CN110412772A - an optical circulator - Google Patents

Abstract

The invention discloses an optical circulator, comprising a first PBS combined prism, a Faraday rotator and a second PBS combined prism arranged in sequence along the optical path, the first PBS combined prism is composed of two oppositely arranged PBSs, The second PBS combined prism is formed by a PBS and a high reflective mirror or a PBS, and there is also a gap between the first PBS combined prism and the Faraday rotator or between the Faraday rotator and the second PBS combined prism. A half-wave plate is provided, and the structure forms three ports, wherein the light of port 1 is output by port 2 after passing through the optical circulator, and the light of port 2 is output by port 3 after passing through the circulator. The scheme of the present invention adopts free space micro-optics Principle design, less number of components, simple and compact structure, easy to integrate, can be widely used in high-speed optical transceiver modules, and has a good application prospect.

Description

an optical circulator

technical field

The invention relates to the field of optical communication devices, in particular to an optical circulator.

Background technique

Optical circulators are important optical passive devices in the field of optical communications. Traditional optical fiber circulators mainly use birefringent crystals as light-splitting elements. Due to the limited beam-splitting angle of birefringent crystals, the length of birefringent crystals is generally long. The structure of the circulator is complex and the number of components is large, which makes the traditional circulator relatively large. It is difficult to integrate the circulator with other optical devices or modules. Generally, it is used as a separate optical device and connected to other optical devices or modules through optical fibers. , which makes the structure of the entire optical fiber link huge and complex.

In recent years, with the increasing development of the communication field, more and more optical devices and modules need to be used. The integration and miniaturization of optical devices has become an inevitable trend, especially in high-speed optical transceiver modules. In order to reduce the link Due to the large number of optical modules, an external optical fiber circulator will not only increase the volume, but also increase the cost.

Contents of the invention

In view of the prior art, the purpose of the present invention is to provide an optical circulator with simple structure, small volume and easy integration and assembly into the free space inside the optical module.

In order to realize above-mentioned technical purpose, the technical scheme that the present invention adopts is:

An optical circulator, which includes a first PBS combined prism, a Faraday rotator and a second PBS combined prism arranged in sequence along the optical path, the first PBS combined prism is composed of two oppositely arranged PBSs, and the The second PBS combined prism is formed by a PBS and a high reflective mirror or a PBS, and a semi-circular prism is arranged between the first PBS combined prism and the Faraday rotator or between the Faraday rotator and the second PBS combined prism. wave plate.

Further, the first PBS combined prism, Faraday rotator, half-wave plate and second PBS combined prism are arranged in sequence.

Further, the first PBS combined prism, the half-wave plate, the Faraday rotator and the second PBS combined prism are arranged in sequence.

Further, the Faraday rotator is used to rotate the polarization direction of the light passing through it by 45°, and the angle between the optical axis of the half-wave plate and the side is 22.5 or 67.5 degrees, which can be set according to needs. Also rotate the light polarization direction by 45 degrees. .

Further, the half-wave plate is used to rotate the polarization direction of the light passing through it by 45°.

Further, the structure of the present invention forms a three-port circulator, wherein the incident light at port 1 is a single linearly polarized light, and the incident light at port 2 has no light polarization state restricted.

Further, the Faraday rotator is a latching type Faraday rotator.

Further, the Faraday rotator is a non-latching type Faraday rotator, and one or more magnetic blocks or magnetic rings are arranged on the outside of the non-latching type Faraday rotator.

Further, the first PBS combined prism, Faraday rotator, half-wave plate and second PBS combined prism are connected as a whole by deepening optical glue.

Further, the first PBS composite prism, the Faraday rotator, the half-wave plate and the second PBS composite prism are glued and connected as a whole, and the refractive index of the glue used for bonding matches the refractive index of the corresponding bonding surface.

With the above-mentioned structure, compared with the prior art, the present invention has a simple optical path, compact structure, easy assembly, not only has good optical performance, but also can achieve low cost. In addition, because the present invention is small in size, it can be integrated Assembled inside the optical module to save the space and cost of connecting the circulator outside the module.

