CN114243431A

CN114243431A - Optical amplifier

Info

Publication number: CN114243431A
Application number: CN202111545087.7A
Authority: CN
Inventors: 阮于华; 郑睿
Original assignee: Suzhou Yirui Optoelectronics Technology Co ltd
Current assignee: Suzhou Yirui Optoelectronics Technology Co ltd
Priority date: 2021-12-16
Filing date: 2021-12-16
Publication date: 2022-03-25

Abstract

The application discloses optical amplifier, optical amplifier includes: the optical function device, the front gain device and the rear gain device; the optical function device is provided with a first end and a second end which are opposite, the first end of the optical function device is used for receiving an input light beam, and the light beam is output through the second end of the optical function device; the post gain device is arranged at the second end of the optical function device and is used for receiving the light beam passing through the second end of the optical function device and gaining the light beam passing through the second end of the optical function device; the pre-gain device is arranged at the first end of the optical function device, the pre-gain device is used for receiving the light beam passing through the post-gain device, and the optical function device is multiplexed to receive the light beam gained by the pre-gain device. Through the multiplexing of light functional device, the light amplifier of this application has the advantage of saving space, can realize the effect of the whole miniaturization of light amplifier.

Description

Optical amplifier

Technical Field

The present application relates to the field of optical communication technologies, and in particular, to an optical amplifier.

Background

In the field of optical communication, optical power attenuation of signal light due to transmission loss, beam splitting, and the like often occurs in signal light, and an optical amplifier can amplify the signal light, and is an indispensable device or equipment in the field of optical transmission.

Optical amplifiers typically use stimulated emission of a multi-level laser species to achieve amplification of input signal light. From the initial xenon lamp pumped red sapphire optical amplifier to the present semiconductor optical amplifier and optical fiber amplifier, the optical amplifier has high cost, short service life and unstable operation to the present low cost, and the service life of the optical amplifier can reach decades. Especially in the field of optical fiber communication, optical fiber amplifiers and semiconductor optical amplifiers have become indispensable key devices or devices in the field of optical transmission.

The conventional optical amplifier has a relatively large volume, and a semiconductor optical amplifier with a miniaturized volume (such as the semiconductor optical amplifier provided in chinese patent CN 1334982A) is provided in the prior art. However, the semiconductor optical amplifier has a large coupling loss with the optical fiber, and is susceptible to environmental temperature due to large noise and crosstalk, so that the semiconductor optical amplifier has poor stability and poor gain characteristics compared with the conventional optical amplifier. Therefore, there is a high demand in the market for an optical amplifier having excellent indexes that can achieve miniaturization of the entire optical amplifier.

Disclosure of Invention

The purpose of the present application is to provide an optical amplifier, which includes an optical function device, a front gain device and a rear gain device, and overcomes the problem that the existing optical amplifier with excellent overall miniaturization index can not be provided.

In order to achieve the purpose, the following technical scheme is adopted in the application:

an optical amplifier, comprising: the optical function device, the front gain device and the rear gain device; the optical function device is provided with a first end and a second end which are opposite, the first end of the optical function device is used for receiving an input light beam, and the light beam is output through the second end of the optical function device; the post gain device is arranged at the second end of the optical function device and is used for receiving the light beam passing through the second end of the optical function device and gaining the light beam passing through the second end of the optical function device; the pre-gain device is arranged at the first end of the optical function device, the pre-gain device is used for receiving the light beam passing through the post-gain device, and the optical function device is multiplexed to receive the light beam gained by the pre-gain device.

Preferably, the optical amplifier further comprises a post wavelength division multiplexing device and/or a pre wavelength division multiplexing device; the rear wavelength division multiplexing device is arranged between the rear gain device and the optical function device, and is used for reflecting a first light beam with a specific wavelength, and the first light beam with the specific wavelength is reflected to the rear gain device so as to gain the light beam; the pre-wavelength division multiplexing device is arranged between the pre-gain device and the optical function device, the pre-wavelength division multiplexing device is used for reflecting the second light beam with the specific wavelength, and the second light beam with the specific wavelength is reflected to the pre-gain device to gain the light beam.

