scholarly journals Semiconductor Laser Linewidth Theory Revisited

2021 ◽  
Vol 11 (13) ◽  
pp. 6004
Author(s):  
Hans Wenzel ◽  
Markus Kantner ◽  
Mindaugas Radziunas ◽  
Uwe Bandelow
Keyword(s):  
Spontaneous Emission ◽  
Numerical Study ◽  
Analytical Formula ◽  
Reduction Factor ◽  
Bragg Reflector ◽  
Hole Burning ◽  
Distributed Bragg Reflector ◽  
Theoretical Understanding ◽  
Longitudinal Modes ◽  
Coupled Wave Equations

More and more applications require semiconductor lasers distinguished not only by large modulation bandwidths or high output powers, but also by small spectral linewidths. The theoretical understanding of the root causes limiting the linewidth is therefore of great practical relevance. In this paper, we derive a general expression for the calculation of the spectral linewidth step by step in a self-contained manner. We build on the linewidth theory developed in the 1980s and 1990s but look from a modern perspective, in the sense that we choose as our starting points the time-dependent coupled-wave equations for the forward and backward propagating fields and an expansion of the fields in terms of the stationary longitudinal modes of the open cavity. As a result, we obtain rather general expressions for the longitudinal excess factor of spontaneous emission (K-factor) and the effective α-factor including the effects of nonlinear gain (gain compression) and refractive index (Kerr effect), gain dispersion, and longitudinal spatial hole burning in multi-section cavity structures. The effect of linewidth narrowing due to feedback from an external cavity often described by the so-called chirp reduction factor is also automatically included. We propose a new analytical formula for the dependence of the spontaneous emission on the carrier density avoiding the use of the population inversion factor. The presented theoretical framework is applied to a numerical study of a two-section distributed Bragg reflector laser.

scholarly journals A short cavity fiber laser for microwave and radio-wave generation

2021 ◽  
Author(s):  
Udari M. Basnayaka
Keyword(s):  
Fiber Laser ◽  
Radio Wave ◽  
Longitudinal Mode ◽  
Gain Medium ◽  
Optical Signal ◽  
Bragg Reflector ◽  
Orthogonal Polarization ◽  
Distributed Bragg Reflector ◽  
Longitudinal Modes ◽  
Microwave Signals

Broadband and low loss capability of photonics has led to increasing interests in its use for generating, processing, controlling and distributing of microwave and radio-wave signals with low phase noise for applications such as Radio over Fiber systems (RoF), broadband wireless access networks, sensor networks and satellite communitarians. In this thesis, I have introduced and demonstrated a short cavity Distributed Bragg Reflector (DBR) laser operating in two stable longitudinal modes to generate microwave and radio-wave frequency signals. In the laser, Er/Yb core doped fiber has been used as the gain medium and two wavelength matching fiber Bragg gratings (FBGs) of 99.9% and 90% reflectivity in C-band were used as end reflectors. The dual mode operation was achieved by reducing the cavity length of the fiber laser to 8 mm. It was pumped with a 980 nm pump laser and the laser output has an optical signal-to-noise ratio (SNR) larger than 65 dB at 1533 nm. Due to the birefringence introduced during FBG fabrication two orthogonal polarization modes were observed for each longitudinal mode. Microwave and radio-wave signals were generated by beating these longitudinal polarization laser modes on a fast photo detector. The generated microwave signals were at 1.2687 GHz, 1.2828 GHz, 14.6962 GHz and 14.7103 GHz with a SNR of 45 dB. The generated radio-wave signals were at 14.1 MHz with a SNR of 30 dB. The 3dB bandwidth of microwave and radio-wave signals were measured to be less than 30 kHz and the Allan variance measurements indicate that the signals are highly stable for temperature variations while the generated microwave signals demonstrated a linear relationship with temperature at 1 MHz/Celsius. Due to high stability of the generated radio-wave signal and low complexity of the overall system this short cavity fiber laser has potential applications such as ultrasonic sensors and optical clocks

scholarly journals A short cavity fiber laser for microwave and radio-wave generation

2021 ◽  
Author(s):  
Udari M. Basnayaka
Keyword(s):  
Fiber Laser ◽  
Radio Wave ◽  
Longitudinal Mode ◽  
Gain Medium ◽  
Optical Signal ◽  
Bragg Reflector ◽  
Orthogonal Polarization ◽  
Distributed Bragg Reflector ◽  
Longitudinal Modes ◽  
Microwave Signals

