Publications de Mohammad Mehdi Alem Karladani

Analytical expression and experimental validation of the Brillouin gain spectral broadening at any sensing spatial resolution

Luc Thévenaz, Mohammad Mehdi Alem Karladani, Marcelo Alfonso Soto Hernandez

A novel and simple analytical expression to describe the Brillouin gain spectral broadening as a function of the spatial resolution in time-domain Brillouin distributed fiber sensors is deduced. The proposed model is experimentally validated using a pump-p ...

Ieee2017

Impact of modulation instability on distributed optical fiber sensors

Mohammad Mehdi Alem Karladani

Modulation instability (MI) as the main limit to the sensing distance of distributed fiber sensors is thoroughly investigated in this thesis in order to obtain a model for predicting its characteristics and alleviating its effects. Starting from Maxwell's ...

EPFL2016

Performance limit of two-pump Brillouin fiber sensors obtained by Manakov modulation instability

Luc Thévenaz, Mohammad Mehdi Alem Karladani, Marcelo Alfonso Soto Hernandez, Javier Urricelqui Polvorinos

The Manakov modulation instability is shown to determine the performance limit of long-distance Brillouin fiber sensors utilizing orthogonally-polarized pumps. Numerical simulations of the Manakov equation are supported by the experimental measurement of a ...

IEEE2015

System and method for producing optical sinc-shaped pulses

Luc Thévenaz, Mohammad Mehdi Alem Karladani, Marcelo Alfonso Soto Hernandez, Camille Sophie Brès, Mohammad Amin Shoaie

System and methods for producing a plurality of Sinc shaped pulses in the time domain include a light source for providing an input light signal having an input frequency, and at least one spectrum shaper for producing the plurality of Sinc shaped pulses f ...

United States Patent and Trademark Office2015

Mitigation of modulation instability in Brillouin distributed fiber sensors by using orthogonal polarization pulses

Luc Thévenaz, Mohammad Mehdi Alem Karladani, Marcelo Alfonso Soto Hernandez, Javier Urricelqui Polvorinos

A technique based on the use of orthogonally-polarized pulses is proposed to mitigate the detrimental impact of modulation instability on Brillouin distributed fiber sensors. While the theoretical underpinnings of the method are described by introducing a ...

SPIE2015

Analytical model and experimental verification of the critical power for modulation instability in optical fibers

Luc Thévenaz, Mohammad Mehdi Alem Karladani, Marcelo Alfonso Soto Hernandez

Modulation instability is thoroughly investigated and a simple analytical model for its power critically modifying the wave properties in terms of system parameters is derived and experimentally validated. The differences on the modulation instability gain ...

Optical Society of America2015

Towards highest spectral efficiency: Optical sinc-shaped Nyquist pulses generation from rectangular frequency comb

Luc Thévenaz, Mohammad Mehdi Alem Karladani, Marcelo Alfonso Soto Hernandez, Camille Sophie Brès, Mohammad Amin Shoaie

In this paper, we review a method to produce optical sinc-shaped Nyquist pulses with unprecedented quality. The method is based on the synthesis of a rectangular shaped and phase-locked frequency comb from a combination of intensity modulators. The result ...

IEEE2014

Modelling the depletion length induced by modulation instability in distributed optical fibre sensors

Luc Thévenaz, Mohammad Mehdi Alem Karladani, Marcelo Alfonso Soto Hernandez

An analytical model for the depletion length of modulation instability in single-mode optical fibres is proposed. The model gives the possibility to determine the maximum sensing distance that distributed optical fibre sensors can reach before being limite ...

SPIE2014

Optical sinc-shaped Nyquist pulses of exceptional quality

Luc Thévenaz, Mohammad Mehdi Alem Karladani, Marcelo Alfonso Soto Hernandez, Camille Sophie Brès, Mohammad Amin Shoaie

Sinc-shaped Nyquist pulses possess a rectangular spectrum, enabling data to be encoded in a minimum spectral bandwidth and satisfying by essence the Nyquist criterion of zero inter-symbol interference (ISI). This property makes them very attractive for com ...

Nature Research2013

Optical Nyquist-pulse generation with a power difference to the ideal sinc-shape sequence of < 1%

Luc Thévenaz, Mohammad Mehdi Alem Karladani, Marcelo Alfonso Soto Hernandez, Camille Sophie Brès, Mohammad Amin Shoaie

Sinc-shaped Nyquist-pulses possess a rectangular spectrum. Thus, a sinc-pulse transmission minimizes the carrier spacing down to the baud rate, and therefore, substantially increases the transmissible data rates. These perspectives have led to a strong res ...

VDE Verlag GmbH2013

Generation of Nyquist sinc pulses using intensity modulators

Luc Thévenaz, Mohammad Mehdi Alem Karladani, Marcelo Alfonso Soto Hernandez, Camille Sophie Brès, Mohammad Amin Shoaie

Optical sinc-shaped Nyquist pulses are produced based on the generation of an ideal frequency comb using cascaded intensity modulators. Nyquist pulses with 9.8-ps temporal width, 82-fs jitter and more than 40 dB SNR are achieved. ...

2013

Highly tunable method to generate sinc-shaped Nyquist pulses from a rectangular frequency comb

Luc Thévenaz, Mohammad Mehdi Alem Karladani, Marcelo Alfonso Soto Hernandez, Camille Sophie Brès, Mohammad Amin Shoaie

A method to produce highly-stable optical sinc-shaped pulses is proposed based on the generation of a rectangular-spectrum frequency comb. Nyquist pulses with

OSA2013

Mitigating modulation instability in Brillouin distributed fibre sensors

Luc Thévenaz, Mohammad Mehdi Alem Karladani, Marcelo Alfonso Soto Hernandez, Wei Chen

A thorough study of the generation of modulation instability (MI) in distributed Brillouin fibre sensors is presented. ASE noise co-propagating with the pump pulses within the MI gain spectrum has been identified to be an important factor seeding modulatio ...

Spie-Int Soc Optical Engineering2013

Optical sinc-shaped Nyquist pulses with very low roll-off generated from a rectangular frequency comb

Luc Thévenaz, Mohammad Mehdi Alem Karladani, Marcelo Alfonso Soto Hernandez, Camille Sophie Brès, Mohammad Amin Shoaie

High-quality optical sinc-shaped Nyquist pulses with a virtual zero roll-off factor are obtained from the generation of a phase-locked, rectangular-spectrum frequency comb. Tunability over more than 4 frequency decades is demonstrated with

Optical Society of America2013