169 results about "Injection locking" patented technology

Aspects of the disclosure relate generally to a circuit for sustaining an radio frequency (RF) modulated optical signal. The circuit may comprise a self injection locking component having a fiber optic delay line over which a portion of the optical signal propagates. The circuit may also comprise a self phase locked loop component having at least two fiber optic cables having different lengths and over which another portion of the optical signal propagates and a phase detector coupled to the at least two fiber optic cables and configured to determine a phase difference between the signals propagating over one of the respective fiber optic cables. The circuit may further comprise a voltage controlled oscillator configured to generate a stable oscillating signal in response to signals generated by each of the self injection locking and self phase locked loop components, the stable oscillating signal being configured to sustain the optical signal.

Disclosed are a wavelength division multiplexing-passive optical network (WDM-PON) system using self-injection locking, an optical line terminal thereof, and a data transmission method. A wavelength division multiplexing-passive optical network (WDM-PON) system according to an aspect of the invention includes an optical line terminal. The optical line terminal includes a reflector that is installed at the input side of a multiplexer and reflects an optical signal having a predetermined wavelength, and a light source that generates a multimode optical signal to transmit the generated multimode optical signal to the multiplexer through the reflector, receives reflected light by the reflector, and oscillates at a wavelength of the received reflected light. According to the aspect of the invention, it is not necessary to separately control the temperature of a light source for a downstream signal, and stable communication can be performed by collectively controlling wavelengths of downstream channel optical signals for downstream channels through temperature control of the multiplexer.

The present invention relates to a metal nozzle boss provided with a sealing device, which has highly improved tightness and is combined with a plastic liner of a composite vessel used as a high-pressure vessel. The metal nozzle boss uses an elastic seal ring and a tightening piece in the plastic liner, so that the nozzle boss reliably seals the junction of the nozzle boss and the liner and prevents gas leakage from the vessel. The blade part of the nozzle boss has a dovetail-shaped locking groove, with locking ridges formed in the locking groove. Thus, when the plastic liner is produced by injecting molten resin into the locking groove, the plastic liner is securely combined with the metal nozzle boss. The composite vessel having the metal nozzle boss can be used as a fuel tank for natural gas vehicles or a hydrogen tank for fuel cell vehicles.

A quadrature oscillator includes a master tuned oscillator and two injection-locked slave tuned oscillators.

Briefly, devices and methods for tuning of quadrature oscillators which may be used, for example, in a Complementary Metal-Oxide Semiconductor (CMOS) process. Devices and methods in accordance with some exemplary embodiments of the invention may allow, for example, improved locking, tuning and performance of slave oscillators and a master oscillator within a quadrature oscillator utilizing injection-locking.

The invention relates to a tunable erbium-doped fiber ring laser which can output stable wavelength and power, which relates to an optical fiber communication technology. The tunable laser and an isolator of the invention are connected with the ring cavity through an input terminal of a first optical coupler, the 980nm pumping is optically coupled in the erbium-doped fiber gain medium by a WDM coupler; a second optical coupler is an output terminal; through controlling phase-shift phase of phase-shifted grating, filtering function can be realized; through regulating the wavelength of the injected laser of the tunable laser, injection locking can be realized and the laser can be stably outputted. The tunable single-longitudinal erbium-doped fiber ring laser of the invention has the advantages of low cost, simple device and easy operation; the tunable single-longitudinal mode output with output wavelength and wavelength of stable power can be finally obtained.

The invention provides a high-quality tunable photoproduction microwave source based on a semiconductor double-module laser. The microwave source comprises an amplification feedback laser, a three-port optical circulator, an optical coupler, an optical fiber amplifier and a polarization controller, wherein a port 2 of the optical circulator is connected with the amplification feedback laser, a port 1 of the optical coupler is connected with a port 3 of the optical circulator, the input end of the optical fiber amplifier is connected with a port 2 of the optical coupler to enable the feedback strength to be larger than a threshold value of self-injection locking of the amplification feedback laser, the input end of the polarization controller is connected with the output end of the optical fiber amplifier, the output end of the polarization controller is connected with a port 1 of the three-port optical circulator, and the polarization controller is used for controlling the polarization state of feedback signals, injected back by a feedback circuit, of the amplification feedback laser. The microwave source can overcome the defects of the stability and the line width of the microwave signals generated by the double-module laser, the high-quality microwave source with the tunable narrow line-width can be generated without using an external microwave source as a standard, and the microwave source has the advantages of being high in integration level, compact in structure, good in stability, simple in manufacturing process, low in cost and easy to realize.

The present invention details fabrication guidelines of integrated optoelectronic oscillators with frequency and phase stability, having higher frequency selectivity in a relatively small size (compared to the larger size of a higher order electrically realized RF filter), reduced temperature sensitivity, and minimized frequency drift. The integrated photonic components and RF oscillator may use Silicon photonics and microelectronic integration using CMOS and BiCMOS technology, eliminating the need for bulky and/or discrete optical and microwave components.

