Design and Modelling of a Novel Integrated Photonic Device for Nano-Scale Magnetic Memory Reading

Design and simulations of an integrated photonic device that can optically detect the magnetization direction of its ultra-thin (∼12 nm) metal cladding, thus ‘reading’ the stored magnetic memory, are presented. The device is an unbalanced Mach Zehnder Interferometer (MZI) based on InP Membrane on Silicon (IMOS) platform. The MZI consists of a ferromagnetic thin-film cladding and a delay line in one branch, and a polarization converter in the other. It quantitatively measures the non-reciprocal phase shift caused by the Magneto-Optic Kerr Effect in the guided mode which depends on the memory bit’s magnetization direction. The current design is an analytical tool for research exploration of all-optical magnetic memory reading. It has been shown that the device is able to read a nanoscale memory bit (400 × 50 × 12 nm) by using a Kerr rotation as small as 0.2∘, in the presence of a noise ∼10 dB in terms of signal-to-noise ratio. The device is shown to tolerate performance reductions that can arise during the fabrication.

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Ultrafast Switching Dynamics

10.1093/oso/9780198788669.003.0011 ◽

2017 ◽

Author(s):

Olle Eriksson ◽

Anders Bergman ◽

Lars Bergqvist ◽

Johan Hellsvik

Keyword(s):

Lower Energy ◽

Research Field ◽

Optical Control ◽

Magnetic Memory ◽

Magnetic Media ◽

Switching Dynamics ◽

All Optical ◽

Ultrafast Switching ◽

Stored Information ◽

Intense Research

The time-integrated amount of data and stored information, is doubled roughly every eighteen months, and since the majority of the worlds information is stored in magnetic media, the possibility to write and retrieve information in a magnetic material at ever greater speed and with lower energy consumption, has obvious benefits for our society. Hence the seemingly simple switching of a magnetic unit, a bit, is a crucial process which defines how efficiently information can be stored and retrieved from a magnetic memory. Of particular interest here are the concepts of ultrafast magnetism and all-optical control of magnetism which have in recent decades become the basis for an intense research field. The motivation is natural; the mechanisms behind these phenomena are far from trivial and the technological implications are huge.

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All-Optical Non-Inverted Parity Generator and Checker Based on Semiconductor Optical Amplifiers

Applied Sciences ◽

10.3390/app11041499 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1499

Author(s):

Bingchen Han ◽

Junyu Xu ◽

Pengfei Chen ◽

Rongrong Guo ◽

Yuanqi Gu ◽

...

Keyword(s):

Optical Amplifiers ◽

Signal To Noise Ratio ◽

Low Cost ◽

Extinction Ratio ◽

Semiconductor Optical Amplifiers ◽

Optical Signal ◽

Probe Light ◽

All Optical ◽

Negative Effect ◽

Parity Generator

An all-optical non-inverted parity generator and checker based on semiconductor optical amplifiers (SOAs) are proposed with four-wave mixing (FWM) and cross-gain modulation (XGM) non-linear effects. A 2-bit parity generator and checker using by exclusive NOR (XNOR) and exclusive OR (XOR) gates are implemented by first SOA and second SOA with 10 Gb/s return-to-zero (RZ) code, respectively. The parity and check bits are provided by adjusting the center wavelength of the tunable optical bandpass filter (TOBPF). A saturable absorber (SA) is used to reduce the negative effect of small signal clock (Clk) probe light to improve extinction ratio (ER) and optical signal-to-noise ratio (OSNR). For Pe and Ce (even parity bit and even check bit) without Clk probe light, ER and OSNR still maintain good performance because of the amplified effect of SOA. For Po (odd parity bit), ER and OSNR are improved to 1 dB difference for the original value. For Co (odd check bit), ER is deteriorated by 4 dB without SA, while OSNR is deteriorated by 12 dB. ER and OSNR are improved by about 2 dB for the original value with the SA. This design has the advantages of simple structure and great integration capability and low cost.

