34results about How to "Wide modulation bandwidth" patented technology

Integrated wired and wireless wavelength division multiplexing passive optical network (WDM PON) apparatus using a light source mode-locked to fed incoherent light includes: a fed light generator for providing fed light for up / downstream signals via a broadband light source emitting an incoherent optical signal; a central office (CO) for receiving, mode-locking, and downstream-optical-transmitting the incoherent optical signal generated by the fed light generator and receiving and optical-detecting an upstream optical signal transmitted from a subscriber unit; and the subscriber unit for receiving, mode-locking, and upstream-optical-transmitting the incoherent optical signal generated by the fed light generator and receiving and optical-detecting a downstream optical signal transmitted from the CO, wherein a wired optical transmitter for transmitting a baseband wired signal and a wireless optical transmitter for transmitting a high frequency radio frequency (RF) signal are comprised for up / downstream optical transmission of the CO and the subscriber unit.

The invention relates to the technical field of terahertz spectrums, in particular to a graphene-based all-optically controlled ultra-high speed terahertz intensity modulator. The technical problems of low modulation speed and narrow spectrum range of the conventional terahertz intensity modulator are solved, and the application range of a system is widened. According to the graphene-based all-optically controlled ultra-high speed terahertz intensity modulator, gold nanoparticles are adopted, so that the photon absorption efficiency of graphene is enhanced, the concentration of photon-generated carriers is improved, the absorption of terahertz waves is further enhanced, and the modulation effect of the modulator is enhanced. The graphene-based all-optically controlled ultra-high speed terahertz intensity modulator comprises a terahertz wave generation device, a pumping light wave generation device, a terahertz intensity modulator and a terahertz wave detection device, which are connected to finish the design of the graphene-based all-optically controlled ultra-high speed terahertz intensity modulator. The graphene-based all-optically controlled ultra-high speed terahertz intensity modulator is mainly applied to the fields of terahertz communication systems and terahertz researches.

A solid state device used to modulate the intensity of reflected or transmitted light by modulating with an external voltage the optical thickness of a thin film ferroelectric placed in an etalon cavity is disclosed. The device is constructed by selecting a generally planar supporting substrate, preferably silicon or sapphire in order to be compatible with silicon integrated circuits. A dielectric stack consisting of alternating layers of different index of refraction materials, also specifically selected to be compatible with later growth of the thin film ferroelectric, is deposited thereon to form a partially reflective and partially transmitting mirror, followed by a transparent electrically conductive layer. The thin film ferroelectric is deposited on the conductive layer, followed by a second transparent conductive layer and a second dielectric stack. Leads are connected to the conductive layers and in turn to a voltage generator. In one version of the invention, the functions of both the second (top) electrically conductive layer and dielectric stack are fulfilled by using a semi-transparent conducting film. In another version, the functions of both the first (bottom) electrically conductive layer and dielectric stack are also fulfilled by using a, preferably, highly reflective conducting film.

A spatial terahertz wave phase modulator based on the high electron mobility transistor is provided. The phase modulator combines the quick-response high electron mobility transistor with a novel metamaterial resonant structure, so as to rapidly modulate terahertz wave phases in a free space. The phase modulator includes a semiconductor substrate, an HEMT epitaxial layer, a periodical metamaterial resonant structure and a muff-coupling circuit. A concentration of 2-dimensional electron gas in the HEMT epitaxial layer is controlled through loading voltage signals, so as to change an electromagnetic resonation mode of the metamaterial resonant structure, thereby achieving phase modulation of terahertz waves. The phase modulator has a phase modulation depth of over 90 degrees within a large bandwidth, and a maximum phase modulation depth is about 140 degrees. Furthermore, the phase modulator is simple in structure, easy to machine, high in modulation speed, convenient to use, and easy to package.

A solid state device used to modulate the intensity of reflected or transmitted light by modulating with an external voltage the optical thickness of a thin film ferroelectric placed in an etalon cavity is disclosed. The device is constructed by selecting a generally planar supporting substrate, preferably silicon or sapphire in order to be compatible with silicon integrated circuits. A dielectric stack consisting of alternating layers of different index of refraction materials, also specifically selected to be compatible with later growth of the thin film ferroelectric, is deposited thereon to form a partially reflective and partially transmitting mirror, followed by a transparent electrically conductive layer. The thin film ferroelectric is deposited on the conductive layer, followed by a second transparent conductive layer and a second dielectric stack. Leads are connected to the conductive layers and in turn to a voltage generator. In one version of the invention, the functions of both the second (top) electrically conductive layer and dielectric stack are fulfilled by using a semi-transparent conducting film. In another version, the functions of both the first (bottom) electrically conductive layer and dielectric stack are also fulfilled by using a, preferably, highly reflective conducting film.