Preferably, the rear wavelength division multiplexing device includes a rear spectral filter and a rear collimating lens, and the rear spectral filter and the rear collimating lens are sequentially disposed between the second end of the optical functional device and the rear gain device along a direction from the first end of the optical functional device to the second end; the preposed wavelength division multiplexing device comprises a preposed light splitting filter and a preposed collimating lens, and the preposed collimating lens and the preposed light splitting filter are sequentially arranged between the preposed gain device and the first end of the optical function device along the direction from the first end of the optical function device to the second end.

Preferably, the optical amplifier further comprises a gain fiber for connecting the pre-gain device and the post-gain device; the rear gain device comprises a rear pumping optical fiber, one end of the rear pumping optical fiber is connected with a pumping source, and the other end of the rear pumping optical fiber provides pumping light to one end of the gain optical fiber through the rear wavelength division multiplexing device; the pre-gain device comprises a pre-pump optical fiber, one end of the pre-pump optical fiber is connected with a pump source, and the other end of the pre-pump optical fiber provides pump light to the other end of the gain optical fiber through the pre-wavelength division multiplexing device.

Preferably, the post-pump fibers include first to Nth post-pump fibers, N is a positive integer not less than 1; the preposed pumping fibers comprise a first preposed pumping fiber to an Mth preposed pumping fiber, wherein M is a positive integer not less than 1; the gain optical fiber further comprises a first gain optical fiber to a Kth gain optical fiber, wherein K is a positive integer not less than the maximum value of M and N; one end of the nth rear pumping optical fiber is connected with a pumping source, the other end of the nth rear pumping optical fiber provides pumping light to one end of the kth gain optical fiber, the values of N are positive integers not greater than N, and the values of K are positive integers not greater than K; one end of the mth preposed pumping optical fiber is connected with a pumping source, the other end of the mth preposed pumping optical fiber provides pumping light for the other end of the kth gain optical fiber, and the value of M is each positive integer not greater than M.

Preferably, N ═ 1, M ═ 1; one end of the first rear pump optical fiber is connected with a pump source, and the other end of the first rear pump optical fiber provides pump light to one end of the first gain optical fiber; one end of the first preposed pumping optical fiber is connected with a pumping source, and the other end of the first preposed pumping optical fiber provides pumping light for the other end of the first gain optical fiber.

Preferably, N ═ 2, M ═ 2; one end of the first rear pump optical fiber is connected with a pump source, and the other end of the first rear pump optical fiber provides pump light to one end of the first gain optical fiber; one end of the first preposed pumping optical fiber is connected with a pumping source, and the other end of the first preposed pumping optical fiber provides pumping light to the other end of the first gain optical fiber; one end of the second rear pump optical fiber is connected with a pump source, and the other end of the second rear pump optical fiber provides pump light to one end of the second gain optical fiber; one end of the second preposed pumping optical fiber is connected with a pumping source, and the other end of the second preposed pumping optical fiber provides pumping light for the other end of the second gain optical fiber.

Preferably, the optical function device comprises one or more of a refraction component, a light splitting component and an isolation component, and when the optical function device comprises a plurality of the refraction component, the light splitting component and the isolation component, the light transmitting surfaces of two adjacent components are directly coupled.

Preferably, the light functional device comprises two refraction components arranged oppositely, and the light functional device further comprises a light splitting component and/or an isolation component, wherein the light splitting component and/or the isolation component are arranged between the two refraction components.

Preferably, the refraction component is a roof refraction prism, the light splitting component is a light splitting prism, and the isolation component is an optical isolator.

Preferably, the pre-gain device further comprises an input optical fiber for input of the optical beam of the optical amplifier; the post gain device further comprises an output optical fiber for the output of the optical beam of the optical amplifier.

Compared with the prior art, the beneficial effects of this application include at least:

the optical amplifier comprises an optical function device and a gain device, and signal light on the different side of the optical amplifier is enhanced by multiplexing the optical function device. The structure has the advantage of saving the space of the optical amplifier, and the effect of integrally miniaturizing the optical amplifier can be realized.

Drawings

The present application is further described below with reference to the drawings and examples.

