Growing need of Integrated Optics Characterization
As integrated photonics continue to evolve, precise optical characterization becomes crucial for optimizing performance and ensuring device reliability. Mid-infrared (MIR) spectroscopy provides a powerful, non-contact method for probing integrated optical components, enabling detailed insights into waveguide transmission, coupling efficiency, and material properties.
Why Use Mid-Infrared Spectroscopy for Integrated Optics?
The mid-infrared spectrum (approximately 1.9 – 5.3 µm) is critical for various photonic applications due to its ability to interact with fundamental molecular vibrations and unique optical materials. Many integrated photonic platforms, such as silicon photonics, lithium niobate, and chalcogenide glasses, are designed for MIR operation, requiring specialized probing techniques for performance validation.
Integrated OPTICS' Measurements using Optical Fiber Probing
Using optical fibers to probe integrated optics in the MIR range enhances measurement flexibility and precision. Fiber-coupled MIR spectroscopy solutions can efficiently couple light into and out of on-chip waveguides, enabling:
- Minimal Insertion Loss: Direct fiber coupling reduces optical losses compared to free-space techniques.
- High Spatial Resolution: Enables localized probing of waveguides and photonic structures.
- Broad Spectral Coverage: Mid-IR fiber probes can be optimized for specific wavelength ranges, ensuring compatibility with various integrated optical materials.
- Enhanced Stability & Repeatability: Reduces experimental variability by providing consistent coupling conditions.
Industry requirements for integrated optics' probing
To perform integrated optics sample inspection with mid-infrared light online, you will need MIR light source, fiber optic probes, and a mid-infrared spectrometer. This set of equipment can give detailed information about the state or quality of the sample under inspection for online measurements. The light that returns from the sample provides valuable information on which specific molecular composition dominates the sample.
In this way, even small concentrations of molecules can be measured at the production facilities optimizing your production workflow. Our MIDWAVE Spectrometer empowers straightforward measurements that reveal such information.
Choosing the right eqipment for industrial measurements
In order to perform industrial measurements of integrated optics, it is critical that your measurement equipment is robust to the surrounding environment, is cost-efficient, and – perhaps most importantly – can accommodate production speed. In a production line with either many or very large samples, it is of very high importance that:
- A spectrometer can run undisturbed by high (or low) temperatures and unavoidable vibrations present in a production facility. This is the greatest obstacle in bringing conventional FTIR instruments into production facilities.
- A cost-efficient solution is chosen. Although it is unlikely, that the price of a single instrument will be detrimental in choosing the equipment, a cost-efficient solution would help increase business return on investment, especially when production facilities require many test devices.
- Mid-infrared spectrometer can accommodate the speed of the production to run smoothly. In an Industry 4.0 framework, real-time monitoring must match the speed of manufacturing processes to prevent bottlenecks that could lead to inefficiencies and increased costs.
NLIR's solution for integrated optics characterization
NLIR’s mid-infrared MIDWAVE Spectrometer is designed to fit into an industrial setting: it’s the fastest mid-infrared spectrometer commercially available and it has no moving components, making it very vibration tolerant. It is fiber coupled, very sensitive, and has good resolution making it an ideal choice for characterization of integrated optical components at the production line.
Precise Measurements of the Smallest Samples
Another key feature of a measurement setup is the optical interface. There are many different solutions commercially available depending on the nature of the sample: solid surfaces typically use direct transmission between fiber and fiber or reflection at an angle. Liquid compounds are commonly measured using an attenuated total reflection (ATR) crystal, which may or may not be fiber coupled. Different fiber sizes and materials are available, and bundles are made to bring light to and from the sample. The right solution depends on the sample under consideration.
NLIR has made a close-contact PRECISION Interface for small sample characterization. Light enters through one fiber and is transmitted to the sample with a spot size equal to the fiber size. Using a 400 μm fiber, a 400 μm spot size was achieved at a sample height of 4 mm from the tip of the interface. The light is reflected on the sample and guided back to the other fiber through which it reaches a spectrometer. This interface is ideal for small samples, for example on a wafer.
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Optimizing Integrated Optics' Production with MIR Spectroscopy
Mid-infrared spectroscopy is rapidly becoming an essential tool at integrated optics’ production line. By leveraging NLIR’s fiber-based mid-infrared sensing technology, engineers can gain deeper insights into production performance and sample quality at scale, paving the way for increased production speed, quality, and new business growth opportunities unattainable before.
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