Topic
Injection locking
About: Injection locking is a research topic. Over the lifetime, 4567 publications have been published within this topic receiving 60942 citations.
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TL;DR: In this paper, the phase-noise spectral density of a 9 GHz oscillator was reduced to -160 dBc/Hz at 1-kHz offset frequency, which is the lowest phase noise ever measured at microwave frequencies.
Abstract: Phase-noise spectral density of a 9-GHz oscillator has been reduced to -160 dBc/Hz at 1-kHz offset frequency, which is the lowest phase noise ever measured at microwave frequencies. This performance was achieved by frequency locking a conventional loop oscillator to a high-Q sapphire dielectric resonator operating at the elevated level of dissipated power (~0.4 W). Principles of interferometric microwave signal processing were applied to generate the error signal for the frequency control loop. No cryogenics were used. Two almost identical oscillators were constructed to perform classical two-oscillator phase-noise measurements where one oscillator was phase locked to another. The phase locking was implemented by electronically controlling the level of microwave power dissipated in the sapphire dielectric resonator
47 citations
TL;DR: The operation of a novel all-optical flip-flop which consists of a slave Fabry-Perot laser diode and a specially designed master FP-LD which operates in single longitudinal mode oscillation is demonstrated.
Abstract: We demonstrate the operation of a novel all-optical flip-flop. The flip-flop consists of a slave Fabry-Perot laser diode (FP-LD) and a specially designed master FP-LD which has a built-in external cavity and operates in single longitudinal mode oscillation. The set and reset pulses were generated by external modulators at 1 Gbit/s. The rising and falling times of the output signal in on-off operation of the flip-flop were about 50 ps. The required powers of both set and reset pulses were less than -9 dBm.
47 citations
TL;DR: The dynamics that accompany polarization switching induced by orthogonal optical injection in a vertical-cavity surface-emitting laser (VCSEL) are reported, revealing new bistability mechanisms in optical injection problems.
Abstract: We report on the dynamics that accompany polarization switching induced by orthogonal optical injection in a vertical-cavity surface-emitting laser (VCSEL). As the injection strength increases, the VCSEL bifurcates to injection-locked steady states and time-periodic and possibly chaotic dynamics. Of particular interest is a two-mode injection-locking solution, i.e., locking of the two VCSEL polarization modes. A detailed stability analysis unveils new bistability mechanisms in optical injection problems.
47 citations
TL;DR: In this article, a theoretical analysis of the forward and reflected amplitudes in a diode laser oscillator cavity for both a single resonant mode and an injected signal is presented, including gain saturation and allowing the gain coefficient at the injected frequency to be different from that at the resonant frequency.
Abstract: We present a theoretical analysis of the forward and reflected amplitudes in a diode laser oscillator cavity for both a single resonant mode and an injected signal. The analysis includes gain saturation and allows the gain coefficient at the injected frequency to be different from that at the resonant frequency. Analytic solutions for the axially dependent amplitudes are presented for the case of equal gain coefficients. For the more general case, a formula is presented for the intensity necessary for locking, which is shown to reduce in various limits to other expressions previously published. One immediate consequence of the present formalism is that the use of antireflection coatings on the diode end facets should act to reduce the injected signal intensity necessary for locking. In fact, reduction of the reflectivities to values of a few percent should enable locking over the entire gain curve with incident intensities which are small compared to the slave oscillator's normal output.
47 citations
TL;DR: In this paper, homogeneous quantum cascade lasers (QCLs) emitting around 3 THz with a single stable beatnote are presented, which display bandwidths up to 950 GHz.
Abstract: We present homogeneous quantum cascade lasers (QCLs) emitting around 3 THz which display bandwidths up to 950 GHz with a single stable beatnote. Devices are spontaneously operating in a harmonic comb state, and when in a dense mode regime they can be injection locked at the cavity roundtrip frequency with very small RF powers down to -55 dBm. When operated in the electrically unstable region of negative differential resistance, the device displays ultra-broadband operation exceeding 1.83 THz (Δf/f=50%) with high phase noise, exhibiting self-sustained, periodic voltage oscillations. The low CW threshold (115 A·cm-2) and broadband comb operation (Δf/f=25%) make these sources extremely appealing for on-chip frequency comb applications.
47 citations