ArticlePublisher preview available

Modelling and analysis of polarization noise in vertical cavity surface emitting LASERs

Authors:
Article

Modelling and analysis of polarization noise in vertical cavity surface emitting LASERs

If you want to read the PDF, try requesting it from the authors.

Abstract and Figures

Previous researches have provided mathematical models of vertical cavity surface emitting LASER’s (VCSEL’s) that evaluated the effect of spontaneous noise on the Laser’s performance but completely neglected the effect of polarization noise. Also the results presented were in terms of RIN variation with respect to frequency. In this paper,a model is proposed to analyse the effect of spontaneous and polarization noise on VCSEL’s output power. Spontaneous noise is included by augmenting feedback in photon rate equations. Polarization noise is incorporated in the dynamics with the help of self-stabilizing and gain recovering coefficients. Characteristics of VCSEL’s output power are studied under continuous wave (CW) and sinusoidal modulation. VCSEL dynamics are simulated for both the cases with and without noise , firstly without noise and then with the effect of noise. The output light’s power curves depict the effect of spontaneous and polarization noise in VCSEL. For high frequency modulation, the outputs have fluctuations throughout the simulation time but noise amplifies these fluctuations, affecting the performance of LASER. For CW modulation, the output light shows exponential behaviour with respect to bias.
Content may be subject to copyright.
Multiscale and Multidisciplinary Modeling, Experiments and Design (2019) 2:151–157
https://doi.org/10.1007/s41939-018-0033-9
ORIGINAL PAPER
Modelling and analysis of polarization noise in vertical cavity surface
emitting LASERs
Abhilash Singh1·Mohit Sharma2·Rahul Kumar2·Somendra Prakash Singh2·Jyoti Raj Madhesiya2
Received: 13 June 2018 / Accepted: 20 August 2018 / Published online: 7 September 2018
© Springer Nature Switzerland AG 2018
Abstract
Previous researches have provided mathematical models of vertical cavity surface emitting LASER’s (VCSELs) that evaluated
the effect of spontaneous noise on the Laser’s performance but completely neglected the effect of polarization noise. Also
the results presented were in terms of RIN variation with respect to frequency. In this paper,a model is proposed to analyse
the effect of spontaneous and polarization noise on VCSELs output power. Spontaneous noise is included by augmenting
feedback in photon rate equations. Polarization noise is incorporated in the dynamics with the help of self-stabilizing and gain
recovering coefficients. Characteristics of VCSEL’s output power are studied under continuous wave (CW) and sinusoidal
modulation. VCSEL dynamics are simulated for both the cases with and without noise , firstly without noise and then with the
effect of noise. The output light’s power curves depict the effect of spontaneous and polarization noise in VCSEL. For high
frequency modulation, the outputs have fluctuations throughout the simulation time but noise amplifies these fluctuations,
affecting the performance of LASER. For CW modulation, the output light shows exponential behaviour with respect to bias.
Keywords VCSEL ·CW modulation ·Two-tone modulation ·Spontaneous noise ·Polarization noise
1 Introduction
In today’s world all the communication network’s backbone
is based on fiber optic links. An optical network is comprised
of three major components: optical sources, waveguides and
receivers. To ensure good signal quality all these components
must operate perfectly and to operate at highest efficiency all
the components must be free from noise. Although every
component has its own set of noise that degrades its per-
BAbhilash Singh
sabhilash@iiserb.ac.in
Mohit Sharma
mohitsharma5722@gmail.com
Rahul Kumar
rahulupadhyay2k16@gmail.com
Somendra Prakash Singh
30singhsp@gmail.com
Jyoti Raj Madhesiya
raj95jyoti@gmail.com
1Indian Institute of Science Education and Research, Bhopal,
India
2School of ICT, Gautam Buddha University, Greater Noida,
India
formance. But in a system some noises are introduced into
them through other components. In this paper, the area of
interest is the noise generated by most efficient and widely
used optical sources. Most efficient light source used nowa-
days is VCSEL. It has some inherent qualities that promotes
its usage as a light source in optical communication such
as comparatively low cost, large bandwidth and high den-
sity. For any system, the ability to handle noise, internal or
external is of utmost importance.
Radiation of light in VCSEL is based on two principles:
spontaneous emission and stimulated emission. Stimulated
emission does not generate any noise of its own it just mul-
tiplies the noise generated because of spontaneous emission.
Hence it can be concluded that on the basis of emission
principle, spontaneous emission is the only source of noise
in VCSEL (Ahmed et al. 2014). Apart from spontaneous
noise, VCSEL’s performance is also affected due to the
phenomenon of polarization. Most papers study the effect
of spontaneous noise on VCSEL characteristics neglecting
polarization noise. In this paper, the model incorporates both
spontaneous and polarization noise in previously proposed
VCSEL photon and carrier rate equations of VCSEL with
the novelty of explaining the effect of polarization noise in
VCSEL.
123
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
Article
In this work, polarization property of Vertical Cavity Surface Emitting Laser (VCSEL) is investigated for 5 Gbps optical data transmission in a combined link comprising of Single Mode Fiber (SMF) and Free Space Optic (FSO) channel. The VCSEL considered for simulation is biased just above threshold with RZ current pulses to emit narrow polarized optical pulses. After 20 km SMF link, the received power is launched into two different paths using an optical splitter. It is received by an InGaAs PIN photodiode in one path and a coupling lens in other. A split ratio of 2%, provides the minimum power required for the SMF link to maintain a BER ≤10⁻¹², based on the VCSEL considered in the study. The remaining 98% of power is utilised for FSO transmission beyond the SMF link. The maximum FSO link distances under various loss combinations were found for the two polarised optical pulses, separately. For BER≤10⁻¹², under the combined influence of all losses, an FSO link length of 130 m and 119 m, for x and y polarizations are predicted.
Article
Full-text available
