Frequency Stabilization of a He-Ne Zeeman Laser by Phase- Locking its Beat Frequency to an External Oscillator

Efficient and compact frequency converters are essential for frequency stabilization of terahertz sources. In this paper, we present a 3.5-THz, x6-harmonic, integrated Schottky diode mixer operating at room temperature. The designed frequency converter is based on a single-ended, planar Schottky diode with a sub-micron anode contact area defined on a suspended 2-um ultra-thin GaAs substrate. The dc-grounded anode pad was combined with the radio frequency E-plane probe, which resulted in an electrically compact circuit. At 200 MHz intermediate frequency, a mixer conversion loss of about 59 dB is measured resulting in a 40 dB signal-to-noise ratio in a phase-locking application. Using a quasi-static diode model combined with electromagnetic simulations, good agreement with the measured results was obtained. Harmonic frequency converters without the need of cryogenic cooling will help in the realization of highly sensitive space and air-borne heterodyne receivers.<br>

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A 3.5-THz, x6-Harmonic, Single-Ended Schottky Diode Mixer for Frequency Stabilization of Quantum-Cascade Lasers

10.36227/techrxiv.14847573 ◽

2021 ◽

Author(s):

Divya Jayasankar ◽

Vladimir Drakinskiy ◽

nick rothbart ◽

Heiko Richter ◽

Xiang Lü ◽

...

Keyword(s):

Schottky Diode ◽

Quantum Cascade Lasers ◽

Signal To Noise Ratio ◽

Phase Locking ◽

Frequency Converter ◽

Intermediate Frequency ◽

Frequency Stabilization ◽

Cryogenic Cooling ◽

Frequency Converters ◽

Plane Probe

Efficient and compact frequency converters are essential for frequency stabilization of terahertz sources. In this paper, we present a 3.5-THz, x6-harmonic, integrated Schottky diode mixer operating at room temperature. The designed frequency converter is based on a single-ended, planar Schottky diode with a sub-micron anode contact area defined on a suspended 2-um ultra-thin GaAs substrate. The dc-grounded anode pad was combined with the radio frequency E-plane probe, which resulted in an electrically compact circuit. At 200 MHz intermediate frequency, a mixer conversion loss of about 59 dB is measured resulting in a 40 dB signal-to-noise ratio in a phase-locking application. Using a quasi-static diode model combined with electromagnetic simulations, good agreement with the measured results was obtained. Harmonic frequency converters without the need of cryogenic cooling will help in the realization of highly sensitive space and air-borne heterodyne receivers.<br>

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Coupled Oscillators and Synchronization

Introduction to Modern Dynamics ◽

10.1093/oso/9780198844624.003.0006 ◽

2019 ◽

pp. 177-204

Author(s):

David D. Nolte

Keyword(s):

Phase Locking ◽

Beat Frequency ◽

Normal Modes ◽

Coupled Systems ◽

Torus Action ◽

Slow Phase ◽

Nonlinear Coupling ◽

Frequency Locking ◽

Frequency Entrainment ◽

Central Paradigm

Coupled linear oscillators provide a central paradigm for the combined behavior of coupled systems and the emergence of normal modes. Nonlinear coupling of two autonomous oscillators provides an equally important paradigm for the emergence of collective behavior through synchronization. Simple asymmetric coupling of integrate and fire oscillators captures the essence of frequency locking. Quasiperiodicity on the torus (action-angle oscillators) with nonlinear coupling demonstrates phase locking, while the sine-circle map is a discrete map that displays multiple Arnold tongues at frequency-locking resonances. External synchronization of a phase oscillator is analyzed in terms of the “slow” phase difference, resulting in a beat frequency and frequency entrainment that are functions of the coupling strength.

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