Characterisation of thermal crosstalk-induced wavelength shift in monolithic InP dual DFB lasers PIC

AbstractWe propose and demonstrate a compact and simple vector bending sensor capable of distinguishing any direction and amplitude with high accuracy. The sensor consists of a short segment of asymmetric multicore fiber (MCF) fusion spliced to a standard single mode fiber. The reflection spectrum of such a structure shifts and shrinks in specific manners depending on the direction in which the MCF is bent. By monitoring simultaneously wavelength shift and light power variations, the amplitude and bend direction of the MCF can be unmistakably measured in any orientation, from 0° to 360°. The bending sensor proposed here is highly sensitive even for small bending angles (below 1°).

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Simple tunable chirp of fiber Bragg gratings without center wavelength shift

Optical Engineering ◽

10.1117/1.1589525 ◽

2003 ◽

Vol 42 (8) ◽

pp. 2263

Author(s):

Riccardo Falciai ◽

Cosimo Trono

Keyword(s):

Fiber Bragg Gratings ◽

Bragg Gratings ◽

Wavelength Shift ◽

Center Wavelength

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Variation of Stokes Shift and Peak Wavelength Shift as a Sensing Probe for Detection of Lead in Water Using Laser Induced Fluorescence Resonance Energy Transfer

Journal of Fluorescence ◽

10.1007/s10895-021-02689-1 ◽

2021 ◽

Author(s):

Seikh Mustafa Radiul ◽

Simanta Hazarika

Keyword(s):

Energy Transfer ◽

Fluorescence Resonance Energy Transfer ◽

Stokes Shift ◽

Resonance Energy Transfer ◽

Resonance Energy ◽

Laser Induced Fluorescence ◽

Wavelength Shift ◽

Peak Wavelength ◽

Fluorescence Resonance

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Measuring temperature heterogeneities during solar-photothermal heating using quantum dot nanothermometry

The Analyst ◽

10.1039/d0an02258f ◽

2021 ◽

Author(s):

Stephanie K. Loeb ◽

Haoran Wei ◽

Jae-Hong Kim

Keyword(s):

Quantum Dots ◽

Quantum Dot ◽

Fluorescence Emission ◽

Emission Wavelength ◽

Wavelength Shift ◽

Cdse Quantum Dots ◽

Photothermal Heating

The fluorescence emission wavelength shift of CdSe quantum dots due to heat-induced lattice dilatation is used to spatially resolve temperatures in solar photothermal systems.

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Wavelength and threshold current variation in inhomogeneously pumped InGaAs/AlGaAs single and double quantum well ridge wave-guide lasers

Canadian Journal of Physics ◽

10.1139/p92-144 ◽

1992 ◽

Vol 70 (10-11) ◽

pp. 908-913

Author(s):

K. A. McGreer ◽

D. Moss ◽

R. L. Williams ◽

M. Dion ◽

D. Landheer

Keyword(s):

Quantum Well ◽

Threshold Current ◽

Wave Guide ◽

Double Quantum ◽

Wavelength Shift ◽

Exponential Dependence ◽

Lasing Wavelength ◽

Output Wavelength ◽

Double Quantum Well ◽

Current Variation

We investigate the wavelength and threshold current variation with passive wave-guide length in inhomogeneously pumped single and double quantum well InGaAs/AlGaAs strained layer ridge wave-guide lasers. We observe a linear and extremely low increase in threshold current with unpumped length, both for single and double quantum well lasers. A large red shift in the lasing wavelength as the unpumped length is increased is also observed. We present a model, based on absorption saturation in the unpumped section, which describes both the wavelength shift and the threshold current variation. The increase in threshold current that we observe is much smaller than results reported in the literature for GaAs/AlGaAs lasers, where a large exponential dependence was attributed to gain saturation in the pumped section. Because the threshold current does not dramatically vary with unpumped length for our lasers, this is a potentially useful technique for shifting the output wavelength of the laser. Finally, we investigate the wavelength tuning behavior of lasers having two segments pumped with different currents. A wavelength tunability of ~13 nm for the DQW laser was observed.

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The relationship between photometric and spectroscopic oscillation amplitudes from 3D stellar atmosphere simulations

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab337 ◽

2021 ◽

Author(s):

Yixiao Zhou ◽

Thomas Nordlander ◽

Luca Casagrande ◽

Meridith Joyce ◽

Yaguang Li ◽

...

Keyword(s):

Radial Velocity ◽

Three Dimensional ◽

Quantitative Relationship ◽

Stellar Atmospheres ◽

Spectral Lines ◽

Wavelength Shift ◽

The Sun ◽

Theoretical Derivation ◽

Velocity Amplitude ◽

Good Agreement

Abstract We establish a quantitative relationship between photometric and spectroscopic detections of solar-like oscillations using ab initio, three-dimensional (3D), hydrodynamical numerical simulations of stellar atmospheres. We present a theoretical derivation as proof of concept for our method. We perform realistic spectral line formation calculations to quantify the ratio between luminosity and radial velocity amplitude for two case studies: the Sun and the red giant ε Tau. Luminosity amplitudes are computed based on the bolometric flux predicted by 3D simulations with granulation background modelled the same way as asteroseismic observations. Radial velocity amplitudes are determined from the wavelength shift of synthesized spectral lines with methods closely resembling those used in BiSON and SONG observations. Consequently, the theoretical luminosity to radial velocity amplitude ratios are directly comparable with corresponding observations. For the Sun, we predict theoretical ratios of 21.0 and 23.7 ppm/[m s−1] from BiSON and SONG respectively, in good agreement with observations 19.1 and 21.6 ppm/[m s−1]. For ε Tau, we predict K2 and SONG ratios of 48.4 ppm/[m s−1], again in good agreement with observations 42.2 ppm/[m s−1], and much improved over the result from conventional empirical scaling relations which gives 23.2 ppm/[m s−1]. This study thus opens the path towards a quantitative understanding of solar-like oscillations, via detailed modelling of 3D stellar atmospheres.

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