WO2019037362A1

WO2019037362A1 - Unidirectional tap pd

Info

Publication number: WO2019037362A1
Application number: PCT/CN2017/118252
Authority: WO
Inventors: 王敏; 罗曼; 范杰乔; 肖清明
Original assignee: 武汉光迅科技股份有限公司
Priority date: 2017-08-24
Filing date: 2017-12-25
Publication date: 2019-02-28
Also published as: CN107390329B; CN107390329A

Abstract

A unidirectional TAP PD comprises an inlet optical fiber (20), an optical fiber connector (21), an optical splitting lens (23), a detector assembly (24), and an outlet optical fiber (28). The inlet optical fiber (20) and the outlet optical fiber (28) are disposed in two holes of the fiber connector (21). The optical splitting lens (23) is disposed between the optical fiber connector (21) and the detector assembly (24). One end of the optical splitting lens (23) faces the optical fiber connector (21), and is lapped to an α-degree angle, and another end of the optical splitting lens (23) faces the detector assembly (24) and is partially lapped to a β-degree angle. The α-degree angle and the β-degree angle cause a ray input by the optical inlet fiber (20) to be perpendicular to and exit from a position located on the optical splitting lens (23) and not lapped to the β-degree angle, and cause a ray input by the optical outlet fiber (28) to be totally reflected in the position lapped to the β-degree angle. The two rays are separated by the optical splitting lens (23) before being transmitted to the detector assembly (24), the ray transmitted by the optical inlet fiber (20) is received by the detector assembly (24), and the ray transmitted by the outlet optical fiber (28) is rarely received by the detector assembly (24), thereby achieving high directivity. The optical splitting lens (23) having a lapped angle and used for splitting light has a simple structure, low cost, and high directivity.

Description

Unidirectional TAP PD

Technical field

The present invention relates to the field of optical communication technologies, and in particular, to a unidirectional TAP PD.

Background technique

TAP PD is an optical power detector, which is widely used in optical fiber communication systems to monitor the power of optical signals online, thereby realizing power monitoring and management of optical signals. The non-directional TAP PD does not limit the light returned by the output fiber. The optical power detected by this detector is easily affected by the reflected light. In order to avoid the influence of reflected light, many optical fiber communication systems require a unidirectional TAP PD.

The non-directional TAP PD is mainly composed of an input/output fiber pin 10, a collimator lens 11, a beam splitter 12, a detector assembly 13, a collimating sleeve 14, and a fixed sleeve 15, as shown in Fig. 1, on the basis of The unidirectional TAP PD design scheme is also relatively large, and the imaging lens, the mask, the spacer, the large pitch pin or the wedge angle piece are added to the non-directional design to split the light. An optical power detector disclosed in U.S. Patent No. 7,333,693, the disclosure of which is incorporated herein by reference. An optical power detector disclosed in Chinese Patent Publication No. CN 201100946Y, which uses a large pitch pin and a small detector photosensitive surface to split light; an optical power detector disclosed in Chinese Patent Publication No. CN 204422827, which uses dark The optical fiber increases the distance of the optical fiber to split the light; an optical power detector disclosed in Chinese Patent Publication No. CN 204790086 uses a wedge angle piece and an isolation cavity to split the light. However, there are widespread shortcomings such as complicated structure, high price, and poor directionality.

Summary of the invention

The unidirectional TAP PD designed by the invention is split by the angled splitting lens, and has the characteristics of simple structure, low price and high directivity.

The technical solution adopted by the present invention is as follows:

A unidirectional TAP PD comprising an ingress fiber, a fiber connector, a beam splitting lens, a detector assembly, and an outgoing fiber.

One end of the end fiber and one end of the end fiber are respectively disposed in two holes of the fiber connector, the beam splitting lens is disposed between the fiber connector and the detector assembly; and the split lens is directed toward one end of the fiber connector The front end of the spectroscopic lens is ground to an angle of α, the end of the spectroscopic lens facing the detector assembly is referred to as the rear end of the spectroscopic lens, and the rear end of the spectroscopic lens is divided into two parts, a part of which is ground to a β degree angle; The angles of the α and β degrees of the lens are such that the light input from the input fiber is perpendicular to the position where the rear end of the beam splitting lens is not ground to a β degree angle, and the light input from the trailing end fiber is ground at a β angle of the rear end of the beam splitting lens. Total reflection occurs.

Among them, it also includes a focusing lens, a lens tube, a lens pin sleeve, and a final assembly sleeve.

