阅读说明：本技术 一种光学产生微波信号的装置 (Device for optically generating microwave signal ) 是由 刘铁园 徐荣辉 张先强 邓仕杰 陈明 苑立波 于 2020-07-20 设计创作，主要内容包括：本发明公开了一种光学产生微波信号的装置,包括窄线宽可调激光器(1)、第一光纤耦合器(2)、第一光放大器(3)、四端口光环形器(4)、第一布里渊增益光纤(5)、三端口光环形器(6)、第二布里渊增益光纤(7)、第二光放大器(8)、第二光纤耦合器(9)、第三光纤耦合器(10)、光电探测器(11)。窄线宽可调激光器(1)输出的激光做为布里渊泵浦,布里渊泵浦在第一布里渊增益光纤中发生受激布里渊散射产生一阶斯托克斯,一阶托克斯在第二布里渊增益光纤中发生级联受激布里渊散射产生三阶斯托克斯光,三阶斯托克斯与泵浦发生拍频,拍频光通过光电探测器转换为微波信号。该光生微波信号的结构简单,成本低,在光无线通信、微波光子及光纤传感中均具有应用前景。(The invention discloses a device for optically generating microwave signals, which comprises a narrow-linewidth adjustable laser (1), a first optical fiber coupler (2), a first optical amplifier (3), a four-port optical circulator (4), a first Brillouin gain optical fiber (5), a three-port optical circulator (6), a second Brillouin gain optical fiber (7), a second optical amplifier (8), a second optical fiber coupler (9), a third optical fiber coupler (10) and a photoelectric detector (11). Laser output by the narrow linewidth tunable laser (1) is used as Brillouin pumping, the Brillouin pumping generates stimulated Brillouin scattering in the first Brillouin gain fiber to generate first-order Stokes, the first-order Thanks generates cascade stimulated Brillouin scattering in the second Brillouin gain fiber to generate third-order Stokes, the third-order Stokes and the pumping generate beat frequency, and the beat frequency light is converted into microwave signals through a photoelectric detector. The photo-generated microwave signal has a simple structure and low cost, and has application prospects in optical wireless communication, microwave photon and optical fiber sensing.)

1. An apparatus for optically generating a microwave signal, comprising: the narrow-linewidth tunable laser comprises a narrow-linewidth tunable laser (1), a first optical fiber coupler (2), a first optical amplifier (3), a four-port optical circulator (4), a first Brillouin gain optical fiber (5), a three-port optical circulator (6), a second Brillouin gain optical fiber (7), a second optical amplifier (8), a second optical fiber coupler (9), a third optical fiber coupler (10) and a photoelectric detector (11).

2. The device for optically generating microwave signals is characterized in that: the output end of the narrow linewidth tunable laser (1) is connected with the A1 port of the first optical fiber coupler (2), the B1 port of the first optical fiber coupler (2) is connected with the input end of the first optical amplifier (3), the 41 port of the four-port optical circulator (4) is connected with the output end of the first optical amplifier (3), the 42 port of the four-port optical circulator (4) is connected with one end of the first Brillouin gain optical fiber (5), the 62 port of the three-port optical circulator (6) is connected with the other end of the first Brillouin gain optical fiber (5), the 61 port and the 63 port of the three-port optical circulator (6) are connected, the 43 port of the four-port optical circulator (4) is connected with one end of the second Brillouin gain optical fiber (7), the other end of the second Brillouin gain optical fiber (7) is connected with one end of the second optical amplifier (8), the 44 port of the four-port optical circulator (4) is connected with the D1 port of the second optical fiber coupler (9), the C1 port of the second optical fiber coupler (9) is connected with the other end of the second optical amplifier (8), the D2 port of the second optical fiber coupler (9) is connected with the F2 port of the third optical fiber coupler (10), the F1 port of the third optical fiber coupler (10) is connected with the B2 port of the first optical fiber coupler (2), and the E1 port of the third optical fiber coupler (10) is connected with the photodetector (11).

