590 results about "Injection locked" patented technology

Optical transmitters for radio over fiber systems are disclosed. More particularly, the optical transmitters include optically-injection-locked vertical cavity surface-emitting laser devices (OIL VCSELS). The transmitters include a master laser, at least one slave laser injection-locked by the master laser, and an equalizer/filter unit that enables the ratio of the carrier power to the sideband power in the output signal of the transmitter to be varied and optimized independently of the injection ratio of the transmitter.

A semiconductor memory device with a clock synchronization circuit capable of performing a desired phase/frequency locking operation, without the jitter peaking phenomenon and the pattern jitter of an oscillation control voltage signal using injection locking. The device includes a phase-locked loop that detects a phase/frequency difference between a feedback clock signal and a reference clock signal to generate an oscillation control voltage signal corresponding to the detected phase/frequency difference, and generates the feedback clock signal corresponding to the oscillation control voltage signal. An injection locking oscillation unit sets up a free running frequency in response to the oscillation control voltage signal and generates an internal clock signal which is synchronized with the reference clock signal.

A frequency divider involves a plurality of Injection-locked Ring Oscillators (ILRO). A first ILRO includes a pair of cross-coupled N-channel transistors, a pair of load resistors, an integrating capacitor, and a current injection circuit. The drain of each transistor is coupled to the gate of the other transistor. Each load resistor couples the drain of each transistor to a circuit voltage source. The integrating capacitor couples the sources of each transistor. The current injection circuit alternately opens and closes a path from the source of each transistor to circuit ground in response to an oscillatory input signal of a first frequency. In response, the voltage state at the drain of each transistor is alternately latched and toggled, generating a differential pair of oscillating signals frequency divided by two. A first and second ILRO driven in antiphase generate two differential output signals in phase quadrature.

A two-optical signal generator is provided for generating two optical signals, where a difference between optical frequencies or optical wavelength of the two optical signals can be adjusted. A first optical modulator modulates a single-mode optical signal generated by a first light source according to an inputted signal, and outputs a modulated optical signal including predetermined specific two optical signals having a predetermined optical frequency difference, while a second light source generates a multi-mode optical signal including predetermined two further optical signals having substantially the same wavelengths as those of the predetermined specific two optical signals of the modulated optical signal, respectively. Then an optical injection device optically injects the modulated optical signal into the second light source, and the predetermined specific two optical signals of the modulated optical signal are injection-locked into the predetermined two further optical signals of the multi-mode optical signal, so that the second light source generates an injection-locked predetermined specific two optical signals.

An injection-locked frequency divider (ILFD) can go beyond simple frequency division by an even number. In one embodiment, another differential pair of transistors is added to convert the injection signal into differential currents, which are mixed in the original transistor pair such as that of the conventional ILFD shown above. In another, a double-balanced ILFD structure includes multiple ILFD's which are independently tunable to allow phase differences other than quadrature.

An injection locked transmitter for an optical communication network includes a master seed laser source input substantially confined to a single longitudinal mode, an input data stream, and a laser injected modulator including at least one slave laser having a resonator frequency that is injection locked to a frequency of the single longitudinal mode of the master seed laser source. The laser injected modulator is configured to receive the master seed laser source input and the input data stream, and output a laser modulated data stream.

A signal generator for generating an output signal with a frequency that is a multiple of a frequency of a reference signal, the signal generator including an oscillator configured to generate the output signal in dependence on the reference signal and a control signal and a control circuit configured to generate the control signal to comprise a series of pulses in which one or more of the pulses is offset in phase relative to the reference signal, the control circuit thereby being capable of controlling the frequency and/or phase of the output signal.

A system for generating in-phase and quadrature phase signals is provided. The system includes a first and a second differential output, such as from a sinusoidal oscillator. A first injection-locked frequency divider, such as one that uses an LC oscillator in conjunction with cross-coupled transistors, receives the first differential output and generates a in-phase or in-phase output. A second injection-locked frequency divider receives the second differential output and generates a quadrature phase output.

A supply-regulated VCO exhibits reduced or no supply sensitivity peaking. The VCO includes an oscillator whose supply current is regulated to control the oscillating frequency of the oscillator. A VCO input signal controls the supply current so that there is a relationship between the input signal and the oscillator output frequency. Power supply noise that might otherwise affect oscillator operation is shunted from a supply current input lead of the oscillator to ground by a bypass capacitor. In one example, an auxiliary circuit supplies an auxiliary supply current to the oscillator, thereby reducing the amount of supply current a supply regulation control loop circuit must supply. In another example, a supply regulation control loop circuit supplies a control current to a main oscillator, but the bypass capacitor is not coupled to this oscillator but rather is coupled to a slave oscillator that is injection locked to the main oscillator.

