CN108963747B

CN108963747B - Crystal and manufacturing method thereof

Info

Publication number: CN108963747B
Application number: CN201810836678.1A
Authority: CN
Inventors: 熊芬; 李庭宇; 周日凯; 付永安; 孙莉萍
Original assignee: Wuhan Telecommunication Devices Co Ltd
Current assignee: Wuhan Telecommunication Devices Co Ltd
Priority date: 2018-07-26
Filing date: 2018-07-26
Publication date: 2020-05-12
Anticipated expiration: 2038-07-26
Also published as: CN108963747A

Abstract

The invention discloses a crystal and a manufacturing method thereof, wherein the crystal comprises an incident surface and an emergent surface; the crystal is used for splitting laser light emitted onto the crystal from an incident surface to generate a first light ray and a second light ray; the first light ray is emitted from the emitting surface, and the second light ray is emitted from the incident surface. The crystal can realize laser light splitting without adding a light splitting film, and the light splitting method has good stability and reduces the risk of failure of an optical device.

Description

Crystal and manufacturing method thereof

Technical Field

The invention belongs to the technical field of optical communication, and particularly relates to a crystal and a manufacturing method thereof.

Background

In recent years, the global cloud service market continues to increase, and with the benefit of the demands of network communication and data communication, the optical fiber communication industry is rapidly developed under the dual-power driving of the telecommunication market and the data center market, and the demand of high-speed optical modules is gradually increased.

In practical application, light of the optical module is output by a laser, and the stability of the optical power of the laser is influenced by many factors. For example, the stable output of the optical power of the laser is affected by the heat generation of the laser, the ambient temperature and humidity, the working time of the laser, the change of the threshold current, the heat dissipation of the optical module, and the like, so that an optical device with a backlight monitoring function needs to be introduced into the optical module to realize the real-time monitoring of the optical power of the laser.

At present, most of optical devices with a backlight monitoring function adopt a method of plating a light splitting film for light splitting. However, with the change of temperature and other environments, the polarization characteristic of the light source can be changed, and the film layer of the light splitting film is sensitive to the change, so that the stability of the light splitting mode of the light splitting film is poor, and the risks of failure of the optical device are increased by the processes of film layer design, film material purchase, film coating process, film layer inspection process, film layer reliability test and the like of the light splitting film.

Disclosure of Invention

In view of the above defects or improvement requirements of the prior art, the present invention provides a crystal and a manufacturing method thereof, and aims to perform laser light splitting by using a birefringence effect of the crystal and a specific structure of the crystal, thereby solving the technical problems of poor stability of a light splitting mode using a light splitting film and easy failure risk of an optical device.

To achieve the above object, according to one aspect of the present invention, there is provided a crystal 1 including an incident surface 10 and an exit surface 13; the crystal 1 is used for splitting laser light which is incident on the crystal 1 from the incident surface 10 to generate a first light ray 15 and a second light ray 16; wherein the first light ray 15 exits from the exit surface 13 and the second light ray 16 exits from the entrance surface 10.

In order to achieve the above object, according to another aspect of the present invention, there is provided a method of manufacturing a crystal, the method comprising: manufacturing an incidence surface of the crystal; manufacturing an emergent surface of the crystal, wherein the crystal is used for splitting laser which is emitted from the incident surface to the crystal to generate a first light ray and a second light ray; the first light ray exits from the exit surface, and the second light ray exits from the entrance surface.

Generally, compared with the prior art, the technical scheme of the invention has the following beneficial effects: the invention adopts a crystal with a specific structure, and laser can generate birefringence to generate a first light ray and a second light ray after passing through an incident surface of the crystal, wherein the first light ray is emitted from an emergent surface to be used as a front light; the second light ray is emitted from the incident surface to be used as backlight. The crystal can realize laser light splitting without adding a light splitting film, the light splitting method has good stability, meanwhile, the flows of film layer design, film material purchase, film coating process, film layer inspection process, film layer reliability test and the like of the plated light splitting film are reduced, and the risk of failure of an optical device is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic diagram of a crystal structure provided by an embodiment of the present invention;

FIG. 2 is a schematic diagram of the propagation trajectories of a first light ray and a second light ray when the crystal of FIG. 1 is being dispersed;

FIG. 3 is a schematic diagram of another crystal structure provided by an embodiment of the present invention;

FIG. 4 is a schematic diagram of the propagation trajectories of a first light ray and a second light ray when the crystal of FIG. 1 is being dispersed;

FIG. 5 is a schematic flow chart of a method for fabricating a crystal according to an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of an optical assembly according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of another optical assembly provided by an embodiment of the present invention;

FIG. 8 is a schematic structural diagram of another optical subassembly provided by an embodiment of the present invention;

fig. 9 is a flowchart illustrating a method for manufacturing an optical device according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Example 1:

referring to fig. 1 to 4, the present embodiment provides a crystal 1, where the crystal 1 includes an incident surface 10 and an exit surface 13, and the crystal 1 is used for splitting laser light incident on the crystal 1 from the incident surface 10 to generate a first light ray 15 and a second light ray 16. The first light ray 15 is emitted from the emission surface 13, and the second light ray 16 is emitted from the incident surface 10. In a practical application scenario, the first light ray 15 is used as a front light for data transmission, and the second light ray 16 is used as a back light for monitoring the power of the laser.

Further, the crystal 1 further includes a first reflection surface 11 and a second reflection surface 12, and the first reflection surface 11 is configured to reflect the first light ray 15 incident on the first reflection surface 11, so that the first light ray 15 is incident on the exit surface 13 and then exits from the exit surface 13. The first reflecting surface 11 is used for reflecting the second light 16 incident to the first reflecting surface 11 so that the second light 16 is incident to the second reflecting surface 12; the second reflecting surface 12 is configured to reflect the second light beam 16 incident on the second reflecting surface 12, so that the second light beam 16 is incident on the incident surface 10 and then exits from the incident surface 10.

Specifically, the incident surface 10 has a predetermined first angle with respect to a predetermined reference surface, the first reflecting surface 11 has a predetermined second angle with respect to the reference surface, the second reflecting surface 12 has a predetermined third angle with respect to the reference surface, and the optical axis 5 of the crystal has a predetermined fourth angle with respect to the normal to the incident surface 10.

When laser light is incident into the crystal 1 from the incident surface 10 perpendicular to the reference surface, the first angle, the second angle, the third angle and the fourth angle cause the laser light entering the crystal 1 through the incident surface 10 to be refracted into a first light ray 15 and a second light ray 16, and the first light ray 15 is totally reflected on the first reflecting surface 11 and then is emitted through the emitting surface 13; the second light beam 16 is totally reflected by the first reflecting surface 11 and the second reflecting surface 12 and then exits through the incident surface 10.

It will be appreciated that the reference plane, which is determined by the direction of laser propagation, may be a physical plane or may be a virtual plane. For example, the reference plane may be a horizontal plane based on the earth coordinate system, or may be a plane in another direction, and the direction of laser propagation may be ensured to be perpendicular to the reference plane.

As shown in fig. 2 and 4, when the straight line OG is the normal of the interface of the incident surface 10, the included angle between the optical axis 5 and the straight line OG is γ₁，γ₁I.e. the angle of the optical axis 5 of the crystal 1 with respect to the normal to the entrance face 10, i.e. the fourth angle, is equal to gamma₁. The angle between the incident surface 10 and the reference surface is theta₁I.e. the first angle is equal to theta₁The angle between the first reflecting surface 11 and the reference surface is α, i.e. the second angle is α, the angle between the second reflecting surface 12 and the reference surface is β, i.e. the first angleThe three angles are equal to β.

In practical application scenarios, laser light generated by the laser is elliptically polarized light or circularly polarized light, and polarized light with mutually perpendicular vibration directions can be separated. When birefringence occurs in laser light emitted from the laser, o light and e light having vibration directions perpendicular to each other are separated. The o light is ordinary light, is transmitted by the ordinary refractive index and meets the refraction law and the reflection law; the e light is transmitted by an extraordinary refractive index and does not satisfy the law of refraction and the law of reflection.

