44 results about "Propagation constant" patented technology

The invention relates to the technical field of antenna control, and discloses a control method for a leaky-wave antenna and a communication device. The method comprises the following steps: measuring the dispersion characteristic of the leaky-wave antenna, establishing a second-order nonlinear mapping relation between a propagation constant and a control voltage, and obtaining a dispersion control parameter group; reversely deducing the target beam directional angle to obtain a target propagation constant, and calculating an initial voltage value of each control unit in combination with the parameter group to form a voltage gradient control sequence; correcting the propagation constant of each unit by adopting a distance compensation algorithm, and recalculating to obtain distance self-adaptive voltage distribution data; and detecting a beam quality factor in real time, updating voltage distribution data through a gradient descent algorithm when the beam quality factor deviates from a target value, and outputting a control voltage sequence to drive each control unit. The leaky-wave antenna control method and device solve the problems that in an existing leaky-wave antenna control technology, the beam quality is reduced and the data rate is sharply attenuated during long-distance transmission, and the beam control precision and the long-distance transmission performance of the leaky-wave antenna in the terahertz frequency band are improved.

A non-interferometric thin film lithium niobate electro-optical modulator for data transmission including a laser, configured to generate an input continuous wave light beam; a non-interferometric thin film lithium niobate modulator including an optical waveguide situated along with the coplanar transmission lines and the DC bias conductors. The propagation constant of the optical waveguide is tuned and modulated by the RF data signal and the DC bias voltage traveling on the coplanar transmission lines and the DC bias conductors. The modulator can be tuned at quadrature point by the DC bias voltage. The optical power can be modulated by the RF data signal travelling on the coplanar transmission line; a low noise RF amplifier for data signal amplification; and a bias tee for combining the data signal and DC bias voltage and send them to the coplanar transmission lines.

The invention relates to the field of power line channel modeling, in particular to a power line channel modeling method, system, equipment and medium, power line channel data is actually measured and collected and preprocessed, channel characteristics are extracted, parameters such as characteristic impedance and propagation constant of a power line are calculated by using a transmission line theory, and the power line channel is modeled. Constructing an enhanced conditional generative adversarial network comprising a generator and a discriminator, inputting parameters obtained by theoretical calculation of a transmission line as conditional information in a training process, optimizing structures and loss functions of the generator and the discriminator, enabling the generator to generate a high-quality analog channel sample, fusing a deep learning model with a transmission line theoretical model, and obtaining a high-quality analog channel sample; according to the method, a mixed channel model is formed, model parameters are alternately trained and optimized, accurate prediction of transmission characteristics of the power line channel is realized, complex characteristics of the power line channel can be effectively modeled, and a reliable basis is provided for design optimization of a power line communication system.

The present invention discloses a closed-loop polarization-protected optical fiber temperature sensor with a linear structure, belonging to the field of optical fiber temperature sensors. The sensor comprises: transmitting two orthogonal polarized lights through the fast and slow axes, modulating the two orthogonal polarized lights with a preset modulation signal, rotating the two orthogonal polarized lights by 45 degrees, and transmitting the two orthogonal polarized lights, spliced ​​together through a 45-degree optical fiber connector, at different speeds through the optical fiber fast and slow axes. The difference in propagation constants of the two orthogonal polarized lights within the PM sensing fiber is proportional to the temperature. The two orthogonal polarized lights are reflected and returned along their original paths, and the orthogonal polarized lights output by the fast and slow axes are exchanged to generate an output optical signal, which is then demodulated and calculated to obtain the current temperature. Thus, the sensor utilizes a reciprocal structure to suppress noise and interference in the optical path, overcoming the defect that the system's cosine response is insensitive to small temperature changes. Accurate measurements can be provided in microwave, radio frequency, and electromagnetic interference environments.

