Narrow-linewidth DFB lasers now at 405 and 488nm
Building on recent achievements at an emission wavelength of 450 nm, Swiss company Exalos has announced narrow-linewidth DFB GaN-based laser diodes operating at 405 nm and 488 nm.
According to the company (part of Indie Semiconductor) these developments extend the technology's reach into flow cytometry, Raman spectroscopy, and quantum sensing; applications that need narrow, stable, reliable lasing.
Furthermore, Exalos says the ability to produce stable and controlled blue emissions has broad implications for holographic applications, including near-to-eye displays and head-up displays for the automotive sector, where precise wavelength stability enhances image quality and system performance. Exalos is actively working to extend its emission wavelength capabilities further into the green spectrum.
The performance of these devices stems from a proprietary monolithic distributed feedback (DFB) laser diode design, which is wavelength agnostic across the 375-535nm range.
This design enables a narrow linewidth (typically 20 MHz at 450 nm) and wavelength precision. Additionally, the lasers deliver high spectral purity, achieving a side-mode suppression ratio (SMSR) exceeding 40 dB, with wavelength variation of less than one picometre over 15 hours at constant operating conditions.
These attributes are complemented by a single transverse mode output, and a uniform spatial profile, facilitating efficient collimation or coupling into single-mode waveguides. The diodes also feature low-threshold currents, high differential slopes, and good wall-plug efficiencies, offering a distinct advantage over conventional Fabry-Perot laser diodes in demanding applications.
Exalos says that ongoing continuous-wave life testing has confirmed the robustness of these devices. At a power level of 50 mW, the 450nm DFB laser diodes have demonstrated stable operation of more than 2500 hours with negligible degradation in an ongoing lifetime experiment, a key milestone in ensuring product reliability and readiness for deployment.
Indie offers DFB-related products in a variety of form factors tailored to specific application requirements, including uncooled TO-can modules, temperature-controlled units with fibre or free-space collimated outputs, and turnkey solutions with integrated driver electronics.
The technology will be exhibited at the Indie’s booth during SPIE Photonics West in San Francisco, on January 28-30.
Pictured above: artistic rendering of visible DFB laser diodes in TO-can packages. a) Typical continuous-wave characteristics (power-current-voltage) of DFB LD at 450 nm. b) Spectra of DFB LDs with 405 nm, 450 nm and 488 nm emission wavelength.
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