In the embodiment, a specific crystal 1 is adopted to cause the laser incident to the crystal 1 to generate birefringence so as to separate o light and e light, so that the o light is emitted as front light for data transmission or other purposes, the e light is used as backlight to monitor the light power of the laser emitted by the laser in real time, and the light power is adaptively adjusted according to actual conditions. Optionally, in this embodiment, the e light may also be emitted as front light for data transmission or other purposes, and the o light is used as backlight to monitor the optical power of the laser emitted by the laser in real time, and adaptively adjust the optical power according to actual conditions.

It can be understood that there are two splitting modes of the crystal 1 when splitting laser light, specifically as follows:

a first light splitting mode: the first light ray 15 is e light, i.e. the e light exits from the exit surface 13 as front light; the second light ray 16 is o-light, i.e. the o-light exits the entrance face 10 as backlight.

A second light splitting mode: the first light ray 15 is o light, i.e. the o light exits from the exit face 13 as front light; the second light ray 16 is e-light, i.e. the e-light exits the entrance face 10 as backlight.

Specifically, the crystal 1 shown in fig. 1 is suitable for the first spectroscopic method. For example, when the wavelengths of the first light 15 and the second light 16 are 850nm, the first light 15 is e light, the second light 16 is o light, and the crystal 1 is YVO4 crystal, the first angle is 14 °, the second angle is 51.5 °, the third angle is 38.5 °, and the fourth angle is 45 °. When the first light ray 15 and the second light ray 16 have a wavelength of 850 nm; the first light ray 15 is e light, the first light ray 15 is o light, and when the crystal 1 is LiNbO3 crystal, the first angle is 10 °, the second angle is 47.2 °, the third angle is 42.8 °, and the fourth angle is 45 °.

The crystal 1 shown in fig. 3 is suitable for the second spectroscopic method. For example, when the wavelengths of the first light 15 and the second light 16 are 850nm, the first light 15 is o light, the second light 16 is e light, and the crystal 1 is YVO4 crystal, the first angle is 10 °, the second angle is 40 °, the third angle is 50.7 °, and the fourth angle is 45 °. When the wavelengths of the first light 15 and the second light 16 are 850nm, the first light 15 is o light, the second light 16 is e light, and the crystal 1 is LiNbO3 crystal, the first angle is 10 °, the second angle is 38.5 °, the third angle is 51.3 °, and the fourth angle is 45 °.

For the principle and implementation process of the crystal 1 splitting based on the first splitting mode and the second splitting mode, please refer to the following description.

It should be emphasized that the above values are rounded and the angle values of the crystal 1 of the above-listed embodiments are optimal to ensure the total reflection of light on the reflecting surface for achieving the effect of fully utilizing light energy, but in the actual manufacturing process, the angle values may not be the same as those listed, i.e. there is a certain tolerance range, due to process errors or other factors. The inventor finds through a great deal of experiments that when the tolerance of the first angle, the second angle and the third angle is controlled to be +/-1 degrees, the good light splitting effect can be achieved.

In practical application scenarios, the crystal 1 is mainly applied to the field of optical communication, and the spectral window wavelengths of the optical communication are mainly 850nm, 1310nm and 1550 nm. The foregoing illustrates the matching relationship between the material of the crystal 1 and each angle when the laser wavelength is 850nm, and when the wavelength is 1310nm or 1550nm or other values, the crystal 1 of a suitable material is selected according to the wavelength of the laser, and the first angle θ is designed₁A second angle α, a third angle β, and a fourth angle γ₁Thereby realizing the light splitting function.

Different from the prior art, the crystal provided by the embodiment can realize laser beam splitting without adding a beam splitting film so as to meet the requirements of different scenes. For example, when the function of backlight monitoring needs to be realized, the emission power of the laser can be adaptively adjusted according to the power of the backlight. The light splitting method has good stability and can reduce the risk of failure of the optical device.

Example 2:

referring to fig. 5, the present embodiment provides a method for manufacturing a crystal, which is suitable for the crystal according to any of the above embodiments. The manufacturing method of the crystal comprises the following steps:

step 50: and (5) manufacturing an incidence plane of the crystal.

In the present embodiment, the incident surface of the crystal is fabricated according to actual requirements.

Step 51: manufacturing an emergent surface of a crystal, wherein the crystal is used for splitting laser which is emitted onto the crystal from an incident surface to generate a first light and a second light; the first light ray exits from the exit surface, and the second light ray exits from the entrance surface.

In the present embodiment, the exit surface of the crystal is fabricated according to actual requirements. The crystal of the embodiment is used for splitting laser light incident on the crystal from an incident surface to generate a first light ray and a second light ray; the first light ray exits from the exit surface, and the second light ray exits from the entrance surface.

Specifically, the crystal further comprises a first reflecting surface and a second reflecting surface, and in the actual manufacturing process, the first reflecting surface and the second reflecting surface of the crystal are required to be manufactured. And processing the crystal according to actual requirements so that the optical axis of the crystal meets a preset direction.

The incident surface of the crystal manufactured by the manufacturing method of this embodiment has a predetermined first angle with respect to a predetermined reference surface, the first reflecting surface has a predetermined second angle with respect to the reference surface, the second reflecting surface has a predetermined third angle with respect to the reference surface, and the optical axis of the crystal has a predetermined fourth angle with respect to the normal of the incident surface.

Here, it should be noted that the optical axis of the crystal satisfying the predetermined direction may be understood as a direction in which the optical axis of the crystal is located when the optical axis of the crystal has a predetermined fourth angle with respect to the normal of the incident surface.

In an actual application scene, when laser is incident into the crystal from the incident surface perpendicular to the reference surface, the laser entering the crystal through the incident surface is refracted into a first light ray and a second light ray through the first angle, the second angle, the third angle and the fourth angle, and the first light ray is totally reflected on the first reflecting surface and then is emitted through the emergent surface; the second light ray is totally reflected on the first reflecting surface and the second reflecting surface and then is emitted out through the incident surface.

Specifically, a crystal of a suitable material may be selected according to the wavelength of the laser light required, and then the first angle, the second angle, the third angle, and the fourth angle may be determined according to the material of the crystal and the wavelength of the laser light. And then manufacturing an incident surface, a first reflecting surface and a second reflecting surface according to the first angle, the second angle and the third angle, and cutting the crystal according to the fourth angle so as to ensure that the included angle between the optical axis of the crystal and the normal line of the interface of the incident surface is equal to the fourth angle.

For the crystal of any of the above embodiments that can be manufactured by the manufacturing method of this embodiment, please refer to embodiment 1 for details regarding the structure example of the crystal, which is not described herein again.

Example 3:

referring to fig. 6, the present embodiment provides an optical device, which includes a crystal 1 and a laser device 2, wherein the laser device 2 is configured to generate a collimated laser beam, and the crystal 1 is configured to split laser light emitted by the laser device 2. The crystal of any of the above embodiments and the crystal manufactured by the manufacturing method of any of the above embodiments are suitable for the optical device of this embodiment.

The laser assembly 2 comprises a laser 21 and a collimating lens 22, the collimating lens 22 is arranged on the laser 21, the laser 21 is used for generating laser with preset wavelength, the collimating lens 22 is used for integrating the laser into a collimated laser beam, and then the laser assembly 2 is enabled to generate the collimated laser beam.

The laser light generated by the laser 21 is elliptically or circularly polarized light, and polarized light with vibration directions perpendicular to each other can be separated. For example, the Laser 21 is a VCSEL (Vertical Cavity Emitting Laser, abbreviated as VCSEL) Laser, which can be used in a fiber optic network to transmit data at a high speed, and can transmit a larger amount of data at a higher speed than a conventional cable system. The laser light emitted by the VCSEL laser can separate o light and e light with mutually perpendicular vibration directions when birefringence occurs. The o light is ordinary light, is transmitted by the ordinary refractive index and meets the refraction law and the reflection law; the e light is transmitted by an extraordinary refractive index and does not satisfy the law of refraction and the law of reflection.

In this embodiment, by reasonably designing the structure of the crystal 1 and presetting the incident angle of the laser on the incident surface 10, the light splitting function can be effectively realized, so that a part of light is emitted as front light, and the other part of light is used as backlight, thereby achieving the purpose of monitoring and adaptively adjusting the emitted power of the laser 21. For example, a specific crystal 1 is adopted to cause the laser light incident to the crystal 1 to generate birefringence so as to separate o light and e light, so that the o light is emitted as front light for data transmission or other purposes, and the e light is used as backlight to monitor the light power of the laser light emitted by the laser 21 in real time and adjust the light power adaptively according to actual conditions. Optionally, in this embodiment, the e light may also be emitted as a front light for data transmission or other purposes, and the o light is used as a backlight to monitor the optical power of the laser light emitted by the laser 21 in real time, and adaptively adjust the optical power according to actual conditions.

