Search results for " coupler"
showing 10 items of 23 documents
Passive interferometric interrogation of a magnetic field sensor using an erbium doped fiber optic laser with magnetostrictive transducer
2015
Abstract An erbium doped (Er3+) fiber optic laser is proposed for magnetic field measurement. A pair of FBGs glued onto a magnetostrictive material (Terfenol-D rod) modulates the laser wavelength operation when subject to a static or a time dependent magnetic field. A passive interferometer is employed to measure the laser wavelength changes due to the applied magnetic field. A data acquisition hardware and a LabVIEW software measure three phase-shifted signals at the output coupler of the interferometer and process them using two distinct demodulation algorithms. Results show that sensitivity to varying magnetic fields can be tuned by introducing a biasing magnetic field. A maximum error o…
PLZT ceramics Fabry-Perot interferometers for visible and mid-infrared lasers
2001
Abstract Phenomena characteristic for thermo-optically and electro-optically tunable PLZT ceramics Fabry-Perot interferometers are analyzed, when these devices are used with Ar+ ion and solid state erbium lasers. A new original technique of Q-switching of mid-infrared solid state pulse lasers using a Fabry-Perot output coupler with integrated Q-switch function is reported.
Er:YAG laser giant-pulse generation
2002
Three possibilities of mid-infrared Er:YAG lasers Q-switching were investigated: mechanical and two electro-optical ones. The mechanical method of Q-switching was proved by using of a rotating mirror placed inside the resonator; Pockels or Kerr cells were used for the electro-optical Q-switching. The Pockels cell was constructed on the basis of the Brewster angle cut LiNb03 crystal; the Kerr cell used a ceramic PLZT material. In all the three cases the Er:YAG laser resonator was plan parallel and it consisted of the rear copper mirror and output coupler with 50-70% reflectivity. The Er:YAG crystal was pumped by one xenon flashlamp in a single elliptical silver coated cavity. The generated g…
Nonlocal density correlations as a signature of Hawking radiation from acoustic black holes
2008
We have used the analogy between gravitational systems and nonhomogeneous fluid flows to calculate the density-density correlation function of an atomic Bose-Einstein condensate in the presence of an acoustic black hole. The emission of correlated pairs of phonons by Hawking-like process results into a peculiar long-range density correlation. Quantitative estimations of the effect are provided for realistic experimental configurations.
Wavelength-flattened directional couplers for mirror-symmetric interferometers
2005
In the context of guided optics, we derive, analytically and geometrically, a rigorous general criterion to design wavelength insensitive interferometers with mirror symmetry, which are needed for wavelength multiplexing/demultiplexing. The criterion is applied to a practical case, resulting in an interferometer that works on a band wider than 70 nm.
Tunable arrayed waveguide grating driven by surface acoustic waves
2016
We present a design approach for compact reconfigurable phased-array wavelength-division multiplexing (WDM) devices with N access waveguides (WGs) based on multimode interference (MMI) couplers. The proposed devices comprise two MMI couplers which are employed as power splitters and combiners, respectively, linked by an array of N single-mode WGs. First, passive devices are explored. Taking advantage of the transfer phases between the access ports of the MMI couplers, we derive very simple phase relations between the arms that provide wavelength dispersion at the output plane of the devices. When the effective refractive index of the WGs is modulated with the proper relative optical phase d…
Evaluation of performance of a hybrid electro-optic directional coupler and a Mach–Zehnder switch
2017
The efficiency of an electro-optic (EO) directional coupler (DC) and a Mach–Zehnder (MZ) switch is discussed. The specific designs employ a passive waveguide core and an EO cladding. The performance of a DC switch was evaluated by numerical methods, namely coupled mode theory (CMT), eigenmode expansion (EME) method, and beam envelope method. Using the CMT and EME methods, it is shown that in the DC with a passive waveguide core and EO cladding at certain waveguide parameters the switching effect does not take place. The effect is demonstrated for the first time and suggests that careful optimization of the DC switch should be done before experimental realization of the device. The efficienc…
Design scheme for Mach–Zehnder interferometric coarse wavelength division multiplexing splitters and combiners
2006
I propose an analytical approach to design flattened wavelength splitters with cascaded Mach–Zehnder inter- ferometers when wavelength dependence of the directional couplers cannot be neglected. I start from a geo- metrical representation of the action of a doubly point-symmetrical filter, assuming no wavelength dependence of the couplers. Next I derive the analytical formulas behind its working principle and extend them to the wavelength-dependent case. I also show how the geometrical representation allows one to broaden the class of working structures. © 2006 Optical Society of America
Integrated photonic routers driven by surface acoustic waves
2016
Durante la segunda mitad del siglo XX se produjo un desarrollo excepcional de la capacidad de transmitir y procesar información electrónicamente. Esto fue debido en parte a la capacidad de integrar en un único substrato una gran cantidad de transistores, que son las unidades fundamentales de procesamiento de datos. Este comportamiento quedó resumido en la ley de Moore, que predecía que el número de transistores integrados se duplicaría cada 24 meses. Esta tendencia, que se ha mantenido hasta la actualidad con transistores de tamaño nanométrico, no puede continuar indefinidamente. Uno de los problemas fundamentales reside en la capacidad limitada para disipar el calor que generan los disposi…
Titanium Dioxide Waveguides for Data Transmissions at 1.55 µm and 1.98 µm
2017
International audience; We demonstrate error free transmissions of 10 Gbps signals in titanium dioxide waveguides at wavelengths of 1.55 or 2 µm. An efficient coupling of light is achieved thanks to metal grating couplers and we have checked that the component could be used with standard CWDM SFP+ devices.