Frequency comparison involving the Romanian primary length standard RO.1 within the framework of the EUROMET Project #498

2001 ◽  
Author(s):  
Gheorghe Popescu
Keyword(s):  
Length Standard ◽  
Frequency Comparison

ULTRA-ACCURATE INTERNATIONAL TIME AND FREQUENCY COMPARISON VIA AN ORBITING HYDROGEN-MASER CLOCK

1981 ◽  
Vol 42 (C8) ◽  
pp. C8-395-C8-413 ◽  
Author(s):  
D. W. Allan ◽  
C. O. Alley ◽  
N. Ashby ◽  
R. Decher ◽  
R. F.C. Vessot ◽  
...  
Keyword(s):  
Hydrogen Maser ◽  
Frequency Comparison

Frequency comparison of optical lattice clocks

2011 ◽  
Author(s):  
Masao Takamoto ◽  
Tetsushi Takano ◽  
Hidetoshi Katori
Keyword(s):  
Optical Lattice ◽  
Frequency Comparison

scholarly journals Morphometric characters and their relationship in estuarine catfish

1970 ◽  
Vol 6 (2) ◽  
pp. 349-353 ◽  
Author(s):  
M Begum ◽  
Abdullah Al-Mamun ◽  
ML Islam ◽  
MJ Alam
Keyword(s):  
Sexual Dimorphism ◽  
Linear Relationship ◽  
Standard Length ◽  
Head Length ◽  
Pectoral Fin ◽  
Morphometric Characters ◽  
Total Length ◽  
Length Standard ◽  
Eye Diameter ◽  
Males And Females

The morphometric observations were made on total length, standard length, pre-caudal length, head length, eye diameter and depth of body at pectoral fin base of estuarine catfish M. gulio. Males and females showed homogeneity in characters. A linear relationship was found between total length and morphometric characters. Regression of length and weight did not deviate significantly from cube law indicating isometric growth. The fish exhibited sexual dimorphism. Keywords: Morphometric characters; Estuarine catfish; Mystus gulio DOI: 10.3329/jbau.v6i2.4833 J. Bangladesh Agril. Univ. 6(2): 349-353, 2008

All polarization-maintaining Er:fiber-based optical frequency comb for frequency comparison of optical clocks

2021 ◽  
Author(s):  
Zhang Pan ◽  
Zhang Yan-Yan ◽  
Li Ming-Kun ◽  
Rao Bing-Jie ◽  
Yan Lu-Lu ◽  
...  
Keyword(s):  
Frequency Comb ◽  
Signal To Noise Ratio ◽  
Frequency Instability ◽  
Optical Frequency Comb ◽  
Optical Frequency ◽  
Thermal Drift ◽  
Signal To Noise ◽  
Frequency Comparison ◽  
Polarization Maintaining

Abstract In this research, we demonstrate an optical frequency comb (OFC) based on a turnkey mode-locked laser with a figure-9 structure and polarization-maintaining fibers for frequency comparison between optical clocks with wavelengths of 698 nm, 729 nm, 1068 nm and 1156 nm. We adopt a multi-branch approach in order to produce high power OFC signals at these specific wavelengths, enabling the signal-to-noise ratio of the beatnotes between the OFC and the clock lasers beyond 30 dB at a resolution bandwidth of 300 kHz. This approach makes the supercontinuum spectra generating process much easier in comparison to a single branch OFC; however, more out-of-loop fibers degrade the long term frequency instability due to thermal drift. To minimize the thermal drift effect, we set the fiber lengths of different branches to be similar, and we stabilize the temperature as well. The out-of-loop frequency instability of the OFC due to the incoherence of the multi-branch is about 5.5×10-19 @ 4000 s, while the in-loop frequency instability of f ceo and that of f beat are 7.5×10-18 @1 s and 8.5×10-18 @1 s, respectively. The turnkey OFC meets the requirement of frequency comparison between the best optical clocks.

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