Frequency drift

About: Frequency drift is a research topic. Over the lifetime, 5054 publications have been published within this topic receiving 56191 citations. The topic is also known as: chirp rate.

Performance enhancement of an optically-injected-semiconductor-laser-based optoelectronic oscillator by subharmonic microwave modulation

Abstract: An approach to enhancing the performance of an optically-injected-semiconductor-laser-based optoelectronic oscillator (OEO) is proposed by subharmonic microwave modulation. A free-running OEO is first established based on period-one dynamics of an optically injected semiconductor laser. The oscillation frequency can be tuned in the range of 8.87 to 18.41 GHz by controlling the injection strength, but the output signal suffers from strong side modes and poor frequency stability. To address these problems, subharmonic microwave modulation is applied to the injected semiconductor laser. In the experiment, microwave modulation with 1/2, 1/4, and 1/6 subharmonics is demonstrated. The side-mode suppression ratio is improved by over 40 dB, while the phase noise at a 1 kHz offset is reduced by about 18 dB. Furthermore, the frequency drift over a period of 20 min, which characterizes the long-term stability, is reduced from 8.7 kHz to less than 1 Hz, indicating a significant reduction of over three orders.

A Low Cost Superregenerative Saw Stabilized Receiver

Abstract: This paper describes a new superregenerative receiver that overcomes the frequency drift and excessive bandwidth problems of the present state-of-the-art devices with little or no sacrifice in receiver simplicity and cost. The receiver makes use of a new third generation surface acoustic wave device to stabilize the center frequency and decrease the bandwidth of the regenerative circuit.

Scalable feedback control of single photon sources for photonic quantum technologies

Abstract: Large-scale quantum technologies require exquisite control over many individual quantum systems. Typically, such systems are very sensitive to environmental fluctuations, and diagnosing errors via measurements causes unavoidable perturbations. In this work we present an in situ frequency locking technique that monitors and corrects frequency variations in single photon sources based on microring resonators. By using the same classical laser fields required for photon generation as a probe to diagnose variations in the resonator frequency, our protocol applies feedback control to correct photon frequency errors in parallel to the optical quantum computation without disturbing the physical qubit. We implement our technique on a silicon photonic device and demonstrate sub 1 pm frequency stabilization in the presence of applied environmental noise, corresponding to a fractional frequency drift of <1 % of a photon linewidth. Using these methods we demonstrate feedback controlled quantum state engineering. By distributing a single local oscillator across a single chip or network of chips, our approach enables frequency locking of many single photon sources for large-scale photonic quantum technologies.

Temperature compensated oscillator, its manufacturing method, and integrated circuit for temperature compensated oscillator

Abstract: An object of the invention is to provide a temperature compensated oscillator and reduce manufacture cost of this oscillator. Therefore, the temperature compensated oscillator has a frequency comparing circuit for comparing the frequency of an oscillating output signal of an oscillator circuit and the frequency of an external reference frequency signal externally inputted, and also has a sequential comparing register for determining each bit on the basis of results of this comparison. A digital signal from the sequential comparing register is set to an input of a D/A converter for generating a control voltage of a varicap diode. The temperature compensated oscillator performs a self compensating operation for sequentially determining each bit of the sequential comparing register every frequency comparison, and conforming the frequency of the oscillating output signal to that of the external reference frequency signal. The digital signal from the sequential comparing register is set to compensating data corresponding to a detecting temperature of a temperature detector at that time. The compensating data are determined by performing the self compensating operation every predetermined temperature change detected by the temperature detector.

Voltage controlled digital analog oscillator and frequency synthesizer using the same

Abstract: Provided are a voltage controlled digital analog oscillator and a frequency synthesizer using the same, the oscillator comprising an oscillator having a frequency of an output signal being determined by a voltage inputted to an analog input end and a digital value inputted to a digital input end; and a digital tuner for comparing the voltage inputted to the analog input end to first and second threshold voltages and changing the digital value inputted to the digital input end according to the result, whereby it is possible to obtain a broadband frequency output with less noise.