M. López-Amo | Public University of Navarre (original) (raw)

Papers by M. López-Amo

Journal of Lightwave Technology, 2003

We report on a new concept for InGaAsP-InP 1.55-m lasers with integrated spot-size converters (SS... more We report on a new concept for InGaAsP-InP 1.55-m lasers with integrated spot-size converters (SSCs) based on antiresonant reflecting optical waveguides (ARROW). The mode expanders consist of a laterally tapered active region on top of a fiber-matched passive slab waveguide. The large slab mode is laterally confined by an antiresonant configuration of a couple of lateral waveguides defined in the same fabrication process as the active ridge. This feature makes the presented spot-size transformer as simple to fabricate as a standard waveguide, only requiring a planar growth step and a single conventional etch process. The fabricated tapers exhibit a low transformation loss and reduce the coupling loss to standard single-mode fibers from 8 to 4 dB. We also analyze by simulation two variants of the concept proposed in this work, including a taper structure for a buried waveguide, which are expected to show better performance. Simulation results show fiber-coupling efficiencies as low as 2.4 and 1.1 dB for both variants.

This paper presents the first optical fiber sensor gateway for integrating these special measurem... more This paper presents the first optical fiber sensor gateway for integrating these special measurement devices in Home Automation Systems, concretely in those buildings that use the KNX European Intelligent Buildings Standard.

1998 International Conference on Applications of Photonic Technology III: Closing the Gap between Theory, Development, and Applications, 1998

ABSTRACT Influence of first order mode excitation in input/output waveguides of multimode interfe... more ABSTRACT Influence of first order mode excitation in input/output waveguides of multimode interference couplers is analyzed. Emphasis in common mode rejection ratio penalty in 3-dB couplers as part of balance coherent detection receivers is encountered. Design analysis is carried out in InGaAsP/InP buried waveguides. Coupler behavior is modified basically when first order mode is excited at input waveguides. A drastically reduction of 25% couplers width tolerance is derived from first order mode partial presence (10% of full input optical power) in accessing waveguides. Some guidelines about width tolerance improvement in restricted interference couplers against general interference couplers is also reported. Couplers dependence on fabrication tolerance was described as a function of power distribution between different modes in multimode section.

SPIE Proceedings, 1995

Variable delays in fiber optic optical transmission have been achieved by using photochromic- dop... more Variable delays in fiber optic optical transmission have been achieved by using photochromic- doped sol-gel silica glasses. Gaps between two commercial fibers in V-groove connectors, when filled with these materials, produce variable propagation times. Variations of the optical propagation time depending on the input power, wavelength, and dopant concentration are shown.

Optics Express, 2013

This work experimentally demonstrates a long-range optical fiber sensing network for the multiple... more This work experimentally demonstrates a long-range optical fiber sensing network for the multiplexing of fiber sensors based on photonic crystal fibers. Specifically, six photonic crystal fiber sensors which are based on a Sagnac interferometer that includes a suspended-core fiber have been used. These sensors offer a high sensitivity for microdisplacement measurements. The fiber sensor network presents a ladder structure and its operation mode is based on a fiber ring laser which combines Raman and Erbium doped fiber amplification. Thus, we show the first demonstration of photonic crystal fiber sensors for remote measurement applications up to 75 km.

IEEE Sensors Journal, 2003

Three networks based on fused biconical wavelength division multiplexers (WDMs) and fiber Bragg g... more Three networks based on fused biconical wavelength division multiplexers (WDMs) and fiber Bragg gratings (FBGs) are theoretically and experimentally demonstrated for photonic-intensity-sensor multiplexing. The aim of replacing standard couplers for WDMs in the power division process is to reduce power losses and improve the robustness of the systems to FBG wavelength shifts. The different network topologies are analyzed both in

IEEE Journal of Quantum Electronics, 2006

A two modes rate equation model for vertical-cavity surface-emitting lasers (VCSELs) subject to o... more A two modes rate equation model for vertical-cavity surface-emitting lasers (VCSELs) subject to optical feedback from an extremely short external cavity (ESEC) is presented. By making use of it we develop a map of bistability to investigate the parametric dependence of polarization properties of VCSELs in such configuration, finding out a periodic dependence of the polarization switching (PS) currents on the ESEC length. By increasing the external mirror reflectivity we can make this periodic dependence stronger and strongly asymmetric providing the possibility to prevent PS for any injection current achieving polarization stabilization in VCSELs. Further numerical simulations with isotropic and non isotropic feedback show how parameters as the compression coefficients, the frequency splitting between the linearly polarized (LP) modes, the differential gain and the top mirror reflection coefficient, affect the map of bistability.

