Papers by Roberto Rojas Laguna
Journal of Food Processing and Preservation
Latin America Optics and Photonics Conference, 2018
An angular deflection laser sensor in ring configuration is presented, based on a wavelength sele... more An angular deflection laser sensor in ring configuration is presented, based on a wavelength selective filter (WSF), which was manufactured by splicing a segment of thin core fiber (Thin-Core Fiber, TCF) between two segments of single-mode fiber SMF-28 (Single-Mode Fiber). A spectral shift of the thin core fiber modal interferometer TCFMI (Thin-Core Fiber Modal Interferometer) was obtained at different angles of deflection in steps of 17.86 µrad.
Laser Physics, 2016
In this experimental paper, a multi-wavelength erbium-doped ring fiber laser based on an all fibe... more In this experimental paper, a multi-wavelength erbium-doped ring fiber laser based on an all fiber intrinsic Fabry–Perot interferometer is presented and demonstrated. The interferometer was fabricated by an arc and splicing technique using hollow core photonic crystal fiber (HCPCF) and conventional single mode fiber (SMF28). The fiber laser can be operated in single, dual and triple lasing mode by applying a transversal load over the all fiber interferometer. The laser spectrums present minimal mode spacing of 1 nm, high wavelength stability and power fluctuations around 0.5 dB. The average signal to noise ratio (SNR) of the laser emissions spectrum is around 35 dB. This fiber laser offers low cost, compactness and high wavelength stability.
4th Iberoamerican Meeting on Optics and 7th Latin American Meeting on Optics, Lasers, and Their Applications, 2001
ABSTRACT
Optics Communications, 1997
The effect of nonlinear polarization rotation in a fiber loop mirror constricted from a low-biref... more The effect of nonlinear polarization rotation in a fiber loop mirror constricted from a low-birefringent fiber was numerically examined. We have shown that it provides in itself the intensity variation of the transmission coefficient from I to 0 in the configuration with a OS/OS coupler and a birefringent bias rotating polarization by 7r/2 at one end of the fiber. By appropriate choice of the fiber parameters both notmal and inverted characteristics of the interferometer can be achieved.
Optical Fiber Communications, OFC.
Summary form only given. A regenerator is an important element in the long-haul fiber communicati... more Summary form only given. A regenerator is an important element in the long-haul fiber communication systems. It must provide the conservation of the contrast between the pulses corresponding to logic ones and pulses corresponding to logic zeros; high enough level of the logic ones; and restoration of the pulses position in the sequence. To solve these problems a nonlinear element has to be used. Optical elements based on the nonlinear phenomena in fibers are preferable because of their high pulse repetition frequency operation. Recently elements based on the nonlinear interaction of solitons have been demonstrated. We discuss the possibility of using the SRS for this purpose. The scheme of the SRS-logic element is shown consisting of an SRS-amplifier, an SRS-generator, and a spectral filter transmitting the pump wavelength and rejecting the Stokes one.
Frontiers in Optics + Laser Science APS/DLS, 2019
Fiber optic sensor with an SC source through at 1km optical fiber to obtain a broad spectrum in t... more Fiber optic sensor with an SC source through at 1km optical fiber to obtain a broad spectrum in the 1300-1650 nm section for the realization of a displacement sensor by means of a Fabry-Perot interferometer.
Frontiers in Optics / Laser Science, 2018
A fiber optic laser arrangement for temperature sensing applications is presented. The multi-wave... more A fiber optic laser arrangement for temperature sensing applications is presented. The multi-wavelength spectrum has a SMSR of 40dB and moreover, the temperature generated tunable multi-wavelength effect, here, a sensitivity of 20pm/°C is achieved.
Frontiers in Optics / Laser Science, 2018
Supercontinuum generation was achieved with numerous setups of optical fibers which include SMF-2... more Supercontinuum generation was achieved with numerous setups of optical fibers which include SMF-28, high-Numerical Aperture and dispersion-shifted fiber. Supercontinuum flatness was studied by modifying the configurations and inducing fiber losses.