The crystal 1 includes an incident surface 10, a first reflective surface 11, a second reflective surface 12, and an exit surface 13, where the incident surface 10 is configured to refract light propagating to the incident surface 10, the first reflective surface 11 and the second reflective surface 12 are configured to perform total reflection on light propagating to corresponding reflective surfaces, and the exit surface 13 is configured to emit light for receiving and using by a subsequent optical module.

For the sake of clarity, the principle and process of the crystal 1 of the present embodiment for splitting laser light are introduced into a predetermined reference plane, wherein the laser beam emitted by the laser assembly 2 is perpendicular to the predetermined reference plane. It is understood that the reference plane is determined by the propagation direction of the laser beam, and the reference plane is only for convenience of illustration and analysis of the light splitting principle of the embodiment, and may be a physical plane or a virtual plane. For example, the reference plane may be a horizontal plane based on the earth coordinate system, or may be a plane in another direction, and the direction of propagation of the laser beam may be perpendicular to the reference plane.

Specifically, the incident surface 10 has a first angle with respect to the reference surface, the first reflecting surface 11 has a second angle with respect to the reference surface, and the second reflecting surface 12 has a third angle with respect to the reference surface; the optical axis 5 of the crystal 1 has a fourth angle with respect to the normal to the entrance face 10. The first angle, the second angle, the third angle and the fourth angle enable laser entering the crystal 1 through the incident surface 10 to be refracted into a first light ray and a second light ray, and the first light ray is totally reflected on the first reflecting surface 11 and then is emitted through the emitting surface 13 to be emitted as front light; the second light is totally reflected on the first reflecting surface 11 and the second reflecting surface 12, and then is emitted through the incident surface 10 to be emitted as backlight.

In the present embodiment, the first light is used as front light, the second light is used as back light, the optical assembly further includes a receiving assembly 3 and a monitoring assembly 4, the receiving assembly 3 is disposed on the exit surface 13 side of the crystal 1, and the monitoring assembly 4 is disposed on the same side of the laser assembly 2, that is, the monitoring assembly 4 is disposed on the incident surface 10 side of the crystal 1. The receiving assembly 3 is configured to receive a first light, the receiving assembly 3 includes a first condensing lens 31 and an optical fiber 32, and the first condensing lens 31 is configured to couple the first light into the optical fiber 32. The monitoring assembly 4 is configured to receive the second light, and the monitoring assembly 4 includes a monitoring device 41 and a second condenser lens 42, and the first condenser lens 42 is disposed on the monitoring device 41. The monitoring assembly 4 is specifically configured to adjust the emission power of the laser assembly 2 in accordance with the power of the received second light. In an alternative embodiment, the monitoring component 4 analytically determines the power of the received second light and adjusts the emission power of the laser 21 in dependence on this feedback power. The monitoring device 41 is a backlight detector, which may also be called a monitoring photodiode.

In addition, the optical assembly further comprises a circuit board 6, and the laser 21 and the monitoring device 41 are correspondingly arranged on the circuit board 6. In general, the laser light emitted by the laser 21 is collimated and then perpendicular with respect to the circuit board 6, and the plane of the circuit board 6 can be used as a reference plane for explaining the reference plane more intuitively.

In an alternative embodiment, the optical assembly may be suitable for application scenarios of multipath data transmission, and accordingly, the laser assembly 2 and the monitoring assembly 4 are correspondingly distributed in a multipath array along the direction of extension of the incident surface 10 of the crystal 1, and the laser assembly 2 is used for generating multipath laser; each path of laser correspondingly generates a first light 15 and a second light 16 after passing through the crystal 1, the receiving component 3 is used for receiving the first light 15 corresponding to multiple paths of laser, and the monitoring component 4 is used for adjusting the emitting power of the corresponding branch laser of the laser component 2 according to the power of the received second light 16 of each path. Specifically, the laser module 2 includes a plurality of lasers 21, the monitoring module 4 includes a plurality of monitoring devices 41, and the monitoring devices 41 correspond to the lasers 21 one by one to correspond to the emitted optical power of the monitoring lasers 21.

Assuming that a collimated laser beam emitted from the laser element 2 enters the crystal 1 through the point O, the point O is used as the origin of the normal line of the interface of the incident surface 10, a straight line parallel to the reference plane is emitted from the vertex a of the crystal 1, and the straight line intersects the normal line of the interface of the incident surface 10 at the point G, as shown in fig. 6, the included angle between the optical axis 5 and the normal line OG is γ₁，γ₁I.e. the angle of the optical axis 5 of the crystal 1 with respect to the normal to the entrance face 10, i.e. the fourth angle, is equal to gamma₁. The angle between the incident surface 10 and the line AG is θ₁，θ₁I.e. the angle of the plane of incidence 10 with respect to the reference plane, i.e. the first angle is equal to theta₁Starting from the vertex B of the crystal 1, a straight line BL parallel to the reference plane is made, the angle between the first reflecting surface 11 and the straight line BL being α, i.e. the angle of the first reflecting surface 11 relative to the reference plane, i.e. the second angle being equal to α, starting from the vertex V of the crystal 1, a straight line UV parallel to the reference plane is made, the angle between the second reflecting surface 12 and the straight line UV being β, i.e. the angle of the second reflecting surface 12 relative to the reference plane, i.e. the third angle being equal to β.

Crystals of different materials can be selected based on laser light with different wavelengths, and α, β, gamma are designed₁And theta₁Can pass through the crystalThe body realizes the function of light splitting.

Because the crystal 1 is made of anisotropic material, the optical axis 5 is not coincident with the normal interface of the crystal 1, and the light entering from the outside can generate double refraction, namely, one light beam is refracted into two refracted light beams. The light splitting principle of the present embodiment is explained by using one refracted light beam as an o light beam and the other refracted light beam as an e light beam. The refractive indices of o light and e light in the crystal 1 are different, the refraction of o light obeys the law of refraction and the law of reflection, and the refraction of e light obeys the following formula (1):

wherein n is_oIs the refractive index of o light in the crystal, n_eIs the refractive index of e-light in the crystal, gamma₁Is the angle between the optical axis of the crystal and the normal of the incident surface, and n is the refractive index of the medium except the crystal; theta₁The incident angle of the laser incident on the incident surface; theta_eThe refraction angle of e light when the incident surface refracts.

The reflection of e-light at the crystal obeys the following formula (2):

wherein, theta_{Incident light}Is the angle of incidence of e light with respect to the reflective surface, θ_ReflectionIs the angle of reflection of e light relative to the reflecting surface, n_oIs the refractive index of o light in the crystal, n_eThe refractive index of e light in the crystal is shown, gamma is an included angle between the normal line of the reflecting surface and the optical axis, and epsilon is an included angle between the reflecting surface and the optical axis.

As can be seen from example 1, there are two spectroscopic methods for separating laser light by the crystal 1, as follows:

a first light splitting mode: the first light is e light, i.e. the e light is coupled out of the exit face 13 to the optical fiber 32 as front light; the second light is o light, i.e. the o light enters the monitoring component 4 as backlight after being refracted from the incident surface 10.

A second light splitting mode: the first light ray is o light, i.e. the o light is coupled out of the exit face 13 to the optical fiber 32 as front light; the second light is e light, i.e. the e light is refracted from the incident surface 10 as a backlight and enters the monitoring component 4.

Please refer to fig. 7 to derive the first implementation of the light splitting method.

As shown in fig. 7, the collimated laser beam generated by the laser module 2 is birefringent after passing through the incident surface 10 of the crystal 1, and separates e-light 15 (first light) and o-light 16 (second light).

