IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 28, NO. 14, JULY 15, 2016 1593
Spectrum Broadening in Optical Frequency-Shifted
Feedback of Microchip Laser
Shaohui Zhang, Shulian Zhang, Liqun Sun, and Yidong Tan
Abstract—The influence of feedback level and shifted
frequency on laser spectrum and power spectrum is investigated
experimentally and theoretically. Due to optical frequency-shifted
feedback, the spectrum of Nd:YVO
4
microchip laser is expanded
into one with multi equal-spaced sidebands around its initial
central frequency. The detail of expanded spectrum depends on
both the shifted frequency and relaxation oscillation frequency.
Optical feedback level decides the possible maximum spectrum
range. Nevertheless, the actual spectrum range depends on both
the frequency shift and the feedback level. The power spectrum
turns from simple to complex with the increase of feedback level
when the shifted frequency is a constant. A rate-equation model
with optical frequency-shifted feedback is built to interpret the
experimental phenomena. The theoretical results accord with the
experiments very well. This letter can help choose appropriate
parameters for feedback interferometry systems and promote the
accomplishment of optical frequency-shifted feedback diagram,
which could be a guide for feedback interferometry applications.
Index Terms— Spectra, interferometry, feedback lasers,
frequency modulated, solid-state lasers.
I. INTRODUCTION
O
PTICAL feedback interference, known as
self-mixing interference, has shown great
advantages in non-cooperate targets measurement [1], [2].
Compared with Michelson interference, characters and
phenomena of self-mixing is more complicated [3].
Tkach and Chraplyvy (T-C) diagram identifies five regimes of
feedback according to the distance of reflector and feedback
level [4]. Spectrum compressing or broadening, mode splitting
and chaos will happen with the increase of feedback level.
Appropriate conditions could be chosen based on T-C diagram
to realize geometrical measurement. Nevertheless, the T-C
diagram is applied to semiconductor laser instead of solid
state laser. What’s more, spectrum and power spectrum show
more complex phenomena when frequency-shifted technology
is applied in self-mixing interference [5]–[7]. In recent
years, self-mixing interferometry with optical frequency-shift
Manuscript received March 14, 2016; revised April 15, 2016; accepted
April 18, 2016. Date of publication April 25, 2016; date of current version
May 19, 2016. This work was supported in part by the Beijing Municipal
Science and Technology Commission under Grant Z151100002415027 and
in part by the National Natural Science Foundation of China under
Grant 61475082. (Corresponding author: Yidong Tan.)
The authors are with the Institude of Opto-Electronic Engineering,
Precision Instruments, Tsinghua University, Beijing 100084, China
(e-mail: zhangshaohui1108@sina.com; zsl-dpi@tsinghua.edu.cn; sunlq@
tsinghua.edu.cn; tanyd@tsinghua.edu.cn).
Color versions of one or more of the figures in this letter are available
online at http://ieeexplore.ieee.org.
Digital Object Identifier 10.1109/LPT.2016.2556708
Fig. 1. Schematic of experimental setup. ML1 and ML2: solid state microchip
Nd:YVO
4
lasers; BS1, BS2 and BS3: beam splitter; AOMs: acousto-optics
modulator; ATT: attenuator; T: target; PD: photo diode; OS: oscilloscope;
PD&AF: photo diode and amplifier; FS: frequency spectrograph.
feedback has displayed ultrahigh sensitivity to laser feedback,
leading to such exciting applications as laser optical feedback
tomography [8], laser feedback interferometer [9], laser
Doppler velocimetry and vibrometry [2]. Nevertheless, the
resolution, measurement range and accuracy of this kind
interferometry largely depends on the effect of frequency
shift and feedback level on laser spectrum and laser power
spectrum. Almost all self-mixing interference applications
claim for weak optical feedback level. However, the standard
of “weak optical feedback level” is not specific. T-C diagram
holds the opinion that the spectrum will become more
complicated with the increase of feedback level. In the case
of optical frequency-shifted feedback, the situation is more
complex. In consequence, in order to draw a diagram about
optical frequency-shifted feedback effects, it is necessary to
investigate the effect of feedback level and shifted frequency
on spectrum and power spectrum of Nd:YVO
4
microchip
laser (ML) with optical frequency-shifted feedback.
II. E
XPERIMENT AND RESULTS
Fig.1 shows the schematic of experimental setup.
Two identical 3mm square, 0.78mm thick Nd:YVO
4
crystals with coated input face (99.9% reflection at the
lasing wavelength 1064 nm, high transmission at the pump
wavelength of 808 nm) and output surface (99% reflection
at 1064 nm and about 95% reflection at 808 nm) are used
as ML1 and ML2. Spectrum of ML1 can be obtained by
heterodyne interference with ML2. The driven frequency of
AOMs and the transmittance of ATT could be adjusted in
order to get different shifted frequencies and feedback levels.
Oscilloscope (Tektronic TDS2014C 100MHz 2GS/s) and
1041-1135 © 2016 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission.
See http://www.ieee.org/publications_standards/publications/rights/index.html for more information.
资源评论
weixin_38557980
- 粉丝: 7
- 资源: 925
最新资源
- 白色大气风格的上线倒计时模板下载.zip
- 白色大气风格的商业合作公司模板下载.zip
- 白色大气风格的商业模板下载.zip
- 白色大气风格的设计公司网页模板下载.zip
- 白色大气风格的设计公司CSS3单页模板.zip
- 白色大气风格的设计公司整站网站模板下载.zip
- matlab实现并行计算在无线传感器网络中的应用与实现-并行计算-无线传感器网络-WSN-matlab-分布式算法
- 白色大气风格的摄影照片展示网页模板下载.zip
- 白色大气风格的摄影主题网页模板下载.zip
- 白色大气风格的设计师作品模板下载.zip
- 白色大气风格的生活商品网上销售商城模板.zip
- 白色大气风格的生活工具网店网页模板下载.zip
- 白色大气风格的施工建设企业网站模板.zip
- 白色干净大气的企业网站模板下载.zip
- 白色干净简单的app软件网站模板下载.zip
- 白色风景的人物相册整站网站模板下载.zip
资源上传下载、课程学习等过程中有任何疑问或建议，欢迎提出宝贵意见哦~我们会及时处理！
点击此处反馈