Fig. 1 is a schematic structural diagram of an optical amplifier provided in an embodiment of the present application;

fig. 2 is a schematic optical path diagram of an optical amplifier provided in an embodiment of the present application;

FIG. 3 is a schematic optical path diagram of another optical amplifier provided in the embodiments of the present application;

FIG. 4 is a schematic optical path diagram of another optical amplifier provided in the embodiments of the present application;

the figure is as follows:

10. a light function device; 11. a refractive component; 12. a light splitting component; 13. an isolation component; 20. a pre-gain device; 21. a pre-pump fiber; 211. a first pre-pump fiber; 212. a second pre-pump fiber; 30. a post gain device; 31. a rear pump fiber; 311. a first rear pump fiber; 312. a second rear pump fiber; 40. a front-end wavelength division multiplexing device; 41. a front spectral filter; 42. a pre-collimating lens; 50. a rear wavelength division multiplexing device; 51. a rear spectral filter; 52. a rear collimating lens; 60. a gain fiber; 601. a first gain fiber; 602. a second gain fiber.

Detailed Description

The present application is further described with reference to the accompanying drawings and the detailed description, and it should be noted that, in the present application, the embodiments or technical features described below may be arbitrarily combined to form a new embodiment without conflict.

As shown in fig. 1 and 2, an embodiment of the present application provides an optical amplifier including: an optical function device 10, a pre-gain device 20 and a post-gain device 30.

The optical function device 10 has a first end and a second end opposite to each other, the first end of the optical function device 10 is used for receiving an input light beam, and the light beam is output through the second end of the optical function device 10; the post gain device 30 is disposed at the second end of the optical function device 10, and the post gain device 30 is configured to receive the light beam passing through the second end of the optical function device 10 and gain the light beam passing through the second end of the optical function device 10; the pre-gain device 20 is disposed at a first end of the optical function device 10, the pre-gain device 20 is configured to receive the light beam passing through the post-gain device 30, and the optical function device 10 is configured to receive the light beam gained by the pre-gain device 30. Wherein the light beam passing through the optical amplifier may be signal light, and the signal light may be gained by the pre-gain device 20 and the post-gain device 30, respectively.

Thus, the optical signal is subjected to gain by the post gain device 30 and the pre gain device 20 provided in the optical amplifier, respectively, and the signal light can be amplified multiple times on the opposite side of the optical amplifier. By multiplexing the optical function device 10 in the optical amplifier, the space of the optical amplifier is saved, and the overall miniaturization effect of the optical amplifier can be achieved on the premise of not influencing the gain characteristic of the optical amplifier.

As shown in fig. 1, in some embodiments, the optical amplifier further comprises a post wavelength division multiplexing device 50 and/or a pre wavelength division multiplexing device 40. The post wavelength division multiplexing device 50 is disposed between the post gain device 30 and the optical function device 10, the post wavelength division multiplexing device 50 is configured to reflect the first light beam with a specific wavelength, and the first light beam with the specific wavelength is reflected to the post gain device 30 to gain the light beam. The pre-wavelength division multiplexing device 40 is disposed between the pre-gain device 20 and the optical function device 10, the pre-wavelength division multiplexing device 40 is configured to reflect the second light beam with a specific wavelength, and the second light beam with the specific wavelength is reflected to the pre-gain device 20 to gain the light beam.

In specific implementation, the pre-wdm apparatus 40 is, for example, a wdm structure disclosed in chinese patent CN 213581439U; the pre-wavelength division multiplexing device 40 is further, for example, a pre-splitting filter 41 and a pre-collimating lens 42, and the pre-splitting filter 41 and the pre-collimating lens 42 are sequentially disposed between the first end of the optical function device 10 and the pre-gain device 20 along a direction from the second end of the optical function device 10 to the first end. The pre-collimating lens 42 may be any one of a G lens (G-lens) and a C lens (C-lens), and when the pre-collimating lens is a G lens, the time division optical filter and the collimating lens may be tightly attached together, so as to reduce the volume of the wavelength division multiplexing device, and facilitate the assembly of the pre-wavelength division multiplexing device 40.