Applied Physics Letters, 2007

The authors present experimental results showing that polarization selective optical feedback fro... more The authors present experimental results showing that polarization selective optical feedback from an extremely short external cavity induces switching between the two fundamental transverse modes with orthogonal linear polarization of the otherwise ͑without optical feedback͒ polarization stable vertical cavity surface emitting laser. Moreover, when properly selecting the external cavity length within a subwavelength range the polarization state of the emitted light can be chosen in either of the two fundamental transverse modes and stabilized against injection current variations. The numerical results reported are in good agreement with experiments.

Applied Optics, 2003

We propose a concept for InGaAsP-InP 1.55-microm lasers integrated with spot-size converters base... more We propose a concept for InGaAsP-InP 1.55-microm lasers integrated with spot-size converters based on modal interference between the modes of the structure formed by an active waveguide and an underlying fiber-matched antiresonant reflecting optical waveguide. Simulation results show that the spot-size converters exhibit low transformation loss, and narrowed far-field emission patterns (10 degrees x 20 degrees) and reduce the coupling loss to standard single-mode fibers from 8 to 2.6 dB over lengths approximately 200 microm shorter than the adiabatic concept. A tolerant design to fabrication variations is also proposed, which could be realized by standard processing techniques.

Applied Optics, 2003

A network for multiplexing fiber Bragg gratings (FBGs) and intensity-modulated fiber-optic sensor... more A network for multiplexing fiber Bragg gratings (FBGs) and intensity-modulated fiber-optic sensors with no need to distinguish between the two kinds of sensor is proposed and experimentally demonstrated. Two FBG sensors and two intensity-modulated sensors are wavelength-division multiplexed; the electrical phase of the output signal is measured as a common parameter for both types of sensor. Furthermore, the intensity sensors become power referenced, and the FBG sensors are interrogated by a low-cost technique. Low cross talk is achieved by use of a tunable optical filter at the detector.

2015 3rd Experiment International Conference (exp.at'15), 2015

23rd International Conference on Optical Fibre Sensors, 2014

Fiber Bragg Grating Sensors: Recent Advancements, Industrial Applications and Market Exploitation, 2011

Journal of Lightwave Technology, 2011

Different multiwavelength Raman fiber lasers based on a hybrid cavity setup are proposed. The las... more Different multiwavelength Raman fiber lasers based on a hybrid cavity setup are proposed. The lasing schemes are based in highly birefringent photonic crystal fiber loop mirrors combined with random cavities. The Hi-Bi PCF loop mirrors are characterized by an interferometric output; whereas the random mirrors are created by cooperative Rayleigh scattering due to Raman gain. This configuration allows suppression of Rayleigh associated noise growth, while taking advantage of it as an active part of the laser cavity, enhancing the achievable gain. The proposed fiber lasers present stable operation at room temperature although different output maxima and shapes depending on the fiber loop mirror/random mirror combination.

IEEE Photonics Technology Letters, 2000

A novel distributed optically amplified double-bus topology used for photonic sensor wavelength-d... more A novel distributed optically amplified double-bus topology used for photonic sensor wavelength-division multiplexing is proposed. This new topology virtually eliminates the received amplified spontaneous emission noise generated by the erbium-doped fiber used to provide amplification. This low-noise configuration yields signal-to-noise ratios over 54 dB and increases the number of sensors that could be multiplexed in a single structure. Furthermore, this improvement is done without increasing the complexity of the regular double-bus topologies. The performance of this new topology is compared to a previously reported optically amplified double-bus topology.

