Researchers at Penn State University in the United States said that soon, the semiconductor core fiber itself may be able to perform expensive “electrical-optical-electrical” conversion without relying on the electric-optical ( electronic-optical) converters, and expensive optical-electronic converters at the receiving end.

This new invention is to combine a single crystal silicon core in a glass capillary with an inner diameter of 1.7 microns, and solidify and seal at both ends to form single crystal silicon, thereby combining cheaper single crystal silicon germanium and single crystal silicon at both ends. This research was conducted jointly by professors Venkatraman Gopalan and John Badding in the Department of Materials Science and Engineering at Penn State University, and doctoral student Xiaoyu Ji.

Incorporate an amorphous silicon core in a glass capillary with an inner diameter of 1.7 microns

The simple optical fiber used today can only emit photons along a glass tube covered with a soft polymer coating. The best signal is retained in the optical fiber by reflecting from the glass to the polymer, so there is almost no signal loss during the long-distance transmission. Unfortunately, all data transmitted from the computer requires the use of expensive electro-optical conversion modules at the transmitting end.

Similarly, the receiver is a computer that requires expensive photoelectric converters at the receiving end. In order to strengthen the signal, the ultra-long distance between different cities requires a “repeater” to perform a more sensitive optical-electrical conversion, then amplify the electrons, and then pass through a super electro-optical converter to let the optical signal pass to the next one The relay finally reaches its destination.

Researchers at Penn State University hope to develop optical fibers filled with smart semiconductors, giving them the ability to perform electrical-optical-electrical conversion on their own. At present, the research team has not yet reached its goal, but has successfully combined all the required materials in its semiconductor optical fiber and proved that it can transmit photons and electrons at the same time. Next, they need to pattern single crystal silicon on both ends of the optical fiber to perform the necessary optical-electrical and electric-optical conversion in real time.

Badding demonstrated the feasibility of using silicon-filled fibers in 2006, and Ji then used lasers to combine high-purity single crystal silicon germanium with glass capillaries in his doctoral thesis research. The result is a smart monosilicon seal that is 2,000 times longer, which converts Badding’s high-efficiency original prototype into a commercially viable material.

Xiaoyu Ji, a PhD candidate in the Department of Materials Science at Penn State University, conducts crystallization tests at Argonne National Laboratory

This ultra-small single crystal silicon core also allows Ji to use a laser scanner to melt and refine the crystal structure in the center of the glass core at a temperature of 750-900 degrees Fahrenheit, thereby avoiding silicon contamination of the glass.

Therefore, it has taken more than 10 years from Badding’s first attempt to combining smart semiconductors and simple optical fibers with the same optical-electrical fiber.

Next, the researchers will start to optimize (in order to make the smart fiber reach the transmission speed and quality comparable to the simple fiber), and pattern the silicon germanium for practical applications, including endoscopes, imaging and fiber lasers.