3. The device for optically generating microwave signals is characterized in that: laser output by the narrow linewidth tunable laser is taken as Brillouin Pump (BP), the Brillouin Pump (BP) is transmitted to a first optical fiber coupler (2) and then split, a part of BP is amplified by a first optical amplifier (3), and then is injected into a first Brillouin gain optical fiber (5) through a four-port optical circulator (4), and then stimulated Brillouin scattering occurs in the first Brillouin gain optical fiber to generate first-order Stokes (S1), S1 is injected into one end of a second Brillouin gain optical fiber (7) through the four-port optical circulator to generate second-order Stokes (S2), S2 enters a second optical amplifier (8) through the four-port optical circulator to be amplified, S2 is injected into the other end of the second Brillouin gain optical fiber, and then stimulated Brillouin scattering occurs in the second Brillouin gain optical fiber to generate S3, s3 is amplified by a second optical amplifier, transmitted to a third optical fiber coupler (10) through a second optical fiber coupler (9), and then subjected to beat frequency with BP from the first optical fiber coupler, and the beat frequency is converted into a microwave signal through a photoelectric detector (11).

4. The device for optically generating microwave signals is characterized in that: the first Brillouin gain fiber and the second Brillouin gain fiber have the same Brillouin frequency shift value.

5. The device for optically generating microwave signals is characterized in that: the second optical amplifier is an optical amplifier capable of bidirectional amplification.

Technical Field

The invention relates to a communication technology, an optical fiber laser technology and a microwave photon technology, in particular to a device for optically generating microwave signals.

Background

The increasing demand for high definition video and various multimedia devices in recent years has led to rapid development of wireless communication technology and optical fiber communication technology. With the development trend, microwave photonics is produced and becomes a research hotspot. The photo-generated microwave technology is used as the most important content in microwave photonics, has the advantages of high frequency, low phase noise, compact structure and the like, and is applied to the fields of microwave communication, satellite communication, radar systems, radio astronomy, microwave remote sensing, optical fiber wireless communication, terahertz spectrum analysis and the like.

There are many methods for generating microwave signals in the optical microwave technology, such as optical heterodyne method, external modulation method, and optoelectronic oscillator method. The variation of the frequency of the laser source signal and the noise in the optical heterodyne method have a great influence on the stability and the purity of the beat frequency signal. External modulation requires the use of a microwave source and modulator and stability is affected by them. The optoelectronic oscillator method requires many optoelectronic devices, which makes the structure very complicated and difficult to integrate.

Disclosure of Invention

The invention provides a device for optically generating microwave signals, which can obtain higher broadband and high-speed microwave signals. The method and the device structure realized by the method are simpler than the prior structure.

The invention adopts the following technical scheme for realizing the purpose:

an apparatus for optically generating a microwave signal, comprising: the narrow-linewidth tunable laser comprises a narrow-linewidth tunable laser (1), a first optical fiber coupler (2), a first optical amplifier (3), a four-port optical circulator (4), a first Brillouin gain optical fiber (5), a three-port optical circulator (6), a second Brillouin gain optical fiber (7), a second optical amplifier (8), a second optical fiber coupler (9), a third optical fiber coupler (10) and a photoelectric detector (11).

The connection relationship of the microwave signal optical generating device is as follows: the output end of the narrow linewidth tunable laser (1) is connected with the A1 port of the first optical fiber coupler (2), the B1 port of the first optical fiber coupler (2) is connected with the input end of the first optical amplifier (3), the 41 port of the four-port optical circulator (4) is connected with the output end of the first optical amplifier (3), the 42 port of the four-port optical circulator (4) is connected with one end of the first Brillouin gain optical fiber (5), the 62 port of the three-port optical circulator (6) is connected with the other end of the first Brillouin gain optical fiber (5), the 61 port and the 63 port of the three-port optical circulator (6) are connected, the 43 port of the four-port optical circulator (4) is connected with one end of the second Brillouin gain optical fiber (7), the other end of the second Brillouin gain optical fiber (7) is connected with one end of the second optical amplifier (8), the 44 port of the four-port optical circulator (4) is connected with the D1 port of the second optical fiber coupler (9), the C1 port of the second optical fiber coupler (9) is connected with the other end of the second optical amplifier (8), the D2 port of the second optical fiber coupler (9) is connected with the F2 port of the third optical fiber coupler (10), the F1 port of the third optical fiber coupler (10) is connected with the B2 port of the first optical fiber coupler (2), and the E1 port of the third optical fiber coupler (10) is connected with the photodetector (11).

