I. Esquivias

Universidad Politécnica de Madrid

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Co-Authors

J. M. G. Tijero

Universidad Politécnica de Madrid

Antonio Pérez Serrano

Universidad Politécnica de Madrid

E.C. Larkins

University of Nottingham

L. Borruel

Universidad Politécnica de Madrid

S. Weisser

Nokia (Germany)

J. Rosenzweig

Fraunhofer Institute for Applied Solid State Physics

J.D. Ralston

Fraunhofer Institute for Applied Solid State Physics

A. Consoli

Universidad Rey Juan Carlos

M. Krakowski

III V Lab

H. Odriozola

Universidad Politécnica de Madrid

Cooperative Institutions

Universidad Politécnica de Madrid

Bellingham Technical College

Thales (France)

Fraunhofer Institute for Applied Solid State Physics

Alcatel Lucent (Germany)

University of Nottingham

III V Lab

Centre National de la Recherche Scientifique

Fraunhofer Society

Commissariat à l'Énergie Atomique et aux Énergies Alternatives

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Photo-induced electrical defects in low-temperature photochemical vapor-deposited silicon nitride films

Journal of Applied Physics (1990)

E. Iborra J. A. López-Rubio I. Esquivias J. Sanz-Maudes T. Rodrı́guez

The electrical properties of the photochemical vapor-deposited silicon nitride/silicon interface are presented as a function of deposition temperature (70 to 200 °C). High values of interface state density Nss (about 3×1012 cm−2 eV−1), an equivalent charge at the interface Qss (about 5×1011 cm−2), and an important injection-type hysteresis of the capacitance voltage C-V curves are observed in the as-grown material. Most defects are found to be generated during the deposition process by the ultraviolet illumination used to activate the chemical reaction of the gases. Low-temperature (250 °C) and short-time (30 min) annealings eliminate part of the defects, resulting in lower values of Nss (about 1×1012 cm−2 eV−1), Qss (about 5×1010 cm−2), and reduced injection-type hysteresis.

Hysteresis

Ultraviolet

10.1063/1.345627

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Citations (2)

Analysis of degradation mechanisms in high power AlGaAs 808 nm laser bars

J. M. Arias I. Esquivias Franz X. Daiminger S. Heineman E. Vassilakis

In this work we study the degradation mechanisms of 20 W CW AlGaAs linear array bars by analyzing the subthreshold Optical Power-Current-Voltage characteristics (P-I-V) at different aging times. The laser structure is a single quantum well graded index separate confinement heterostructure (SQW-GRINSCH) grown by metal organic chemical vapor deposition. Monolithic 1 cm linear array bars with multiple emitters were mounted p-side down onto high thermal conductivity submounts. Seven different laser bars coming from the same wafer were aged at a constant current of 30 A. The main optoelectronic characteristics (threshold current, slope efficiency, conversion efficiency, lasing wavelength) and the subthreshold P-I-V characteristics were measured as a function of the aging time. The spontaneous optical power emitted from the low-reflectivity facet and the external voltage were accurately measured at drive currents ranging between 1 nA and 1 A.

Subthreshold conduction

Quantum well laser

10.1109/leos.1997.645256

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Citations (1)

Low repetition rate optical frequency combs generated by pulsed gain-switching of semiconductor lasers

2022 28th International Semiconductor Laser Conference (ISLC) (2021)

Pablo López-Querol Clara Quevedo-Galán Antonio Pérez Serrano J. M. G. Tijero I. Esquivias

We report flat and wide low-frequency Optical Frequency Combs generated by pulsed gain-switching of optically injected semiconductor lasers. Combs as wide as 133 GHz at 100 MHz repetition rate and good quality combs at a record low frequency of 10 MHz were obtained.

Repetition (rhetorical device)

Semiconductor optical gain

Q-switching

10.1109/islc51662.2021.9615720

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Hot-cavity modelling of high-power tapered laser diodes using wide-angle 3D FD-BPM

J. Wykes L. Borruel S. Sujecki I. Esquivias P. Sewell

The effective design of high power tapered laser diodes requires a detailed understanding of the coupled nonlinear optical, electrical and thermal processes which take place in the cavity. These nonlinearities result in phenomena such as spatial hole burning, self-focussing and filamentation, all of which play a significant role at higher output powers. Consequently, care must be taken in optimising the design of these devices to maximise the output power whilst maintaining good beam quality. Simulation gives the device designer the ability to experiment with the numerous degrees of freedom available in the design of these laser diodes, thus minimising the expense and time incurred for fabrication.

