My Research and Inventions

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Spin -Photon memory


The same content can be found in Zayets, Electronics (2017) and Zayets, APL 94 (2009)( pdf is here)


The paper on this topic (V. Zayets and K. Ando, APL 2009) was included in the 50 of the most notable APL articles published in recent years.


This research aims to fabricate an optical memory, which has extremely fast speed about 1 TBit/sec. This memory is compact, integratable, compatible with present semiconductor technology and it has fast operation speed. If realized, it will advance data processing and computing technology towards faster operation speed. Significant advance have been already achieved in fabrication of this memory. However, some functions of this memory have not reached required performance. The research work is still going on to reach all required parameters for its commercial realization.

Even recent tremendous success of the spintronics, when the technological breakthrough was achieved in the fields of hard disk technology and magnetic random access memory (MRAM), the unique properties of the spin  have not yet been explored in fields of optical devices and high-speed optical communication. By the combining the spin and the light, both the high-speed switching and non-volatile recording can be achieved. That makes the spin-photon devices very attractive for new designs of a non-volatile high-speed optical. I believe that ability of ultra high speed switching of spin polarization of photo excited electrons is wonderful and important feature of the spin. It has a great prospective for use in high-speed data processing.

The data processing and transmission need ever faster operational speed. At present, the transfer rate of 25.4 TBit/sec through single optical fiber was demonstrated [1].  However, due to the speed limitation of present electronic components, the data is transferred using many channels at different optical frequencies. Since each channel needs individual electrical and electro-optical components, such a system is complex, expensive and has high power consumption. With availability of ultra-fast optical non-volatile memory, the high broadband of optical fibers can be used in a wider range of applications and significant reduction power consumption for data processing could be achieved.  High-speed data processing, chip-to-chip optical connection, optical buffer memory are a few of the possible applications of a high-speed non-volatile optical memory. 

Even high-speed optical fiber links are widely installed worldwide, only a little of their high-speed capacity are used. At present, the speed of a network is mostly limited by the speed of the network routers. The network router switches data streams between different nods in a network. The function of the network router is to receive the data package from one channel, to store it, and send it to the second channel.  Since the availability of second cannel is basically unknown, the non-volatile memory has to be used in the router. The routers made of electrical components are installed in the present optical networks.  The routers, which can process data at speed up to 10 GBit/sec, are already commercially available. Now significant efforts were applied to fabricate the routers, which could process data at speed of 40 GBit/sec. It is a very challenging task, because the required operational speed is significantly above of the speed limit for the most of electrical components. In order to increase the network speed significantly, high-speed non-volatile optical memory is required. 

[1] 1. A. H. Gnauck, G. Charlet, P. Tran, P. J. Winzer, C. R. Doerr, J. C. Centanni, E. C. Burrows, T. Kawanishi, T. Sakamoto, and K. Higuma, "25.6-Tb/s WDM Transmission of Polarization-Multiplexed RZ-DQPSK Signals" IEEE J.of Lightwave Technol., 26, 79 (2008).



1. Applications

The spin-photon memory has unique properties such as a very fast operational speed and a non-volatile recording. It makes it desirable for a wide variety of applications, but I will show 2 most important of them: chip-to-chip connection and optical buffer memory

2. Operational principal

main part

3. High-speed demultiplexing experiment

Here I will prove that the recording speed of the memory can reach 2.2 TBit/sec

4. Reading

I will show how we are solving the challenging task of high-speed reading of magnetization of very tiny nanomagnet

5. High-Speed Spin Injection

I will show how we do the injection of spin-polarized photo-excited electrons from a semiconductor into nanomagnet at very fast speed to achieve the injection time shorter than the spin life time in semiconductor

6. Spin-photon memory with MTJ

This is memory, where magnetic tunnel junction (MTJ) is used instead of nanomagnet. It has an advantage that both the optical optical and electrical writing and reading can be realized.





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