To provide an irreversible transmission line having a two-dimensional structure and capable of uniformly distributing an electromagnetic field in a two-dimensional plane.SOLUTION: An irreversible transmission line includes first and second transmission lines that are orthogonal to each other by configuring basic cells having two transmission line portions that are orthogonal to each other and have parallel branch circuits so as to be juxtaposed and cascaded in orthogonal first and second directions. The transmission line part at a position other than an intersection point of the first and second transmission lines is formed of a material magnetized by spontaneous magnetization or the like so as to have gyro anisotropy by being magnetized in a different direction with respect to a propagation direction of a microwave. In a dispersion curve indicating a relationship between an operating frequency of a microwave signal input to each transmission line and a propagation constant of each transmission line, at least one of the parallel branch circuits of each transmission line is configured such that a wave component propagating along each of the parallel branch circuits in a longitudinal direction of each transmission line has an irreversible characteristic and is asymmetrical with respect to the transmission line portion.SELECTED DRAWING: Figure 5

The invention provides a design method of a wave-absorbing material based on fractal geometry, the wave-absorbing material is formed by periodically arranging three-dimensional unit cell structures in a plane, and the unit cell structures are layered structures; comprising the following steps: determining an impedance gradient correction coefficient of each layer of a unit cell structure according to layer structure parameters and fractal dimensions of the unit cell structure of the wave-absorbing material; determining equivalent electromagnetic parameters of each layer of the unit cell structure according to the intrinsic electromagnetic parameters of each layer and the layer structure parameters; determining a complex propagation constant and an intrinsic impedance of each layer of the unit cell structure by using the equivalent electromagnetic parameter and the working frequency; the input impedance of the surface layer of the unit cell structure is determined by using the impedance gradient correction coefficient, the complex propagation constant, the intrinsic impedance and the layer structure parameters of each layer of the unit cell structure, and then the surface reflectivity and the reflection loss are determined; judging whether the wave-absorbing material meets the working frequency band index requirement or not, if not, continuing to optimize the unit cell structure until the unit cell structure meets the working frequency band index requirement, and completing the design of the wave-absorbing material.

The application provides a design method of a wave-absorbing material based on fractal geometry, the wave-absorbing material is composed of a periodic arrangement of a three-dimensional unit cell structure in a plane, and the unit cell structure is a layered structure; the method comprises the following steps: determining impedance gradient correction coefficients of each layer of the unit cell structure according to layer structure parameters and a fractal dimension of the unit cell structure of the wave-absorbing material; determining equivalent electromagnetic parameters of each layer of the unit cell structure according to intrinsic electromagnetic parameters and layer structure parameters of each layer; determining complex propagation constants and intrinsic impedances of each layer of the unit cell structure by using the equivalent electromagnetic parameters and a working frequency; determining an input impedance of a surface layer of the unit cell structure by using the impedance gradient correction coefficients, the complex propagation constants, the intrinsic impedances and the layer structure parameters of each layer of the unit cell structure, and then determining surface reflectivity and reflection loss; determining whether the wave-absorbing material meets working frequency band index requirements, and if not, continuously optimizing the unit cell structure until the unit cell structure meets the working frequency band index requirements, and completing the design of the wave-absorbing material.

A system including a mode coupler has at least one waveguide section connected between a mode coupler input and a mode coupler output. The waveguide section supports a set of guided coupler modes and a set of cutoff coupler modes, and has a transverse refractive index profile and a longitudinal refractive index profile. The transverse refractive index profile is adjusted by free-form optimization to yield a set of desired spacings between a set of propagation constants of the sets of coupler modes such that the longitudinal refractive index profile induces desired couplings between the guided coupler modes, while inhibiting undesired couplings between the guided coupler modes and the cutoff coupler modes, and undesired couplings between the guided coupler modes.

The present disclosure relates to a method for obtaining a wave speed or propagation velocity in a power grid comprising a transmission line connected between two buses comprising determining a voltage and current at at least one bus, determining a propagation constant5 using the voltage and the current, determining line parameters based on the propagation constant and determining a wave speed or propagation velocity based on the line parameters. The disclosure also relates to a corresponding storage medium, device and power grid.

The invention discloses a broadband self-imaging device based on combined waveguide induced zigzag gradient scalar potential, a preparation method and application, and belongs to the technical field of laser processing, the broadband self-imaging device comprises n periodically arranged imaging units, each imaging unit comprises m combined waveguides, and the coupling distance between the adjacent combined waveguides is d; each combined waveguide is formed by splicing two waveguides with circular cross sections at a center-to-center distance a; in a single imaging unit, the center distance a of the combined waveguides is gradually increased from the first waveguide to the mth waveguide at a fixed step length, so that the propagation constant beta of the combined waveguides is in gradient distribution, a propagation constant gradient delta beta is formed in each imaging unit, Bloch oscillation can be triggered when optical signals are transmitted in the imaging units, and when the optical signals are transmitted to LBloch, the propagation constant gradient delta beta is not changed. And the wave packet shrinks to a light field distribution state which is the same as that of the initial input light signal, so that self-imaging is realized. The periodically distributed zigzag gradient potential is introduced into the waveguide array by using the combined waveguides with different center distances, the self-imaging waveguide array can be expanded infinitely and periodically, and large-scale and multi-channel parallel signal transmission can be realized.