The process of generating microwave signals by the microwave signal optical generating device is as follows: laser output by the narrow linewidth tunable laser is used as a Brillouin Pump (BP), the Brillouin Pump (BP) is transmitted to a first optical fiber coupler (2) and then split, a part of the BP is amplified by a first optical amplifier (3) and then is injected into a first Brillouin gain optical fiber (5) through a four-port optical circulator (4), when the power of the BP is enough, stimulated Brillouin scattering of the BP occurs in the first Brillouin gain optical fiber to generate first-order Stokes (S1), the three-port optical circulator (6) plays the role of an optical reflector, possibly existing BP transmission light in the first Brillouin gain optical fiber can be reflected back to the first Brillouin gain optical fiber to enhance S1, S1 is injected into one end of a second Brillouin gain optical fiber (7) through the four-port optical circulator, when the power of S1 is larger than the stimulated Brillouin scattering threshold of the second Brillouin gain optical fiber, stimulated brillouin scattering occurs in the second brillouin gain fiber to generate second-order stokes (S2), S2 enters the second optical amplifier (8) through the four-port optical circulator and the second fiber coupler (9) to be amplified, the amplified S2 is injected into the other end of the second brillouin gain fiber, when the power of S2 is greater than the stimulated brillouin scattering threshold of the second brillouin gain fiber, stimulated brillouin scattering occurs in the second brillouin gain fiber to generate S3, and after S3 is amplified by the second optical amplifier, and then transmitted to a third optical fiber coupler (10) through a second optical fiber coupler (9), S3 and BP from the first optical fiber coupler generate beat frequency at the third optical fiber coupler, the beat frequency enters a photoelectric detector (11) through an E1 port of the third optical fiber coupler to be converted into a microwave signal, and the microwave signal can be observed through a spectrum analyzer.

The output laser line width of the narrow line width adjustable laser is lower than 1MHz, the output wavelength and the power can be continuously tuned, the output power is 15mW, and the wavelength range is C + L wave band.

The first optical amplifier and the second optical amplifier are self-lapping erbium-doped optical fiber amplifiers, and are formed by connecting a 980nm or 1480nm pump laser, a 1550nm/980nm or 1550nm/1480nm wavelength division multiplexer and a section of erbium-doped optical fiber, so that bidirectional optical amplification can be realized.

The first Brillouin gain fiber and the second Brillouin gain fiber are both single-mode quartz fibers, and have the same Brillouin frequency shift value and the length of 20 km.

The first optical fiber coupler, the second optical fiber coupler and the third optical fiber coupler are all single-mode optical fiber couplers.

The four-port optical circulator and the three-port optical circulator are both single-mode optical fiber optical circulators.

Drawings

FIG. 1 is a schematic diagram of a device for optically generating a microwave signal.

The reference numerals in the figures are to be interpreted: 1-narrow linewidth tunable laser, 2-first optical fiber coupler, a 1-port of the first optical fiber coupler a, B1-first port of the first optical fiber coupler B, B2-second port of the first optical fiber coupler B, 3-first optical amplifier, 4-four port optical circulator, 41-first port of four port optical circulator, 42-second port of four port optical circulator, 43-third port of four port optical circulator, 44-fourth port of four port optical circulator, 5-first brillouin gain fiber, 6-three port optical circulator, 61-first port of three port optical circulator, 62-second port of three port optical circulator, 63-third port of optical circulator, 7-second brillouin gain fiber, 8-a second optical amplifier, 9-a second optical fiber coupler, C1-a port at the C end of the second optical fiber coupler, D1-a first port at the D end of the second optical fiber coupler, D2-a second port at the D end of the second optical fiber coupler, 10-a third optical fiber coupler, E1-a port at the E end of the third optical fiber coupler, F1-a first port at the F end of the third optical fiber coupler, F2-a second port at the F end of the third optical fiber coupler, and 11-a photodetector.

Detailed Description

The technical scheme of the invention is further explained by combining the attached drawings.

An apparatus for optically generating a microwave signal, comprising: the narrow-linewidth tunable laser comprises a narrow-linewidth tunable laser (1), a first optical fiber coupler (2), a first optical amplifier (3), a four-port optical circulator (4), a first Brillouin gain optical fiber (5), a three-port optical circulator (6), a second Brillouin gain optical fiber (7), a second optical amplifier (8), a second optical fiber coupler (9), a third optical fiber coupler (10) and a photoelectric detector (11).