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Ultrafast all-optical switching utilizing the optical Kerr effect in polarization-maintaining single-mode fibers

IEEE Journal on Selected Areas in Communications ◽

10.1109/49.7839 ◽

1988 ◽

Vol 6 (7) ◽

pp. 1186-1198 ◽

Cited By ~ 64

Author(s):

T. Morioka ◽

M. Saruwatari

Keyword(s):

Kerr Effect ◽

Optical Switching ◽

Single Mode ◽

Optical Kerr Effect ◽

All Optical ◽

Polarization Maintaining ◽

All Optical Switching

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Magneto-photonic on-chip device for all-optical reading of magnetic memory

10.1109/cleo/europe-eqec52157.2021.9541558 ◽

2021 ◽

Author(s):

Figen Ece Demirer ◽

Sander Reniers ◽

Reinoud Lavrijsen ◽

Bert Koopmans ◽

Jos van der Tol

Keyword(s):

Magnetic Memory ◽

All Optical ◽

On Chip

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In-Band OSNR Measurement Method for All-Optical Regenerators in Optical Domain

Applied Sciences ◽

10.3390/app9245438 ◽

2019 ◽

Vol 9 (24) ◽

pp. 5438

Author(s):

Feng Wan ◽

Baojian Wu ◽

Feng Wen ◽

Kun Qiu

Keyword(s):

Measurement Method ◽

Signal To Noise Ratio ◽

Optical Signal ◽

Error Vector Magnitude ◽

Regeneration System ◽

Data Rates ◽

All Optical ◽

Communication Links ◽

Shift Keying ◽

Nonlinear Devices

We propose an in-band measurement method of optical signal-to-noise ratio (OSNR) output from an all-optical regeneration system with a nonlinear power transfer function (PTF) according to the fact that there are different average gains of signal and noise. For the all-optical quadrature phase-shift keying (QPSK) regenerator as an example, the output OSNR is derived from the input OSNR and the total gain of the degraded QPSK signal. Our simulation shows that the OSNR results obtained by this method are in agreement with those calculated from the error vector magnitude (EVM) formula. The method presented here has good applicability for different data rates but is also useful for analyzing the OSNR degradation of other nonlinear devices in optical communication links.

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All-optical electrophysiology with improved genetically encoded voltage indicators reveals interneuron network dynamics in vivo

10.1101/2021.11.22.469481 ◽

2021 ◽

Author(s):

He Tian ◽

Hunter C. Davis ◽

J. David Wong-Campos ◽

Linlin Z. Fan ◽

Benjamin Gmeiner ◽

...

Keyword(s):

Gap Junction ◽

Signal To Noise Ratio ◽

Voltage Imaging ◽

All Optical ◽

Precision Voltage ◽

Coupling Strengths ◽

Junction Coupling ◽

Multiple Cells ◽

Voltage Indicator

All-optical electrophysiology can be a powerful tool for studying neural dynamics in vivo, as it offers the ability to image and perturb membrane voltage in multiple cells simultaneously. The "Optopatch" constructs combine a red-shifted archaerhodopsin (Arch)-derived genetically encoded voltage indicator (GEVI) with a blue-shifted channelrhodopsin actuator (ChR). We used a video-based pooled screen to evolve Arch-derived GEVIs with improved signal-to-noise ratio (QuasAr6a) and kinetics (QuasAr6b). By combining optogenetic stimulation of individual cells with high-precision voltage imaging in neighboring cells, we mapped inhibitory and gap junction-mediated connections, in vivo. Optogenetic activation of a single NDNF-expressing neuron in visual cortex Layer 1 significantly suppressed the spike rate in some neighboring NDNF interneurons. Hippocampal PV cells showed near-synchronous spikes across multiple cells at a frequency significantly above what one would expect from independent spiking, suggesting that collective inhibitory spikes may play an important signaling role in vivo. By stimulating individual cells and recording from neighbors, we quantified gap junction coupling strengths. Together, these results demonstrate powerful new tools for all-optical microcircuit dissection in live mice.

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