A novel and useful digitally controlled injection-locked RF oscillator with an auxiliary loop. The oscillator is injection locked to a time delayed version of its own resonating voltage (or its second harmonic) and its frequency is modulated by manipulating the phase and amplitude of injected current. The oscillator achieves a narrow modulation tuning range and fine step size of an LC tank based digitally controlled oscillator (DCO). The DCO first gets tuned to its center frequency by means of a conventional switched capacitor array. Frequency modulation is then achieved via a novel method of digitally controlling the phase and amplitude of injected current into the LC tank generated from its own resonating voltage. A very linear deviation from the center frequency is achieved with a much lower gain resulting in a very fine resolution DCO step size and high linearity without needing to resort to oversampled noise shaped dithering.

An injection-locked phase-locked loop (ILPLL) circuit includes a delay-locked loop (DLL) and an ILPLL. The DLL is configured to generate a DLL clock by performing a delay-locked operation on a reference clock. The ILPLL includes a voltage-controlled oscillator (VCO), and is configured to generate an output clock by performing an injection synchronous phase-locked operation on the reference clock. The DLL clock is injected into the VCO as an injection clock of the VCO.

The invention discloses a millimeter-wave phase-locked loop, which comprises a voltage-controlled oscillator, an orthogonal output injection locked frequency divider, a charge pump and a loop filter, wherein the voltage-controlled oscillator is used for generating an oscillating signal of a set frequency by adopting a differential input tuning way; the orthogonal output injection locked frequency divider is used for performing frequency division processing on the oscillating signal to output multiple paths of orthogonal frequency division signals; the charge pump is used for converting a pulse signal into an analog voltage signal for realizing differential output; the loop filter is connected between the charge pump and the voltage-controlled oscillator, and is used for filtering an analog voltage signal output by the charge pump to input into the voltage-controlled oscillator. The millimeter-wave phase-locked loop is used for supplying a local oscillator signal of a set frequency to a 60GHz millimeter-wave communication system. According to the structure of the differential tuning voltage-controlled oscillator in the phase-locked loop, the noise of the oscillator is optimized, and the noise optimization of the entire phase-locked loop is facilitated greatly. A differential input control voltage is provided for a differential voltage-controlled oscillator through the charge pump, so that higher phase noise performance is achieved.

In one aspect, the invention relates to a semiconductor laser. The laser includes a substrate and an elongate unitary laser structure disposed on the substrate. In turn, the elongate unitary laser structure includes a first laser section, a second laser section, and a plurality of shared layers. The first and second laser sections are capable of lasing independently of each other. The shared layers form both the first laser section and the second laser section. The first laser section is adapted for injection locking the second laser section.

Disclosed is a dense wavelength division multiplexing-passive optical network (DWDM-PON) system utilizing self-injection locking of Fabry-Perot laser diodes, in which output optical signals of different wavelengths are partially fed back by a partial mirror, so as to injection-lock the Fabry-Perot laser diodes, respectively. In accordance with this system, inexpensive Fabry-Perot laser diodes can be used as respective light sources of a central office and optical network units (ONUs). Accordingly, it is possible to minimize the system construction costs, as compared to conventional optical networks.

The embodiment of the invention discloses a self-injection locking light source which comprises a polarized light splitter as well as a first self-injection locking laser and a second self-injection locking laser which are coupled with the polarized light splitter, wherein the polarized light splitter is used for carrying out polarized coupling on polarized light provided by the first self-injection locking laser and the second self-injection locking laser and polarized light splitting on received reflected light, and respectively providing the split light for the first self-injection locking laser and the second self-injection locking laser; and the polarization directions of the first self-injection locking laser and the second self-injection locking laser are respectively aligned to the two polarization directions of the polarized light splitter. The embodiment of the invention also provides a light source self-injection locking method and system as well as a wavelength division multiplexing passive optical network system.

The invention discloses a microwave photon receiving method, and belongs to the technical field of microwave photonics. Firstly, the received radio frequency signal is sent to one radio frequency input port of a dual-drive-Mach-Zehnder modulator; an optical modulation signal outputted by the dual-drive-Mach-Zehnder modulator is divided into two paths, and one of the paths forms a photoelectric oscillation loop which is fed back to the other radio frequency input port of the dual-drive-Mach-Zehnder modulator, wherein oscillation frequency of the photoelectric oscillation loop is close to carrier frequency in the radio frequency signal and sufficient to enable the photoelectric oscillation loop to work under an injection locking mode; DC bias voltage of the dual-drive-Mach-Zehnder modulator is adjusted so that phases between input signals on the two radio frequency input ports are non-orthogonal; and the optical modulation signal outputted by the other path is photo-electrically converted so that a down-conversion base band or an intermediate frequency signal is obtained. The invention also discloses a microwave photon receiving device. The device is high in conversion efficiency, low in loss, simple in structure and low in cost.