The focusing lens is disposed between the fiber connecting head and the beam splitting lens, and the focusing lens and the beam splitting lens are fixedly connected by a lens sleeve; the fiber connecting head and the focusing lens are fixedly connected by a lens pin bushing; The needle cannula and detector assembly are fixedly connected by a cannula.

Wherein, the focusing lens is a G lens, and a planar end thereof is plated with a beam splitting film.

Wherein, the front end of the spectroscopic lens is coated with an anti-reflection film.

Wherein, the rear end of the spectroscopic lens is bounded by its center line, wherein the upper half is ground to a β degree angle.

The in-end fiber and the out-end fiber are all single-mode fibers.

Wherein, the fiber optic connector has a fiber aperture spacing of between 125 um and 250 um.

Wherein, the lens sleeve and the lens pin sleeve material may be any one of glass, metal or ceramic; the assembly sleeve material is metal.

Wherein, the angle between the angle of the α and the angle θ is θ ₁ when the light input from the input fiber passes through the focusing lens and the angle between the angle θ ₁ is:

θ ₁ =α-arccos[n ₁ cosα/n ₀ ]

Where n ₀ is the refractive index of the medium between the focusing lens and the spectroscopic lens, and n ₁ is the refractive index of the spectroscopic lens.

Wherein, the angle of the β angle and the θ _{2 is} the relationship between the β angle and the θ ₂ when the light input from the optical fiber passes through the focusing lens and the angle between the horizontal direction and the horizontal direction is θ ₂ :

θ ₂ =arccos[n ₁ /n _o *cos(α+β-arcsin(n _o /n ₁ ))]-α

Beneficial effects:

The invention provides a unidirectional TAP PD, comprising an inlet fiber, a fiber connector, a beam splitting lens, a detector component and an outlet fiber, wherein one end of the fiber and one end of the fiber are respectively connected to the fiber. In the first two holes, the spectroscopic lens is disposed between the fiber optic connector and the detector assembly; the spectroscopic lens is referred to as a front end of the fiber optic connector as a front end of the spectroscopic lens, and is ground to an angle of α, and the spectroscopic lens faces the detector assembly. One end of the spectroscopic lens is divided into two parts, and the rear end of the spectroscopic lens is divided into two parts, one part of which is ground to a β degree angle; the α and β degree angles of the spectroscopic lens are such that the input light of the input end fiber is perpendicular to the spectroscopic lens. The rear end is not ground to a position of β angle, and the light input from the end fiber is totally reflected at a position where the rear end of the spectroscopic lens is ground at a β angle. It can be seen that the two beams of light have been separated by the spectroscopic lens before being transmitted to the detector assembly, and the light transmitted by the ingress fiber is received by the detector component, and the light transmitted by the outgoing fiber is rarely received by the detector component, thereby achieving high directivity. . The invention splits the light by the angle grinding lens, and has the characteristics of simple structure, low price and high directivity.

DRAWINGS

FIG. 1 is a schematic structural view of a non-directional TAP PD.

2 is a schematic structural view of a unidirectional TAP PD provided by the present invention.

3 is a cross-sectional view of the fiber optic connector 21 provided by the present invention.

4 is a schematic structural view of a spectroscopic lens 23 provided by the present invention.

Fig. 5 is a spectroscopic optical path diagram of the spectroscopic lens 23 provided by the present invention.

Fig. 6 is a view showing the optical path of the angle of the spectroscopic lens 23α provided by the present invention.

Fig. 7 is a view showing the optical path of the angle β of the spectroscopic lens 23 provided by the present invention.

In the picture:

10-input and output fiber pin; 11-collimating lens; 12-splitter; 13-detector assembly; 14-collimating sleeve; 15--fixed sleeve;

20-input fiber; 21-fiber connector; 22-focusing lens; 23-splitting lens; 24-detector assembly; 25-lens sleeve; 26-lens pin bushing; 27-total sleeve; Outgoing fiber.

Detailed ways

The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

2 is a schematic structural view of a unidirectional TAP PD provided by the present invention. 4 is a schematic structural view of a spectroscopic lens 23 provided by the present invention. Fig. 5 is a spectroscopic optical path diagram of the spectroscopic lens 23 provided by the present invention. As shown in FIG. 2, FIG. 4, and FIG. 5, a unidirectional TAP PD according to the present invention includes an ingress fiber 20, a fiber connector 21, a beam splitting lens 23, a detector assembly 24, and an outgoing fiber 28.