Description of drawings

Below in conjunction with accompanying drawing and specific embodiment, the present invention is further elaborated:

Fig. 1 is the implementation structure of Embodiment 1 of the optical circulator of the present invention and its forward light transmission schematic diagram;

Fig. 2 is the implementation structure of Embodiment 1 of the optical circulator of the present invention and its schematic diagram of reverse light transmission;

Fig. 3 is a three-dimensional schematic diagram when the implementation structure of Embodiment 1 of the optical circulator of the present invention is integrated;

Fig. 4 is the implementation structure of Embodiment 2 of the optical circulator of the present invention and its forward light transmission schematic diagram;

Fig. 5 is the implementation structure of the optical circulator embodiment 2 of the present invention and its reverse light transmission schematic diagram;

FIG. 6 is a schematic diagram of an application of the optical circulator of the present invention.

Detailed ways

Example 1

As shown in Figure 1 or 2, the present embodiment comprises the first PBS combined prism 10, Faraday rotator 11, half-wave plate 12 and the second PBS combined prism 13 arranged in sequence along the optical path, the first PBS combined prism described 10 is composed of two oppositely arranged PBS101, 102, and the second PBS combined prism 13 is formed by a PBS131 and a high reflection mirror 132 or a PBS arranged oppositely, and the structure of this embodiment forms a prism for input or output light The three ports are port 1, port 2 and port 3 shown in Fig. 1 or Fig. 2 respectively.

Figure 1 shows a schematic diagram of the forward light path of this embodiment, the single linearly polarized light (P light) incident from port 1 enters the Faraday rotator 11 after passing through the PBS101 of the first PBS combination prism 10, and the Faraday rotator 11 will The incident P light polarization direction rotates 45 degrees and enters the half-wave plate 12, and the half-wave plate 12 reversely rotates the polarization direction of the incident light by 45 degrees, so that the incident light changes back to P before entering the second PBS combination prism 13. The light exits port 2 after passing through PBS131 of the second PBS combination prism 13 .

Figure 2 shows the schematic diagram of the reverse light transmission path of this embodiment, the reverse light beam (P light & S light) incident from port 2 passes through the PBS131 of the second PBS combination prism 13 and separates the P light and the S light, and the P light The horizontal transmission enters the half-wave plate 12, and the half-wave plate 12 rotates the polarization state of the beam by 45 degrees and then enters the Faraday rotator 11, and the Faraday rotator 11 continues to rotate the polarization state of the incident light along the same rotation direction of the half-wave plate 12 by 45 degrees, so that The light beam becomes S light before entering the first PBS combination prism 10 , the S light enters PBS101 and is reflected to PBS102 , and then output from port 3 after being reflected by PBS102 . The reverse light beam S light incident from port 2 is reflected to PBS or high reflection mirror 132 after passing through the PBS131 of the second PBS combination prism 13, and S light is transmitted into half-wave plate 12 after being reflected by PBS or high reflection mirror 132, half-wave Sheet 12 rotates the polarization state of the light beam by 45 degrees and enters the Faraday rotator 11, and the Faraday rotator 11 continues to rotate the polarization state of the incident light along the same rotation direction of the half-wave plate 12 by 45 degrees, so that the light beam enters the first PBS combination prism 10 It becomes P light, and the P light enters the PBS102, transmits it and outputs it from port 3. In this way, the reverse light beams (P light & S light) incident from port 2 are all output from port 3 after passing through the optical circulator.

Among them, in the implementation structure of this embodiment (Figure 1 or Figure 2), the positions of the Faraday rotator 11 and the half-wave plate 12 can be mutually rotated (that is, the positions of the Faraday rotator 11 and the half-wave plate 12 can be reversed), the half-wave The included angle between the optical axis and the side of the sheet 12 is 22.5 or 67.5 degrees, which can be set as required, and it also rotates the light polarization direction by 45 degrees.

