JP2013123068A5 - - Google Patents

Description

In the atomic oscillator 1 having such a configuration, the frequency difference between the first sideband wave W1 and the second sideband wave W2 of the first light L1 generated by the semiconductor laser 110 is the two ground levels of alkali metal atoms contained in the gas cell 130. Since the alkali metal atom does not cause the EIT phenomenon unless it exactly matches the frequency corresponding to the energy difference between the first sideband wave W1 and the second sideband wave W2, the detection amount of the photodetector 140 is It changes very sensitively. Therefore, due to the feedback loop passing through the semiconductor laser 110, the wavelength selection element 120, the gas cell 130, the photodetector 140, and the modulation circuit 160, the frequency difference between the first sideband W1 and the second sideband W2 is 2 of the alkali metal atom. Feedback control is applied so as to match the frequency corresponding to the energy difference between the two ground levels very accurately. As a result, since the modulation frequency becomes a very stable frequency, the modulation signal can be used as the output signal (clock output) of the atomic oscillator 1.

Here, the wavelength selection element 120 has been described is an etalon, the wavelength selection element 120 may be a fiber grating that gave a periodic refractive index variation in the longitudinal direction in the core of the optical fiber. Since the fiber grating uses an optical fiber, it can be easily deformed and the degree of design freedom can be improved.

By using an edge-emitting laser as the semiconductor laser 110, it is possible to emit laser light perpendicular to the stacking direction of the layers 112, 114, and 116 of the semiconductor laser 110. Therefore, alignment between the semiconductor laser 110 and the wavelength selection element 120 can be performed by controlling the film thickness of each of the layers 112, 114, and 116. Furthermore, for example, an optical element such as a prism for making the laser beam incident on the wavelength selection element 120 formed on the same substrate 170 becomes unnecessary. Therefore, the alignment accuracy between the semiconductor laser 110 and the wavelength selection element 120 can be improved.

Claims (9)

An optical module of the original child oscillator,
A basic wave, a side band of the fundamental wave having a smaller intensity than the intensity of the fundamental wave, a light source for generating a first light containing,
Said first light is incident, the wavelength selection means makes the injection a second light including said fundamental wave the strength is less than the said sideband sideband,
Encapsulating the A alkali metal gas, and the gas cell to the second light is irradiated,
And an optical detection means for detecting an intensity of the second light transmitted through the gas cell. In claim 1,
The optical module, wherein the wavelength selection means is an etalon. In claim 2,
The etalon is
A first mirror and a second mirror that reflect the first light and face each other;
A substrate disposed between the first mirror and the second mirror,
An optical module in which the material of the substrate is a compound semiconductor. In claim 3,
And further including a substrate,
The material of the substrate is a compound semiconductor,
The light source is a semiconductor laser;
The etalon and the light source are optical modules formed on a base. In claim 4,
The substrate of the etalon has a first layer, a second layer, and a third layer formed in order from the base side,
The refractive index of the first layer and the refractive index of the third layer are smaller than the refractive index of the second layer,
The second layer is an optical module for propagating the first light. In claim 4 or 5,
The optical module is an optical module, wherein the light source is an edge-emitting laser. In any one of Claims 1 thru | or 5,
The optical module, wherein the light source is a surface emitting laser. In claim 1,
The optical module, wherein the wavelength selection means is a fiber grating.   An atomic oscillator comprising the optical module according to claim 1.