Outstanding results regarding the efficiency of infrared laser components with long wavelengths beyond 1300 nm on an industrial-grade manufacturing level have been reported by Trumpf Photonic Components, which aims to industrialize the production of SWIR VCSELs above 1300 nm to support high volume applications such as in smartphones in under-OLED applications. This takes the company one step further towards mass production of indiumphosphide-based (InP) VCSELs in the range from 1300 nm to 2000 nm. “At Trumpf we are working hard to mature this revolutionary production process and to implement standardization, which would further develop this outstanding technology into a cost-attractive solution. We aim to bring the first products to the high-volume market in 2025,” said CEO Berthold Schmidt.

By developing the new industrial production platform, Trumpf is expanding its current portfolio of Gallium arsenide- (GaAs-) based VCSELs in the 760 nm to 1300 nm range for NIR applications. The new platform is more flexible in the longer wavelength spectrum than are GaAs, but it still provides the same benefits as compact, robust and economical light sources. “The groundwork for the successful implementation of long-wavelength VCSELs in high volumes has been laid. But we also know that it is still a way to go, and major production equipment investments have to be made before ramping up mass production,” said Schmidt.

A broad application field can be revolutionized by the industrialization of long-wavelength VCSELs, as the SWIR VCSELs can be used in applications with higher output power while remaining eye-safe compared to shorter-wavelength VCSELs. The long wavelength solution is not susceptible to disturbing light such as sunlight in a broader wavelength regime. One popular example from the mass markets of smartphone and consumer electronics devices, is under-OLED applications. The InP-based VCSELs can be easily put below these OLED displays, without disturbing other functionalities and with the benefit of higher eye-safety standards. OLED displays are a huge application field for long wavelength sensor solutions. “In future we expect high volume projects not only in the fields of consumer sensing, but automotive lidar, data communication applications for longer reach, medical applications such as spectroscopy applications, as well as photonic integrated circuits (PICs), and quantum photonic integrated circuits (QPICs). The related demands enable the SWIR VCSEL technology to make a breakthrough in mass production”, said Schmidt. 

Better illumination quality for smartphones, AR and VR applications

At Photonics West, the company also showcased new multimode VCSEL with stable polarization to support the increasing demand for advanced VCSEL sources. By integrating additional functionalities such as linear polarization, the VCSEL technology is becoming smarter and the illumination quality is increasing. “It’s great to see the VCSEL technology evolving and to tap into new application fields for VCSELs by integrating additional features. With the market release of our new multimode VCSEL with stable polarization, we serve application demands with optimal illumination quality, like in smartphones”, says Ralph Gudde, vice president marketing and aales at Trumpf Photonic Components.

The new 940-nm multimode VCSEL with controllable polarization is entering mass production and comes with high yield. The proprietary surface grating is directly etched into the Gallium arsenide (GaAs). With the two emission zones, the new VCSEL generates an optical power of 8 mW. Applications in consumer electronic devices and smartphones benefit from this optimum efficiency in optical power, as the VCSEL technology combines high laser efficiency and slope efficiency of 1 W/A with full polarization control. Measurements confirm that the electro-optical properties of VCSELs with integrated grating and stabilizing linear polarization are the same as VCSELs without grating. “Thanks to the polarization feature, controlled laser light improves the quality of the overall sensing system, enabling a positive user experience and power savings”, says Gudde.

Two in one: switchable polarization on its way

Trumpf also announces its next products with polarization features, that will be released later in 2023. One is a multimode VCSEL with dual polarization that is now ready for customer sampling. Here, one single VCSEL chip can individually address two polarization directions, which significantly reduces the form factor and the optical system complexity. This supports further miniaturization demands in smartphone applications and consumer electronics. In the actual concept, two VCSEL arrays at 0° and 90° linear polarization, are combined and interlaced on one VCSEL chip, using orthogonal surface gratings. The two polarization directions are individually addressable, each yielding about 1.35 W of output power.

Combined with polarization-selective optics this results in a reduction of components, as only one VCSEL chip is needed to create both flood illumination and dot patterns. “Dual polarization VCSELs will revolutionize the consumer electronics business”, says Gudde. “Device manufacturers will get one component that functions as a dual-pattern projector”, Gudde adds. The second release will be a large polarization controlled single emitter, single-mode VCSEL component with 2 mW output power. This serves industrial sensing applications like industrial optical encoders and spectroscopy. Evaluation samples will be available from June onwards and mass production is scheduled for the end of 2023.