The Japan Society of Applied Physics, 2015
We show refractive-index tip sensor of an all Fabry-Perot(FP) interferometer made by conventional... more We show refractive-index tip sensor of an all Fabry-Perot(FP) interferometer made by conventional fiber and hollow-core photonic crystal fiber. We obtained two cavities that were formed at the conventional fiber tip using arc discharges by splicing tecnique and generate a Modified Intrinsic Fabry-Perot Interferometer(MIFPI). As a result of the interaction between these cavities was obtained a refractive index sensor. The MIFPI tip was immersed into a water-glycerol concentrations, these mixtures provided a refractive index variation. In addition, the MIFPI presents good resolution and sensitivity. The structure offers compactness, robustness, high repeatability, and stability measurement.
In this work, an Erbium doped ring fiber laser cavity based on in-line fiber optic interferometer... more In this work, an Erbium doped ring fiber laser cavity based on in-line fiber optic interferometer (IFOI) for multiwavelength operation is proposed. To fabricate the modal filter small sections of thin-core fiber (TCF) and no-core fiber (NCF) were used. The TCF is a highly Erbium doped fiber that generated special characteristics such as: side mode suppression ratio of 43.10 dB, low threshold (75mA), minimal power instabilities (0.47dB) and lower wavelength drift (0.1nm). By controlling the bending of the fiber filter and adjusting the polarization stage is possible to obtain: single, dual and triple laser emission. The laser offers compactness and low-cost implementation.
We present a multi-wavelength ring fiber laser cavity based on modified loop fiber optic interfer... more We present a multi-wavelength ring fiber laser cavity based on modified loop fiber optic interferometer. Here, the interferometer is composed by three segments: two thin-core fiber (TCF) sections and one no-core fiber (NCF) section, these fibers are arranged as follows: TCF-NFC-TCF, then this structure is set into a fiber loop. Hence, by using a conventional ring laser cavity the proposed fiber optic loop is seed. Afterward, by controlling the modal fiber curvature and the ring cavity polarization state: single, dual and triple lasing modes can be achieved. The laser offers good power and wavelength stability, the maximal variations are 0.2 nm and 0.12 dB.
In recent years, laser radiation has been proposed as a therapy tool in the medical field (laser ... more In recent years, laser radiation has been proposed as a therapy tool in the medical field (laser therapy). This work presents the efficiency of a pulsed fiber optic laser in its interaction with synthetic monosodium urate monohydrate (MSUM) crystals, for the management of inflammatory processes and lesions in tissues, muscles and osteoarticular joints affected by crystalline pathologies. The synthetic monosodium urate crystals were made based on the McCarthy method. Such samples were exposed to the direct radiation of the laser light source, whose characteristics are as follows: wavelength centered at λ = 1058 nm, pulse width of τ = 13 ns, repetition frequency of fR = 210 kHz and peak energy of EP = 55 nJ. This radiation is absorbed by the tissue, which produces a photochemical interaction at the molecular level in the crystalline formations. The exposure times were from 7 to 12 minutes, and the best exposure time was presented in 12 m. As a result, the photochemical interaction of ...
This work describes an experimental demonstration of transmission of High Definition Television s... more This work describes an experimental demonstration of transmission of High Definition Television signal using a microwave photonic filter in an optical fiber communication system. The transmission is carried out through 25-km of single-mode standard fiber. The effect of a photonic filter (notch filter), is generated by the use of a distributed feedback laser emitting at 1550 nm. The use of this wavelength causes that the chromatic dispersion parameter of the optical fiber be considerable, generating a periodic notch filter. The electrical bandwidth of each notch is in the order of GHz. Transmission of TV signal is carried out in the first notch window. The effect of notch filter is corroborated by means of a set of simulations with various fiber lengths. A potential application of this technique lies in the field of optical telecommunications to deliver services as Internet, TV, and data.