One end of the end fiber 20 and one end of the end fiber 28 are respectively disposed in two holes of the fiber connector 21, and the beam splitting lens 23 is disposed between the fiber connector 21 and the detector assembly 24; the beam splitting lens 23 One end facing the fiber optic connector 21 is referred to as the front end of the spectroscopic lens 23, and is ground to an angle of α. The end of the spectroscopic lens 23 toward the detector assembly 24 is referred to as the rear end of the spectroscopic lens 23. The rear end of the beam splitter lens 23 is divided into two. a part of which is ground to a β degree angle; the spectroscopic lens 23 is provided with α and β degrees so that the light input from the end fiber 20 is perpendicular to the position at the rear end of the spectroscopic lens 23 without being ground to a β degree angle, and the end The light input from the optical fiber 28 is totally reflected at a position where the rear end of the spectroscopic lens 23 is ground at a β angle.

Further, as shown in FIG. 2, the focus lens 22, the lens sleeve 25, the lens pin sleeve 26, and the final assembly sleeve 27 are further included.

The focusing lens 22 is disposed between the fiber connecting head 21 and the beam splitting lens 23, and the focusing lens 22 and the beam splitting lens 23 are fixedly connected by a lens sleeve 25; the fiber connecting head 21 and the focusing lens 22 pass through a lens pin sleeve The tube 26 is fixedly connected; the lens pin sleeve 26 and the detector assembly 24 are fixedly connected by a final sleeve 27. The invention has the advantages of simple structure, easy packaging and high directionality.

As shown in FIG. 5, the light rays 1 input from the entrance end fiber 20 and the light 2 input from the end fiber 28 pass through the focus lens 22, and the angles between the horizontal direction and the horizontal direction are θ ₁ and θ ₂ , respectively, and the spectroscopic lens 23 is disposed. Between the focus lens 22 and the detector assembly 24; one end of the spectroscopic lens 23 toward the focus lens 22 is referred to as the front end of the spectroscopic lens 23, and is ground to an angle of α, and the end of the spectroscopic lens 23 toward the detector assembly 24 is recorded as At the rear end of the spectroscopic lens 23, the rear end of the spectroscopic lens 23 is divided into two parts, a part of which is ground to a β degree angle. Preferably, the rear end of the spectroscopic lens 23 is bounded by its center line, wherein the upper half is ground to a β degree angle.

As shown in FIG. 5, the light 1 input from the inlet fiber 20 and the light 2 input from the output fiber 28 are transmitted to the rear end of the beam splitter 23, and are separated by refraction and total reflection. The light 1 is perpendicular to the rear end of the beam splitter 23. When the side of the angle β is ground, the light 2 is totally reflected at the rear end of the beam splitting lens 23 at an angle β plane, and the two beams are separated by the spectroscopic lens 23 before being transmitted to the detector assembly 24, and the light transmitted by the end fiber 20 is transmitted. Received by the detector assembly 24, the light 2 transmitted by the exit fiber 28 is rarely received by the detector assembly 24 to achieve high directivity; the alpha and beta angles of the splitter lens 23 are such that the light 1 is perpendicular to the splitting The rear end of the lens 23 is not ground at a position of a β degree angle, and the light ray 2 is totally reflected at a position where the rear end of the spectroscopic lens 23 is ground at a β angle.

FIG. 6 is an optical path diagram for calculating the α-degree angle of the spectroscopic lens 23. According to the law of refraction, the law of reflection, and the optical path diagram of Fig. 6, the relationship between the angle α and θ ₁ can be calculated:

θ ₁ =α-arccos[n ₁ cosα/n ₀ ]

Where: n ₀ is the refractive index of the medium between the focus lens 22 and the spectroscopic lens 23, and n ₁ is the refractive index of the spectroscopic lens 23.

FIG. 7 is a diagram showing the optical path of the β-angle of the spectroscopic lens 23. According to the law of refraction, the law of reflection and the optical path diagram of Fig. 7, the relationship between β angle and θ ₂ can be calculated:

θ ₂ =arccos[n ₁ /n _o *cos(α+β-arcsin(n _o /n ₁ ))]-α

It can be seen that the light 1 input from the inlet fiber 20 and the light 2 input from the outgoing fiber 28 are separated by the beam splitter 23 before being transmitted to the detector assembly 24. The light 1 transmitted by the incoming fiber 20 is received by the detector assembly 24. The light 2 transmitted by the outgoing fiber 28 is rarely received by the detector assembly 24, thereby achieving high directivity. The invention splits the light by the angled splitting lens 23, and has the characteristics of simple structure, low cost and high directivity, and the directivity can be more than 30 dB.

The focus lens 22 is a G lens whose flat end is plated with a beam splitting film.

The front end of the spectroscopic lens 23 is plated with an anti-reflection film.

The incoming fiber 20 and the outgoing fiber 28 are both single mode fibers.