The embodiment of the invention provides a data processing method, device and equipment applied to cable insulation aging monitoring. The method comprises the following steps: acquiring initial geometric parameters of a clamp, acquiring temperature data of the clamp, and acquiring an initial reflection coefficient of electromagnetic waves between an insulating sheet of a cable and air; correcting the initial geometric parameters according to the temperature data to obtain corrected geometric parameters, and determining corrected characteristic impedance and a corrected propagation constant according to the corrected geometric parameters; according to the corrected geometric parameters, the corrected characteristic impedance, the corrected propagation constant and the initial reflection coefficient, the intrinsic impedance of the insulating sheet is determined; determining a complex dielectric constant of the insulating sheet according to the intrinsic impedance, and determining an insulation aging index according to the complex dielectric constant; wherein the insulation aging index is used for monitoring the insulation aging degree of the cable. The method is used for achieving the effect of improving the accuracy of cable insulation aging monitoring.

The invention discloses a miniaturized metasurface broadband wide-angle scanning circularly polarized antenna, and belongs to the technical field of antennas. A wide-angle scanning phased-array antenna can be formed by using the miniaturized metasurface broadband wide-angle scanning circularly polarized antenna as a unit. The miniaturized metasurface broadband wide-angle scanning circularly polarized antenna comprises three layers of dielectric plates, four metal layers and a group of metalized via holes. And by utilizing the non-linear characteristic of a metasurface dispersion curve, the first-order resonant frequency and the second-order resonant frequency are fused to realize broadband radiation. The metasurface antenna is miniaturized by increasing the propagation constant, so that the array element spacing in the array is reduced, and wide-angle scanning is realized. The invention has the characteristics of few layers, small size, large bandwidth, wide-angle scanning and the like.

A high-conversion-efficiency integrated frequency comb device (100; 200; 310a – 310c) comprises at least one micro-resonator (120; 220) configured to receive pump laser light from at least one pump laser source, convert at least partially the received pump laser light for generating a laser frequency comb, and output frequency comb light based on the produced laser frequency comb. The micro-resonator (120; 220) comprises at least one closed-circuit waveguide (122; 222) integrated in a semi-conductor topography of the micro-resonator (120; 220). The closed-circuit waveguide (122; 222) comprises at least one structure for producing periodic perturbation (124; 224) configured to produce mode hybridization via coupling of forwards and backwards travelling modes in the closed-circuit waveguide (122; 222) by means of rapid, in particular sub-wavelength, modulation of a propagation constant of light propagating in the closed-circuit waveguide (122; 222). The structure for producing periodic perturbation (124; 224) has been designed with respect to at least one of an intended width, in terms of comb lines, of the frequency comb and / or an intended intensity distribution within a target width, in terms of comb lines, of the frequency comb, based at least partially on the stipulation that a dispersion-loss operator to achieve an ideally flat microcomb according to an exact solution of a generalized Lugiato-Lefever Equation exists in the form [iD+K], and, as a function of resonator mode index μ, the dispersion-loss operator takes the following generic form: wherein a, b, c, d 3 ... d ∞ , h, p, q, r, s, u 3 , u ∞ are constants, and μ ≤ N / 2 for N being the number of intended comb lines apart from a potential comb line corresponding to the pump laser light.

The invention provides a circuit board measuring piece set and a circuit board measuring method. The circuit board measurement method comprises the following steps: measuring a first measurement scattering parameter of a first measurement circuit board through a single port; measuring a second measurement scattering parameter of the second measurement circuit board through the single port; measuring a third measurement scattering parameter of a third measurement circuit board through a single port; according to the first measurement scattering parameter, the second measurement scattering parameter and the third measurement scattering parameter, calculating a characteristic impedance value, a tail end inductance impedance value and a propagation constant of the coaxial through hole of the circuit board; according to the circuit board measuring piece group and the circuit board measuring method, the electrical parameter of the coaxial through hole can be calculated by using the single-port measuring result, so that a reliable and simple verification tool and method are provided.