The propagation trajectory OF e-light 15 (OF-FY) is derived as follows:

first, an analysis auxiliary line is prepared according to the following steps (1) to (6):

(1) the intersection point of the laser and the incident surface 10 is an O point, and the O point is taken as an origin and is perpendicular to the normal of the incident surface 10;

(2) starting from the vertex A, making a straight line parallel to the reference surface, wherein the intersection point of the straight line and the normal line is G;

(3) starting from the vertex B, drawing a straight line BL parallel to the reference plane, wherein the intersection point of the straight line BL and the normal of the incidence plane 10 is D;

(4) the e-ray 15 propagates in the crystal 1 along a straight line until reaching the first reflecting surface 11, and total reflection occurs at point F (where the straight line OF intersects with the straight line BL and point C), and a normal FT perpendicular to the first reflecting surface 11 is made with point F as an origin, where the normal FT intersects with the optical axis 5 and point T. Wherein the incident angle of the e-light 15 on the first reflecting surface 11 is θ₂(ii) a e light 15 is totally reflected on the first reflecting surface 11 at a reflection angle theta₃。

Since the laser light is perpendicular to the reference surface and the line AG is parallel to the reference surface, and the line AG is perpendicular to the laser light, it can be determined that the angle between the laser light and the normal line is equal to ∠ OAG, i.e. the incident angle of the laser light on the incident surface 10 is θ₁。

In △ OCD and △ CEF, since △ 0OCD and △ 1FCE are opposite angles, ∠ OCD is ∠ FCE, ∠ CDO + ∠ COD is ∠ CFE + ∠ CEF, where ∠ COD is the angle between e-ray and the normal of the incident surface 10, i.e. the refraction angle of e-ray, ∠ COD is θ 52_e∠ CFE is the incident angle of e light with respect to the first reflecting surface 11, so ∠ CFE is θ₂。

In the △ AOG, the optical sensor is,OG⊥AO，∠OAG＝θ₁if ∠ OGA is 90-theta₁In △ BFE, EF ⊥ BF, &lTtTtranslation = angle "& &gTt &/T &gTtFBE ═ α, then ∠ FEB ═ ∠ CEF ═ 90 ° - α, since BL/AG, &lTtTtranslation = &" &gTt &/T &gTtCDO ═ ∠ OGA, ∠ CDO ═ 90 ° - θ₁。

In summary, θ can be obtained_e+90°-θ₁＝θ₂+90 ° - α, so that e-light is earlier than the incident angle θ of the first reflecting surface 11₂Satisfies the following formula (3):

θ₂＝θ_e+α-θ₁(3)

wherein, theta_eAngle of refraction of e-light, α is the angle of the first reflective surface 11 relative to a reference plane, θ₁Is the incident angle (theta) of the laser light on the incident surface 10₁The angle of the entrance face 10 with respect to the reference plane).

In △ FTO,. gamma.₂∠ TFO + ∠ TOF, where γ₂An included angle between the optical axis 5 and the normal of the first reflecting surface 11 is ∠ TOD- ∠ TOD- ∠ COD, and since ∠ TOD is an included angle between the optical axis 5 and the normal of the incident surface 10, ∠ TOD- γ₁∠ COD is the refraction angle of e light on the incident surface 10, then ∠ COD is theta_eThus ∠ TOF ═ γ₁-θ_eFrom the foregoing analysis, ∠ TFO ═ θ₂Then, in combination with the formula (3), γ can be obtained₂＝θ₂+γ₁-θ_e＝θ_e+α-θ₁+γ₁-θ_e＝α-θ₁+γ₁；

Namely gamma₂Satisfies the following formula (4)

γ₂＝α-θ₁+γ₁(4)

Where α is the angle of the first reflecting surface 11 relative to the reference plane, θ₁Is the incident angle (theta) of the laser light on the incident surface 10₁Angle of the incident surface 10 with respect to the reference surface), γ₁Is the angle of the optical axis of the crystal relative to the normal to the plane of incidence.

(5) Starting from point F, a straight line FR (FR/OT) parallel to the optical axis 5 is formed, the straight line FR forming an angle ε with the first reflecting surface 11₂Is the angle between the optical axis 5 and the first reflecting surface 11. Since FR/OT,. epsilon₂+90°+γ₂＝180°，ε₂＝90°-γ₂In combination with formula (4) ∈₂＝90°-γ₂＝90°-(α-θ₁+γ₁) Then e₂Satisfies the following formula (5):

ε₂＝90°+θ₁-α-γ₁(5)

According to the wavelength of the laser and the material of the crystal, α and theta are set reasonably₁And gamma₁The angle may be such that e-light 15 is reflected by the first reflective surface 11 and enters the exit surface 13 perpendicularly.

In the present embodiment, the exit surface 13 is arranged perpendicular to the reference surface, and the e-light 15 is incident perpendicularly to the exit surface 13 and then exits from the exit surface 13 by refraction and emission.

(6) Assuming that the intersection point of the e-light 15 and the exit surface 13 is a point Y, the point Y is taken as a straight line XY parallel to the optical axis 5, and the point Y is taken as an origin point as an interface normal YP of the exit surface 13, an included angle (∠ XYP) between the straight line XY and the normal YP is an included angle between the interface normal of the exit surface 13 and the optical axis 5, and ∠ XYP is made to be γ₃；

Since the straight line YP is the normal of the interface of the exit surface 13 and the exit surface 13 is perpendicular to the reference surface, the straight line YP is parallel to the reference surface, YP/AG, as shown in fig. 7, the straight line AG intersects the optical axis 5 at the point S, ∠ XYP ∠ OSG, in △ OSG, ∠ OSG 180 ° - ∠ SOG- ∠ OGS, ∠ SOG γ₁，∠OGS＝∠OGA＝90°-θ₁Therefore, ∠ OSG is 90 ° + θ₁-γ₁. The refraction angle theta of e-light 15 is obtained according to the formula (1)₁', finally according to the angle of refraction theta₁' the angle of the light-emitting direction of the e-light 15 relative to the reference surface can be determined, so as to determine the position where the receiving component 3 is arranged, thereby effectively coupling the e-light 15 into the optical fiber 32 and realizing the light-emitting function.

In a preferred embodiment, the angle of the exit surface 13 relative to the reference surface can also be designed according to actual conditions, so that the e-light 15 exits perpendicular to the exit surface 13, thereby reducing the difficulty of the coupling process.

The propagation trajectory (OH-HI-IQ) of the o-light 16 is derived, explained below by way of example with the exit face 13 perpendicular to the reference plane:

after the laser is refracted by the incident surface 10 of the crystal 1, the o-light 16 satisfies the law of refraction and the law of reflection, and the refraction angle theta of the o-light 16 on the incident surface 10_oThen theta_oCan be formed by o light 16 with refractive index n of crystal 1_oAngle of incidence θ of laser beam on incident surface 10₁And the refractive index n of the medium other than the crystal 1. The o-light 16 propagates in the crystal 1 along a preset propagation track, and the H point of the o-light 16 propagating to the first reflecting surface 11 is totally reflected.

First, an analysis auxiliary line is prepared according to the following steps (1) to (4):

(1) an interface normal HL with the point H as an origin reflecting surface, and a point K (namely the intersection of OH and BL) and the point K are intersected with a straight line BL in the propagation process of the o light 16;

for convenience of description, let the incident angle of the o-light 16 on the first reflecting surface 11 be θ₄The reflection angle of the o-ray 16 on the first reflection surface 11 is θ₅Since o-ray 16 follows the law of reflection, then the law of reflection n_osinθ₄＝n_osinθ₅As can be seen, θ₄＝θ₅。

Of △ HKL and △ DKO, ∠ KHL + ∠ KLH ∠ KDO + ∠ KOD because ∠ KDO ∠ AGO 90 ° - θ₁∠ KOD is the angle of refraction of o-light 16 after it has been refracted through the incident surface 10 of the crystal 1, i.e. ∠ KOD is θ_o。

In △ BHL, HL ⊥ BH, &lttttransition = & "&gtt &/t &gtthbl ═ α, ∠ KLH ═ ∠ BLH ═ 90 ° - α, and therefore ∠ KHL +90 ° - α ═ 90 ° - θ =₁+θ_o，∠KHL＝α-θ₁+θ_o，θ₅＝θ₄∠ KHL, then theta₄And theta₅Satisfies the following formula (6):

θ₅＝θ₄＝α-θ₁+θ_o(6)

after the o-light 16 is reflected by the first reflecting surface 11, the o-light 16 reaches the second reflecting surface 12 along a predetermined propagation path, and intersects the second reflecting surface 12 at the point I.

