News: Optoelectronics
18 January 2023
TRUMPF expands portfolio of polarization-stable multi-mode VCSELs to improve illumination quality in 3D applications
TRUMPF Photonic Components GmbH of Ulm, Germany (part of the TRUMPF Group) – which makes vertical-cavity surface-emitting lasers (VCSELs) and photodiodes for the consumer electronics, datacoms, industrial sensing, heating and automotive markets – has released a new multi-mode VCSEL with stable polarization to support the increasing demand for advanced VCSEL sources.
By integrating additional functionalities such as linear polarization, VCSEL technology is becoming smarter and illumination quality is increasing, notes the firm. “It’s great to see the VCSEL technology evolving and to tap into new application fields for VCSELs by integrating additional features,” says Ralph Gudde, VP marketing & sales. “With the market release of our new multi-mode VCSEL with stable polarization, we serve application demands with optimal illumination quality, like in smartphones,” he adds.
The new 940nm multi-mode 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 optical power of 8mW. 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 1W/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.
Better illumination quality for smartphones, AR and VR applications
The smartphone and consumer electronics industries are constantly looking for smarter components for their devices, all while increasing illumination quality. VCSELs with polarization-controlled light address these demanding 3D illumination applications not only in smartphones but also in OLED screens or in virtual-reality (VR) and augmented-reality (AR) applications. The illumination quality is greatly increased, as polarized light helps to eliminate optical losses. VCSELs with stable polarization also avoid disturbing reflections and enable innovative optical concepts like a collinear arrangement of transceiver and receiver optics. This is supported by TRUMPF’s own designs and processes, which enable high quality and perform without any losses.
Two in one: switchable polarization on its way
TRUMPF has also announced its next products with polarization features, which will be released later in 2023.
One is a multi-mode 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 1.35W of output power. Combined with polarization-selective optics, this results in a reduction in the number 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,” believes Gudde. “Device manufacturers will get one component that functions as a dual-pattern projector,” he adds.
The second release will be a large polarization-controlled single emitter, single-mode VCSEL component with 2mW 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.