Broadband and low loss capability of photonics has led to increasing interests in its use for generating, processing, controlling and distributing of microwave and radio-wave signals with low phase noise for applications such as Radio over Fiber systems (RoF), broadband wireless access networks, sensor networks and satellite communitarians. In this thesis, I have introduced and demonstrated a short cavity Distributed Bragg Reflector (DBR) laser operating in two stable longitudinal modes to generate microwave and radio-wave frequency signals. In the laser, Er/Yb core doped fiber has been used as the gain medium and two wavelength matching fiber Bragg gratings (FBGs) of 99.9% and 90% reflectivity in C-band were used as end reflectors. The dual mode operation was achieved by reducing the cavity length of the fiber laser to 8 mm. It was pumped with a 980 nm pump laser and the laser output has an optical signal-to-noise ratio (SNR) larger than 65 dB at 1533 nm. Due to the birefringence introduced during FBG fabrication two orthogonal polarization modes were observed for each longitudinal mode. Microwave and radio-wave signals were generated by beating these longitudinal polarization laser modes on a fast photo detector. The generated microwave signals were at 1.2687 GHz, 1.2828 GHz, 14.6962 GHz and 14.7103 GHz with a SNR of 45 dB. The generated radio-wave signals were at 14.1 MHz with a SNR of 30 dB. The 3dB bandwidth of microwave and radio-wave signals were measured to be less than 30 kHz and the Allan variance measurements indicate that the signals are highly stable for temperature variations while the generated microwave signals demonstrated a linear relationship with temperature at 1 MHz/Celsius. Due to high stability of the generated radio-wave signal and low complexity of the overall system this short cavity fiber laser has potential applications such as ultrasonic sensors and optical clocks

Experimental and numerical study of Distributed-Bragg-Reflector tapered lasers

2009 ◽  
Vol 99 (1-2) ◽  
pp. 209-214 ◽  
Author(s):  
C. Fiebig ◽  
V. Z. Tronciu ◽  
M. Lichtner ◽  
K. Paschke ◽  
H. Wenzel
Keyword(s):  
Numerical Study ◽  
Bragg Reflector ◽  
Distributed Bragg Reflector

OPTIMAL DESIGN OF SINGLE-PHOTON SOURCE EMISSION FROM A QUANTUM-DOT IN MICRO-PILLAR MICROCAVITY

2005 ◽  
Vol 03 (supp01) ◽  
pp. 229-238 ◽  
Author(s):  
Y.-L. D. HO ◽  
T. CAO ◽  
P. S. IVANOV ◽  
M. J. CRYAN ◽  
I. J. CRADDOCK ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Spontaneous Emission ◽  
Single Photon ◽  
Collection Efficiency ◽  
Large Fraction ◽  
Broad Band ◽  
Fdtd Method ◽  
Bragg Reflector ◽  
Dipole Source ◽  
Distributed Bragg Reflector

We have modelled wavelength scale micro-pillar microcavities of group III-V semiconductor materials using the 3-D finite difference time domain (FDTD) method. A broad band dipole source within the microcavity probes the microcavity mode structure and spectrum. We then investigated the modifications to spontaneous emission of photons form narrowband emitters (e.g. quantum dots) at the centre of the resonance. We find strongly enhanced emission due to small modal volumes and high quality factor (Q-factor). A large fraction of the quantum-dot spontaneous emission is coupled into the fundamental cavity mode. Increasing the number of mirror pairs in the bottom distributed Bragg reflector (DBR) obviously reduces the bottom light leakage, leading to light collection efficiency up to 90%. Moreover, we are now looking at more sophisticated structures with both lateral and perpendicular confinements based on annular and photonic crystal defect cavities in order to suppress the remaining sidewall scattering.

scholarly journals Purcell effect in Tamm plasmon structures with QD emitter

2018 ◽  
Vol 52 (4) ◽  
pp. 467
Author(s):  
A.R. Gubaydullin ◽  
C. Symonds ◽  
J. Bellessa ◽  
K.A. Ivanov ◽  
E.D. Kolykhalova ◽  
...  
Keyword(s):  
Spontaneous Emission ◽  
Plasmon Mode ◽  
Bragg Reflector ◽  
Silver Layer ◽  
Spontaneous Emission Rate ◽  
Distributed Bragg Reflector ◽  
Purcell Factor ◽  
Inas Quantum Dots ◽  
Order Of Magnitude ◽  
Quantization Formalism

AbstractWe study Tamm plasmon structure based on GaAs/Al_0.95GaAs distributed Bragg reflector covered by thin silver layer, with active area formed by InAs quantum dots. We have measured the spectral and angular characteristics of photoluminescence and performed theoretical calculation of the spontaneous emission rate (modal Purcell factor) in the structure by using S-quantization formalism. We show that for Tamm plasmon mode the spontaneous emission can be enhanced by more than an order of magnitude, despite absorption in metallic layer.

scholarly journals InGaAs metamorphic laser power converters with distributed Bragg reflector for wavelength range λ=1 – 1.1 µm

2020 ◽  
Author(s):  
Nikolay A. Kalyuzhnyy ◽  
Viktor M. Emelyanov ◽  
Sergey A. Mintairov ◽  
Mariia V. Nahimovich ◽  
Roman A. Salii ◽  
...  
Keyword(s):  
Wavelength Range ◽  
Laser Power ◽  
Power Converters ◽  
Bragg Reflector ◽  
Distributed Bragg Reflector
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