JPS5845215B2 - Gas cell type atomic oscillator - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in gas cell type atomic oscillators.

Conventionally, atomic oscillators, which control crystal oscillators based on the resonance frequencies of atoms and molecules, have been used as high-precision frequency generation sources because of their extremely high long-term frequency stability.

However, the atomic oscillator has the disadvantage of being large, and the same applies to the gas cell type atomic oscillator, which can be realized in a relatively small size among atomic oscillators.

FIG. 1 shows a block diagram of this gas cell type atomic oscillator.

In the figure, 1 is a lamp cell, 2 is a filter cell, and 3 is an atomic resonance cell, each of which is sealed with low pressure Rb.

4 is a microwave resonator, and 5 is a photodetector.

The operation of this device is to input the output of a voltage controlled crystal oscillator 6 to a frequency multiplier/synthesizer 7 as a multiplier, further modulate it in a modulation oscillator 8, and input it to a microwave resonator 4 accommodating a resonant cell.

As a result, the resonance of the optically pumped resonant cell 3 is detected by the photodetector 5, this detected signal is amplified by the amplifier 9, and the phase of this signal is detected by the phase detector 10 connected to the modulation oscillator 8. Then, the low frequency waveform unit 11
The oscillation frequency is input to the voltage controlled crystal oscillator 6 via the atomic resonance cell 3, and its oscillation frequency is adjusted to have a constant relationship with the resonant frequency of the atomic resonance cell 3, so that stable oscillation is always performed.

Therefore, in such a gas cell type atomic oscillator, an oscillator with a constant temperature bath using a high Q crystal oscillator is used as the voltage controlled crystal oscillator to improve short-term frequency stability, and an oscillator equipped with a constant temperature chamber is used as the voltage controlled crystal oscillator. In order to increase the S/N of the signal and to ensure the stability of the atomic resonance frequency, each of the atomic resonance cell, filter cell, and lamp cell requires a constant temperature bath in order to maintain their respective temperatures constant.

Therefore, it is larger and consumes more power than a general highly stable crystal oscillator for frequency standards.

The present invention has been devised to improve this drawback.

Therefore, the present invention provides a gas cell type atomic oscillator comprising an atomic resonance cell, a lamp cell and voltage controlled crystal oscillator for exciting the atomic resonance cell, and a photodetector for detecting resonance of the atomic resonance cell. This patent is characterized in that a resonance cell and a lamp cell are housed in the same thermostatic oven, and a crystal resonator of the voltage-controlled crystal oscillator is thermally coupled to the thermostatic oven.

Embodiments of the present invention will be described in detail below based on the accompanying drawings.

FIG. 2 shows a sectional view of the embodiment.

In the figure, 12 is an atomic resonance cell, and 13 is a lamp cell, and the atomic resonance cell 12 and the lamp cell 13 are housed in the same thermostatic chamber 14.

This constant temperature bath 14 also serves as a microwave resonator, and is equipped with a heater 15 for heating, and is maintained at a constant temperature by a temperature controller 16.

Further, a recessed portion is formed in a part of this constant temperature oven 14, and a crystal resonator 18 of a voltage controlled crystal oscillator 1T is attached thereto and thermally coupled thereto.

Note that 19 is a lamp exciter that excites the lamp cell 13;
16 is an outer casing that also serves as a magnetic shield for 1, and 16 is equipped with an amplifier and a photodetector 21 in addition to a temperature controller.
7 is equipped with electric circuits such as a frequency multiplier and synthesizer in addition to a voltage controlled crystal oscillator.

This embodiment, which is configured in this way, has only one thermostat to keep the atomic resonance cell, lamp cell, and crystal oscillator at a constant temperature, so it can significantly reduce power consumption and make the device more compact than before. In the past, the atomic resonance cell and the lamp cell had different appropriate temperatures, so separate thermostats were required for each. However, for example, in the case of a rubidium atomic oscillator, natural rubidium (Rb85 and R
1, , 87), it is possible to make the temperature the same as that of the lamp cell, and the filter 2 shown in FIG. 1 is no longer necessary.

As explained above, the gas cell type atomic oscillator of the present invention uses only one thermostatic chamber, which accounts for most of its power consumption, thereby making it possible to achieve lower power consumption, smaller size, and lower cost. be.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional gas cell type atomic oscillator, and FIG. 2 is a schematic diagram showing a cross section of a gas cell type atomic oscillator according to an embodiment of the present invention. 12... Atomic resonance cell, 13... Lamp cell, 14... Constant temperature chamber/microwave resonator,
15...Heater, 16...Amplifier and temperature controller, 17...Voltage controlled crystal oscillator and frequency multiplication synthesizer, 18...Crystal resonator,
19...Lamp exciter, 20...Outer casing, 21...Photodetector.

Claims (1)

[Claims] 1. A gas cell type atomic oscillator comprising an atomic resonance cell, a lamp cell and voltage-controlled crystal oscillator for exciting the atomic resonance cell, and a photodetector for detecting resonance of the atomic resonance cell, in which the atomic resonance cell and the lamp cell and a gas cell type atomic oscillator O, characterized in that the crystal resonator of the voltage controlled crystal oscillator is thermally coupled to the thermostatic chamber.