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.

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.

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 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 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.

A laser system and method for self-injection locking. The system includes a laser having a laser output at a frequency ω_o. 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 ω_m generates two sidebands at ω_o±ω_m. 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.

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.

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 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.