An optical modulator includes a waveguide Mach-Zehnder interferometer having a first and a second input and a first and a second output, a feedback waveguide segment connecting the second output with the second input, and a traveling-wave electrode; wherein the Mach-Zehnder interferometer, feedback waveguide segment and traveling-wave electrode are substantially arranged at or adjacent the perimeter of a smooth curve defining a closed geometric figure, the traveling-wave electrode extending along at least 50% of the length of the perimeter of the smooth curve.

The invention discloses a terahertz space external phase modulator based on a high electron mobility transistor. The phase modulator combines the quick response type high electron mobility transistor with a novel artificial electromagnetic medium resonant structure, so as to be able to conduct quick phase modulation on terahertz waves transmitted in free space. The phase modulator is composed of a semiconductor material substrate, an HEMT epitaxial layer, a periodical artificial metal electromagnetic resonant structure and a muff-coupling circuit. The concentration of two-dimensional electron gas in the HEMT epitaxial layer is controlled through loaded voltage signals, so that the electromagnetic resonance mode of the artificial electromagnetic medium resonant structure is changed, and then phase modulation of terahertz waves is achieved. Over-90-degree phase modulation depth can be realized within a large bandwidth, and the maximum phase modulation depth can be about 140 degrees. Furthermore, the phase modulator is simple in structure, easy to machine, high in modulation speed, convenient to use and easy to package.

The embodiment of the application discloses a visible optical signal transmission control method, a transmission control device and transmission equipment. The method comprises the following steps of: confirming first transmission power of at least one to-be-transmitted information; displaying the display trait of at least one image at least according to the first transmission power and a display device, and confirming the partial pixel unit of the display device related to the to-be-transmitted information corresponding to the first transmission power; controlling to modulate the at least one to-be-transmitted information to the optical signal transmitted by the confirmed relative partial pixel unit. In the method and the device, the display device capable of emitting colorful visible optical signals with controllable color and multiple blended frequencies is used as one light source, so that the colorful visible optical signals are used as carrier optical signals to modulate the to-be-transmitted information so as to obtain a wider modulation bandwidth, at the same time, by the method and the device, the utilization rate of the resource is improved and the energy consumption of the display device is also saved.

The invention discloses a quantum dot optical fiber core material with PMMA as a substrate and the preparation and application thereof. The optical fiber core material adopts PMMA as the substrate, adopts PbS or PbSe quantum dots as dophant, the doping method of the PbS or PbSe quantum dots is spatial uniform doping, the size of the PbS or PbSe quantum dots is 4nm to 20nm, and the number density of the PbS or PbSe quantum dots in the optical fiber core material is 1*1016-1*1019cm-3. The optical fiber core material is heated to 150 to 185DEG C, and becomes gelatinous; the gelatinous optical fiber core material is poured into a capillary through a pressure drop method, and quantum dot optical fibers with the number density of the quantum dots of 1*1016-1*1019cm-3 are prepared. When the quantum dot optical fibers are applied to an optical fiber amplifier, high optical gain, wide modulation bandwidth and low noise can be realized in a 1.2 to 1.6 micron communication waveband.

Hybrid plasmonic waveguides are described that employ a high-gain semiconductor nanostructure functioning as a gain medium that is separated from a metal substrate surface by a nanoscale thickness thick low-index gap. The waveguides are capable of efficient generation of sub-wavelength high intensity light and have the potential for large modulation bandwidth >1 THz.

