A Variable Optical Attenuator With Tunable Mirror Curvature

2002 ◽  
Author(s):  
Cheng-Hsuan Lin ◽  
Shih-Yi Wen ◽  
Chieh Hu ◽  
Hsiao-Wen Lee ◽  
Wensyang Hsu
Keyword(s):  
Insertion Loss ◽  
Input Voltage ◽  
Attenuation Effect ◽  
Variable Optical Attenuator ◽  
Central Displacement

A novel variable optical attenuator is proposed, fabricated, and tested here. The attenuation effect is achieved by changing the curvature of a reflection mirror membrane. In order to demonstrate the proposed principle, concave mirrors with different radii are first used to confirm the attenuation effect. Then a thermal bimorph structure with membrane is used to deform the mirror membrane at different input voltages to show the variable attenuation effect. The size of the mirror membrane, which is made of low-stress Nitride (1.0 μm) with Cr/Au (0.4 μm) on the top surface, is 800 μm × 800 μm. The major two materials in bimorph actuator are low-stress Nitride and Al (1.2 μm). Two other materials, Poly-Si (0.4 μm) and SiO2 (0.5μm), act as the heating and insulation layers in the bimorph beams, respectively. The minimum insertion loss of the attenuator is found to be 0.74 –dB. The attenuation and deflections of the mirror membrane at the central part are calibrated at different input voltages. It shows that and the attenuation is more than 40 –dB at input voltage of 44 V when the central displacement of the mirror membrane is about 16 μm.

Fabrication of polymer variable optical attenuator with ultra-low power consumption

2014 ◽  
Vol 28 (14) ◽  
pp. 1450113 ◽  
Author(s):  
Jian Sun ◽  
Xibin Wang ◽  
Jingwen Sun ◽  
Xiaoqiang Sun ◽  
Changming Chen ◽  
...  
Keyword(s):  
Power Consumption ◽  
Low Power ◽  
Wavelength Range ◽  
Insertion Loss ◽  
Zehnder Interferometer ◽  
Low Power Consumption ◽  
Spectral Variation ◽  
Ultra Low Power ◽  
Optical Attenuation ◽  
Variable Optical Attenuator

In this paper, a Mach–Zehnder interferometer (MZI) variable optical attenuator (VOA) based on Norland Optical Adhesive73 (NOA73) material has been designed and fabricated. At 1550 nm wavelength, the insertion loss of the VOA was measured to be about 8.1 dB. The developed VOA exhibited ultra-low power consumption of 1.96 mW and high optical attenuation of -29.3 dB. When the attenuation at 1550 nm wavelength was -24.6 dB, the spectral variation was ±2.5 dB within wavelength range of 1510 nm to 1590 nm. The rise and fall times of the device were 1.7 ms and 1.3 ms, respectively.

Comparison of Dc-Dc SEPIC, CUK and Flyback Converters Based LED Drivers

2020 ◽  
pp. 99-107
Author(s):  
Erdal Sehirli
Keyword(s):  
Integrated Circuit ◽  
Closed Loop ◽  
Input Voltage ◽  
Open Loop ◽  
Current Sensor ◽  
Switching Frequency ◽  
Led Driver ◽  
Advantages And Disadvantages ◽  
Led Drivers ◽  
Conduction Mode

This paper presents the comparison of LED driver topologies that include SEPIC, CUK and FLYBACK DC-DC converters. Both topologies are designed for 8W power and operated in discontinuous conduction mode (DCM) with 88 kHz switching frequency. Furthermore, inductors of SEPIC and CUK converters are wounded as coupled. Applications are realized by using SG3524 integrated circuit for open loop and PIC16F877 microcontroller for closed loop. Besides, ACS712 current sensor used to limit maximum LED current for closed loop applications. Finally, SEPIC, CUK and FLYBACK DC-DC LED drivers are compared with respect to LED current, LED voltage, input voltage and current. Also, advantages and disadvantages of all topologies are concluded.

Method for Evaluating Insertion Loss of EMI Filter Connected to Semiconductor Power Converters

2012 ◽  
Vol 132 (7) ◽  
pp. 727-735 ◽  
Author(s):  
Michio Tamate ◽  
Tamiko Sasaki ◽  
Akio Toba ◽  
Yasushi Matsumoto ◽  
Keiji Wada ◽  
...  
Keyword(s):  
Insertion Loss ◽  
Power Converters ◽  
Emi Filter

Parametric Study of Damping Characteristics of Magneto-Rheological Damper: Mathematical and Experimental Approach

2020 ◽  
Vol 15 (3) ◽  
pp. 37-48
Author(s):  
Zubair Rashid Wani ◽  
Manzoor Ahmad Tantray
Keyword(s):  
Structural Control ◽  
Research Work ◽  
Testing Machine ◽  
Input Voltage ◽  
Damping Coefficient ◽  
Control Technique ◽  
Damping Force ◽  
Active Devices ◽  
Active Structural Control ◽  
Magneto Rheological

The present research work is a part of a project was a semi-active structural control technique using magneto-rheological damper has to be performed. Magneto-rheological dampers are an innovative class of semi-active devices that mesh well with the demands and constraints of seismic applications; this includes having very low power requirements and adaptability. A small stroke magneto-rheological damper was mathematically simulated and experimentally tested. The damper was subjected to periodic excitations of different amplitudes and frequencies at varying voltage. The damper was mathematically modeled using parametric Modified Bouc-Wen model of magneto-rheological damper in MATLAB/SIMULINK and the parameters of the model were set as per the prototype available. The variation of mechanical properties of magneto-rheological damper like damping coefficient and damping force with a change in amplitude, frequency and voltage were experimentally verified on INSTRON 8800 testing machine. It was observed that damping force produced by the damper depended on the frequency as well, in addition to the input voltage and amplitude of the excitation. While the damping coefficient (c) is independent of the frequency of excitation it varies with the amplitude of excitation and input voltage. The variation of the damping coefficient with amplitude and input voltage is linear and quadratic respectively. More ever the mathematical model simulated in MATLAB was in agreement with the experimental results obtained.

Performance and Reliability of a MEMS-based tunable optical filter operating in the 1565 nm-1525 nm wavelength range

2002 ◽  
Vol 722 ◽  
Author(s):  
T. S. Sriram ◽  
B. Strauss ◽  
S. Pappas ◽  
A. Baliga ◽  
A. Jean ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Line Width ◽  
Insertion Loss ◽  
Optical Filter ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Reliability Testing ◽  
Silicon Nitride Membrane ◽  
Tunable Optical Filter ◽  
Extensive Performance

AbstractThis paper describes the results of extensive performance and reliability characterization of a silicon-based surface micro-machined tunable optical filter. The device comprises a high-finesse Fabry-Perot etalon with one flat and one curved dielectric mirror. The curved mirror is mounted on an electrostatically actuated silicon nitride membrane tethered to the substrate using silicon nitride posts. A voltage applied to the membrane allows the device to be tuned by adjusting the length of the cavity. The device is coupled optically to an input and an output single mode fiber inside a hermetic package. Extensive performance characterization (over operating temperature range) was performed on the packaged device. Parameters characterized included tuning characteristics, insertion loss, filter line-width and side mode suppression ratio. Reliability testing was performed by subjecting the MEMS structure to a very large number of actuations at an elevated temperature both inside the package and on a test board. The MEMS structure was found to be extremely robust, running trillions of actuations without failures. Package level reliability testing conforming to Telcordia standards indicated that key device parameters including insertion loss, filter line-width and tuning characteristics did not change measurably over the duration of the test.

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