Fig. 3 is the three-dimensional schematic diagram when the implementation structure of this embodiment is combined into one, the first PBS composite prism 10, Faraday rotator 11, half-wave plate 12 and the second PBS composite prism can be combined by deepening optical glue or optical refractive index matching glue 13 are connected together to form an assembly, forming a compact structure, and further, when the first PBS composite prism 10, the Faraday rotator 11, the half-wave plate 12 and the second PBS composite prism 13 are glued and connected as one, the glue used for gluing The refractive index matches that of the corresponding binding surface.

Example 2

As shown in Figure 4 or 5, the present embodiment includes the first PBS combined prism 20, Faraday rotator 21, half-wave plate 22 and the second PBS combined prism 23 arranged in sequence along the optical path, the first PBS combined prism 20 is composed of two oppositely arranged PBS201, 202, and the second PBS combined prism 23 is formed by a PBS231 and a high reflection mirror 232 or a PBS arranged oppositely, and the structure of this embodiment forms a prism for input or output light The three ports are port 1, port 2 and port 3 shown in Fig. 4 or Fig. 5 respectively.

Fig. 4 shows the schematic diagram of the forward light transmission of the implementation structure of this embodiment. The single linearly polarized light (P light) incident from port 1 enters the Faraday rotator 21 after passing through the PBS201 of the first PBS combination prism 20, and the Faraday rotator 21 Rotate the polarization direction of the incident P light by 45 degrees to enter the half-wave plate 22, and the half-wave plate 22 rotates the polarization direction of the incident light by 45 degrees in the same direction, so that the incident light becomes S light before entering the second PBS combination prism 23 , enters the PBS232 after passing through the PBS of the second PBS combination prism 23 or the high reflection mirror 231, and the S light is reflected by the PBS232 and exits from the port 2.

Figure 5 is a schematic diagram of the reverse light transmission of the implementation structure of this embodiment. The reverse light beam (P light & S light) incident from port 2 passes through the PBS232 of the second PBS combination prism 23 and separates the P light and S light, and the P light level Transmission enters half-wave plate 22, and half-wave plate 22 enters Faraday rotator 21 after the beam polarization state is rotated 45 degrees, and Faraday rotator 21 rotates 45 degrees along the opposite direction of incident light polarization state along half-wave plate 22, and light beam is in like this Before entering the first PBS combination prism 20, it is still P light, and the P light enters the PBS 201 and is output from the port 3 after being transmitted. The reverse light beam S light incident from port 2 is reflected to PBS or high reflection mirror 231 after passing through the PBS232 of the second PBS combined prism 23, and S light is transmitted into half-wave plate 22 after being reflected by PBS or high reflection mirror 231, half-wave Sheet 22 rotates the polarization state of the light beam by 45 degrees and enters the Faraday rotator 21, and the Faraday rotator 21 rotates the polarization state of the incident light by 45 degrees in the opposite direction of the half-wave plate 22, so that the light beam remains the same before entering the first PBS combination prism 20 It is S light, which is reflected into PBS202 after entering PBS201, and output from port 3 after being reflected by PBS202. In this way, the reverse light beams (P light & S light) incident from port 2 are all output from port 3 after passing through the optical circulator.

Wherein, in the implementation structure of this embodiment (Figure 4 or Figure 5), the positions of the Faraday rotator 21 and the half-wave plate 22 can be interchanged, and the angle between the optical axis of the half-wave plate 22 and the side is 22.5 or 67.5 degrees , set according to needs, it also rotates the light polarization direction by 45 degrees, and the first PBS can be combined with the prism 20, the Faraday rotator 21, the half-wave plate 22 and the second by deepening optical glue or optical refractive index matching glue. The PBS combination prism 23 is connected together to form an assembly, forming a compact structure, the first PBS combination prism 20, the Faraday rotator 21, the half-wave plate 22 and the second PBS combination prism 23 are connected as a whole by gluing, for gluing The refractive index of the glue matches that of the corresponding bonding surface.