The invention provides an optical-control external phase modulator of terahertz space and belongs to the technical field of electromagnetic function devices. The external phase modulator provided by the invention is composed of a semiconductor substrate, an artificial micro structure and a controllable dynamic switch. Through application of external optical induction, an electric conduction rate and a dielectric constant of a switch material are changed. Hence, an electromagnetic resonance mode of the artificial micro structure can be changed and thus phase modulation of terahertz waves can be achieved. The phase modulator provided by the invention has the advantages that a phase modulation depth of over 100 DEG within a large bandwidth and maximum phase modulation capacity of over 150 DEG can be achieved; micro-fabrication techniques can be used for implementation, and the preparation technology is mature and reliable; and a dynamic phase control device which combines a semiconductor material and an artificial microstructure array is achieved, the switch material can be selected from multiple types of high-performance semiconductor materials, multiple control modes can be selected, and the phase modulator has very high practical application values in fields such as terahertz wireless communication, terahertz spectrum technology and terahertz security check imaging.

The invention is directed to a phase locked loop with a ΣΔ modulator. A multimodulus divider in the feedback path of the PLL is actuated by the ΣΔ modulator. The latter has a design which can be described by a complex transfer function H(s) in the Laplace plane, said transfer function having a complex-conjugate pair of pole points. The arrangement allows a significant reduction in the noise in critical frequency domains and hence allows adherence to transmission masks based on radio specification even when the PLL bandwidth is as large as the modulation bandwidth.

The invention is directed to a phase locked loop with a ΣΔ modulator. A multimodulus divider in the feedback path of the PLL is actuated by the ΣΔ modulator. The latter has a design which can be described by a complex transfer function H(s) in the Laplace plane, said transfer function having a complex-conjugate pair of pole points. The arrangement allows a significant reduction in the noise in critical frequency domains and hence allows adherence to transmission masks based on radio specification even when the PLL bandwidth is as large as the modulation bandwidth.

The invention relates to a metamaterial modulator, which comprises a surface layer, a graphene layer, a first flexible dielectric layer, a perovskite layer, a metal structure layer, a second flexible dielectric layer and a bottom substrate layer which are arranged from top to bottom, wherein the metal structure layer is composed of a plurality of metal structures, the conductivity change of the graphene layer and the perovskite layer is caused by laser incidence in a modulation process, incident terahertz waves are regulated twice while the graphene layer and the surface layer are provided with electrodes so as to carrying out multi-material photoelectric combined regulation on the terahertz waves through an electric field, and in the modulation process, the metal structure interacts with the terahertz waves to generate resonance so as to increase the modulation depth.

The invention discloses a three-dimensional displacement measurement system and method based on laser self-mixing grating interference, and the system comprises a semiconductor laser sensor head, a plane reflector, a reflective two-dimensional plane grating, a data acquisition card and a computer, wherein the laser emitted from the semiconductor laser sensor head is incident on the reflective two-dimensional grating, the corresponding diffracted light is fed back to the semiconductor laser sensor head along the original optical path to generate self-mixing interference, the self-mixing interference signal is converted into an electrical signal by the photodetector built in the semiconductor laser and is output to the data acquisition card to obtain three-dimensional displacement of the target to be measured after computer processing. The invention solves the problem that the range of a traditional grating interferometer is limited when performing out-of-plane displacement measurement,is more compact than the traditional grating interferometer, maintains the advantages of self-collimation of the laser self-mixing interferometer, and can realize three-dimensional real-time displacement measurement system and method with a simple structure, wide rang and high resolution.

In an optical modulator of the invention, a signal electrode and a ground electrode are formed along a pair of branching waveguides of a Mach-Zehnder type optical waveguide, and a first region positioned on an input side of an interaction section of light and an electric signal is made a forward modulation section, and a second region positioned on an output side is made an inverse modulation section, and a spacing or the like of the signal electrode and the ground electrode is optimized so that that a loss produced in the second region is relatively greater than a loss produced in the first region, with respect to a high frequency component of an electric signal propagated through the signal electrode. As a result a wider modulation bandwidth can be realized.

This invention discloses one photon crystal Hertz wave modulation device and its method, wherein, the device comprises silicon photon crystal with deficiency, electrode, liquid crystal, silica dioxide underlay; the underlay is set with silicon photon crystal on and injects liquid crystal into silicon photon crystal holes with deficiency and sets electrode on both sides of silicon photon crystal with deficiency; The photon crystal Hertz wave modulation method is to use photon edge to modulate Hertz wave signals.