IEEE Photonics Technology Letters, 2001

A new technique is presented to make vertically coupled semiconductor microring resonators that e... more A new technique is presented to make vertically coupled semiconductor microring resonators that eases the fabrication process with devices more robust to ring-to-waveguide misalignments. Single-mode microring optical channel dropping filters are demonstrated for the first time in this configuration with Qs greater than 3000 and an on-resonance channel extinction greater than 12 dB. A 1 4 multiplexer/demultiplexer crossbar array with second-order microrings was also made and exhibited channel-to-channel crosstalk lower than 10 dB.

IEEE Journal of Selected Topics in Quantum Electronics, 2002

We report on a new concept for InGaAsP-InP 1.55-m lasers with integrated spot-size converters bas... more We report on a new concept for InGaAsP-InP 1.55-m lasers with integrated spot-size converters based on antiresonant reflecting optical waveguides (ARROWs). The mode expanders consist of a tapered active region on top of a fiber-matched passive vertical ARROW waveguide. The large fundamental leaky mode with its low propagation loss makes ARROW waveguides useful for fiber coupling functions and avoids typical growth-related problems as encountered with traditional designs. The tapers exhibit a low transformation loss and narrowed far-field emission patterns (10.4 22) and reduce the coupling loss to standard single-mode fibers from 8 to 2.6 dB. We also present the design and the results obtained with a relaxed ARROW design with thinner ARROW layers to reduce the overall layer stack thickness considerably, without affecting the fiber-coupling performance. The antiresonant effect has also been used for the lateral confinement of the fiber-matched mode. This feature makes the presented spot-size transformer as simple to fabricate as a standard waveguide, only requiring a planar growth step and a single conventional etch process. The fabricated tapers exhibit a low transformation loss and minimum far-field divergence angles of 13.8 30.8 , reducing the coupling loss to a standard single-mode fiber from 8 to 4 dB. We also analyze by simulation two variants of the concept proposed in this work, including a taper structure for a buried waveguide, which are expected to show better performance. Simulation results show fiber-coupling efficiencies as low as 2.4 and 1.1 dB and reduced far-field divergence angles as low as 7.2 14 and 7.2 9 for both variants.

Journal of Lightwave Technology, 2003

We report on a new concept for InGaAsP-InP 1.55-m lasers with integrated spot-size converters (SS... more We report on a new concept for InGaAsP-InP 1.55-m lasers with integrated spot-size converters (SSCs) based on antiresonant reflecting optical waveguides (ARROW). The mode expanders consist of a laterally tapered active region on top of a fiber-matched passive slab waveguide. The large slab mode is laterally confined by an antiresonant configuration of a couple of lateral waveguides defined in the same fabrication process as the active ridge. This feature makes the presented spot-size transformer as simple to fabricate as a standard waveguide, only requiring a planar growth step and a single conventional etch process. The fabricated tapers exhibit a low transformation loss and reduce the coupling loss to standard single-mode fibers from 8 to 4 dB. We also analyze by simulation two variants of the concept proposed in this work, including a taper structure for a buried waveguide, which are expected to show better performance. Simulation results show fiber-coupling efficiencies as low as 2.4 and 1.1 dB for both variants.

This paper presents the first optical fiber sensor gateway for integrating these special measurem... more This paper presents the first optical fiber sensor gateway for integrating these special measurement devices in Home Automation Systems, concretely in those buildings that use the KNX European Intelligent Buildings Standard.

1998 International Conference on Applications of Photonic Technology III: Closing the Gap between Theory, Development, and Applications, 1998

ABSTRACT Influence of first order mode excitation in input/output waveguides of multimode interfe... more ABSTRACT Influence of first order mode excitation in input/output waveguides of multimode interference couplers is analyzed. Emphasis in common mode rejection ratio penalty in 3-dB couplers as part of balance coherent detection receivers is encountered. Design analysis is carried out in InGaAsP/InP buried waveguides. Coupler behavior is modified basically when first order mode is excited at input waveguides. A drastically reduction of 25% couplers width tolerance is derived from first order mode partial presence (10% of full input optical power) in accessing waveguides. Some guidelines about width tolerance improvement in restricted interference couplers against general interference couplers is also reported. Couplers dependence on fabrication tolerance was described as a function of power distribution between different modes in multimode section.

