their development of surface-emitting SWIR lasers at 1460nm further expands their reach. This wavelength offers its own set of compelling advantages, including low water absorption for long-distance fiber optic communication and high modulation capability for advanced data transmission and sensing. Potential applications span telecommunications, cutting-edge medical sensing and imaging (think non-invasive skin and glucose sensors), and precision industrial and environmental monitoring.
Illuminating New Paths: Resolight RCLEDs
Complementing their laser portfolio, CoreOptics also offers Resolight Resonant-Cavity Light-Emitting Diodes (RCLEDs) across a broad spectrum from 400nm to 1550nm. These aren't your average LEDs. Their resonant cavity structure dramatically enhances optical confinement, resulting in:
• Highly Directional Emission: Focusing light along a specific axis, unlike the omnidirectional output of standard LEDs.
• Small Divergence Angle: Enabling excellent beam collimation, minimizing light spread.
• Exceptional Color Purity: The resonant cavity acts as a filter, suppressing unwanted spectral leakage for a purer monochromatic output.
• Narrow Spectral Width: Achieving Full-Width at Half Maximum (FWHM) values between 10-20nm, significantly narrower than conventional LEDs.
• Robust Operation: Withstanding a wide temperature range of -40 to 85 degrees Celsius.
These enhanced characteristics make Resolight RCLEDs ideal for applications ranging from short-reach optical communication and high-resolution displays to the burgeoning field of visible light communication (VLC), precise optical sensing and scanning, and advanced medical and cosmetic devices.
Tailored Solutions: Design Flexibility at its Core
Recognizing the diverse needs of their clientele, CoreOptics leverages its unique HCSEL platform to offer customized solutions. By precisely engineering the reflector angle based on the specific grating angles of the PIC, they can optimize performance for individual customer requirements.
CoreOptics' the feature product lines, encompassing a wide range of Horizontal Cavity Surface Emitting Lasers (HCSELs) and high-performance Resonant Cavity LEDs (ResoLight), position them as a key innovator in the rapidly evolving landscape of integrated photonics.
As the demand for compact, efficient, and high-performance light sources continues to surge, CoreOptics' pioneering work in surface-emitting lasers and their seamless integration onto PICs is poised to revolutionize industries and unlock a new era of photonic innovation.
Article edited by Sherri Wang
