Optical frequency control device, optical oscillation device, frequency conversion device, and radio wave generation device

Patent metadata

Field	Value
Publication number	US-2022244617-A1
Application number	US-202217712667-A
Country	US
Kind code	A1
Filing date	Apr 4, 2022
Priority date	Nov 19, 2019
Publication date	Aug 4, 2022
Grant date	—

Abstract

An optical frequency control device includes: a detection circuit to receive first light including a first frequency, receive second light including a second frequency, modulate the first light with a local oscillation signal, and detect a differential beat signal between the frequency of sideband light included in the modulated first light and the second frequency; a light source control circuit to change the second frequency by frequency-dividing the differential beat signal with a first frequency division number, by frequency-dividing a reference signal with a second frequency division number, and by outputting a phase error signal indicating a phase difference between the frequency-divided differential beat signal and the frequency-divided reference signal; and a signal processing unit to set each of the first frequency division number and the second frequency division number according to the set value of a frequency difference between the first frequency and the second frequency.

First claim

1 . An optical frequency control device, comprising:
a detection circuit to receive first light including a first frequency from a first light source, receive second light including a second frequency from a second light source, modulate the first light with a local oscillation signal oscillated by a first local oscillation signal source, and detect a differential beat signal including a differential frequency between a frequency of sideband light included in the first light, which is modulated, and the second frequency; a light source control circuit to change the second frequency included in the second light oscillated by the second light source by frequency-dividing a differential beat signal detected by the detection circuit with a first frequency division number, by frequency-dividing a reference signal oscillated by a reference signal source with a second frequency division number, and by outputting, to the second light source, a phase error signal, which indicates a phase difference between the differential beat signal after the frequency division and the reference signal after the frequency division number; and a signal processor to set each of a first frequency division number and a second frequency division number in accordance with a set value of a frequency difference between the first frequency division number and the second frequency division number.

2 . The optical frequency control device according to claim 1 , wherein the signal processor determines an order of the sideband light on a basis of the set value and sets the first frequency division number in accordance with each of the set value and the order.

3 . The optical frequency control device according to claim 1 , wherein the signal processor switches a polarity of a phase error signal output from the light source control circuit.

4 . The optical frequency control device according to claim 2 , further comprising a power regulator to regulate power of a local oscillation signal oscillated by the first local oscillation signal source,
wherein the signal processor controls regulation of power by the power regulator on a basis of an order of the sideband light.

5 . The optical frequency control device according to claim 1 , wherein the detection circuit modulates the second light oscillated by the second light source with a local oscillation signal oscillated by a second local oscillation signal source, and detects
a differential beat signal including a differential frequency between a frequency of sideband light included in the first light after modulation and a frequency of sideband light included in the second light after modulation, instead of detecting a differential beat signal including a differential frequency between the frequency of the sideband light and the second frequency.

6 . The optical frequency control device according to claim 1 , wherein the detection circuit modulates the second light oscillated by the second light source with a local oscillation signal oscillated by a first local oscillation signal source, and detects
a differential beat signal including a differential frequency between a frequency of sideband light included in the first light after modulation and a frequency of sideband light included in the second light after modulation, instead of detecting a differential beat signal including a differential frequency between the frequency of the sideband light and the second frequency.

7 . The optical frequency control device according to claim 1 , wherein the light source control circuit regulates a frequency of a local oscillation signal oscillated by the first local oscillation signal source by outputting the phase error signal to the first local oscillation signal source.

8 . An optical oscillation device comprising:
the optical frequency control device according to claim 1 ; a first light source to oscillate first light; a second light source to oscillate second light; a first local oscillation signal source to oscillate a local oscillation signal; and a reference signal source to oscillate a reference signal.

9 . The optical oscillation device according to claim 8 , wherein the signal processor outputs a first control signal for controlling a first frequency included in first light oscillated by the first light source and a second control signal for controlling a second frequency included in second light oscillated by the second light source in accordance with the set value,
the first light source changes a first frequency included in the first light in accordance with the first control signal output from the signal processor, and the second light source changes a second frequency included in the second light in accordance with each of a phase error signal output from the light source control circuit and the second control signal output from the signal processor.

10 . The optical oscillation device according to claim 9 , wherein the signal processor regulates each of the first control signal and the second control signal on a basis of a phase error signal output from the light source control circuit.

11 . The optical oscillation device according to claim 8 , further comprising:
a first optical distributor to distribute the light oscillated by the first light source, output one light after the distribution to the detection circuit, and output another light after the distribution as one light in offset locking light; and a second optical distributor to distribute the light oscillated by the second light source, to output one light after the distribution to the detection circuit, and to output the other light after the distribution as another light in the offset locking light.

12 . The optical oscillation device according to claim 8 , further comprising a second local oscillation signal source to oscillate a local oscillation signal,
wherein the detection circuit modulates the second light oscillated by the second light source with a local oscillation signal oscillated by the second local oscillation signal source, and detects a differential beat signal including a differential frequency between a frequency of sideband light included in the first light after modulation and a frequency of sideband light included in the second light after modulation, instead of detecting a differential beat signal including a differential frequency between the frequency of the sideband light and the second frequency.

13 . The optical oscillation device according to claim 8 , wherein the detection circuit modulates the second light oscillated by the second light source with a local oscillation signal oscillated by the first local oscillation signal source, and detects
a differential beat signal including a differential frequency between a frequency of sideband light included in the first light after modulation and a frequency of sideband light included in the second light after modulation, instead of detecting a differential beat signal including a differential frequency between the frequency of the sideband light and the second frequency.

14 . The optical oscillation device according to claim 8 ,
wherein the light source control circuit outputs the phase error signal to the first local oscillation signal source, and the first local oscillation signal source regulates a frequency of an oscillating local oscillation signal in accordance with the phase error signal output from the light source control circuit.

15 . The optical oscillation device according to claim 8 , wherein one or more of the first light source, the second light source, and the detection circuit are integrated as a planar lightwave circuit.

Assignees

• Mitsubishi Electric Corp

Inventors

• Nishioka Junya
• Akiyama Tomohiro
• Takemoto Yuta
• Ando Toshiyuki

Classifications

• H01S5/0687

  Stabilising the frequency of the laser · CPC title

• H01S5/06837

  Stabilising otherwise than by an applied electric field or current, e.g. by controlling the temperature · CPC title

• H01S5/06817

  Noise reduction · CPC title

• H01S5/4087

  emitting more than one wavelength · CPC title

• G02F1/353

  Frequency conversion, i.e. wherein a light beam is generated with frequency components different from those of the incident light beams · CPC title