The Effect of Polarization Control in Loss-Compensated Recirculating Delayed Self-Heterodyne Interferometry Measurement of Laser Linewidth

2013 ◽  
Vol 303-306 ◽  
pp. 859-862
Author(s):  
Si Ya Dong Xiong ◽  
Yi Yang ◽  
Chao Peng ◽  
Zhen Rong Zhang ◽  
Zheng Bin Li

In the implementation of the loss-compensated recirculating delayed self-heterodyne interferometry (LC-RDSHI) measurement of laser linewidth, we observe the fluctuations among the different orders of beat spectra, which are not expected according to theoretical analysis and may lead to the distortion of lineshape and inaccurate estimation of the laser linewidth. To explain the observation, we in this paper simplify the polarization model in the recirculating heterodyne ring interferometer containing a polarization controller (PC) and point out the effect of the polarization control in the LC-RDSHI measurement. The simulation result of our model explains well the observed fluctuations.

2012 ◽  
Vol 20 (11) ◽  
pp. 12247 ◽  
Author(s):  
M. Jofre ◽  
G. Anzolin ◽  
F. Steinlechner ◽  
N. Oliverio ◽  
J. P. Torres ◽  
...  

2021 ◽  
Vol 2086 (1) ◽  
pp. 012092
Author(s):  
E E Mekhtiev ◽  
I S Gerasin ◽  
N V Rudavin ◽  
A V Duplinsky ◽  
Y V Kurochkin

Abstract The crucial task for polarization-encoding fiber QKD is to compensate polarization drift occurring in a quantum channel. To solve this problem, the receiver usually uses a polarization controller. For proper operation, this device must be efficiently managed in real-time. In this work, a gradient-descent-based algorithm is proposed to solve this problem. The algorithm was implemented and tested on a QRate commercial QKD fiber system, that utilizes BB84-protocol. Low and stable QBER has been obtained during a day of continuous operation.


2019 ◽  
Vol 9 (7) ◽  
pp. 1436 ◽  
Author(s):  
Weichao Ma ◽  
Bing Xiong ◽  
Changzheng Sun ◽  
Xu Ke ◽  
Jian Wang ◽  
...  

A simple and effective approach to semiconductor laser linewidth narrowing via mutual injection locking is proposed and demonstrated in both short and long delay regimes. A theoretical analysis is presented to investigate the linewidth behavior of semiconductor lasers under mutual injection locking. Experimental demonstrations in short and long delay regimes are implemented by integrated devices and a fiber link system, respectively. Locking condition and dependence of laser linewidth on coupling parameters in both regimes are studied, confirming mutual injection locking as a practical method for linewidth narrowing. For the short-delayed integrated lasers, a linewidth narrowing factor of 13 is demonstrated and sub-MHz linewidth is achieved, while for the long-delayed lasers coupled by fiber link, the intrinsic linewidth is reduced to sub-100 Hz.


Photonics ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 137
Author(s):  
Jing Gao ◽  
Dongdong Jiao ◽  
Xue Deng ◽  
Jie Liu ◽  
Linbo Zhang ◽  
...  

A polarization-insensitive recirculating delayed self-heterodyne method (PI-RDSHM) is proposed and demonstrated for the precise measurement of sub-kilohertz laser linewidths. By a unique combination of Faraday rotator mirrors (FRMs) in an interferometer, the polarization-induced fading is effectively reduced without any active polarization control. This passive polarization-insensitive operation is theoretically analyzed and experimentally verified. Benefited from the recirculating mechanism, a series of stable beat spectra with different delay times can be measured simultaneously without changing the length of delay fiber. Based on Voigt profile fitting of high-order beat spectra, the average Lorentzian linewidth of the laser is obtained. The PI-RDSHM has advantages of polarization insensitivity, high resolution, and less statistical error, providing an effective tool for accurate measurement of sub-kilohertz laser linewidth.


2012 ◽  
Vol 10 (10) ◽  
pp. 100602-100605 ◽  
Author(s):  
Hao Zhou Hao Zhou ◽  
Lixia Xi Lixia Xi ◽  
Jianping Li Jianping Li ◽  
Xiaoguang Zhang Xiaoguang Zhang ◽  
Na Liu Na Liu

Author(s):  
A. Gómez ◽  
P. Schabes-Retchkiman ◽  
M. José-Yacamán ◽  
T. Ocaña

The splitting effect that is observed in microdiffraction pat-terns of small metallic particles in the size range 50-500 Å can be understood using the dynamical theory of electron diffraction for the case of a crystal containing a finite wedge. For the experimental data we refer to part I of this work in these proceedings.


2001 ◽  
Vol 84 (7) ◽  
pp. 27-36
Author(s):  
Aki Yuasa ◽  
Daisuke Itatsu ◽  
Naoki Inagaki ◽  
Nobuyoshi Kikuma

1997 ◽  
Vol 2 (2) ◽  
pp. 118-124
Author(s):  
Geoffrey Hall

Patients who have undergone several sessions of chemotherapy for cancer will sometimes develop anticipatory nausea and vomiting (ANV), these unpleasant side effects occurring as the patients return to the clinic for a further session of treatment. Pavlov's analysis of learning allows that previously neutral cues, such as those that characterize a given place or context, can become associated with events that occur in that context. ANV could thus constitute an example of a conditioned response elicited by the contextual cues of the clinic. In order to investigate this proposal we have begun an experimental analysis of a parallel case in which laboratory rats are given a nausea-inducing treatment in a novel context. We have developed a robust procedure for assessing the acquisition of context aversion in rats given such training, a procedure that shows promise as a possible animal model of ANV. Theoretical analysis of the conditioning processes involved in the formation of context aversions in animals suggests possible behavioral strategies that might be used in the alleviation of ANV, and we report a preliminary experimental test of one of these.


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