Similarly, the rear wavelength division multiplexing device 50 is, for example, a wavelength division multiplexing structure disclosed in chinese patent CN 213581439U; the post wavelength division multiplexing device 50 is further, for example, a post spectral filter 51 and a post collimating lens 52, and the post spectral filter 51 and the post collimating lens 52 are sequentially disposed between the second end of the optical function device 10 and the post gain device 30 along the direction from the first end to the second end of the optical function device 10. The post-collimator lens 52 may be any one of a G lens (G-lens) and a C lens (C-lens), and when the post-collimator lens is a G lens, the time division optical filter and the collimator lens may be tightly attached together, so as to reduce the volume of the wavelength division multiplexing device, and facilitate the assembly of the post-wavelength division multiplexing device 50.

When the optical amplifier sets the pre-wavelength division multiplexing device 40 and the post-wavelength division multiplexing device 50, the pre-gain device 20 is configured to receive the signal light and receive the second light beam with the specific wavelength reflected by the pre-wavelength division multiplexing device 40 to gain the signal light; the post gain device 30 is also used for receiving the signal light and receiving the first light beam with specific wavelength reflected by the post wavelength division multiplexing device 50 to gain the signal light. The pre-gain device 20 and the post-gain device 30 may be a raman optical amplifier or an optical soliton amplifier, respectively, and the signal light is optically amplified by directly irradiating the signal light with high-energy pump to generate a nonlinear effect in a common silica fiber.

As shown in fig. 3 and 4, the optical amplifier may further include a gain fiber 60, and the gain fiber 60 is used to connect the pre-gain device 20 and the post-gain device 30.

The post gain device 30 may include a post pump fiber 31, and one end of the post pump fiber 31 is connected to a pump source (not shown) for providing a light beam with a specific wavelength, and the light beam with the specific wavelength provided by the pump source may be pump light. The other end of the post-pump fiber 31 provides pump light to one end of the gain fiber 60 through the post-wavelength division multiplexing device 50. The pump source selects the wavelength of the pump light according to the gain fiber 60 and the signal light, for example, when the signal light is 1550nm, the gain fiber 60 may be an erbium-doped fiber, and the wavelength of the pump light may be in a range of 970nm to 985nm or 1465nm to 1485 nm. The gain fiber 60 may also be doped fiber doped with different elements, such as erbium-ytterbium co-doped fiber, praseodymium-doped fiber, thulium-doped fiber, etc., and the amplification characteristics of the doped fiber may be adjusted by changing or adjusting the doped components and concentrations of the fiber, so as to amplify the signal light in cooperation with the pump light with different wavelengths. The amplification requirements of different working wavelengths or waveband ranges of the signal light can be met by matching and selecting the gain fiber 60 and the rear pump fiber 31.

The pre-gain device 20 may be a gain structure including a pre-pump fiber 21, one end of the pre-pump fiber 21 is connected to a pump source (not shown), the pump source is used to provide a light beam with a specific wavelength, and the light beam with the specific wavelength provided by the pump source may be pump light. The other end of the pre-pump fiber 21 provides pump light to the other end of the gain fiber 60 through the pre-wdm apparatus 40. The pump source selects a pump light of a specific wavelength according to the gain fiber 60 and the signal light, for example, when the signal light is 1550nm wavelength, the gain fiber 60 may be an erbium-doped fiber, and the wavelength of the pump light may be in a range of 970nm to 985nm or 1465nm to 1485 nm. The gain fiber 60 may also be doped fiber doped with different elements, such as erbium-ytterbium co-doped fiber, praseodymium-doped fiber, thulium-doped fiber, etc., and the amplification characteristics of the doped fiber may be adjusted by changing or adjusting the doped components and concentrations of the fiber, so as to amplify the signal light in cooperation with the pump light with different wavelengths. The amplification requirements of different working wavelengths or waveband ranges of the signal light can be met by matching and selecting the gain fiber 60 and the pre-pump fiber 21.

The pump source connected to the front pump fiber 21 and the pump source connected to the rear pump fiber 31 may be optical pump sources, and the pump source connected to the front pump fiber 21 and the pump source connected to the rear pump fiber 31 may be the same pump source or the same parameter pump source, or different pump sources.