(2) When the I point is used as the origin of the interface normal of the second reflective surface 12, the interface normal intersects HL (the interface normal of the first reflective surface 11) and J point, and intersects BL and W point.

Let the incident angle (∠ HIJ) of the o-light 16 on the second reflecting surface 12 be theta₆The reflection angle of the o-ray 16 on the second reflection surface 12 is θ₇(∠ UIZ) since o-ray 16 follows the law of reflection, then the law of reflection n_osinθ₆＝n_osinθ₇As can be seen, θ₆＝θ₇；

In △ HJI and △ LJW, ∠ IHJ + ∠ HIJ ∠ JWL + ∠ JLW, and in △ LJW and △ LHB, ∠ JLW ∠ HLB 90 ° - △ 0;

(3) a line parallel to BL is drawn at point V and intersects IW at point U, ∠ IVU β, then in △ IUV UI ⊥ VI, β 2IUV 90 ° - β 0, since UV/BL, ∠ JWL ∠ IUV 90 ° - β 1, and ∠ JWL β 3 ', β' — ∠ JWL 90 ° - β.

In summary, θ₅+θ₆Combining 90 ° - β +90 ° - α to obtain θ according to formula (6)₆＝θ₇Satisfies the following formula (7):

θ₆＝θ₇＝180°+θ₁-θ_o-β-2α (7)

after o-light 16 is reflected by second reflective surface 12, o-light 16 returns to incident surface 10 along a predetermined propagation path and intersects with point Q on incident surface 10. The reflected light of the o light 16 reflected by the second reflecting surface 12 intersects with the reflected light of the e light 15 on the first reflecting surface 11 at point N.

(4) The normal line of the interface of the incident surface is defined by the point Q as the origin, and intersects the reflected light of the e-beam 15 on the first reflecting surface 11 at the point M.

Since MN/(e light 15 exits perpendicularly to the exit face 13), ∠ MNQ ∠ UZN ∠ ZUI + ∠ ZIU β' + θ₇＝90°-β+θ₇Because MN/BL/AG and MQ/DO, ∠ NMQ ∠ CDO ∠ AGO 90-theta₁In △ MNQ, ∠ MQN-180 ° - ∠ NMQ- ∠ MNQ-180 ° - (90 ° - θ)₁)-(90°-β+θ₇)＝θ₁+β-θ₇＝θ₁+β-(180°+θ₁-θ_o-β-2α)＝2β+2α+θ_o-180 °, wherein ∠ MQN is the incident angle of o-light 16 on incident surface 10, i.e. ∠ MQN ═ θ₈Then theta₈Satisfying the following formula (8):

θ₈＝2β+2α+θ_o-180° (8)

according to the wavelength of the laser and the material of the crystal 1, α, β and theta are reasonably arranged₁And gamma₁The angle is such that the o-ray 16 is refracted by the incident surface 10 and exits, and the exiting o-ray 16 is parallel to the laser beam emitted by the laser assembly 2, i.e. the o-ray 16 exits perpendicular to the reference surface.

The foregoing derivation illustrates the derivation formula of each angle when the e-light 15 and the o-light 16 are refracted or emitted on the crystal 1, and the following example is used to specifically illustrate the feasibility of the first splitting mode:

the first alternative is:

taking the crystal 1 as LiNbO3 crystal and the laser wavelength as 850nm as an example, n can be known by looking up a table_o＝2.25，n_e2.17; according to the total reflection condition, the relation from the optically dense medium to the optically sparse medium is satisfied as follows:

n_osinθ_{total reflection}＝1，n_esinθ_{Total reflection}1 is ═ 1; then theta can be obtained_{0 total reflection}＝26.41°，θ_{e total reflection}＝27.43°。

θ₁、γ₁N, α and β are combined into a value theta₁＝10°，γ₁＝45°，n＝1，α＝47.2°，β＝42.8°。

According to the above equations (1) to (8), it can be found that:

θ₀＝23°，θ_e＝6.5°，θ₂＝43.7°，θ₃＝42.8°，θ₄＝60.2°，θ₅＝60.2°，θ₆＝29.8°，θ₇＝29.8°，θ₈＝23°；

it can be derived that:

θ₂>θ_{e total reflection}E light 15, the first reflecting surface 11 meets the total reflection condition, and total reflection occurs;

θ₄>θ_{0 total reflection}The o light 16 satisfies the total reflection condition on the first reflecting surface 11, and total reflection occurs;

θ₆>θ_{0 total reflection}The o light 16 satisfies the total reflection condition on the second reflecting surface 12, and total reflection occurs;

due to theta₈＝θ₀According to the principle of reversible optical path, the o-ray 16 emerging from the incident face 10 of the crystal 1 is perpendicular to the reference plane.

∠HFN＝90°-θ₃Since FN/BL, that is, FN is parallel to the reference direction, 47.2 ° - α, the e-beam 15 reflected by the first reflecting surface 11 of the crystal 1 enters the emission surface in a direction parallel to the reference surface.

A second alternative:

taking crystal 1 as YVO4 crystal and laser wavelength as 850nm as an example, n can be known by looking up a table_o＝1.97，n_e2.18; according to the total reflection condition, the relation from the optically dense medium to the optically sparse medium is satisfied as follows:

n_osinθ_{total reflection}＝1，n_esinθ_{Total reflection}1 is ═ 1; then theta can be obtained_{0 total reflection}＝30.54°，θ_{e total reflection}＝27.26°。

θ₁、γ₁N, α and β are combined into a value theta₁＝14°，γ₁＝45°，n＝1，α＝51.5°，β＝38.5°。

According to the above equations (1) to (8), it can be found that:

θ₀＝20.0°，θ_e＝-1.1°，θ₂＝36.35°，θ₃＝38.5°，θ₄＝57.5°，θ₅＝57.5°，θ₆＝32.5°，θ₇＝32.5°，θ₈＝20°；

it can be derived that:

θ₂>θ_{e total reflection}The e light 15 satisfies the total reflection condition on the first reflecting surface 11, and total reflection occurs;

∠HFN＝90°-θ₃Since FN/BL, that is, FN is in the horizontal direction, 49.4 ° - α, the e-beam 15 reflected by the first reflecting surface 11 of the crystal 1 enters the emission surface in a direction parallel to the reference surface.

In this embodiment, the receiving module 3 receives the e-beam 15 as a front beam to be emitted, the monitoring module 4 receives the o-beam 16 as a backlight, and the laser power of the laser module 2 is adaptively adjusted according to the power of the received o-beam 16, thereby ensuring that the power of the e-beam 15 meets the actual requirement.

The implementation of the second light splitting mode is described below with reference to fig. 8:

as shown in fig. 8, the collimated laser beam generated by the laser module 2 is birefringent after passing through the incident surface 10 of the crystal 1, and o-light 15 (first light) and e-light 16 (second light) are separated.

The derivation OF the o-ray 15 (OF-FN) propagation trajectory is as follows:

firstly, an analysis auxiliary line is made according to the following steps (1) to (5):

(1) the intersection point of the laser and the incident surface 10 is O, and the normal perpendicular to the incident surface 10 is made by taking O as the origin;

(3) starting from the vertex B, drawing a straight line BE parallel to the reference surface, wherein the intersection point of the straight line BE and the normal of the incidence surface 10 is D;

(4) after entering the crystal 1 from the incident surface 10, the o-ray 15 propagates in the crystal 1 along a straight line until reaching the F OF the first reflecting surface 11, where total reflection occurs (the straight line OF and the straight line BE intersect at point C), and a normal FE perpendicular to the first reflecting surface 11 is taken with the point F as an origin;

(5) the incident angle of the o light 15 on the first reflecting surface 11 is θ₂The o light 15 is totally reflected on the first reflecting surface 11 at a reflection angle θ₃(ii) a The o light 15 is reflected and emitted from the emission surface 13 as front light.