In the device for optically generating microwave signals, the output end of a narrow-linewidth tunable laser (1) is connected with the port A1 of a first optical fiber coupler (2), the port B1 of the first optical fiber coupler (2) is connected with the input end of a first optical amplifier (3), the port 41 of a four-port optical circulator (4) is connected with the output end of the first optical amplifier (3), the port 42 of the four-port optical circulator (4) is connected with one end of a first Brillouin gain optical fiber (5), the port 62 of a three-port optical circulator (6) is connected with the other end of the first Brillouin gain optical fiber (5), the port 61 and the port 63 of the three-port optical circulator (6) are connected, the port 43 of the four-port optical circulator (4) is connected with one end of a second Brillouin gain optical fiber (7), the other end of the second Brillouin gain optical fiber (7) is connected with one end of a second optical amplifier (8), the 44 port of the four-port optical circulator (4) is connected with the D1 port of the second optical fiber coupler (9), the C1 port of the second optical fiber coupler (9) is connected with the other end of the second optical amplifier (8), the D2 port of the second optical fiber coupler (9) is connected with the F2 port of the third optical fiber coupler (10), the F1 port of the third optical fiber coupler (10) is connected with the B2 port of the first optical fiber coupler (2), and the E1 port of the third optical fiber coupler (10) is connected with the photodetector (11).

The device for optically generating microwave signals comprises the following processes of: laser output by the narrow linewidth tunable laser is used as a Brillouin Pump (BP), the Brillouin Pump (BP) is transmitted to a first optical fiber coupler (2) and then split, a part of the BP is amplified by a first optical amplifier (3) and then is injected into a first Brillouin gain optical fiber (5) through a four-port optical circulator (4), when the power of the BP is enough, stimulated Brillouin scattering of the BP occurs in the first Brillouin gain optical fiber to generate first-order Stokes (S1), the three-port optical circulator (6) plays the role of an optical reflector, possibly existing BP transmission light in the first Brillouin gain optical fiber can be reflected back to the first Brillouin gain optical fiber to enhance S1, S1 is injected into one end of a second Brillouin gain optical fiber (7) through the four-port optical circulator, when the power of S1 is larger than the stimulated Brillouin scattering threshold of the second Brillouin gain optical fiber, stimulated brillouin scattering occurs in the second brillouin gain fiber to generate second-order stokes (S2), S2 enters the second optical amplifier (8) through the four-port optical circulator and the second fiber coupler (9) to be amplified, the amplified S2 is injected into the other end of the second brillouin gain fiber, when the power of S2 is greater than the stimulated brillouin scattering threshold of the second brillouin gain fiber, stimulated brillouin scattering occurs in the second brillouin gain fiber to generate S3, and after S3 is amplified by the second optical amplifier, and then transmitted to a third optical fiber coupler (10) through a second optical fiber coupler (9), S3 and BP from the first optical fiber coupler generate beat frequency at the third optical fiber coupler, the beat frequency enters a photoelectric detector (11) through an E1 port of the third optical fiber coupler to be converted into a microwave signal, and the microwave signal can be observed through a spectrum analyzer.

The output laser line width of the narrow line width adjustable laser is lower than 1MHz, the output wavelength and the power can be continuously tuned, the output power is 15mW, and the wavelength range is C + L wave band.

The first optical amplifier and the second optical amplifier are self-lapping erbium-doped optical fiber amplifiers and are formed by connecting a 980nm or 1480nm pump laser, a 1550nm/980nm or 1550nm/1480nm wavelength division multiplexer and a section of 6m erbium-doped optical fiber, and the output power of the 980nm or 1480nm pump laser is 400mW and is continuously adjustable.

The first Brillouin gain fiber and the second Brillouin gain fiber are both single-mode quartz fibers, and the Brillouin frequency shift values are the same, 10.85GHz and 20km in length.

The first optical fiber coupler, the second optical fiber coupler and the third optical fiber coupler are all three-port single-mode optical fiber couplers.

The four-port optical circulator and the three-port optical circulator are both single-mode optical fiber optical circulators.

The photoelectric detector is a photoelectric detector with the bandwidth larger than 33 GHz.

While the operation of the present invention has been described in detail, it will be apparent to those skilled in the art that variations in the specific embodiments, such as the type of fiber amplifier, the location of the fiber amplifier, other schemes with the same effect as the three-port optical circulator, etc., are possible according to the concept provided by the present invention, and such variations should be considered as the protection scope of the present invention.