A laser system and method for self-injection locking. The system includes a laser having a laser output at a frequency ωo. An optical port provides a portion of the laser output at the port and a modulator, coupled to the port, is driven by a RF signal at a frequency ωm generates two sidebands at ωo±ωm. A filter passes one of the two sidebands; and an optical path couples an output of the filter to the laser for injection locking.

The invention discloses a graphene micro-striped line traveling wave absorptive type light modulator based on strip-shaped light waveguide, solves the problem that modulation bandwidth is relatively small based on the grapheme light modulator being limited by larger RC constant of the lumped electrode structure in the prior art, and belongs to the technical field of photoelectron. The modulator comprises a substrate layer, a strip-shaped light waveguide, a dielectric filler layer, and a micro-striped line traveling wave electrode structure, wherein the strip-shaped light waveguide and the dielectric filler layer are arranged on the surface of the substrate layer; and the micro-striped line traveling wave electrode structure is arranged on the strip-shaped light waveguide. The graphene micro-striped line traveling wave absorptive type light modulator based on the strip-shaped light waveguide is used for realizing light modulation rate.

A spatial terahertz wave phase modulator based on the high electron mobility transistor is provided. The phase modulator combines the quick-response high electron mobility transistor with a novel metamaterial resonant structure, so as to rapidly modulate terahertz wave phases in a free space. The phase modulator includes a semiconductor substrate, an HEMT epitaxial layer, a periodical metamaterial resonant structure and a muff-coupling circuit. A concentration of 2-dimensional electron gas in the HEMT epitaxial layer is controlled through loading voltage signals, so as to change an electromagnetic resonation mode of the metamaterial resonant structure, thereby achieving phase modulation of terahertz waves. The phase modulator has a phase modulation depth of over 90 degrees within a large bandwidth, and a maximum phase modulation depth is about 140 degrees. Furthermore, the phase modulator is simple in structure, easy to machine, high in modulation speed, convenient to use, and easy to package.

The invention discloses a symmetrical semiconductor laser self-mixing grating interference three-dimensional displacement measurement system and a measurement method thereof. The system comprises a four-channel stable current source, four temperature controllers, four semiconductor lasers, four photoelectric detectors, a reflective two-dimensional plane grating, four electro-optical phase modulators, a four-channel signal generator, a voltage amplifier and a signal processing module. Output lasers of the four semiconductor lasers are modulated by the four electro-optical phase modulators respectively and then incident to the reflective two-dimensional plane grating at + / -1-order Littrow incident angles in the x direction and the y direction respectively, and diffracted light is fed back tothe corresponding semiconductor lasers in the incident direction along the original path to generate self-mixing interference. And the four paths of interference signals are converted into electric signals through the photoelectric detector and output to the signal processing module, and the three-dimensional displacement of the to-be-measured target is restored in real time. The invention has the characteristics of simple and compact structure, strong anti-interference capability and the like, and the symmetrical structure design is beneficial to improving the measurement resolution of the system.

The aim of the invention is to adjust the operating point of a laser that can be modulated by a data signal. The operating point of the laser is adjusted by regulating a direct current flowing through the laser; whereby said direct current correlates with the optical characteristics of the laser. In order to carry out said adjustment, the direct current is controlled above an alterable threshold current. A differential current defined from the difference between the direct current and the threshold current or a variable correlating with the differential current is adjusted to a constant value or one that is solely dependent on temperature for the adjustment of said operating point.

The invention relates to the technical field of terahertz spectroscopy, in particular to a graphene-based all-optical control ultra-high-speed terahertz intensity modulator. The technical problem to be solved by the present invention is: aiming at the problems of low modulation speed and narrow spectral range of existing terahertz intensity modulators and improving the application range of the system, the present invention proposes a graphene-based all-optical control ultra-high-speed terahertz The intensity modulator enhances the photon absorption efficiency of graphene through gold nanoparticles, increases the concentration of photogenerated carriers, and then strengthens the absorption of terahertz waves and enhances the modulation effect of the modulator. The present invention includes: a terahertz wave generating device, a pumping light wave generating device, a terahertz intensity modulator, and a terahertz wave detecting device, and the design of the present invention is completed through the above connections. The invention is mainly applied in the fields of terahertz communication system and terahertz research.