Of Δ OCD and Δ ECF, ∠ COD + ∠ CDO is ∠ CEF + ∠ CFE, and &lttt translation = & "&gtt &/t &gtt CFE is the incident angle of the o-light 15 at the first emitting surface 11, that is, ∠ CFE is θ ═ f₂In Δ BEF, EF ⊥ BF, &lttttransition = h "&" gtt & ltt & cett & ∠ BEF ═ 90 ° - α since BE/AG, ∠ CDO ═ ∠ OGA, in Δ AGO, ∠ OGA ═ 90 ° - θ &inΔ AGO₁Since ∠ COD is the refraction angle of o light 15 in crystal 1, i.e. ∠ COD is θ ═ theta_o。

In summary, θ_o+90°-θ₁＝90°-α+θ₂Therefore, the incident angle θ of the o-light 15 on the first reflecting surface 11₂Satisfies the following formula (10):

θ₂＝θ_o+α-θ₁(10)

wherein, theta_oAngle of refraction of o light, α angle of the first reflecting surface 11 with respect to the reference plane, θ₁Is the incident angle (theta) of the laser light on the incident surface 10₁The angle of the entrance face 10 with respect to the reference plane).

Since the propagation of the o-light 15 within the crystal 1 obeys the law of reflection, it follows from the law of reflection: n is_osinθ₂＝n_osinθ₃Then theta₂＝θ₃Therefore, the reflection angle θ of the o light 15 on the first reflection surface 11₃The above equation (10) is also satisfied.

According to the wavelength of the laser and the material of the crystal, α and theta are set reasonably₁The size of the light source can be such that the o-light 15 is reflected by the first reflecting surface 11 and then enters the emergent surface 13 perpendicularly, so that the o-light 15 is ensured to be emitted from the emergent surface 13 perpendicularly.

The following explanation takes the example of the emission of o-light 15 perpendicular to the emission surface 13 as an example, and the derivation analysis of the propagation trajectory (OH-HI-IQ) of e-light 16:

first, an analysis auxiliary line is prepared according to the following steps (1) to (7):

(1) the laser is refracted by the incident surface 10 of the crystal 1 to generate e-light 16, and the refraction angle of the e-light 16 is theta_eE-beam 16 intersects first reflective surface 11 at point H (relative to interface normal OG of incident surface 10), where OH intersects BE at point K;

(2) taking the point H as the origin as the interface normal of the first reflecting surface 11, wherein the normal intersects with the optical axis 5 and is intersected with the point T, and the normal and the BE intersect at the point L;

of Δ HKL and Δ DKO, ∠ KHL + ∠ KLH is ∠ KDO + ∠ KOD, and since ∠ KHL is the incident angle of e-light 16 with respect to the first reflecting surface 11, ∠ KHL is θ₄Because ∠ KLH ∠ BLH 90 ° - α KDO ∠ AGO 90 ° - θ₁Then theta₄+90°-α＝90°-θ₁+θ_eTherefore, it can be known that the incident angle θ of the e-light 16 with respect to the first reflecting surface 11₄Satisfies the following formula (11):

θ₄＝α-θ₁+θ_e(11)

wherein, theta_eAngle of refraction of e-light 16, α is the angle of first reflective surface 11 relative to a reference plane, θ₁Is the incident angle (theta) of the laser light on the incident surface 10₁The angle of the entrance face 10 with respect to the reference plane).

Since ∠ DOT is the angle between the optical axis 5 and the normal of the incident surface 10, ∠ DOT is γ₁Since ∠ DOT is ∠ HOT + ∠ DOH and ∠ DOH is the angle of refraction of e-light 16 at the entrance face 10, ∠ DOH is θ_eTherefore ∠ HOT ═ γ₁-θ_e. Let the included angle between the optical axis 5 and the normal of the first reflecting surface 11 be gamma₂From FIG. 3, γ is shown₂＝∠THO+∠HOT＝θ₄+γ₁-θ_eThen, in combination with the formula (11), γ can be obtained₂Satisfies the following formula (12):

γ₂＝α-θ₁+γ₁(12)

(3) taking point H as a straight line HR parallel to the optical axis 5, the included angle between HR and the first reflecting surface 11 is epsilon₂(angle between optical axis 5 and first reflecting surface), i.e. ∠ RHF ═ epsilon₂；

Since HR/OT, ∠ RHT + γ₂180 °, i.e. ∠ RHF + ∠ FHT + γ₂180 °, since FH ⊥ FT results in ∠ FHT being 90 °, so ∈₂+90°+γ₂180 °, the angle epsilon between the optical axis 5 and the first reflecting surface 11₂Satisfies the following formula (13):

ε₂＝90°-γ₂(13)

(4) e light 16 is reflected by the first reflecting surface 11, then propagates along a preset propagation path, intersects with the second reflecting surface 12 and a point I, takes the point I as an original point, and is taken as a normal of the second reflecting surface 12, the normal intersects with a line where HL (an interface normal of the first reflecting surface 11) is located and a point J, and the normal intersects with BE and a point W; let the incident angle of e-light 16 on the second reflecting surface 12 be theta₆The reflection angle of the e-light 16 on the second reflecting surface 12 is θ₇；

(5) A straight line parallel to the optical axis 5 is made with the point J as a starting point, and the straight line intersects the second reflecting surface 12 at the point P;

(6) a straight line (namely a straight line parallel to BE) parallel to the reference surface is made by the vertex V, and the straight line intersects with the straight line IJ and a point Z and intersects with the straight line PJ and a point M;

since the straight line BE is parallel to the straight line ZV, ∠ LWJ is ∠ IZV, ∠ LWJ is ∠ IZV is ∠ 0', and in △ IZV IZ ⊥ IV, β is ∠ IZV is 90 ° - β, (where β is the angle of the second reflecting surface 12 relative to the reference surface).

Of Δ HJI and Δ LJW, ∠ IHJ + ∠ HIJ is ∠ WLJ + ∠ LWJ, where ∠ HIJ is the incident angle of e-light 16 on the second reflective surface 12 and ∠ IHJ is the reflection angle of e-light 16 on the first reflective surface 11, i.e., ∠ IHJ is θ₅，∠HIJ＝θ₆Because ∠ WLJ ∠ BLH 90 ° - α, then θ₅+θ₆90 ° - α +90 ° - β it follows that the angle of incidence of e-light 16 at the second reflective surface 12 is θ₆Satisfies the following formula (14):

θ₆＝180°-α-β-θ₅(14)

since pj (pm)/(OT) optical axis 5(OT), ∠ LJM ═ γ₂In △ HJI, ∠ HJI is 180 ° - ∠ JHI- ∠ JIH is 180 ° - θ₅-θ₆Since ∠ MJI- ∠ LJW- ∠ LJM, ∠ MJI- ∠ HJI- ∠ LJM is 180-theta₅-θ₆-γ₂Wherein ∠ MJI is the angle between the normal of the second reflection surface 12 and the optical axis 5, and ∠ MJI is made equal to γ₃Then, gamma is known₃The following formula (16) can be satisfied:

γ₃＝180°-θ₅-θ₆-γ₂(16)

since △ JIP is a right triangle, ∠ JPI is 90- ∠ PJI, and l TtT transition = & "&gTt/T &gTtJPI is the angle between the optical axis 5 and the second reflecting surface 12, and ∠ JPI is equal to epsilon₃Then, ε can be obtained₃Satisfies the following formula (17):

ε₃＝90°-γ₃(17)

(7) e light 16 is incident to the incident surface 10 through the light reflected by the second reflecting surface 12, intersects with the incident surface 10 and serves as a point Q, the point Q serves as a normal of the incident surface 10, the normal intersects with the MV and serves as a point S, and the IQ intersects with the straight line MV and serves as a point U;

since SQ/OG, SU/AG, ∠ USQ- ∠ AGO-90 ° - θ₁In Δ ZIU, ∠ ZIU is the reflection angle of the e-light 16 on the second reflection surface 12, and ∠ ZIU is θ₇，∠IZU＝β’，∠SUQ＝∠ZIU+∠IZU＝θ₇+β’＝θ₇+90 ° - β in Δ SUQ, θ₈180 ° - ∠ USQ- ∠ SUQ, hence θ₈＝180°-(90°-θ₁)-(θ₇+90 ° - β), can be pushed out by θ₈Satisfies the following formula (18)

θ₈＝θ₁+β-θ₇(18)

According to the wavelength of the laser and the material of the crystal 1, α, β and theta are reasonably arranged₁And gamma₁The angle is such that the e-light 16 is refracted by the incident surface 10 and then exits, and the exiting e-light 16 is parallel to the laser beam emitted by the laser assembly 2, i.e. the e-light 16 exits perpendicular to the reference plane.

