A Non-volatile Quasi-Continuous All-Optical Fiber Programmable Platform Based on GST-Coated Microspheres

It is recognized to be challenging to develop a continuous programmable platform for all-optical modulation characterized by macro-scale, long-distance transmission, and effective regulation. This study combines low-loss optical fiber and Ge2Sb2Te5 (GST)-coated microspheres for the first time to demonstrate a large-scale, non-volatile, and quasi-continuous all-optical programming platform. With the help of external modulation of a 793 nm continuous-wave (CW) laser and 532 nm nanosecond pulsed laser, the all-optical modulation scheme here allows the repeatable operations between switching states and provides convenient and reliable access to any potential from 0 to 8 levels. The multi-level modulation is realized by a 793 nm CW laser with different output powers from 6.1 to 12.1 mW, and the reset step is implemented by two 532 nm nanosecond pulses with an average power of 45 mW. As a result, a nonvolatile optical modulation with a high extinction ratio, as large as 15 dB, is demonstrated. Moreover, a demonstration of alphabetic compilation in principle is performed to prove the practical potential of the proposed all-optical modulation system in the construction of the storage memory and the programmable platform. Hopefully, this study can lay some experimental basis and operating experience for all-optical fiber non-volatile optical networks from micro to macro.