The invention discloses an MDI-QKD system and an MDI-QKD method. The MDI-QKD system comprises two clients and a public measurement terminal, the public measurement terminal is provided with a master laser, the two clients are separately provided with slave lasers corresponding to the master laser, and the public measurement terminal is further provided with a detection module used for receiving optical signals from the lasers. A quantum state preparation process of the MDI-QKD system is an internal modulation process that is realized by two master and slave lasers together based on the photoinjection locking idea and has essential defense to the Trojan Horse attack. The first condition for the realization of the Trojan horse attack is that each modulation device for preparing a quantum state in a QKD system structure is independent from a light source and is an external modulation device, while no external modulation device is deployed in the quantum state preparation process of the MDI-QKD system, the quantum state preparation process is realized in the light source, and thus the realization condition of the Trojan Horse attack is damaged.

A CO₂ laser reference oscillator (RO) can provide injection seeding to a Q-switched (QS) or Q-switched cavity dumped (QSCD) CO₂ laser, where the output frequency of the RO laser is locked to the peak of the laser line by the use of appropriate electronics to dither one of the resonator mirrors of the reference oscillator. This injected radiation seeds the radiation building up within the Q-switched laser cavity, such that the oscillating frequency favors the wavelength of the injected radiation. An electronic feedback control circuit can be used to lock an axial mode of the Q-switched laser to line center. The change in build-up time of the pulses within the QS laser can be used to maintain cavity length at a value that enables oscillating at the peak of the same laser line that is injected into QS laser.

The present invention relates to optical gyro, and is especially fiber laser gyro comprising fiber laser, detector and differential frequency processing circuit. It features that the fiber laser consists of semiconductor laser with tail fiber, single-frequency distributed feedback fiber laser DFB, fiber ring and fiber coupler, with the fiber ring comprising wavelength division multiplexer, isolator, gain fiber and fiber coupler. Two fiber rings with gain fiber forms two independent resonant cavities, into which the DFB injects seed laser to lock their work wavelength. The isolator makes the laser work in single-direction traveling wave state, and the laser transmission direction is clockwise in one ring and counterclockwise in the other. The present invention eliminates spatial hole burning in homogeneously expanded gain medium and interlock effect caused by back scattering, and makes laser in two ring cavities work in narrow-line width single-longitudinal mode state.

The invention provides a fiber laser intensity noise suppressing device and a working method thereof. The device comprises a single mode semiconductor pump light source, a wavelength division multiplexer, a fiber resonator, a fiber coupler, a fiber isolator, a fiber circulator and a laser intensity noise suppressing device. Through a self-injection locking structure of a fiber laser, laser signals are injected into the fiber resonator after conventional intensity noise suppressing treatment, so that the finally output laser intensity noise is greatly reduced. The device with a relatively simple structure can realize high performance fiber laser output with ultralow intensity noise, thereby being of great importance for expansion of the application of fiber lasers in the field of high-precision optical fiber sensing, coherent light communication and atomic and molecular spectroscopy.

The invention discloses a self-injection locking resonant optical gyroscope and a working method thereof and belongs to the technical field of optical gyroscopes. The existing resonant optical gyroscope is complex in structure and work. LD is used as a working light source so that the size of the optical gyroscope is reduced. The two LD working light sources share a passive ring resonator so thatnon-reciprocity noise is avoided. Compared with the existing resonant optical gyroscope, the self-injection locking resonant optical gyroscope mainly comprises conventional circuit elements such as circulators, isolators, couplers and resonators in the field of optical fiber technology and has a symmetrical and simple structure. The self-injection locking frequency stabilization method is free ofa modulated signal generator and power-based frequency stabilization. Lights transmitted by the two working light sources carry out resonance along opposite directions in the same passive ring resonator, and two resonance light beams transmitted along different directions are divided through a splitting coupler and are respectively used for frequency stabilization and gyro signal detection. The optical gyroscope has a simple structure and works in a simple work mode.

A method for producing ultrashort pulses from an external injection gain-switched laser comprises the following steps: inputting an ultrashort optical pulse signal having multi-longitudinal mode spectral characteristic, produced by a gain-switched laser, into an optical amplifier to amplify it; selecting, by a spectral component signal selector, a narrow spectral component signal outputted by the optical amplifier that is within an amplified spontaneous emission noise frequency band and has a central wavelength equal to one of the longitudinal modes of the gain-switched laser; and, using one part of the narrow spectral component signal as an external seed light, which is reinjected into the gain-switched laser via a spectral component signal feedback loop so that the oscillation of a selected single longitudinal mode within a cavity of the gain-switched laser is enhanced, thereby forming external light injection locking, another part of the narrow spectral component signal being used as a required ultrashort pulse.

The present disclosure provides a dual loop self injection locked optoelectronic oscillator having a single fiber in its both loops which generates a high Q microwave output signal with a very low phase noise and spurious harmonics levels. The circuit may comprise an optical coupler having different lengths of the output arms and two electronic paths, which form two feedback loops of the oscillator. The circuit may comprise a single fiber with high Q, an optical circulator, and an optical coupler, which serves as a reflector, and two electronic paths which form two feedback loops of the oscillator.