The invention discloses a high-precision fiber frequency transmission system, and the system comprises a PID circuit board, a phase discriminator, a photoelectric detector, a Faraday rotary reflector, a microwave photon phase shifter, a 2*2 optical coupler, a circulator, a slave laser, a frequency reference signal source, a main laser emitter, an isolator, an optical fiber link, and a time frequency receiving and transmitting module. On the basis of a single-fiber bidirectional return error signal obtaining mode, the system carries out the optical fiber link noise compensation based on injection locked coherent detection and the microwave photon phase shifter, thereby achieving the high-precision fiber frequency transmission. The system can achieve the high-precision recovery of a frequency reference signal of a local end at a far end. The system can achieve the two features, needed by phase change, on the same microwave photon phase shifter at the same time: large-bandwidth response and large dynamic range, facilitates the reduction of the complexity, and improves the stability and adaptability. The system can be used in the fields of comparison of the optical clock/atomic clock and the frequency transmission.

Embodiments of the invention provide apparatuses and methods for phase correlated seeding of parametric mixer and for generating coherent frequency combs. The parametric mixer may use two phase-correlated optical waves with different carrier frequencies to generate new optical waves centered at frequencies differing from the input waves, while retaining the input wave coherent properties. In the case when parametric mixer is used to generate frequency combs with small frequency pitch, the phase correlation of the input (seed) waves can be achieved by electro-optical modulator and a single master laser. In the case when frequency comb possessing a frequency pitch that is larger than frequency modulation that can be affected by electro-optic modulator, the phase correlation of the input (seed) waves is achieved by combined use of an electro-optical modulator and injection locking to a single or multiple slave lasers.

A frequency synthesizing apparatus and method having an injection-locked quadrature VCO in an RF transceiver is provided. In the frequency synthesizer, an I signal following a frequency of a high frequency signal that is input using the injection-locked quadrature VCO and a Q signal thereof are simultaneously generated to have an appropriate driving power. Accordingly, the I signal and the Q signal thereof that are generated in the injection-locked quadrature VCO may be utilized as a local signal for frequency up/down-conversion, without being buffered. An output of an SSB mixer may be directly input into the injection-locked quadrature VCO. Also, high frequency signals that are generated in another circuit such as the SSB mixer, a PLL, or a VCO may be selected to be input into the injection-locked quadrature VCO by a selector.

A signal generating circuit for generating an output signal is provided. A phase detection circuit is arranged to detect a phase difference between an input reference signal and a feedback signal, and generate a control signal according to the phase difference. An injected controlled oscillator is arranged to receive the control signal and an injection signal and generate the output signal according to the control signal and the injection signal. A frequency of the output signal is proportional to a frequency of the input reference signal, and a frequency of the injection signal does not equal to the frequency of the output signal.

A phase locked loop includes a voltage controlled oscillator and a frequency divider or frequency multiplier. The voltage controlled oscillator and the frequency divider/multiplier are coupled together in a stacked configuration. A drive current is supplied to the voltage controlled oscillator. The drive current passes from the voltage controlled oscillator to the frequency divider/multiplier, thereby driving the frequency divider/multiplier with the same drive current that was supplied to the voltage controlled oscillator.

The invention discloses a production method of an optical microwave signal with tunable broadband frequency. The method comprises the following steps: constructing a stable dual-loop low-frequency optoelectronic oscillator; injecting an external continuous lights into the optoelectronic oscillator, implementing the injection locking in a directly modulated laser of a core component of the optoelectronic oscillator to finish the up-conversion process of the optical microwave so as to generate a high-frequency optical microwave signal; implementing the tunability of the optoelectronic oscillator by adjusting the wavelength, optical power and polarization state of the external continuous lights so as to generate the optical microwave signal with needed frequency. By injecting the external continuous lights into the directly modulated laser in the optoelectronic oscillator and then locking an optical carrier wave after the up-conversion is generated under a high-order mode, the high-quality optical microwave signal is produced. The method provided by the invention can be used for producing any high-frequency optical microwave signal based on an injection locking technology by using the lower-frequency electric signal, and the tunability of the microwave frequency can be realized by only controlling the wavelength, polarization state and optical power of the injected continuous lights.