In addition, the Faraday rotator 21 can be a latching type Faraday rotator or a non-latching type Faraday rotator, wherein one or more magnetic blocks or magnetic rings are arranged outside the non-latching type Faraday rotator to provide the required magnetic field.

Example 3

FIG. 6 is a schematic diagram of an application embodiment of the optical circulator according to the present invention. The optical circulator according to the present invention can be applied to an optical module for single-fiber bidirectional transmission. The module includes a laser (LD) array or a discrete laser group 30, Wavelength division multiplexer (MUX) 31, optical circulator 32 of the present invention, optical interface 33, wavelength division multiplexer (DEMUX) 34, photodetector (PD) array or discrete photodetector group 35 and housing 36 The working principle of this module is: multi-channel optical signals are sent out via laser array or discrete laser group 30, each channel corresponds to a laser, each laser corresponds to a wavelength, multiple signals of different wavelengths are synthesized by a wavelength division multiplexer 31 One signal, and then the signal is input through port 1 of the optical circulator 32 of the present invention, output through port 2, and then output through the optical interface 33 of the module. On the other hand, the input multi-wavelength signal is input through the optical interface 33 of the module, enters through the port 2 of the optical circulator 32, enters the wave division multiplexer 34 after being output from the port 3, and the wave division multiplexer 34 divides each channel The signal corresponding to the wavelength is transmitted to each corresponding photodetector of the photodetector array or group 35 of discrete photodetectors. In this way, the bidirectional transmission function of the module optical signal is realized with a single optical interface. Because the optical circulator 32 of the present invention is simple and compact in structure, it can be integrated into the optical module and assembled into the inside of the optical module housing 36 to realize the optical module. miniaturization.

It should be noted that variations and changes of the embodiments disclosed herein are possible, and replacements and equivalent components of the embodiments are known to those skilled in the art. It should be clear to those skilled in the art that the present invention can be implemented in other forms, structures, arrangements and proportions without departing from the spirit or essential characteristics of the present invention.

Claims (9)

1. a kind of optical circulator, it is characterised in that: it includes the first PBS combined prism being set in sequence along optical path, faraday's rotation Turning device and the 2nd PBS combined prism, the PBS that the first PBS combined prism is oppositely arranged by two is formed, and described second PBS combined prism is oppositely arranged by PBS and high reflective mirror or a PBS, the first PBS combined prism with Half-wave plate is additionally provided between Faraday rotator or between Faraday rotator and the 2nd PBS combined prism.

2. a kind of optical circulator according to claim 1, it is characterised in that: the first PBS combined prism, faraday Rotator, half-wave plate and the 2nd PBS combined prism are to be set in sequence.

3. a kind of optical circulator according to claim 1, it is characterised in that: the first PBS combined prism, half-wave Piece, Faraday rotator and the 2nd PBS combined prism are to be set in sequence.

4. a kind of optical circulator according to claim 1, it is characterised in that: the Faraday rotator is used for will be from it By light polarization direction rotate 45 °.

5. a kind of optical circulator according to claim 1, it is characterised in that: the half-wave plate is used to pass through from it The polarization direction of light rotates 45 °.

6. a kind of optical circulator according to claim 1, it is characterised in that: the Faraday rotator is latching Type Faraday rotator.

7. a kind of optical circulator according to claim 1, it is characterised in that: the Faraday rotator is non- Latching type Faraday rotator, the non-latching type Faraday rotator outside are provided with one or more magnetic patch Or magnet ring.

8. a kind of optical circulator according to claim 1, it is characterised in that: the first PBS combined prism, faraday Rotator, half-wave plate and the 2nd PBS combined prism are that in-depth optical cement is connected as one.

9. a kind of optical circulator according to claim 1, it is characterised in that: the first PBS combined prism, faraday Rotator, half-wave plate and the 2nd PBS combined prism be gluing be connected as one and gluing used in glue refractive index with it is corresponding combination The refractive index on surface matches correspondence.