The development and manufacturing of laser systems for biomedical and life sciences applications requires extremely high levels of precision, control, and stability. In applications such as photodynamic therapy, photoimmunotherapy, fluorescence imaging, and biomedical illumination, laser output is judged not only by power, but also by spectral performance. The wavelength must be correct, the spectral profile must be clearly understood, and weak optical content close to the main signal must remain visible enough to support confident engineering decisions.
Modulight is a Finnish laser manufacturer serving life sciences and biomedical markets, alongside other high-value applications. Its technologies support demanding uses such as cancer treatment, ophthalmology, fluorescence endoscopy, flow cytometry, and biomedical research. As a vertically integrated laser manufacturer, Modulight’s in-house capabilities span epitaxial growth, chip fabrication, and laser systems assembly, with a laser portfolio covering wavelengths from ultraviolet to beyond 3,000 nm.
For many demanding biomedical laser applications, precise spectral matching between the laser source and a target molecule is essential. Photosensitisers, fluorophores, and other molecules absorb only within a narrow wavelength band, and even small wavelength deviations can reduce effectiveness. For Modulight, the challenge goes beyond confirming centre wavelength alone. The company also needs to control linewidth, maintain wavelength stability over time and temperature, and minimise side modes or secondary peaks that could introduce unwanted wavelengths.
This is particularly important in fluorescence-related systems, where a strong excitation line can sit very close to a much weaker optical feature, and both must be seen clearly. If noise obscures the low-level signal, or if the analyser does not provide enough dynamic range, engineers lose visibility into behaviour that may matter in the final application.
The challenge becomes even greater in the visible range, as Dr. Lasse Orsila, Optical Engineer at Modulight and medical doctor, explains: “Suitable optical spectrum analysers are much less available in the visible range than in telecom or near-infrared bands. Modulight therefore needed a spectrum analyser platform combining wavelength accuracy, strong sensitivity, wide dynamic range, and practical usability across a broad range of laser development tasks.”
To support these requirements, Modulight relies on Yokogawa optical spectrum analysers for both R&D and production-facing work. Engineers use multiple Yokogawa OSAs covering different wavelength ranges to characterise visible-light spectra, evaluate linewidth, assess filter behaviour, and analyse low-level spectral content. The AQ6373E supports visible-light characterisation where wavelength placement and spectral shape are especially important, while AQ6370E units provide flexibility for trace comparison, filter assessment, and detailed laser-source analysis.
“What I value in the Yokogawa optical spectrum analysers is their reliability and precision.” adds Dr Orsila, “They are also very easy to use. The availability of OSAs in the visible range is much more limited than in the telecom or near-infrared ranges. Yokogawa can cover nearly all the wavelength ranges we work with, and performance in the visible range is particularly important to us.”
Yokogawa’s analysers have given Modulight a dependable platform for characterising centre wavelength, linewidth, spectral tails, signal strength, low-level spectral content, and side-mode suppression ratio with greater clarity. This is especially valuable in demanding applications such as fluorescence-based systems, photoimmunotherapy, and ophthalmic lasers, where spectral precision and clean optical output are critical.
“The high signal-to-noise ratio, wide dynamic range, and strong sensitivity in the visible range allows us to obtain reliable measurements – even at very low optical signal levels,” says Dr. Orsila.
Beyond measurement performance, the Yokogawa platform has made optical characterisation more practical in daily engineering work. The ability to record, compare, and analyse traces directly within the instrument workflow gives engineers a faster and more confident way to evaluate devices and optical filters.
Combined with long service life, strong usability, and consistent performance, Yokogawa optical spectrum analysers have become a trusted part of Modulight’s workflow.
By using Yokogawa’s AQ6373E and AQ6370E optical spectrum analysers, Modulight can validate demanding medical and photonic laser technologies with the precision, repeatability, and spectral clarity they require.