The invention belongs to the technical field of integrated photoelectronics, and particularly relates to an optical waveguide device based on a uniform adiabatic degree criterion. The physical contour of the optical waveguide device is a direct materialization or projection of a uniform adiabatic degree criterion in a three-dimensional space, and a curve of a geometric gradient rate dw / dz of the physical contour is completely consistent with a curve of a propagation constant difference delta beta (z) of an interaction mode in the device in form; at places with large delta beta (z), namely the two ends, the structure changes severely; and the structure change is extremely gentle in a place with small delta beta (z), namely a mode hybridization region. According to the method, the device design is improved from geometric fitting to physical criterion driving for the first time. Because each point of the device is in an appropriate'critical adiabatic 'state, no length of any micrometer is wasted on'excessive adiabatic'. This ensures that the total length of the device approaches the theoretically minimum size under a given performance index.

The application provides a flexible direct current line frequency variable parameter identification method and system, belongs to the parameter identification technical field of power grid transmission lines, and changes the number and state of equivalent redundant sub-modules input by each bridge arm; according to the number and state of the input half-bridge sub-modules, a voltage characteristic signal of a direct current line is injected; according to the injected voltage characteristic signal, in combination with a mathematical model of a distributed parameter transmission line, characteristic impedance, propagation constant and attenuation constant corresponding to the frequency of the injected voltage characteristic signal are calculated; and according to the characteristic impedance at different frequencies calculated by injecting voltage characteristic signals at different frequencies for multiple times, the characteristic impedance in the full frequency domain is fitted. The application solves the problem that parameters are difficult to obtain due to the absence of a stable fundamental frequency in a direct current system, and improves the frequency variable parameter identification precision of the flexible direct current line.

The invention discloses a two-port radio frequency device de-embedding method. The method comprises the following steps: calculating characteristic impedance and a propagation constant of a transmission line of a section corresponding to a port through a two-dimensional section solver; calculating an equivalent electromagnetic wave wavelength at the port according to the propagation constant; modifying an original layout, and expanding a port outwards by the length of a half wavelength; setting excitation at a port of the expanded layout, and simulating through a moment method to obtain scattering parameters of a device corresponding to the layout at the moment; and stripping the influence of the added transmission line through matrix operation to obtain a scattering parameter of a device corresponding to the original layout so as to finish a de-embedding process. The invention also discloses a device based on the method, electronic equipment and a storage medium. According to the method, the influence of the lumped excitation source on the scattering parameters of the radio frequency device in the moment method simulation process can be effectively stripped, so that the simulation result is more accurate.

Technologies for a compact and low-crosstalk multilayer waveguide stack are disclosed. In an illustrative embodiment, a photonic integrated circuit (PIC) die includes a 3D array of waveguides arranged in a multilayer stack. Individual waveguides have a propagation constant different from the propagation constant of neighboring waveguides, which can reduce crosstalk between neighboring waveguides. In an illustrative embodiment, the propagation constant can be controlled by changing the width of individual waveguides. In other embodiments, the propagation constant can be controlled by changing any suitable parameter, such as the height of the waveguides, the core of the waveguides, the cladding of the waveguides, etc.

The invention is applicable to the technical field of semiconductor lasers, and provides a cascade coupling super-symmetric semiconductor laser, which comprises a main waveguide region, an N-type waveguide region, an active region and a P-type waveguide region, the cascade super-pairing array comprises super-pairing waveguides and super-pairing waveguide spacer regions, the cascade super-pairing array is formed by multiple cascade coupling transformation, the coupling transformation forms main waveguide region lasing mode, competition mode coupling and coupling waveguide, the coupling waveguide has an optical propagation constant similar to that of the competition mode, and the coupling waveguide has an optical propagation constant similar to that of the competition mode. The coupling module is used for realizing coupling loss of a competition mode; and the main waveguide region lasing mode and the coupling waveguide are combined to form a main waveguide region for next coupling transformation, so that multiple cascade coupling transformation is carried out and a large mode discrimination capability is obtained. Therefore, multiple times of coupling of a main waveguide competition mode can be realized through multiple times of cascade coupling conversion, and the single transverse mode characteristic of the semiconductor laser is further improved.