Theintensitynoisespectraofseveralmulti-transverse mode 1550-nm vertical-cavity surface-emitting lasers (VCSELs) have been experimentally investigated. For a VCSEL emitting in two parallel polarized transverse modes the noise spectra of the individual modes and total power show two resonance peaks. The frequencies at which both peaks appear have been measured as a function of the bias current. Our experimental results confirm the theoreticalpredictionsofValleetal.Differencesinthenoisespectra are experimentally observed when considering a VCSEL emitting in three transverse modes with polarization instabilities. We show that additional peaks appear in the noise spectra of the total power as the bias current is increased. Index Terms—Mode partition noise (MPN), relative intensity noise (RIN), semiconductor lasers, transverse modes, ver- tical-cavity surface-emitting lasers (VCSELs).
Article
Full-text available
This paper investigates mode dynamics, operation characteristics and signal distortions associated with sinusoidal modulation of semiconductor lasers. The study is based on intensive integrations of the multimode rate equation model of semiconductor lasers over wide ranges of the modulation frequency and depth. The rate equations take into account both spectral symmetric and asymmetric suppressions of modal gain. The higher harmonic distortions as well as the half harmonic distortion associated with the period doubling effect are investigated. The study is applied to both cases of single-mode and multimode oscillations of the non-modulated laser. The obtained results showed that the modulated signal has six distinct waveforms depending on the modulation conditions; three types have continuous periodic waveforms and the others have periodic pulsing waveforms. The modulated laser is found to oscillate in a single mode under weak modulation where the modulated signal is continuous, whereas the pulsing signals are associated with multimode oscillation. The higher harmonic distortions of single-mode laser are lower than those of two-mode lasers, and become serious at modulation frequencies around the relaxation oscillation frequency. These distortions are highest when the laser output is pulsating and the pulses are superposed by relaxation oscillations.
Article
Full-text available
a b s t r a c t This paper introduces comprehensive numerical simulations of the static and dynamic characteristics of vertical cavity surface emitting lasers (VCSELs) under both continuous-wave (CW) operation and sinusoidal modulation. Both cases of single and two-tone modulations are studied. The VCSEL is assumed to oscillate in two modes, and the obtained results are compared to those of single mode VCSELs. The study is based on a multimode rate equation model of VCSELs, which describes the time evolution of number of the emitted photons and the density of injected electrons in the active and cladding layers. The higher and half harmonic distortions of the single-tone modulated signals as well as the intermodulated distortion of the two-tone modulated signals are investigated and correlated to the characteristics of the signal waveform.
Conference Paper
The acronym VCSEL stands for Vertical Cavity Surface Emitting Lasers. In this paper design, simulation and analysis of VCSEL at different wavelengths near the third transparent window i.e. 1550nm is presented. Comparative analysis is done for three wavelengths that are 1510nm, 1540nm, and 1580nm. The results suggest overshoots in voltage wavelength plots in 0–1 volts region. The analysis is helpful to identify the advantages and disadvantages of these wavelengths for different applications. Analysis also suggests the threshold voltage before which VCSEL deprives us any sort of output.
Article
We show the polarization characteristics of gain‐guided vertical‐cavity surface emitting lasers are related to the temperature‐dependent cavity optical resonance and laser gain spectral alignment. Simultaneous nearly degenerate orthogonal eigen polarization states are observed at and above lasing threshold. The partitioning of power between the linear polarization states is shown to depend on the relative spectral overlap of the cavity resonance of each state with the gain. Near the condition of cavity resonance/gain alignment, an abrupt switch in the dominant eigen polarization with a region of polarized output fluctuations is evident. Rotation of the eigen polarization directions relative to the crystal axes is also observed at temperatures where the gain is blue shifted from the cavity resonances.
Article
The bistable switching between the TE and TM modes in semiconductor lasers has been analyzed using the rate equations. The condition of bistability has been determined using linear and nonlinear gain constants. The observed bistable switching behavior can be explained by a numerical simulation.
Conference Paper
This work reports on an experimental and theoretical study of the polarization dynamics of a VCSEL submitted to optical injection. A detailed bifurcation analysis extended to optical injection is also conducted experimentally. The application of a continuation method allows mapping of the bifurcation boundaries and the corresponding polarization instabilities in the plane of the injection parameters. The polarization mode competition is found to be responsible for new dynamical instabilities, such as bistability between a linearly polarized and an elliptically polarized injection locked state, and new chaotic regimes in the two polarization modes.
Article
We have observed an excess-intensity noise that is attributed to polarization fluctuations of InGaAs-GaAs vertical-cavity surface-emitting lasers (VCSELs). It was observed, for the first time, that the intensity noise increased remarkably by the polarization fluctuation even when the single transverse mode operation was maintained. This result indicates that it is necessary to control the polarization state of VCSELs as well as control the transverse modes for low-noise operations.< >
digest of LEOS summer topical meetings: advanced semiconductor lasers and applications/ultraviolet and blue lasers and their applications/ultralong haul DWDM transmission and networking/WDM compo
  • Hlt Lee
  • R J Ram
Lee HLT, Ram RJ (2001) Mode partition noise in vertical cavity surface emitting lasers. In: 2001 digest of LEOS summer topical meetings: advanced semiconductor lasers and applications/ultraviolet and blue lasers and their applications/ultralong haul DWDM transmission and networking/WDM compo, Copper Mountain, CO, USA, p 2.https://doi.org/10.1109/LEOSST.2001.941888