CN112490829A

CN112490829A - Method for generating GHz-level white noise electric signal

Info

Publication number: CN112490829A
Application number: CN201910857058.0A
Authority: CN
Inventors: 尹冬; 薛晓敏; 张贵平
Original assignee: Shanghai Kenaite Laser Technology Co ltd
Current assignee: Shanghai Kenaite Laser Technology Co ltd
Priority date: 2019-09-11
Filing date: 2019-09-11
Publication date: 2021-03-12
Anticipated expiration: 2039-09-11
Also published as: CN112490829B

Abstract

The invention discloses a method for generating GHz level white noise electric signals, which adopts a noise signal generating device comprising an amplified spontaneous emission ASE light source, a fiber grating, a photoelectric detector and a circulator to generate the GHz level white noise electric signals, wherein the circulator is a three-port circulator, a port 1 of the circulator is used as an input end and connected with the ASE light source, a port 2 of the circulator is used as an output end and connected with the fiber grating, a port 3 of the circulator is used as a return light output end and connected with the photoelectric detector, reflected light of the circulator passes through the photoelectric detector, and the photoelectric detector outputs the required white noise electric signals after the system runs.

Description

Method for generating GHz-level white noise electric signal

Technical Field

The invention belongs to the technical field of optoelectronics and laser optics, and particularly relates to a method for generating a GHz-level white noise electric signal.

Background

White noise is noise having equal noise energy in a wide frequency range and in a frequency band of equal bandwidth, and such a signal has wide applications in the fields of communications, electronics, and the like.

In the laser field, the nonlinear effect threshold of the laser can be effectively improved by widening the single-frequency laser and amplifying the laser again, and the high-power laser of a single longitudinal mode is obtained. The single-frequency laser is widened by loading a white noise signal through the electro-optical modulator, which is an important widening mode. However, a white noise signal required by a high-power amplifier requires a GHz level and has a higher requirement on amplitude, a noise signal generated by a common electrical signal generator in the GHz level often has a very low amplitude, and generally, a noise signal generator above a giga generally adopts a solid-state noise source (capable of working in a whole frequency band below 18 GHz) of noise in a reverse current of a crystal diode, and the general amplitude of the noise is below 20mV, and the noise cannot be directly used for the high-power amplifier (an electro-optical modulator for broadening matched with the high-power amplifier needs an amplitude input of 400mV and above), and the required amplitude can be reached by amplifying again, but an amplification system has a more complicated structure and a very high cost.

Disclosure of Invention

In view of the above technical problems, the present invention is directed to providing a method for generating a white noise signal in GHz level.

In order to solve the technical problems, the invention adopts the following technical scheme:

a method for generating GHz-level white noise electric signals adopts a noise signal generating device comprising an amplified spontaneous emission ASE light source, a fiber grating, a photoelectric detector and a circulator to generate the GHz-level white noise electric signals, wherein the circulator is a three-port circulator, a port 1 of the circulator is used as an input end and connected with the ASE light source, a port 2 of the circulator is used as an output end and connected with the fiber grating, a port 3 of the circulator is used as a return light output end and connected with the photoelectric detector, reflected light reflected by the fiber grating passes through the circulator to the photoelectric detector, and the photoelectric detector outputs the required white noise electric signals after the system operates.

Preferably, the ASE light source structure adopts a single-mode pump with added protection to inject the single-mode pump into the gain fiber through the WDM, so that the fiber radiates spontaneously, which is the output light of the ASE light source.

Preferably, the output optical power of the ASE light source is 100mW, and the ASE light source is broadband spectrum output within the spontaneous emission bandwidth of the optical fiber; the gain optical fiber is ytterbium-doped gain optical fiber or erbium-doped gain optical fiber, if the ytterbium-doped gain optical fiber is selected, the output is 1 micron, and if the erbium-doped gain optical fiber is selected, the output is 1.5 microns.

Preferably, the reflection spectrum of the fiber grating is a uniform grating within the spectrum width of the ASE light source, the fiber grating is a high-reflectivity grating, and the reflectivity is more than 99%.

Preferably, the core device of the photodetector is a fiber-optic input photodiode, and the sensing wavelength range of the selected photodiode should include the reflection spectrum of the grating.

Preferably, the photodiode is a silicon photodiode, a germanium photodiode or an InGaAs photodiode. The invention has the following beneficial effects: high bandwidth, high amplitude white noise output can be achieved at a lower cost. For practitioners of fiber laser, the ASE light source is a laser type with low manufacturing difficulty, and the fiber grating, the circulator and the detector involved in the method belong to general products which are convenient to obtain and do not need to be customized.

