Recent developments in silicon-based photonic chip technology have demonstrated the capability to guide light with an efficiency comparable to that of optical fibre. This advancement holds significant promise for applications in quantum computing, biomedical imaging, and augmented reality.
Researchers have successfully created a photonic chip that can control light across a broad spectrum, ranging from violet to telecom wavelengths, with minimal loss and exceptional stability. Kellan Colburn from the California Institute of Technology will present these findings at the 2026 Optical Fiber Communications Conference and Exhibition (OFC), the largest annual gathering of optical networking and communications professionals, scheduled for 15-19 March 2026 at the Los Angeles Convention Center.
Colburn noted, “By bringing fibre-like performance across a broad spectral range onto a chip, this new technology could be used to build compact photonic quantum computers and quantum networks, reduce the energy cost of server infrastructure, improve biomedical imaging systems that use visible light, support lightweight photonic engines for augmented-reality displays, and enable portable precision timing and navigation systems.”
Overcoming Technical Challenges
Many emerging technologies depend on stable, multi-wavelength light sources that operate in the visible spectrum. According to Hao-Jing Chen, co-first author of the study, achieving this on a chip has traditionally been challenging due to significant losses at shorter wavelengths. To address this issue, the research team developed a CMOS-compatible process that utilises germanium-doped silica, a material known for its low absorption properties, commonly used in optical fibres.
The new platform not only results in significantly lower optical loss across visible and near-infrared wavelengths but also accommodates large optical mode areas on the chip. This design facilitates near-perfect index and size matching between the chip and optical fibre, while also mitigating thermal noise effects, leading to enhanced laser coherence within the circuit.
Colburn stated, “Our work demonstrates a clear pathway for translating technologies traditionally confined to optical fibre into scalable semiconductor manufacturing platforms. Over time, this could lead to smaller medical devices, more accurate navigation systems without GPS, faster communications, and new consumer technologies based on photonic chips.”
Measuring Optical Loss and Future Applications
To assess the optical loss of the new material platform, researchers fabricated on-chip optical ring resonators. Remarkably, these devices achieved optical quality factors exceeding 180 million across all measured wavelengths, corresponding to waveguide losses below 0.1 dB/m in the telecom band.
Takashi Matsui, OFC program chair from NTT Inc. in Japan, remarked, “This work demonstrates how ultralow loss-germanosilica integrated circuits enable fibre-class waveguide performance on chip. Achieving sub-dB/m loss and ultrahigh-Q resonators across 458 to 1550 nm marks a significant step toward advanced integrated platforms for precision and quantum photonics.”
The research team has utilised the new platform to develop various complex photonic systems, including dispersion-engineered single-ring soliton microcombs, Brillouin lasers enhanced by simultaneous optical and acoustic confinement, and self-injection-locked semiconductor lasers with Hertz-level linewidths. Additionally, they achieved a more than 20dB (100x) increase in coherence of self-injection locked lasers compared to previous records, transforming low-cost multimode diode lasers into single-mode lasers with significantly reduced linewidths.
This innovative combination of economical lasers with a foundry-compatible chip-based platform is poised to create a new class of compact ultra-narrow linewidth lasers at a mass production scale, potentially revolutionising various fields that rely on visible light lasers.
The researchers are now focusing on further enhancing the platform by reducing light loss and integrating additional active components, such as lasers, amplifiers, and electro-optic devices, directly onto the chip. Future applications may include complete photonic systems for portable clocks, quantum technologies, and advanced sensing solutions.
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