Abstract: Disclosed herein is an optical frequency shifter (1) provided with: an electro-optical substrate (3) having a main surface (3a); an optical waveguide structure (2) formed in the substrate (3) and having two waveguide portions (7), which are spaced apart by a distance (S) such as to ensure mutual optical coupling therebetween; and an electrode structure (10) arranged above the main surface (3a) of the substrate (3) and having at least a first electrode (11). The substrate (3) has a Z-cut crystalline structure with Z crystal axis orthogonal to the main surface (3a) and comprises two oppositely poled portions (20, 21) having opposite orientations of the Z crystal axis; the two waveguide portions (7) are arranged underneath the first electrode (11), each in a respective one of the two oppositely poled portions (20, 21).

Abstract: An optical modulator comprising an input suitable to receive an optical carrier, and two Mach-Zender modulators in parallel, which constitute two different optical paths, the whole circuit constituting a third Mach-Zender modulator, the optical modulator being characterized in that: the first Mach-Zender modulator is provided with an electrode suitable to carry two signals, each obtained by the sum of the two tones fR and fD, of equal power but dephased of ?/2, and with an electrode for realizing a Single Side Band modulation of the tones fR and fD; the second Mach-Zender modulator is biased by means of a DC electrode; the third Mach-Zender modulator comprising an electrode suitable to realize the reversal of the optical carrier phase of the signals deriving from the first and the second Mach-Zender modulator, so as to suppress the optical carrier and thus obtaining only the tones fR and fD in the optical spectrum.

Abstract: The invention concerns a Optical modulator, comprising an input suitable to receive an optical carrier, a high-frequency input and an output suitable to transmit an optical signal, the optical modulator comprising two Mach-Zender (1,2) modulators in parallel between the input and output, which constitute two different optical paths, the whole circuit constituting a third Mach-Zender modulator (3), the optical modulator being characterised in that: the first Mach-Zender modulator (1) is provided with an electrode suitable to carry, inside the modulator (1), two signals (RF1, RF2), each obtained by the sum of the two tones fR and fD, of equal power but dephased of ?/2, being further provided an electrode (Bias 1) for realising a Single Side Band modulation of the tones fR and fD; the second Mach-Zender modulator (2) is provided with an electrode (Bias 2) to realise statically a phase inversion of the optical carrier; the third Mach-Zender modulator (3) comprising an electrode (Bias 3) suitable to realise the

Abstract: Disclosed herein is an optical frequency shifter (1) provided with: an electro-optical substrate (3) having a main surface (3a); an optical waveguide structure (2) formed in the substrate (3) and having two waveguide portions (7), which are spaced apart by a distance (S) such as to ensure mutual optical coupling therebetween; and an electrode structure (10) arranged above the main surface (3a) of the substrate (3) and having at least a first electrode (11). The substrate (3) has a Z-cut crystalline structure with Z crystal axis orthogonal to the main surface (3a) and comprises two oppositely poled portions (20, 21) having opposite orientations of the Z crystal axis; the two waveguide portions (7) are arranged underneath the first electrode (11), each in a respective one of the two oppositely poled portions (20, 21).

Abstract: A system based on integrated optical technologies for the measurement and diagnostics of physical parameters on whatever structure, by the use of optical sensors, made by the fiber embedded Bragg grating method and by the use of a planar integrated optics device for the analysis of the optical signal. The sensors may be embedded or bonded to the structure, allowing the measurement of parameters like strain and temperature, in either a static or dynamic regime. The system pertains to the technical field of the diagnostics and measurements of mechanical or thermal parameters and to the application field of ground, water and aerospace transportation and also to the application field of construction.

Abstract: An embedded optical sensor has a plurality of layers 10-20 and an optical fiber 21 with a fiber grating 28, disposed between the layers 14,16. The layers 10-20 comprise filaments 22 and resin 24 which have different thermal expansion coefficients and the filaments 22 are oriented so as to create unequal transverse residual stresses that act through the geometry of a resin-rich region that surrounds on the grating 28 in the fiber 21. The unequal transverse residual stresses cause birefringence in the grating 28, thereby causing the grating 28 to reflect light 32 having two wavelengths with a predetermined separation, each along a different polarization axis. The wavelength separation and average wavelength between such separation have different sensitivities to temperature and strain, thereby allowing independent temperature and strain measurements using only a single grating.

Abstract: A manufacturing process for high performance single mode channel optical guides of the LiNbO.sub.3 using five successive steps: photo-etched optical path definition, deposition of the dielectric layer, lift-off definition of the channels, proton exchange and thermal cycling. The method can be used to produce multi-function devices to be interfaced with optical fibers to obtain sensors, telecommunications devices and devices for processing wide-band microwave signals the proton exchange is affected in benzoic acid diluted with lithium benzoate and eliminates the time instability of the electro-optical structure due to the presence of an insulating layer above the optical guide.

Abstract: Lithium niobate is Li.sup.+ /H.sup.+ proton exchange in two stages. The first masked stage is a treatment with benzoic acid followed by a thermal treatment in oxygen at about 400.degree. C. The thermal treatment is followed by masking a second coincident area and treating that area in a second Li.sup.+ /H.sup.+ proton exchange with benzoic acid and lithium benzoate without altering the refractive index of the region outside the second area.