SPIE Proceedings, 1995

Variable delays in fiber optic optical transmission have been achieved by using photochromic- dop... more Variable delays in fiber optic optical transmission have been achieved by using photochromic- doped sol-gel silica glasses. Gaps between two commercial fibers in V-groove connectors, when filled with these materials, produce variable propagation times. Variations of the optical propagation time depending on the input power, wavelength, and dopant concentration are shown.

Optics Express, 2013

This work experimentally demonstrates a long-range optical fiber sensing network for the multiple... more This work experimentally demonstrates a long-range optical fiber sensing network for the multiplexing of fiber sensors based on photonic crystal fibers. Specifically, six photonic crystal fiber sensors which are based on a Sagnac interferometer that includes a suspended-core fiber have been used. These sensors offer a high sensitivity for microdisplacement measurements. The fiber sensor network presents a ladder structure and its operation mode is based on a fiber ring laser which combines Raman and Erbium doped fiber amplification. Thus, we show the first demonstration of photonic crystal fiber sensors for remote measurement applications up to 75 km.

IEEE Sensors Journal, 2003

Three networks based on fused biconical wavelength division multiplexers (WDMs) and fiber Bragg g... more Three networks based on fused biconical wavelength division multiplexers (WDMs) and fiber Bragg gratings (FBGs) are theoretically and experimentally demonstrated for photonic-intensity-sensor multiplexing. The aim of replacing standard couplers for WDMs in the power division process is to reduce power losses and improve the robustness of the systems to FBG wavelength shifts. The different network topologies are analyzed both in

IEEE Journal of Quantum Electronics, 2006

A two modes rate equation model for vertical-cavity surface-emitting lasers (VCSELs) subject to o... more A two modes rate equation model for vertical-cavity surface-emitting lasers (VCSELs) subject to optical feedback from an extremely short external cavity (ESEC) is presented. By making use of it we develop a map of bistability to investigate the parametric dependence of polarization properties of VCSELs in such configuration, finding out a periodic dependence of the polarization switching (PS) currents on the ESEC length. By increasing the external mirror reflectivity we can make this periodic dependence stronger and strongly asymmetric providing the possibility to prevent PS for any injection current achieving polarization stabilization in VCSELs. Further numerical simulations with isotropic and non isotropic feedback show how parameters as the compression coefficients, the frequency splitting between the linearly polarized (LP) modes, the differential gain and the top mirror reflection coefficient, affect the map of bistability.

Applied Physics Letters, 2007

The authors present experimental results showing that polarization selective optical feedback fro... more The authors present experimental results showing that polarization selective optical feedback from an extremely short external cavity induces switching between the two fundamental transverse modes with orthogonal linear polarization of the otherwise ͑without optical feedback͒ polarization stable vertical cavity surface emitting laser. Moreover, when properly selecting the external cavity length within a subwavelength range the polarization state of the emitted light can be chosen in either of the two fundamental transverse modes and stabilized against injection current variations. The numerical results reported are in good agreement with experiments.

Applied Optics, 2003

We propose a concept for InGaAsP-InP 1.55-microm lasers integrated with spot-size converters base... more We propose a concept for InGaAsP-InP 1.55-microm lasers integrated with spot-size converters based on modal interference between the modes of the structure formed by an active waveguide and an underlying fiber-matched antiresonant reflecting optical waveguide. Simulation results show that the spot-size converters exhibit low transformation loss, and narrowed far-field emission patterns (10 degrees x 20 degrees) and reduce the coupling loss to standard single-mode fibers from 8 to 2.6 dB over lengths approximately 200 microm shorter than the adiabatic concept. A tolerant design to fabrication variations is also proposed, which could be realized by standard processing techniques.

