Breakthroughs have been made in the field of organic photonic devices and their integration technology

Recently, Professor Zhang Dan's team from the School of Electronic Science and Technology of Xiamen University and Professor Xu Hui's team from the School of Chemistry, Chemical Engineering and Materials of Heilongjiang University have made a breakthrough in the field of organic photonic devices and their integration technology. The relevant results were published on Advanced Materials, an international economic journal in the field of materials science. And was selected as the frontispiece of the current issue.

Rare earth doped optical waveguide amplifiers are widely used in integrated photonic chips as important photonic devices to compensate various optical losses. Such devices generally use lasers as pump sources and rely on the intrinsic absorption and radiation transition of rare earth ions to achieve optical amplification. However, laser pumping is easy to cause thermal damage to waveguides and upconversion and luminescence of rare earth ions. Therefore, the supporting cost of commercialization of devices is high, and they cannot be flexibly placed in silicon optical chips. These problems limit the scale application of rare earth doped optical waveguide amplifiers in planar photonic integration. Therefore, it is of great scientific significance and engineering application value to explore new optical amplification mechanism and method.

In this work, Professor Zhang Dan and Professor Hui Xu constructed a phosphonodymium complex luminescent material Nd (TTA) 3 (XPO) with high efficiency intramolecular energy transfer. The material uses thiophenyl trifluoromethylacetyl acetone (TTA) as anion ligand and XPO containing diphenylphosphonoxy group as neutral ligand. By establishing an effective intramolecular energy transfer path between the organic ligand and the central rare earth neodymium ion, the efficient luminescence of neodymium ion at two near-infrared wavelengths of 1.06μm and 1.31μm was realized. At the same time, two kinds of silicon optical waveguide devices with buried strip and evanescent wave type were designed and fabricated. Low power light emitting diode (LED) was used instead of traditional laser as the pump source, and the optical gain of 22.5dB/cm was achieved at the wavelength of 1.06μm, which is the highest reported gain of organic optical waveguide amplifier at this wavelength. At the same time, the optical gain of 8.4dB/cm is obtained at the wavelength of 1.31μm, which is an important breakthrough for the device to achieve high gain optical amplification in the O-band of optical communication.

This study combines the theory of intramolecular energy transfer with LED pumping technology, and for the first time realizes the high gain of dual-wavelength devices in near infrared band under a low power LED pump, which greatly reduces the cost of commercializing optical waveguide amplifiers. Moreover, the polymer materials doped with neodymium complex can be conveniently coated on different types of photonic chips such as silicon nitride, silicon and glass to achieve optical loss compensation, with universal compatibility. This technology provides a strong support for promoting the industrialization of organic photonic devices in the field of optical interconnection and integration.

This work involves the interdisciplinary fields of information photonics, chemistry, physics and so on. It was funded by the National Key Research and Development Program of Information Photonics Technology, the National Natural Science Foundation of China, the Natural Science Foundation of Fujian Province and other projects. Xiamen University was the first to complete the work.

Source: Fujian Daily