As shown in FIG. 3, the fiber optic connector 21 has a fiber aperture spacing of between 125 um and 250 um.

The lens sleeve 25 and the lens pin sleeve 26 may be made of any one of glass, metal or ceramic.

The material of the assembly sleeve 27 is metal.

In summary, the present invention provides a unidirectional TAP PD in which the input optical fiber 20 and the outgoing optical fiber 28 simultaneously input light, and the two paths of light are collimated by the focusing lens 22 into two bundles of collimated light having a small angle. 1 and light 2, the light 1 and the light 2 are refracted and totally reflected by the spectroscopic lens 23, and the light 1 is perpendicular to the position where the spectroscopic lens 23 is not ground to a β angle, and the ray 2 is ground at a β angle by the spectroscopic lens 23. Total reflection occurs, the two beams are split, the light transmitted by the incoming fiber 20 is received by the detector assembly 24, and the light transmitted by the outgoing fiber 28 is rarely received by the detector assembly 24, thereby achieving high unidirectionality.

The present invention has been described in detail and described with reference to the specific embodiments of the embodiments of the invention Various changes in the form and details of the device can be made in the function of the device. These changes are intended to fall within the scope of protection as claimed in the appended claims.

Claims

A unidirectional TAP PD, comprising: an inlet fiber (20), a fiber connector (21), a beam splitting lens (23), a detector assembly (24), and an outgoing fiber (28),

One end of the inlet fiber (20) and one end of the outlet fiber (28) are respectively disposed in two holes of the fiber connector (21), and the beam splitting lens (23) is disposed on the fiber connector (21) and the detector. Between the components (24); one end of the beam splitting lens (23) facing the fiber connecting head (21) is referred to as the front end of the beam splitting lens (23), is ground to an angle of α, and the beam splitting lens (23) faces the detector assembly ( One end of 24) is referred to as the rear end of the spectroscopic lens (23), and the rear end of the spectroscopic lens (23) is divided into two parts, one of which is ground to a β degree angle; and the α and β degree angles of the spectroscopic lens (23) are set. The light input from the inlet fiber (20) is perpendicular to the rear end of the beam splitting lens (23) and is not ground to a β angle, and the light input from the fiber (28) is ground at the rear end of the beam splitting lens (23). The position of the angle angle is totally reflected.
A unidirectional TAP PD according to claim 1, further comprising a focusing lens (22), a lens tube (25), a lens pin bushing (26), and a final assembly sleeve (27).

The focusing lens (22) is disposed between the fiber connecting head (21) and the beam splitting lens (23), and the focusing lens (22) and the beam splitting lens (23) are fixedly connected by a lens sleeve (25); The connector (21) and the focus lens (22) are fixedly coupled by a lens pin bushing (26); the lens pin bushing (26) and the detector assembly (24) are fixedly coupled by a housing sleeve (27).
A unidirectional TAP PD according to claim 2, wherein said focusing lens (22) is a G lens having a planar end plated with a beam splitting film.
A unidirectional TAP PD according to claim 1, characterized in that the front end of the spectroscopic lens (23) is plated with an anti-reflection film.
A unidirectional TAP PD according to claim 1, characterized in that the rear end of the beam splitting lens (23) is bounded by its center line, wherein the upper half is ground to a β angle.
The unidirectional TAP PD according to claim 1, wherein the input fiber (20) and the outgoing fiber (28) are single mode fibers.
A unidirectional TAP PD according to claim 1, wherein the fiber connector (21) has a fiber aperture of between 125 um and 250 um.
The unidirectional TAP PD according to claim 2, wherein the lens sleeve (25) and the lens pin sleeve (26) are made of any one of glass, metal or ceramic;

The material of the final casing (27) is metal.
The unidirectional TAP PD according to claim 2, wherein the light input from the optical fiber (20) passes through the focusing lens (22) and the angle between the horizontal direction and the horizontal direction is θ 1 , respectively, The relationship between the angle and θ 1 is:

θ 1 =α-arccos[n 1 cosα/n 0 ]

Where n 0 is the refractive index of the medium between the focusing lens (22) and the spectroscopic lens (23), and n 1 is the refractive index of the spectroscopic lens (23).
The unidirectional TAP PD according to claim 9, wherein the light input from the optical fiber (28) passes through the focusing lens (22) and has an angle with the horizontal direction of θ 2 , and the angle β The relationship with θ 2 is:

θ 2 =arccos[n 1 /n o *cos(α+β-arcsin(n o /n 1 ))]-α

Where n 0 is the refractive index of the medium between the focusing lens (22) and the spectroscopic lens (23), and n 1 is the refractive index of the spectroscopic lens (23).