Embodiments of the present application provide a lithium niobate dispersion compensation method, system, device and storage medium, belonging to the technical field of integrated photonics. The method comprises: obtaining the mode effective refractive index of the target lithium niobate waveguide in a preset frequency spectrum range, and calculating the corresponding propagation constant based on the mode effective refractive index to construct a mode dispersion function; calculating the phase mismatch parameter corresponding to each frequency point based on the mode dispersion function, and constructing a frequency domain phase mismatch distribution function based on the phase mismatch parameter of each frequency point; generating a phase compensation amount corresponding to each frequency point based on the frequency domain phase mismatch distribution function; generating a modulation control parameter based on the phase compensation amount, and applying it to the lithium niobate waveguide to achieve dispersion compensation. The present application scheme realizes continuous compensation of phase mismatch of each frequency component in a wide frequency range, and changes the phase matching from local effectiveness to consistency in the whole frequency domain.

This invention discloses an on-chip optical phased array device based on phase change materials and its control method. The device includes an input waveguide, a beam splitter network, arrayed waveguide arms, a phase modulation unit, and an output grating radiation structure. The output grating radiation structure integrates a phase change material. Changes in the phase state, crystallinity, or spatial distribution of the phase change material are used to alter the equivalent refractive index, propagation constant, radiative coupling strength, or phase matching conditions of the output grating region, thereby achieving second-dimensional output angle adjustment at a fixed operating wavelength. This invention not only eliminates the dependence on tunable lasers but also possesses advantages such as simplified structure, ease of integration, non-volatile state preservation, zero static power consumption, and greater suitability for engineering implementation. It provides a new implementation path for on-chip two-dimensional optical phased arrays and has good application value and promising prospects for widespread application.

The purpose of the present disclosure is to provide a multicore optical fiber which enables suppression of crosstalk between a core and a marker and easy confirmation of the marker, and a marker identification method for the multicore optical fiber.　A multicore optical fiber (10) comprises: a plurality of communication cores (11); a cladding (12) that surrounds the communication cores (11); and at least one marker core (13) that is provided to the cladding (12). A normalized propagation constant (b) of the marker core (13) is b≤0.2 in a communication wavelength band of the communication cores (11), and is b>0.2 at at least one wavelength in a region having a wavelength shorter than that of the communication wavelength band of the communication cores (11).

Embodiments relate to generating a configuration of waveguide propagation constants formed in a waveguide array system. The configuration of propagation constants can be made via a recursive detuning process that produces approximations to a fractal structure designed to maximally localize eigenstates of a waveguide array. The eigenstates being maximally localized enables strong suppression of crosstalk between the waveguides. Performing more detuning iterations can produce a configuration of propagation constants that better approximates the fractal structure and suppresses crosstalk over larger distances.

The invention relates to a structure for compensating impedance discontinuity of a three-dimensional coaxial interconnection link and a design method, the structure is arranged at an impedance discontinuity point of the three-dimensional coaxial interconnection link which comprises coaxial through silicon vias and is interconnected with a rewiring layer, and the structure is composed of two coaxial through silicon via stubs which are connected in parallel on the rewiring layer; the design method is used for determining the length of two coaxial through-silicon-via stub lines and the distance between the two coaxial through-silicon-via stub lines. The design method comprises the following steps: acquiring a complex number characteristic impedance and a complex number propagation constant of a three-dimensional coaxial interconnection link in a target frequency band; constructing an optimization function taking the length of the two coaxial through silicon via stub lines and the distance between the two coaxial through silicon via stub lines as variables by combining a transmission line theory; setting related constraints such as a value boundary; and solving the optimization function under constraint conditions to obtain a group of structure parameter combinations enabling the reflection coefficients to meet preset requirements. The device can solve the impedance mismatch caused by the structure discontinuity of the coaxial silicon through hole and the rewiring layer under the sub-terahertz frequency band.