Applied Optics, 2003

A network for multiplexing fiber Bragg gratings (FBGs) and intensity-modulated fiber-optic sensor... more A network for multiplexing fiber Bragg gratings (FBGs) and intensity-modulated fiber-optic sensors with no need to distinguish between the two kinds of sensor is proposed and experimentally demonstrated. Two FBG sensors and two intensity-modulated sensors are wavelength-division multiplexed; the electrical phase of the output signal is measured as a common parameter for both types of sensor. Furthermore, the intensity sensors become power referenced, and the FBG sensors are interrogated by a low-cost technique. Low cross talk is achieved by use of a tunable optical filter at the detector.

2015 3rd Experiment International Conference (exp.at'15), 2015

23rd International Conference on Optical Fibre Sensors, 2014

Fiber Bragg Grating Sensors: Recent Advancements, Industrial Applications and Market Exploitation, 2011

Journal of Lightwave Technology, 2011

Different multiwavelength Raman fiber lasers based on a hybrid cavity setup are proposed. The las... more Different multiwavelength Raman fiber lasers based on a hybrid cavity setup are proposed. The lasing schemes are based in highly birefringent photonic crystal fiber loop mirrors combined with random cavities. The Hi-Bi PCF loop mirrors are characterized by an interferometric output; whereas the random mirrors are created by cooperative Rayleigh scattering due to Raman gain. This configuration allows suppression of Rayleigh associated noise growth, while taking advantage of it as an active part of the laser cavity, enhancing the achievable gain. The proposed fiber lasers present stable operation at room temperature although different output maxima and shapes depending on the fiber loop mirror/random mirror combination.

IEEE Photonics Technology Letters, 2000

A novel distributed optically amplified double-bus topology used for photonic sensor wavelength-d... more A novel distributed optically amplified double-bus topology used for photonic sensor wavelength-division multiplexing is proposed. This new topology virtually eliminates the received amplified spontaneous emission noise generated by the erbium-doped fiber used to provide amplification. This low-noise configuration yields signal-to-noise ratios over 54 dB and increases the number of sensors that could be multiplexed in a single structure. Furthermore, this improvement is done without increasing the complexity of the regular double-bus topologies. The performance of this new topology is compared to a previously reported optically amplified double-bus topology.

IEEE Photonics Technology Letters, 2001

A new technique is presented to make vertically coupled semiconductor microring resonators that e... more A new technique is presented to make vertically coupled semiconductor microring resonators that eases the fabrication process with devices more robust to ring-to-waveguide misalignments. Single-mode microring optical channel dropping filters are demonstrated for the first time in this configuration with Qs greater than 3000 and an on-resonance channel extinction greater than 12 dB. A 1 4 multiplexer/demultiplexer crossbar array with second-order microrings was also made and exhibited channel-to-channel crosstalk lower than 10 dB.

IEEE Journal of Selected Topics in Quantum Electronics, 2002

We report on a new concept for InGaAsP-InP 1.55-m lasers with integrated spot-size converters bas... more We report on a new concept for InGaAsP-InP 1.55-m lasers with integrated spot-size converters based on antiresonant reflecting optical waveguides (ARROWs). The mode expanders consist of a tapered active region on top of a fiber-matched passive vertical ARROW waveguide. The large fundamental leaky mode with its low propagation loss makes ARROW waveguides useful for fiber coupling functions and avoids typical growth-related problems as encountered with traditional designs. The tapers exhibit a low transformation loss and narrowed far-field emission patterns (10.4 22) and reduce the coupling loss to standard single-mode fibers from 8 to 2.6 dB. We also present the design and the results obtained with a relaxed ARROW design with thinner ARROW layers to reduce the overall layer stack thickness considerably, without affecting the fiber-coupling performance. The antiresonant effect has also been used for the lateral confinement of the fiber-matched mode. This feature makes the presented spot-size transformer as simple to fabricate as a standard waveguide, only requiring a planar growth step and a single conventional etch process. The fabricated tapers exhibit a low transformation loss and minimum far-field divergence angles of 13.8 30.8 , reducing the coupling loss to a standard single-mode fiber from 8 to 4 dB. We also analyze by simulation two variants of the concept proposed in this work, including a taper structure for a buried waveguide, which are expected to show better performance. Simulation results show fiber-coupling efficiencies as low as 2.4 and 1.1 dB and reduced far-field divergence angles as low as 7.2 14 and 7.2 9 for both variants.