In a specific application, the gain fiber 60 is an erbium fiber, the pre-gain device 20 gains the signal light passing through the optical amplifier by using pump light of 980nm, erbium ions at one end of the erbium fiber, which is gained by the pre-gain device 20, can be in a three-level working state, the noise coefficient of signal light amplification is better controlled, and the pump light leakage is smaller; the post gain device 30 gains the signal light by adopting 1480nm pump light, and erbium ions at one end of the erbium fiber, which are gained by the post gain device 30, are in a double-energy-level working state, so that the power conversion efficiency of signal light amplification is higher. Therefore, the optical amplifier has better effect on signal optical gain.

Specifically, the post-pump fibers 31 include first to nth post-pump fibers 311 to 311, where N is a positive integer not less than 1; the pre-pump fiber 21 comprises a first pre-pump fiber 211 to an Mth pre-pump fiber, M is a positive integer not less than 1; the gain fiber 60 further includes first to K-th gain fibers 601 to 601, K being a positive integer not less than the maximum of M and N; one end of the nth rear pumping optical fiber is connected with a pumping source, the other end of the nth rear pumping optical fiber provides pumping light to one end of the kth gain optical fiber, the values of N are positive integers not greater than N, and the values of K are positive integers not greater than K; one end of the mth preposed pumping optical fiber is connected with a pumping source, the other end of the mth preposed pumping optical fiber provides pumping light for the other end of the kth gain optical fiber, and the value of M is each positive integer not greater than M.

As shown in fig. 3, in one specific application N ═ 1, M ═ 1; one end of the first rear pump fiber 311 is connected to a pump source, and the other end of the first rear pump fiber 311 provides pump light to one end of the first gain fiber 601; one end of the first pre-pump fiber 211 is connected to a pump source, and the other end of the first pre-pump fiber 211 provides pump light to the other end of the first gain fiber 601.

The pump light passing through the first rear pump fiber 311 and the signal light passing through the optical functional device 10 are input to the input end of the first gain fiber 601 together, so that the signal light realizes the first gain; the signal light after the gain is output from the output end of the first gain fiber 601, and the pump light from the first pre-pump fiber 211 and the signal light input from the output end of the first gain fiber 601 are optically coupled with the signal light at the output end of the first gain fiber 601 to gain the signal light for the second time. The signal light after the secondary gain passes through the first end and the second end of the optical functional device 10 in sequence, and the amplified signal light can be output from the opposite side of the input end of the optical amplifier.

As shown in fig. 4, in one specific application, N ═ 2, M ═ 2; one end of the first rear pump fiber 311 is connected to a pump source, and the other end of the first rear pump fiber 311 provides pump light to one end of the first gain fiber 601; one end of the first pre-pump fiber 211 is connected to a pump source, and the other end of the first pre-pump fiber 211 provides pump light to the other end of the first gain fiber 601; one end of the second post-pump fiber 312 is connected to a pump source, and the other end of the second post-pump fiber 312 provides pump light to one end of the second gain fiber 602; one end of the second pre-pump fiber 212 is connected to a pump source, and the other end of the second pre-pump fiber 212 provides pump light to the other end of the second gain fiber 602. Therefore, the signal light passing through the optical amplifier can realize four gains, and the amplified signal light is output from the opposite side of the input end of the optical amplifier. In a specific application scenario, a gain can be achieved on the signal light passing through the optical amplifier through the pre-gain device 20 and the post-gain device 30 more times.

As shown in fig. 1 and 2, in some embodiments, the optical function device 10 includes one or more of a refraction component 11, a light splitting component 12 and a separation component 13, and when the optical function device 10 includes a plurality of the refraction component 11, the light splitting component 12 and the separation component 13, the light-passing surfaces of two adjacent components are directly coupled.

By providing the refraction element 11, it is possible to deflect the direction of the incident signal light. When the optical function device 10 is provided with the refraction member 11 that can deflect the direction of the incident signal light, the number or volume of collimators for the signal light can be reduced. When the polarized light crystal pair is selected as the refraction component 11, because the polarized light crystal pair can have no inclined plane, the polarized light crystal pair and other optical components can be compactly assembled, and the volume of the optical function device 10 is further saved; when the roof refraction prism is selected, the cost is lower; it is also possible to use two or more triangular prisms, or a combination of flat mirrors, for the purpose of refraction.

