SABIC has expanded its optical materials portfolio with the launch of ULTEM™ 3310TD resin, which is well suited for optical transceiver collimator lenses used in single-mode fiber optic systems.
This new polyetherimide (PEI) resin delivers a significantly lower coefficient of thermal expansion (CTE) than that of standard ULTEM grades.
A low CTE is essential to optimize the dimensional stability of the collimator lenses and ensure alignment with single-mode fibers. Furthermore, the new grade provides near-infrared (IR) transmission without degrading signal quality. As a potential replacement for glass, ULTEM 3310TD resin offers the efficiency of high-volume micro-molding, avoids the need for costly secondary operations, expands design freedom and lowers part weight.
“SABIC is helping to facilitate further adoption of single-mode fiber optics, an emerging datacenter infrastructure technology for high-speed transmission of large data volumes over long distances,” said Scott Fisher, business director, ULTEM Resins and Additives, SABIC. “Our new lower-CTE ULTEM 3310TD resin, a great candidate for single-mode optical transceiver lenses, provides better design and production capability, and potential cost savings, compared to traditional aspherical glass lenses. This new material builds on decades of customer success using incumbent ULTEM resins for multi-mode fiber optic components. As the industry embraces new advancements such as increasing use of single-mode fiber optics, SABIC continues to innovate with targeted, high-performance products.”
Addressing Challenges with Single-mode Fiber Optics
As datacenters handle larger data volumes that generate more heat, temperature fluctuations can cause expansion and shrinkage in optical lenses. Dimensionally stable lens materials are needed to avoid misalignment with the fiber, which can lead to signal loss or distortion. This challenge is more critical with single-mode fiber than multi-mode fiber, due to the difference in core diameter (8-9 μm vs. 50-62.5 μm, respectively). Collimation in the smaller light bundles of single-mode fiber is highly sensitive to misalignment, with less tolerance for heat-induced dimensional changes.
New ULTEM 3310TD resin has a CTE of ~38 ppm/C, a reduction of 30 percent compared to the CTE of ULTEM™ 1010 resin, which is widely used in multi-mode optical transceiver lenses. The new material’s CTE, while not as low as that of glass, expands the implementation opportunities for thermoplastics in single-mode fiber optics. Furthermore, ULTEM 3310TD resin offers several advantages over glass, including the ability to be micro-molded into a wide variety of shapes without the time-consuming secondary grinding and polishing required for aspherical glass lenses. As a thermoplastic, the new resin helps enable complex part designs, like free-form optics and multi-channel lens arrays, which may be difficult to achieve with glass. It also helps to achieve easy integration of mechanical and optical components such as alignment fixtures.
For customers that use ULTEM 1010 resin for multi-mode fiber optic lenses, choosing ULTEM 3310TD resin instead of glass for single-mode optics provides continuity in processing and simplifies the supply chain. The two grades complement each other, offering a complete solution for single-mode and multi-mode applications.
“Until now, the industry has been forced to use glass for single-mode optical lenses because the CTE of conventional thermoplastics was too high,” said David Wang, senior product manager, SABIC. “We formulated ULTEM 3310TD resin with a low CTE to address the increased dimensional stability requirements of single mode fiber, while maintaining near IR transmission above 85 percent. To assist customers around the world in transitioning to ULTEM resin, SABIC’s Technology Centers in Europe and Japan provide micro-molding capabilities, including state-of-the-art equipment to test optical properties, metrology and aging.”
In addition to optical transceiver lenses, ULTEM 3310TD resin can potentially be used in other telecommunications applications such as optical modems and optical cables. Furthermore, it can be considered for components in other industries that call for a low CTE and good IR transmission, such as LiDAR sensors (automotive), drones (electronics) and robots (industrial).