Belonging to the field of optoelectronic technology, a graphene-based coplanar traveling-wave electrode absorption type optical modulator is disclosed, including a substrate layer, a strip optical waveguide, a dielectric filling layer, a dielectric isolation layer, graphene striplines and electrodes, the A first dielectric isolation layer, a first graphene stripline, and a second dielectric isolation layer are sequentially arranged above the strip optical waveguide, and a second graphene stripline and a third graphene isolation layer are arranged on the second dielectric isolation layer. Stripline, the two ends of the first graphene stripline are respectively connected to the first electrode and the second electrode, one end of the second graphene stripline is connected to the first ground electrode and the second ground electrode, and the third One end of the graphene strip line is connected to the third ground electrode and the fourth ground electrode; this structure increases the bandwidth of the optical modulator, and at the same time, the optical modulator is compatible with the microwave probe, and the coplanar waveguide traveling wave electrode structure is adopted, and the preparation is relatively simple , to enhance the practicability of the device.

The invention relates to a cross-polarization laser feedback grating interferometer of a phase modulation type, and a measurement method thereof. The measurement principle is based on the grating diffraction, optical Doppler effect, Lamb semi-classical theory and time-domain orthogonal demodulation principle. The orthogonally polarized light outputted by a birefringent dual-frequency helium-neon laser is perpendicularly incident to a polarization beam splitting prism and is divided into two linearly polarized light beams in different polarization directions. The two polarized light beams respectively pass through two different electrooptical modulators and then are respectively reflected by a reflector at a + / -1-order Littrow incidence angle to a reflection-type diffraction grating. The diffracted light returns to the laser cavity along the respective incident light, and performs self-mixing interference with the light in the cavity. The backward output light of the laser passes through a polarizer and then only the single-mode light is retained and accepted by a photodetector. An output signal of the photodetector is outputted to a data processing module for data processing, and the two-dimensional displacement of a target to be measured is obtained. The grating interferometer has the advantages of simple structure, large measuring range and high measurement resolution.

The invention discloses a PMMA-based quantum dot optical fiber core material and its preparation and application. The fiber core material is based on PMMA, and PbS or PbSe quantum dots are used as dopants. The doping method of the PbS or PbSe quantum dots is spatially uniform doping, and the size of the PbS or PbSe quantum dots is 4nm -20nm, the number density of PbS or PbSe quantum dots in the fiber core material is 1×1016-1×1019cm-3. Heat the optical fiber core material to 150-185°C to make it into a gel; pour the gel-like optical fiber core material into a quartz capillary by the differential pressure method to obtain the number density of quantum dots Quantum dot fiber between 1×1016-1×1019cm-3. When the quantum dot optical fiber of the present invention is applied to the optical fiber amplifier, high optical gain, wide modulation bandwidth and low noise can be obtained in the 1.2-1.6 micron communication band.

The invention discloses a metamaterial modulator which comprises a surface layer, a graphene layer, a flexible dielectric layer and a silicon rectangular strip structure substrate layer which are arranged from top to bottom. A silicon rectangular strip structure is etched on a silicon substrate to form an all-dielectric metamaterial, resonance is generated through interaction of the silicon rectangular strip structure and terahertz waves, the conductivity of the graphene layer is changed through an excitation mode of laser incidence or voltage application, and therefore optical / electric regulation and control over the terahertz waves are achieved. The characteristic of low loss of the all-dielectric material is utilized, so that higher modulation depth can be realized.

The invention discloses a three-dimensional displacement measurement system and measurement method based on laser self-mixing grating interference. The system includes a semiconductor laser sensor head, a plane mirror, a reflective two-dimensional plane grating, a data acquisition card and a computer. The laser light emitted by the head is incident on the reflective two-dimensional grating, and the corresponding diffracted light is fed back to the semiconductor laser sensor head along the original optical path to generate self-mixing interference. The self-mixing interference signal is converted into an electrical signal by the built-in photodetector of the semiconductor laser, and output To the data acquisition card, after computer processing, the three-dimensional displacement of the target to be measured is obtained. The invention solves the problem of the limited range of the traditional grating interferometer when measuring the out-of-plane displacement, and is more compact than the traditional grating interferometer, and maintains the advantages of self-collimation of the laser self-mixing interferometer, and can realize simple structure, a large number of High-resolution, high-resolution three-dimensional real-time displacement measurement system and measurement method.