20 research outputs found
Optical receiver with helicity-dependent magnetization eversal
In this paper, we propose helicity-dependent switching (HDS) of magnetization in Co/Pt for an energy efficient optical receiver. Designing a low-power optical receiver for optical-to-electrical signal conversion has proven to be very challenging. Current day optical receivers use a photodiode that produces a photocurrent in response to input optical signals, and power hungry transimpedance amplifiers are required to amplify the small photocurrents. These limitations can be overcome by using light helicity-induced switching of magnetization which can avoid the requirement of photodiodes and subsequent transimpedance amplification by sensing the change in magnetization with a magnetic tunnel junction (MTJ). Magnetization switching of a thin ferromagnet layer using circularly polarized laser pulses has recently been demonstrated which shows a one-to-one correspondence between light helicity and the magnetization state. We use these phenomena to directly switch the magnetization state of a thin Co/Pt ferromagnet layer at the receiver via circularly polarized laser pulses. The circular polarization is controlled in accordance with digital input data which establishes a one-to-one correspondence between the transmitted data and output magnetization state. The Co/Pt layer is used as the free layer of an MTJ, the resistance of which is modified by the laser pulses. Since the output magnetization state is controlled by the input data, the MTJ resistance is directly converted to a digital output signal. Our device-to-circuit level simulation results indicate that HDS-based optical receiver circuit consumes only 0.124 pJ/bit energy, which is much lower than existing techniques
Laser Induced Magnetization Reversal for Detection in Optical Interconnects
Optical interconnect has emerged as the front-runner to replace electrical interconnect especially for off-chip communication. However, a major drawback with optical interconnects is the need for photodetectors and amplifiers at the receiver, implemented usually by direct bandgap semiconductors and analog CMOS circuits, leading to large energy consumption and slow operating time. In this letter, we propose a new optical interconnect architecture that uses a magnetic tunnel junction (MTJ) at the receiver side that is switched by femtosecond laser pulses. The state of the MTJ can be sensed using simple digital CMOS latches, resulting in significant improvement in energy consumption. Moreover, magnetization in the MTJ can be switched on the picoseconds time-scale and our design can operate at a speed of 5 Gb/s for a single link
Self-Consistent C-V Characterization of Depletion Mode Buried Channel InGaAs/InAs Quantum Well FET Incorporating Strain Effects
We investigated Capacitance-Voltage (C-V) characteristics of the Depletion
Mode Buried Channel InGaAs/InAs Quantum Well FET by using Self-Consistent
method incorporating Quantum Mechanical (QM) effects. Though the experimental
results of C-V for enhancement type device is available in recent literature, a
complete characterization of electrostatic property of depletion type Buried
Channel Quantum Well FET (QWFET) structure is yet to be done. C-V
characteristics of the device is studied with the variation of three important
process parameters: Indium (In) composition, gate dielectric and oxide
thickness. We observed that inversion capacitance and ballistic current tend to
increase with the increase in Indium (In) content in InGaAs barrier layer.Comment: 5 pages, ICEDSA conference 201
Self Consistent Simulation of C-V Characterization and Ballistic Performance of Double Gate SOI Flexible-FET Incorporating QM Effects
Capacitance-Voltage (C-V) & Ballistic Current- Voltage (I-V) characteristics
of Double Gate (DG) Silicon-on- Insulator (SOI) Flexible FETs having sub 35nm
dimensions are obtained by self-consistent method using coupled Schrodinger-
Poisson solver taking into account the quantum mechanical effects. Although,
ATLAS simulations to determine current and other short channel effects in this
device have been demonstrated in recent literature, C-V & Ballistic I-V
characterizations by using self-consistent method are yet to be reported. C-V
characteristic of this device is investigated here with the variation of bottom
gate voltage. The depletion to accumulation transition point (i.e. Threshold
voltage) of the C-V curve should shift in the positive direction when the
bottom gate is negatively biased and our simulation results validate this
phenomenon. Ballistic performance of this device has also been studied with the
variation of top gate voltage.Comment: 4 pages, ICEDSA 2012 conferenc