IEEE Sensors Letters, 2021
Journal of Stored Products Research, 2020
Abstract Radio frequency treatments were evaluated for the control of Sitophilus zeamais Motschul... more Abstract Radio frequency treatments were evaluated for the control of Sitophilus zeamais Motschulsky in white maize, and their effects on physiological and biochemical properties were evaluated. A 12 kW, 27.12 MHz radio frequency machine was used with an electrode gap of 20 cm; batches of 10 and 20 kg of white maize (11.8% moisture content, w.b.) were treated. Radio frequency heating treatments at 50 °C for 3 min or 60 °C in white maize were effective to achieve 100% mortality of Sitophilus zeamais 4th instar larvae. Significant changes were observed in the moisture content, water activity and color in the corn kernels after the treatments (P 0.05). Radio frequency has potential to be a postharvest treatment against this pest without damage to white maize.
Journal of Food Science, 2021
Dielectric properties (DPs) of fresh rabbit meat in the microwave range (0.5 to 20 GHz) were dete... more Dielectric properties (DPs) of fresh rabbit meat in the microwave range (0.5 to 20 GHz) were determined. Three different muscles (Biceps femoris, Tensor fasciae latae, and Longissimus thoracis) from California rabbits (male and female) were measured with the open-ended coaxial probe method at temperatures of 20, 40, and 60 °C. To assess the possible effect of age, females of 100 and 180 days old were analyzed. DPs were affected by frequency, muscle type, age, gender, and temperature (p < 0.05). Dielectric constant decreased with increasing frequency. Loss factor decreased from 0.5 to 2.5 GHz due to ionic conduction, followed by an increase up to 20 GHz, dominated by dipolar relaxation. PRACTICAL APPLICATION: These results are key parameters for further quality sensing applications and for heating processes of meat rabbit using microwaves. Longer penetration depths were achieved at 915 MHz; this frequency is recommended for further applications. Besides, dielectric properties have potential to be a tool for identification of gender and age for slaughtered rabbits.
Optics Communications, 2020
Abstract We introduce a photochemical alternative procedure for uric-acid crystals degradation by... more Abstract We introduce a photochemical alternative procedure for uric-acid crystals degradation by controlled exposure of pulsed near infrared radiation from a ring fiber laser. The laser provides a wide spectrum from 1050 nm to 1120 nm, this spectrum exhibits a burst pulsed response with a pulse packet frequency rate of 210 kHz and an internal pulse frequency of 29 MHz. To demonstrate the technique, uric acid crystals were prepared synthetically and exposed under different radiation conditions, then by using an effective digital image processing the samples are before and after compared. Results confirm it is possible to exponentially reduce the number of crystals by an adequate combination of energy and number of pulses. The technique offers the possibility to reduce up to 50 % of the initial uric acid in a long period of safety wavelength radiation.
Electronics, 2020
In this paper, we proposed a system to integrate optical and electronic instrumentation devices t... more In this paper, we proposed a system to integrate optical and electronic instrumentation devices to predict a mode-locking fiber laser response, using a remote data acquisition with processing through an artificial neural network (ANN). The system is made up of an optical spectrum analyzer (OSA), oscilloscope (OSC), polarimeter (PAX), and the data acquisition automation through transmission control protocol/internet protocol (TCP/IP). A graphic user interface (GUI) was developed for automated data acquisition with the purpose to study the operational characteristics and stability at the passively mode-locked fiber laser (figure-eight laser, F8L) output. Moreover, the evolution of the polarization state and the behavior of the pulses are analyzed when polarization is changed by proper control plate adjustments. The data is processed using deep learning techniques, which provide the characteristics of the pulse at the output. Therefore, the parameter classification-identification is in...
2018 Detroit, Michigan July 29 - August 1, 2018, 2018
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Papers by Roberto Rojas Laguna