By arranging the light splitting component 12, the light splitting detection function of the signal light can be realized, and the amplification factor or the amplification capacity of the signal light can be controlled accurately. The light splitting component 12 can be a light splitting prism, and when the light splitting component 12 is the light splitting prism, the optical function device 10 is easier to assemble, and the volume is better controlled; the light splitting component 12 can also be assembled by adopting a light splitting plain film and additionally arranging a bracket, so that the cost can be better reduced compared with a light splitting prism. The splitting ratio of the splitting assembly 12 can be selected according to needs, but is not limited in this application, and may be, for example, 0.1% splitting ratio, 1% splitting ratio, or 5% splitting ratio. The beam splitting prism can be set in a form as shown in fig. 2 to realize the respective collection of each signal light, so that the light amplification condition can be observed in real time, and the required signal light can be obtained by adjusting in real time.

Through setting up isolation component 13, can keep apart the spontaneous emission light of amplifier itself, avoid the signal source of signal light to receive interference such as spontaneous emission light, improve the job stabilization nature of signal source, wherein isolation component 13 can be optical isolator.

Specifically, a plurality of refraction components 11, light splitting components 12 and isolation components 13 can be arranged in one light function device 10 to meet different requirements of customers. For example, the combination of the optical function device 10 can be two refractive components 11 arranged oppositely, and a light splitting component 12, an optical isolator and a light splitting component 12 positioned between the two refractive components 11; or two refraction components 11 which are arranged oppositely, and an optical isolator which is positioned between the two refraction components 11; or two refraction components 11 which are arranged oppositely, and a light splitting component 12 which is positioned between the two refraction components 11. The combination of different optical elements can be selected according to the actual situation of the signal source, for example, when the optical amplifier does not need to precisely control the amplification factor or the amplification capacity, the light splitting component 12 can be omitted; when the signal receiving end has very good rejection of the backreflection of the optical amplifier and there is no backreflection of the amplifier output, the isolation component 13 can be omitted. The cost and volume of the optical amplifier can be reduced by combining different types of optical function devices 10 according to the requirements.

The optical function device 10 with the above structure can adopt a micro-optical integration mode to integrate each optical function component into the optical function device 10, thereby reducing the connection of tail fibers among each optical function component and obviously improving the integration degree of the optical amplifier. The optical functional structure reduces the coupling connection part among a plurality of optical functional components, so that the overall loss of the optical amplifier is smaller, the noise coefficient of the optical amplifier is obviously improved, and compared with the existing optical amplifier in the market, the stability of the optical amplifier is better and the gain characteristic performance is better. In addition, each optical functional component can be assembled automatically through a machine, and the production efficiency is higher.

The terms "first," "second," "third," "fourth," and the like in the description and in the claims of the present application and in the drawings described above, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be appreciated that the data so used may be interchanged under appropriate circumstances such that the embodiments described herein may be practiced otherwise than as specifically illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

While the present application is described in terms of various aspects, including exemplary embodiments, the principles of the invention should not be limited to the disclosed embodiments, but are also intended to cover various modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

Claims

1. An optical amplifier, comprising: the optical function device, the front gain device and the rear gain device;

the optical function device is provided with a first end and a second end which are opposite, the first end of the optical function device is used for receiving an input light beam, and the light beam is output through the second end of the optical function device;

the post gain device is arranged at the second end of the optical function device and is used for receiving the light beam passing through the second end of the optical function device and gaining the light beam passing through the second end of the optical function device;

the pre-gain device is arranged at the first end of the optical function device, the pre-gain device is used for receiving the light beam passing through the post-gain device, and the optical function device is multiplexed to receive the light beam gained by the pre-gain device.

2. An optical amplifier according to claim 1, wherein the optical amplifier further comprises a post wavelength division multiplexing device and/or a pre wavelength division multiplexing device;

the rear wavelength division multiplexing device is arranged between the rear gain device and the optical function device, and is used for reflecting a first light beam with a specific wavelength, and the first light beam with the specific wavelength is reflected to the rear gain device so as to gain the light beam;

the pre-wavelength division multiplexing device is arranged between the pre-gain device and the optical function device, the pre-wavelength division multiplexing device is used for reflecting the second light beam with the specific wavelength, and the second light beam with the specific wavelength is reflected to the pre-gain device to gain the light beam.