The foregoing derivation explains the derivation formula of each angle when the o-light 15 and the e-light 16 are refracted or emitted on the crystal 1, and the following example is used to specifically describe the implementability of the above-mentioned second light splitting mode:

with crystal 1 as LiNbO3 crystal, laser wavelength 850nm as an example, and n can be found by looking up the table_o＝2.25，n_e2.17; according to the total reflection condition, the relation from the optically dense medium to the optically sparse medium is satisfied as follows: n is_osinθ_{Total reflection}＝1，n_esinθ_{Total reflection}1 is ═ 1; then theta can be obtained_{0 total reflection}＝26.41°，θ_{e total reflection}＝27.43°。

θ₁、γ₁N, α and β are combined into a value theta₁＝10°，γ₁＝45°，n＝1，α＝38.5°，β＝51.3°。

From the above equations (1), (2), (10) to (18), it follows:

θ₀＝23°，θ_e＝6.5°，θ₂＝51.5°，θ₃＝51.5°，θ₄＝35°，θ₅＝34.7°，θ₆＝55.5°，θ₇＝54.8°，θ₈＝6.5°；

it can be derived that:

θ₂>θ_{0 total reflection}The o light 15 satisfies the total reflection condition on the first reflecting surface 11, and total reflection occurs;

θ₄>θ_{e total reflection}E light 16 satisfies the total reflection condition on the first reflecting surface 11, and total reflection occurs;

θ₆>θ_{e total reflection}E light 16 satisfies the total reflection condition on the second reflecting surface 12, and total reflection occurs;

due to theta₈＝θ_eAccording to the principle of reversible optical path, the e-light 16 emitted from the incident surface 10 of the crystal 1 is perpendicular to the reference surface.

∠XFN＝90°-θ₃When FN/BL, i.e. FN is parallel to the reference direction, 38.5 ° - α, the o-light 15 reflected by the first reflecting surface 11 of the crystal 1 enters the exit surface in a direction parallel to the reference surface, and the o-light 15 exits in a direction perpendicular to the exit surface 13 because the exit surface 13 is perpendicular to the reference surface.

A second alternative:

taking crystal 1 as YVO4 crystal, laser wavelength as 850nm as an example,by looking up a table, n is known_o＝1.97，n_e2.18; according to the total reflection condition, the relation from the optically dense medium to the optically sparse medium is satisfied as follows: n is_osinθ_{Total reflection}＝1，n_esinθ_{Total reflection}1 is ═ 1; then theta can be obtained_{0 total reflection}＝30.54°，θ_{e total reflection}＝27.26°。

θ₁、γ₁N, α and β are combined into a value theta₁＝10°，γ₁＝45°，n＝1，α＝40°，β＝50.7°。

From the above equations (1), (2), (10) to (18), it follows:

θ₀＝20°，θ_e＝-1.1°，θ₂＝50°，θ₃＝50°，θ₄＝28.9°，θ₅＝29.6°，θ₆＝59.7°，θ₇＝61.8°，θ₈＝-1.1°；

it can be derived that:

∠XFN＝90°-θ₃If FN/BL is equal to α, i.e. FN is parallel to the reference direction, the o-light 15 reflected by the first reflecting surface 11 of the crystal 1 enters the exit surface in a direction parallel to the reference surface, and since the exit surface 13 is perpendicular to the reference surface, the o-light 15 exits in a direction perpendicular to the exit surface 13.

It should be emphasized that the values listed above are the result of rounding off, and the values of the angles of the crystal 1 in the various embodiments listed above are the optimal result, so as to ensure that the total reflection of the light on the reflecting surface is achieved, so as to achieve the effect of utilizing the light energy sufficiently, but the values of the angles may not be the same as those listed above, i.e. there is a certain tolerance range, due to process errors or other factors during the actual manufacturing process. The inventor has found through a lot of experiments that when the tolerance of the first angle, the second angle, the third angle and the fourth angle is controlled to be ± 1 °, although a small amount of light is refracted, a good light splitting effect can be achieved.

As can be seen from the foregoing analysis, the structures of the crystals 1 in the two light splitting manners provided in this embodiment are different, and specifically, the process requirement of the crystal 1 corresponding to the first light splitting manner is relatively low, and the size of the crystal 1 corresponding to the second light splitting manner is smaller, which can be selected according to the actual situation during the actual use.

In addition, the present embodiment is derived by using the wavelength of the laser as 850nm, in other embodiments, the laser with the wavelength of 1310nm or 1550nm is also applicable to the light splitting method of the present embodiment, and in practical application scenarios, the angles of the surfaces of the crystal 1 may be calculated and correspondingly set according to the above formulas (1) to (18).

Different from the prior art, the invention adopts the crystal with a specific structure, and the collimated laser beam can generate a first light ray and a second light ray through birefringence after passing through the incident surface of the crystal, wherein the first light ray is totally reflected on the first reflecting surface and then is emitted through the emergent surface to be used as a front light; the second light is totally reflected on the first reflecting surface and the second reflecting surface and then is emitted through the incident surface to be used as backlight. The invention can realize the light splitting of the laser without adding a light splitting film so as to realize the function of backlight monitoring and self-adaptively adjust the emission power of the laser. The light splitting method has good stability and reduces the risk of failure of the optical device.

Example 4:

referring to fig. 9, the present embodiment provides a method for manufacturing an optical device, which is suitable for the optical device of any of the embodiments. The manufacturing method of the optical assembly comprises the following steps:

step 90: the laser assembly is arranged on a preset reference surface, and the direction of laser emitted by the laser assembly is configured.

In this embodiment, the optical device includes a crystal and a laser device, wherein the crystal of any of the above embodiments can be used to prepare the optical device of this embodiment, and the crystal can be selected according to actual requirements.

Specifically, the laser assembly comprises a laser and a collimating lens, wherein the collimating lens is arranged on the laser, the laser is used for generating laser with a preset wavelength, and the collimating lens is used for integrating the laser into a collimated laser beam, so that the laser assembly generates the collimated laser beam.

The reference plane is only for convenience of explaining the position of the crystal in the embodiment, and may be a physical plane or a virtual plane. For example, the reference plane may be a horizontal plane based on the earth coordinate system, or may be a plane in other directions, or the predetermined reference plane may be on a circuit board or other platform, and the direction of the laser beam propagation is ensured to be perpendicular to the reference plane, which is not limited herein.

For convenience of description, the reference plane is taken as an example of the circuit board. In the actual manufacturing process, the laser is disposed on the circuit board while the collimator lens is disposed on the laser. In this embodiment, the laser emitted by the laser is generally elliptically or circularly polarized light, and in order to ensure that the directions of the laser light incident on the crystal incident plane are consistent, the laser emitted by the laser is collimated by the collimating lens, so that the laser emitted by the laser component is perpendicular to the reference plane.

On the other hand, because the laser emitted by the laser assembly is a parallel beam, the height of the crystal relative to the circuit board can be reduced, and the packaging size of the optical assembly is reduced.

Step 91: the crystal satisfying the light splitting condition is arranged at a preset position, so that the crystal splits the laser light incident from the incident surface into a first light and a second light, wherein the first light is emitted from the emergent surface, and the second light is emitted from the incident surface.

The optical axis of the crystal is not coincident with the interface normal of the crystal, and the light entering from the outside can generate double refraction, namely, one light beam is refracted into two refracted light beams. Specifically, the crystal includes an incident surface, an exit surface, a first reflecting surface, and an exit surface. The function of light splitting can be realized by reasonably designing the structure of the crystal.

In an actual application scenario, when the wavelengths of the laser light emitted by the laser component are different, the refractive index of the laser light in the crystal is also changed, and further the propagation path of the light is affected. Accordingly, when the materials of the crystals are different, the refractive index of the laser light with the same wavelength in the crystals is changed, and the propagation path of the light is affected. Therefore, in the present embodiment, the wavelength of the laser emitted by the laser component is determined according to the actual application scenario, for example, the wavelength of the laser may be 850nm, 1310nm, 1550nm, or the like. Then, a material of a crystal is selected based on the wavelength of laser light emitted from the laser module, wherein the material of the crystal may be LiNbO3 crystal, YVO4 crystal, or the like. The wavelength of the laser emitted by the laser component and the material of the crystal are selected according to actual requirements.