Drawings

FIG. 1 is a schematic structural diagram of a white noise signal generator in the method for generating a white noise signal of GHz level according to an embodiment of the present invention;

FIG. 2 is an actual electrical signal output measured by the method of the present invention;

FIG. 3 is a detailed view of the amplitude of the actual electrical signal output measured by the method of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The embodiment of the invention provides a method for generating a GHz-level white noise electric signal, which adopts a noise signal generating device (see the structure in figure 1) comprising an amplified spontaneous emission ASE light source, a fiber grating, a photoelectric detector and a circulator to generate the GHz-level white noise electric signal, wherein the circulator is a three-port circulator, a port 1 of the circulator is used as an input end and connected with the ASE light source, a port 2 of the circulator is used as an output end and connected with the fiber grating, a port 3 of the circulator is used as a return light output end and connected with the photoelectric detector, reflected light of the circulator passes through the photoelectric detector, and the photoelectric detector outputs the required white noise electric signal after the system operates.

In the concrete application example, the ASE light source, the wide spectrum light source, the power is stable, its structure is to use and add the monomode pumping of protection and inject the gain fiber through WDM, thus make the fiber spontaneous radiation, the spontaneous emission light is the output light of ASE light source, the spectrum is related to the kind of gain fiber, this example adopts the gain fiber doped with ytterbium. The reflection spectrum is a uniform grating within the spectrum width of the ASE light source, the fiber grating is a high-reflectivity grating, and the reflectivity is more than 99%.

In a specific application example, a core device of the photodetector is a photodiode with optical fiber input, the example selects an InGaAs photodiode, the sensing wavelength range of the photodiode should include a reflection spectrum of a grating, and the photodiode includes a circuit for supplying power to the photodiode and a circuit for outputting a signal of the photodiode except the core device, and does not include a circuit for processing a diode signal.

Further, the output optical power of the ASE light source is 100mW, and the ASE light source outputs in a broad spectrum within the spontaneous radiation bandwidth of the optical fiber; the gain optical fiber is ytterbium-doped gain optical fiber or erbium-doped gain optical fiber, if the ytterbium-doped gain optical fiber is selected, the output is 1 micron, and if the erbium-doped gain optical fiber is selected, the output is 1.5 microns.

Further, the photodiode is a silicon photodiode, a germanium photodiode, or an InGaAs photodiode.

The method for generating GHz level white noise electric signals through the method is characterized in that an ASE light source outputs wide-spectrum laser with stable power, the wide-spectrum laser is connected to a fiber grating through a circulator, the fiber grating reflects light in the bandwidth of the fiber grating in the wide-spectrum light source, meanwhile, due to the characteristics of the fiber grating, the part of reflected light has noise on the power spectrum, the part of light noise is consistent with required electric noise in nature, the circulator separates incident light of the ASE light source from reflected light of the fiber grating, and the reflected light is output to a photoelectric detector from a port 3 of the circulator. The laser output with noise signal is converted into electric signal by photoelectric detector, and the noise information is converted out, so that the electric signal shown in fig. 2 is realized, the noise bandwidth reaches above GHz, the noise of electric signal is uniform, and the characteristics of electric signal are consistent with those of white noise. As can be seen in FIG. 3, the noise amplitude of the electrical signal is about 400mV, which reaches a higher amplitude.

It is to be understood that the exemplary embodiments described herein are illustrative and not restrictive. Although one or more embodiments of the present invention have been described with reference to the accompanying drawings, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

Claims

1. A method for generating GHz level white noise electric signal is characterized in that a noise signal generating device comprising an amplified spontaneous emission ASE light source, a fiber grating, a photoelectric detector and a circulator is adopted to generate GHz level white noise electric signal, the circulator is a three-port circulator, a port 1 of the circulator is used as an input end and connected with the ASE light source, a port 2 of the circulator is used as an output end and connected with the fiber grating, a port 3 of the circulator is used as a return light output end and connected with the photoelectric detector, reflected light reflected by the fiber grating passes through the circulator to the photoelectric detector, and after a system runs, the photoelectric detector outputs the required white noise electric signal.

2. The method of generating a white noise signal in the GHz level according to claim 1, wherein the ASE light source structure injects a single-mode pump with added protection into the gain fiber through the WDM, so that the fiber spontaneously radiates, i.e., the output light of the ASE light source.

3. The method of generating a white noise electrical signal of GHz level as claimed in claim 2, wherein the ASE source has an output optical power of 100mW and a broad spectral output within the spontaneous emission bandwidth of the optical fiber; the gain optical fiber is ytterbium-doped gain optical fiber or erbium-doped gain optical fiber, if the ytterbium-doped gain optical fiber is selected, the output is 1 micron, and if the erbium-doped gain optical fiber is selected, the output is 1.5 microns.

4. The method of generating a white noise electrical signal in the GHz level according to claim 1, wherein the fiber grating has a uniform grating with a reflection spectrum within the spectral width of the ASE light source, the fiber grating is a high reflectivity grating, and the reflectivity is greater than 99%.

5. The method of generating a white noise signal in the GHz range according to claim 1, wherein the core device of the photodetector is a fiber-optic input photodiode, and the sensing wavelength range of the selected photodiode should include the reflection spectrum of the grating.

6. The method of generating a white noise signal in the GHz level as claimed in claim 5 wherein the photodiode is a silicon photodiode, a germanium photodiode or an InGaAs photodiode.