3. An optical amplifier according to claim 2, wherein the post wavelength division multiplexing device comprises a post spectral filter and a post collimating lens, the post spectral filter and the post collimating lens are sequentially disposed between the second end of the optical function device and the post gain device along a direction from the first end of the optical function device to the second end;

the preposed wavelength division multiplexing device comprises a preposed light splitting filter and a preposed collimating lens, and the preposed collimating lens and the preposed light splitting filter are sequentially arranged between the preposed gain device and the first end of the optical function device along the direction from the first end of the optical function device to the second end.

4. An optical amplifier according to claim 2, further comprising a gain fiber for connecting the pre-gain means and the post-gain means;

the rear gain device comprises a rear pumping optical fiber, one end of the rear pumping optical fiber is connected with a pumping source, and the other end of the rear pumping optical fiber provides pumping light to one end of the gain optical fiber through the rear wavelength division multiplexing device;

the pre-gain device comprises a pre-pump optical fiber, one end of the pre-pump optical fiber is connected with a pump source, and the other end of the pre-pump optical fiber provides pump light to the other end of the gain optical fiber through the pre-wavelength division multiplexing device.

5. An optical amplifier in accordance with claim 4, wherein the post-pump fibers include first through Nth post-pump fibers, N being a positive integer not less than 1;

the preposed pumping fibers comprise a first preposed pumping fiber to an Mth preposed pumping fiber, wherein M is a positive integer not less than 1;

the gain optical fiber further comprises a first gain optical fiber to a Kth gain optical fiber, wherein K is a positive integer not less than the maximum value of M and N;

one end of the nth rear pumping optical fiber is connected with a pumping source, the other end of the nth rear pumping optical fiber provides pumping light to one end of the kth gain optical fiber, the values of N are positive integers not greater than N, and the values of K are positive integers not greater than K;

one end of the mth preposed pumping optical fiber is connected with a pumping source, the other end of the mth preposed pumping optical fiber provides pumping light for the other end of the kth gain optical fiber, and the value of M is each positive integer not greater than M.

6. An optical amplifier as claimed in claim 5, wherein N-1, M-1;

one end of the first rear pump optical fiber is connected with a pump source, and the other end of the first rear pump optical fiber provides pump light to one end of the first gain optical fiber;

one end of the first preposed pumping optical fiber is connected with a pumping source, and the other end of the first preposed pumping optical fiber provides pumping light for the other end of the first gain optical fiber.

7. An optical amplifier as claimed in claim 5, wherein N-2, M-2;

one end of the first preposed pumping optical fiber is connected with a pumping source, and the other end of the first preposed pumping optical fiber provides pumping light to the other end of the first gain optical fiber;

one end of the second rear pump optical fiber is connected with a pump source, and the other end of the second rear pump optical fiber provides pump light to one end of the second gain optical fiber;

one end of the second preposed pumping optical fiber is connected with a pumping source, and the other end of the second preposed pumping optical fiber provides pumping light for the other end of the second gain optical fiber.

8. An optical amplifier in accordance with claim 1, wherein the optical function means comprises one or more of a refractive component, a beam splitting component and an isolation component, and when the optical function means comprises a plurality of the refractive component, the beam splitting component and the isolation component, the light-passing surfaces of two adjacent components are directly coupled.

9. The optical amplifier of claim 8, wherein the optical functional device comprises two refractive components disposed opposite to each other, and further comprising a light splitting component and/or an isolating component disposed between the two refractive components.

10. An optical amplifier in accordance with claim 9, wherein said refractive element is a roof prism, said beam splitting element is a beam splitter prism, and said isolation element is an optical isolator.

11. An optical amplifier according to claim 1, wherein said pre-gain means further comprises an input optical fiber for input of the optical beam of said optical amplifier;

the post gain device further comprises an output optical fiber for the output of the optical beam of the optical amplifier.