Filamentation

10.1109/leos.2002.1133933

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Citations (3)

Optical properties of tapered laser cavities

IEE Proceedings - Optoelectronics (2003)

S. Sujecki E.C. Larkins T.M. Benson J. Wykes I. Esquivias

The properties of a tapered semiconductor laser cavity, which can be used to generate a high-brightness optical beam, are studied. The cavity consists of a narrow straight waveguide section and a tapered power amplifier section. The influence of the input waveguide width and length, as well as of the length and taper angle of the power amplifier section, on the overall performance of the cavity are discussed. Finally, the application of beam spoilers is studied. In order to solve the wave equation, the wide-angle-beam propagation method incorporating a higher-order finite-difference scheme is applied.

Beam propagation method

Waveguide

10.1049/ip-opt:20030387

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Citations (10)

High-frequency signal generation using 1550 nm VCSEL subject to two-frequency optical injection

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2013)

A. Consoli Ana Quirce Á. Valle I. Esquivias L. Pesquera

We experimentally investigate high-frequency microwave signal generation using a 1550 nm single-mode VCSEL subject to two-frequency optical injection. We first consider a situation in which the injected signals come from two similar VCSELs. The polarization of the injected light is parallel to that of the injected VCSEL. We obtain that the VCSEL can be locked to one of the injected signals, but the observed microwave signal is originated by beating at the photodetector. In a second situation we consider injected signals that come from two external cavity tunable lasers with a significant increase of the injected power with respect to the VCSEL-by-VCSEL injection case. The polarization of the injected light is orthogonal to that of the free-running slave VCSEL. We show that in this case it is possible to generate a microwave signal inside the VCSEL cavity.

Vertical-cavity surface-emitting laser

SIGNAL (programming language)

Injection locking

10.1117/12.2004010

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Modelling And Characterization Of High-speed GaAs And In/sub 0.35/Ga/sub 0.65/As Multiple-quantum-well Laser Diodes

A. Schönfelder S. Weisser I. Esquivias J.D. Ralston J. Rosenzweig

Modelling and experimental results are presented, comparing the performance of vertically compact, high-speed GaAs and Ina j,GN As multiple-quantum-well lasers. Both devices' show superior performance, although the advantages of replacing the GaAs quantum wells with paeudomorphic InG&s quantum wells are clearly demonstrated.

Characterization

Indium gallium arsenide

10.1109/leos.1992.693907

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Sound of lasers (SOL) — An audiovisual approach to semiconductor laser dynamics

A. Consoli Borja Bonilla Paloma R. Horche I. Esquivias

We present an educational software addressed to the students of optical communication courses, for a simple visualization of the basic dynamic processes of semiconductor lasers. The graphic interface allows the user to choose the laser and the modulation parameters and it plots the laser power output and instantaneous frequency versus time. Additionally, the optical frequency variations are numerically shifted into the audible frequency range in order to produce a sound wave from the computer loudspeakers. Using the proposed software, the student can simultaneously see and hear how the laser intensity and frequency change, depending on the modulation and device parameters.

Modulation (music)

10.1109/icl.2012.6402037

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Dynamical characterization of monolithic MOPAs emitting at 1.5 μm

J. Javaloyes M. Vilera A. Consoli P. Adamiec J. M. G. Tijero

Eye-safety requirements in important applications like LIDAR or Free Space Optical Communications make specifically interesting the generation of high power, short optical pulses at 1.5 μm. Moreover, high repetition rates allow reducing the error and/or the measurement time in applications involving pulsed time-of-flight measurements, as range finders, 3D scanners or traffic velocity controls [1]. The Master Oscillator Power Amplifier (MOPA) architecture is an interesting source for these applications since large changes in output power can be obtained at GHz rates with a relatively small modulation of the current in the Master Oscillator (MO). We have recently demonstrated short optical pulses (100 ps) with high peak power (2.7 W) by gain switching the MO of a monolithically integrated 1.5 μm MOPA [2]. Although in an integrated MOPA the laser and the amplifier are ideally independent devices, compound cavity effects due to the residual reflectance at the different interfaces are often observed [3,4], leading to modal instabilities such as self-pulsations [5-7].

Modulation (music)

10.1109/cleoe-iqec.2013.6800761

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Design and fabrication of high brightness semiconductor tapered lasers with a clarinet-like shape

L. Borruel I. Esquivias J. M. G. Tijero H. Odriozola M. Krakowski

In this letter we present a new fully index-guided tapered laser design showing a balance between the competing mechanisms modifying the far-field divergence at high operating powers. Simulations and experimental investigations of this device show a low divergence and a stable far-field along a high range of operating conditions, together with negligible astigmatism at high power.

Beam divergence

Divergence (linguistics)

10.1109/cleoe.2005.1567903

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