After the wavelength of laser light emitted by the laser assembly and the material of the crystal are determined, setting the angles of the incident surface, the first reflecting surface and the second reflecting surface relative to the reference surface and the angle of the optical axis of the crystal relative to the normal of the incident surface according to the material of the crystal and the wavelength of the laser light, so that the laser light incident from the incident surface is divided into a first light ray and a second light ray, and the first light ray is totally reflected on the first reflecting surface and then is emitted out through the emergent surface; the second light ray is totally reflected on the first reflecting surface and the second reflecting surface and then is emitted out through the incident surface.

Further, the receiving assembly is arranged on the light emitting surface side of the crystal, wherein the receiving assembly comprises a condensing lens and an optical fiber, and the condensing lens condenses the first light and then couples the first light to the optical fiber to realize data transmission. In order to monitor and adjust the emission power of the laser component in real time, in a preferred embodiment, a monitoring component may be disposed on the circuit board, wherein the monitoring component includes a monitoring device and a condensing lens, the condensing lens is used for condensing the second light and then transmitting the second light to the monitoring device, the monitoring device is used for monitoring the power of the second light in real time, and adjusting the current in real time according to a monitoring result to adjust the emission power of the laser component, thereby implementing a backlight monitoring function to ensure that the power of the first light meets the requirements.

When the polarization states of the laser assemblies are different, the energy ratios corresponding to the first light and the second light are different, the first light is emitted as front light and has higher requirements on power, the second light is used as backlight and has lower requirements on power, and light energy is fully utilized in order to ensure. In a preferred embodiment, the type of the first light and the type of the second light are determined based on a polarization state of laser light emitted by the laser assembly, wherein the energy of the first light is greater than the energy of the second light.

Further, selecting a material of the crystal based on a wavelength of laser light emitted by the laser assembly, specifically, setting an incident surface, an angle of the first reflecting surface and the second reflecting surface relative to a reference surface and an angle of an optical axis of the crystal relative to a normal of the incident surface according to a type of the first light, a type of the second light, the material of the crystal and the wavelength of the laser light, so that the laser light incident from the incident surface is divided into the first light and the second light, and the first light is totally reflected on the first reflecting surface and then emitted through the emitting surface; the second light ray is totally reflected on the first reflecting surface and the second reflecting surface and then is emitted out through the incident surface.

The optical assembly of any of the above embodiments can be manufactured according to the manufacturing method of the present embodiment, please refer to fig. 6 to 8 and the related text description, which are not repeated herein.

Different from the prior art, the invention adopts the crystal with a specific structure, and the collimated laser beam can generate a first light ray and a second light ray through birefringence after passing through the incident surface of the crystal, wherein the first light ray is totally reflected on the first reflecting surface and then is emitted through the emergent surface to be used as a front light; the second light is totally reflected on the first reflecting surface and the second reflecting surface and then is emitted through the incident surface to be used as backlight. The invention can realize the light splitting of the laser without adding a light splitting film so as to realize the function of backlight monitoring and self-adaptively adjust the emission power of the laser. The light splitting method provided by the invention has good stability, meanwhile, the flows of film layer design, film material purchase, film coating process, film layer inspection process, film layer reliability test and the like of the light splitting film are reduced, and the risk of failure of the optical device is reduced.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. Crystal, characterized in that the crystal (1) comprises an entrance face (10) and an exit face (13); the crystal (1) is used for splitting laser light which is incident on the crystal (1) from the incidence surface (10) to generate a first light ray (15) and a second light ray (16);

wherein the first light ray (15) emerges from the exit face (13) and the second light ray (16) emerges from the entrance face (10);

the crystal (1) further comprises a first reflecting surface (11) and a second reflecting surface (12);

the first reflecting surface (11) is used for reflecting the first light ray (15) incident to the first reflecting surface (11) so that the first light ray (15) is incident to the emergent surface (13) and then is emergent from the emergent surface (13);

the first reflecting surface (11) is used for reflecting the second light ray (16) incident to the first reflecting surface (11) so as to enable the second light ray (16) to be incident to the second reflecting surface (12); the second reflecting surface (12) is used for reflecting the second light ray (16) incident to the second reflecting surface (12) so that the second light ray (16) is incident to the incident surface (10) and then exits from the incident surface (10);

the incidence plane (10) has a preset first angle relative to a preset reference plane, the first reflecting plane (11) has a preset second angle relative to the reference plane, the second reflecting plane (12) has a preset third angle relative to the reference plane, and the optical axis (5) of the crystal has a preset fourth angle relative to the normal of the incidence plane (10);

when the laser light is emitted into the crystal (1) from the incidence plane (10) perpendicular to the reference plane; the first angle, the second angle, the third angle and the fourth angle are such that the laser light entering the crystal (1) through the incident surface (10) is refracted into the first light ray (15) and the second light ray (16), and the first light ray (15) is emitted through the exit surface (13) after being totally reflected on the first reflecting surface (11); the second light (16) is totally reflected on the first reflecting surface (11) and the second reflecting surface (12) and then is emitted out through the incident surface (10);

wherein the second light ray (16) is parallel to the laser after being emitted from the incident surface (10);

wherein, the laser is elliptical polarized light or circular polarized light, and polarized light with mutually vertical vibration directions is separated; when the laser generates birefringence, o light and e light with mutually vertical vibration directions are separated, and the first light (15) and the second light (16) respectively correspond to one of the o light and the e light;

wherein the first light (15) and the second light (16) have a wavelength of 850 nm; the first light ray (15) is e-light, and the second light ray (16) is o-light; the crystal (1) is a YVO4 crystal, the first angle is 14 ° ± 1 °, the second angle is 51.5 ° ± 1 °, the third angle is 38.5 ° ± 1 °, and the fourth angle is 45 ° ± 1 °; alternatively, the first and second electrodes may be,

the first light (15) and the second light (16) have a wavelength of 850 nm; the first light ray (15) is e-light, and the second light ray (16) is o-light; the crystal (1) is a LiNbO3 crystal, the first angle is 10 ° ± 1 °, the second angle is 47.2 ° ± 1 °, the third angle is 42.8 ° ± 1 °, and the fourth angle is 45 ° ± 1 °; alternatively, the first and second electrodes may be,

the first light (15) and the second light (16) have a wavelength of 850 nm; the first light ray (15) is an o-ray and the second light ray (16) is an e-ray; the crystal (1) is a YVO4 crystal, the first angle is 10 ° ± 1 °, the second angle is 40 ° ± 1 °, the third angle is 50.7 ° ± 1 °, and the fourth angle is 45 ° ± 1 °; alternatively, the first and second electrodes may be,

the first light (15) and the second light (16) have a wavelength of 850 nm; the first light ray (15) is an o-ray and the second light ray (16) is an e-ray; the crystal (1) is a LiNbO3 crystal, the first angle is 10 ° ± 1 °, the second angle is 38.5 ° ± 1 °, the third angle is 51.3 ° ± 1 °, and the fourth angle is 45 ° ± 1 °.

2. The crystal according to claim 1, characterized in that the exit face (13) is perpendicular to the reference face, so that the first light ray (15) exits parallel to the reference face.

3. A method for manufacturing a crystal, the method comprising:

manufacturing an incidence surface of the crystal;

manufacturing an emergent surface of the crystal, wherein the crystal is used for splitting laser which is emitted from the incident surface to the crystal to generate a first light ray and a second light ray; the first light ray is emitted from the emergent surface, and the second light ray is emitted from the incident surface;

manufacturing a first reflecting surface and a second reflecting surface of the crystal;

processing the crystal so that the optical axis of the crystal meets a preset direction;

the incidence plane has a preset first angle relative to a preset reference plane, the first reflecting plane has a preset second angle relative to the reference plane, the second reflecting plane has a preset third angle relative to the reference plane, and the optical axis of the crystal has a preset fourth angle relative to the normal of the incidence plane;

when laser light is incident into the crystal from the incidence plane perpendicular to the reference plane; the first angle, the second angle, the third angle and the fourth angle enable laser entering the crystal through the incident surface to be refracted into a first light ray and a second light ray, and the first light ray is totally reflected on the first reflecting surface and then is emitted through the emergent surface; the second light rays are totally reflected on the first reflecting surface and the second reflecting surface and then are emitted out through the incident surface;

the second light ray is parallel to the laser after being emitted from the incident surface;