scholarly journals Effect of fiber and solenoid variation parameters on the elements of a corrector PID for electromagnetic fiber squeezer based polarization controller

2020 ◽  
Vol 10 (3) ◽  
pp. 2441 ◽  
Author(s):  
Abdallah Zahidi ◽  
Amrane Said ◽  
Nawfel Azami ◽  
Naoual Nasser
Keyword(s):  
Detection System ◽  
Light Output ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Open Loop ◽  
Polarization Controller ◽  
Heterodyne Detection ◽  
System Parameters ◽  
Stability Performance ◽  
The Stability

Controlling the polarization of the light output from single-mode fiber systems is very important for connecting it to polarization-dependent integrated optical circuits, while applications using a heterodyne detection system. Polarization controller using fiber squeezer is attractive for a low-loss, low-penalty coherent optical fiber trunk system. However, for polarization controllers using electromagnetic fiber squeezer, the stability problem due to the saturation of their magnetic circuit must be studied. In fact, in their conventional configuration, open-loop stability affects performance and limits applications. First at all, this effect has been analyzed and a feedback circuit with correctors has been proposed to improve stability performance. Then a simulation study is proposed to examine the influence of the system parameters on the corrector constants. The results of the simulation show that if the system parameters change the constants Kp, Ki and Kd of the PID corrector must be adjusted to keep an optimized dynamic response.

Laser Linewidth Measurements Using Self-Heterodyne Detection with Total-Reflected Delay Line

2012 ◽  
Vol 571 ◽  
pp. 467-470 ◽  
Author(s):  
Jian Li ◽  
Nan Xu ◽  
Jian Wei Li ◽  
Zhi Xin Zhang
Keyword(s):  
Delay Line ◽  
Detection Method ◽  
Tunable Laser ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Heterodyne Detection ◽  
Laser Source ◽  
Laser Communication ◽  
Narrow Linewidth ◽  
Fiber Delay Line

As an important parameter in the laser communication system, the narrow linewidth of tunable laser source (TLS) must be measured accurately. Therefore, the linewidth of a TLS was measured with the delayed self-heterodyne detection method in the present work. The total-reflected delay line was used in the measurement system for make full use of 25km single-mode fiber delay line. The measured linewidth of the 1550 TLS is of 127 kHz, in agreement with the nominal value.

scholarly journals Imbalanced Mach-Zehnder Modulator for Fading Suppression in Dispersion-Uncompensated Direct Detection System

Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2866
Author(s):  
Yixiao Zhu ◽  
Xin Miao ◽  
Qi Wu ◽  
Longjie Yin ◽  
Weisheng Hu
Keyword(s):  
Forward Error Correction ◽  
Direct Detection ◽  
Detection System ◽  
Single Mode ◽  
Pulse Amplitude ◽  
Single Mode Fiber ◽  
Error Rates ◽  
Transmission Experiment ◽  
Mach Zehnder Modulator ◽  
The Impact

In this work, we systematically analyze the impact of three kinds of Mach-Zehnder modulator (MZM) imbalances, including bias deviation, amplitude mismatch, and differential time skew in intensity-modulation direct-detection (IM-DD) links. It is shown that, for power fading limited transmission, the imbalances can be utilized as advantages rather than impairments. Specifically, the bias deviation with single-arm driven mode and amplitude mismatch with differential driven mode can increase the available bandwidth by shifting the frequency of fading notches. Meanwhile, time skew provides another way to avoid fading by shaping the double sideband (DSB) signal into a vestigial sideband (VSB) with an asymmetrical transfer function. In the transmission experiment, 34 Gbaud Nyquist 6/8-ary pulse amplitude modulation (PAM-6/8) signals are used for investigation in a 20 km dispersion-uncompensated standard single-mode fiber (SSMF) link. With the help of a Volterra nonlinear equalizer, all three kinds of imbalances can achieve bit-error rates (BERs) below the 7% and 20% hard-decision forward error correction (HD-FEC) thresholds for PAM-6 and PAM-8 signals, respectively. The received power sensitivity is also compared at the back-to-back (BTB) case and after fiber transmission. Both numerical simulation and experimental demonstration confirm that the dispersion-induced power fading can be effectively suppressed with bias, amplitude, or skew imbalance, providing a feasible solution for transmission distance extension of C-band DD links.