The invention discloses a method and system for converting PI type line parameters into distribution parameter line applicable parameters, and belongs to the technical field of electric power system electromagnetic transient modeling and simulation. The method comprises the following steps: acquiring an impedance parameter matrix ZL and an admittance parameter matrix YC of a three-item PI type distribution parameter line, and selecting voltage and current phase-mode transformation matrixes M and N adapted to the distribution parameter line; calculating a propagation constant matrix gamma and a characteristic impedance matrix ZC of the distribution parameter line; based on the propagation constant matrix gamma and the characteristic impedance matrix ZC, calculating a matrix Z and a matrix Y in the form of phase components of a distribution parameter line matrix, converting the phase components of the distribution parameter line into sequence components based on the matrix Z and the matrix Y, and obtaining applicable parameters of the distribution parameter line according to the sequence components. Parameters of a PI type line are converted into distribution parameter line parameters, and the line parameters do not need to be measured again.

The mode field diameter acquisition device according to the present disclosure is a device for acquiring a mode field diameter of each spatial mode of an optical fiber having a core, through which a plurality of spatial modes can propagate, from a near field pattern, and includes a mode field diameter acquisition unit configured to acquire a mode field diameter of a freely-selected spatial mode using a near field pattern of the spatial mode, and a mathematical expression based on a variational expression of a propagation constant of the spatial mode.

The invention provides a flexible RFID tag antenna suitable for a non-good conductor, which belongs to the field of radio and comprises a flexible dielectric substrate, an annular radiation unit positioned on the flexible dielectric substrate and a radio frequency chip positioned on the annular radiation unit, the arched matching unit is bridged to the inner ring of the annular radiation unit and is radially symmetrical about the annular radiation unit, the arrow-shaped units are uniformly connected to the inner ring of the annular radiation unit, and each arrow-shaped unit points to the center of the annular radiation unit; the flexible requirement is met, the arched matching unit can reduce discontinuity of a traditional right-angle transition position and improve radiation efficiency and gain, and the arched matching unit is used for adjusting antenna impedance so as to make up resonant frequency deviation caused by a human body, achieve conjugate matching with a radio frequency chip and achieve long-distance reading. The arrow-shaped units form a slow wave structure, the electromagnetic wave propagation constant is increased, the phase velocity is reduced, meanwhile, the equivalent electrical length and the effective radiation area are increased, and miniaturization is achieved.

This invention discloses a method for measuring the electromagnetic wave propagation constant of an electromagnetic structure. Based on the field values ​​at three equally spaced points, this invention uses analytical expressions incorporating these three field values ​​to represent the phase constant and attenuation constant of a one-dimensional homogeneous or periodic structure. This method is simple, fast, and accurate. It can be applied to both homogeneous and periodic structures; both closed transmission line structures such as waveguides and open transmission lines such as microstrip lines; both waveguide structures of transmission lines and radiating structures of antennas; and both lossless and lossy structures.

To provide a signal processing device, a signal processing method, and a signal processing program that can avoid divergence of acoustic distribution.SOLUTION: A signal processing device 30 generates an impulse response signal corrected for air absorption attenuation from a measured impulse response signal, and includes a derivation unit 30A2 that derives the corrected impulse response signal using the following equation, where h^(ν) is the Fourier transform of the impulse response signal before correction, t is time, γh is the propagation constant before correction, γr is the propagation constant after correction, n is an index specifying a poles, a is a value determined in advance according to the required accuracy, ωnp(ν) are the poles of the integrand, and r(t) is the corrected impulse response signal.SELECTED DRAWING: Figure 6

The application discloses a fast light waveguide device based on a photonic crystal material heterostructure, which comprises a core layer and a cladding layer arranged symmetrically on the upper and lower sides of the core layer; the core layer comprises a plurality of regularly arranged first photonic crystals; the cladding layer comprises a plurality of regularly arranged second photonic crystals; the first photonic crystal comprises a silicon substrate and a ring-shaped air column; the second photonic crystal comprises a silicon substrate and a circular air column; the first photonic crystal and the second photonic crystal are both left-handed materials and have negative refractive indexes when the incident wave frequency is within the range of 1.9322E14 Hz to 1.9328E14 Hz. The application utilizes the abnormal dispersion characteristics of the three-layer flat waveguide based on the left-handed material, and the waveguide propagation constant beta and the frequency f present a negative correlation relationship, and the function of generating fast light is realized within the frequency range of 1.9322E14 Hz to 1.9328E14 Hz. Since the waveguide width is in the nanometer level, the problems of waveguide miniaturization, high transmission bandwidth and low transmission loss in integrated optics are solved, and an excellent solution for future integrated optics is provided.