Coherent self-heterodyne detection of spontaneously Brillouin-scattered light waves in a single-mode fiber

1993 ◽  
Vol 18 (3) ◽  
pp. 185 ◽  
Author(s):  
Kaoru Shimizu ◽  
Tsuneo Horiguchi ◽  
Yahei Koyamada ◽  
Toshio Kurashima
Keyword(s):  
Scattered Light ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Heterodyne Detection ◽  
Light Waves

Optimal Design of a Stable Fuzzy Controller for Beyond Pull-In Stabilization of Electrostatically Actuated Circular Microplates

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Mohsen Bakhtiari-Shahri ◽  
Hamid Moeenfard
Keyword(s):  
Noise Suppression ◽  
Fuzzy Controller ◽  
Single Mode ◽  
Open Loop ◽  
Positioning Systems ◽  
Electrostatically Actuated ◽  
Proposed Model ◽  
Linguistic Rules ◽  
The Stability ◽  
Stability Enhancement

The current paper aims to provide an optimal stable fuzzy controller to extend the travel range of a pair of flexible electrostatically actuated circular microplates beyond their pull-in limit. The single mode assumption is utilized to derive the equation of motion of the system based on a Lagrangian approach. The static behavior of the system is studied using the proposed model, and the utilized assumption and the relevant results are closely verified by nonlinear finite element simulations. The open-loop dynamic analysis is also performed to derive the linguistic rules governing the voltage-deflection behavior of the system. The mentioned rules are then employed for designing a fuzzy controller, which controls the deflection of the microplates. The controller is then optimized to provide better response specifications. The performance of the optimal fuzzy controller is compared with that of the optimal proportional–integral–derivative (PID) controller and obvious superiorities in terms of noise suppression and stability enhancement are observed. To guarantee the stability of the closed-loop system, another higher level controller is designed to oversee the behavior of the fuzzy controller. Simulation results reveal that the superintended fuzzy controller can prevent instability, while fairly extending the travel range of system and providing it with a better transient response. The suggested design approach proposed in this paper may be used to improve the performance of many nano/micro devices and nano/micro positioning systems.

scholarly journals Dynamic Stability of Open-Loop Hopping

2006 ◽  
Vol 129 (3) ◽  
pp. 275-284 ◽  
Author(s):  
Jorge G. Cham ◽  
Mark R. Cutkosky
Keyword(s):  
Sensory Feedback ◽  
Motor Pattern ◽  
Open Loop ◽  
Legged Robots ◽  
Open Loop System ◽  
System Parameters ◽  
Model Driven ◽  
The Stability ◽  
And Control ◽  
Hopping Model

Simulations and physical robots have shown that hopping and running are possible without sensory feedback. However, stable behavior is often limited to a certain range of the parameters of the open-loop system. Even the simplest of hopping systems can exhibit unstable behavior that results in unpredictable nonperiodic motion as system parameters are adjusted. This paper analyzes the stability of a simplified vertical hopping model driven by an open-loop, feedforward motor pattern. Periodic orbits of the resulting hybrid system are analyzed through a generalized formula for the system’s Poincare Map and Jacobian. The observed behavior is validated experimentally in a physical pneumatically actuated hopping machine. This approach leads to observations on the stability of this and similar systems, revealing inherent limitations of open-loop hopping and providing insights that can inform the design and control of dynamic legged robots capable of rapid and robust locomotion.

scholarly journals Hydrogen Detection System Based on Pd Coated Single Mode Fiber Sensor

2007 ◽  
Vol 18 (6) ◽  
pp. 389-394 ◽  
Author(s):  
Kwang-Taek Kim ◽  
Son-Oc Park ◽  
Seung HwangBo ◽  
Jae-Pyung Mah ◽  
Se-Jong Baik ◽  
...  
Keyword(s):  
Detection System ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Fiber Sensor ◽  
Hydrogen Detection

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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