CN205263362U - Fiber optic coupling module - Google Patents

Abstract

The utility model discloses a fiber optic coupling module belongs to the optical components in the active optical cable, and there are shortcomings such as the module volume is great, receiving and dispatching port quantity is limited, technology complicacy in the active optical cable among the prior art, the utility model provides a fiber optic coupling module to 45 rectangular prism and microlens array and light detector coupling are passed through with a planar end surface fiber array to beveled tip face fiber array and laser array coupling, and will launch subassembly and the integration of receipt subassembly in a module, and modular structure compactness, interconnection density are high, and have simple process's advantage.

Description

A fiber optic coupling module

technical field

The utility model belongs to an optical component in an active optical cable, in particular to a high-density multi-mode optical fiber coupling module.

Background technique

With the advent of the era of big data, bandwidth-consuming Internet applications such as streaming media, social networking, and cloud computing have flourished, and the scale of the data centers that support them has become larger and larger. Data exchange puts forward higher requirements on interconnection speed and density. Traditional electronic interconnection technology cannot meet the needs of new data centers. Currently, active optical cables (AOC) are commonly used for interconnection between cabinets. In systems such as high-performance computers and large-capacity storage, active optical cables are often used to achieve high-speed interconnection between devices.

An active optical cable is an integrated optoelectronic module, which consists of a pair of optical fiber transceiver modules and a ribbon optical cable, as shown in Figure 1. At terminal A, the data input is an electronic signal, and the electrical signal is converted into an optical signal of a specific wavelength through the electro-optical conversion component.

The optical fiber transceiver module includes a semiconductor laser array-optical fiber array coupling assembly (that is, a transmitting assembly), an optical fiber array-photodetector array coupling assembly (that is, a receiving assembly), and a driving circuit for the laser array and the photodetector array. Large-scale data centers urgently need high-density interconnection technology, so it is necessary to integrate each component in the optical fiber transceiver module in the most compact form.

There are three main types of active optical cable technology at present: the first type is to package the transmitting component and the receiving component into independent modules, and the total volume of the module of this solution is twice that of the integrated solution. The second type is to arrange semiconductor lasers and photodetectors in a linear array, couple them with an optical fiber array, and package them into an integrated module. The disadvantage of this solution is that when the width of the module is limited, the number of parallel transceiver ports that can be accommodated is limited. . The third type is to arrange the semiconductor lasers and photodetectors in a 2×N array, couple the laser array and the photodetector array with two fiber arrays, and package them into an integrated transceiver module. This solution can accommodate the most parallel The number of sending and receiving ports.

For the above-mentioned third type of optical fiber transceiver module, the Science Education of the Korea Electronics and Communications Research Institute reported a technical solution. They polished a two-dimensional optical fiber array with 2×N ports to a 45° bevel, and mounted it on the optical fiber array. The microlens array on the lower surface is coupled with the laser array and the photodetector array. This technical solution has very high requirements on the manufacturing process of the optical fiber array, because it is difficult to ensure the positioning accuracy between two rows of optical fibers for a two-dimensional optical fiber array.

In view of the above situation, existing active optical cables have disadvantages such as large module size, limited number of transceiver ports, and complicated process.

Utility model content

Aiming at the disadvantages of the prior art, such as large volume, limited number of transceiver ports, complicated process, etc., the utility model proposes a new type of optical fiber coupling module, aiming to solve the above technical problems.

In order to achieve the above object, the utility model provides a fiber coupling module, characterized in that the fiber coupling module includes: a laser array, an optical fiber array with a 45° end face, an optical fiber connector, a flat end face optical fiber array, a microlens array, rectangular prism, photodetector array and substrate;

The laser array and the photodetector array are arranged on the substrate; the microlens array is pasted on the incident rectangular surface of the rectangular prism; the optical fiber array of the 45° end face and the flat end optical fiber array Paste together back to back, the pigtails of the optical fiber array with the 45° end face and the pigtails of the flat end optical fiber array are both inserted into the optical fiber connector;

The laser array is directly coupled with the 45° end-face fiber array to form a transmitting component in the fiber coupling module;

The flat-end optical fiber array is coupled with the photodetector array through the rectangular prism and the microlens array to form a receiving component of the optical fiber coupling module.

Preferably, the laser array is a VCSEL laser array;

Preferably, the optical fiber connector is a 2×N core MPO optical fiber connector;

Preferably, the microlens array is a microlens array made of polysilicon material.

Generally speaking, through the above technical solutions conceived by the utility model, compared with the prior art, the following technical beneficial effects can be obtained:

(1) This utility model proposes a new type of optical fiber coupling module, which is coupled with a 45° inclined end face fiber array and a laser array, and a flat end face fiber array is coupled with a photodetector through a rectangular prism and a microlens array, and the emitting assembly It is integrated with the receiving component in a module, which has the advantages of compact structure, high interconnection density, and simple process.

Description of drawings

Figure 1 is a schematic diagram of a typical active optical cable structure;

Fig. 2 is a schematic structural view of the high-density optical fiber coupling module described in the present invention;

Figure 3 is a three-view view of the 45° end-face optical fiber array, (a) is the main view, (b) is the top view, and (c) is the left view;

Fig. 4 is a three-view view of a flat-end optical fiber array, (a) is a main view, (b) is a top view, and (c) is a left view;

Fig. 5 is a schematic diagram of the optical path from the end face of the optical fiber to the end face of the photodetector;

Fig. 6 is three views of the microlens array, (a) is the front view, (b) is the top view, and (c) is the left view.

detailed description

In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model, and are not intended to limit the utility model.

Below in conjunction with accompanying drawing, the utility model is further described:

As shown in Figure 2, the high-density optical fiber transceiver module described in the present invention includes a VCSEL laser array 1, an optical fiber array 2 with a 45° end face, a 2×N core MPO optical fiber connector 3, a flat end face optical fiber array 4, and a microlens array 5. Right angle triangular prism 6, photodetector array 7 and ceramic substrate 8. Among them, the laser array 1 and the photodetector array 7 are mounted on the same ceramic substrate 8 with a high-precision placement machine; the microlens array 5 is pasted on the incident right-angle surface of the rectangular prism 6; the optical fiber array 2 with a 45° end face and the flat surface The end-face optical fiber arrays 4 are pasted back to back with glue, and the pigtails are inserted into the MPO optical fiber connector 3 to form a pluggable optical fiber transceiver module.

The VCSEL laser array 1 and the 45° end-face fiber array 2 are directly and closely coupled to form a transmitting component in the optical fiber transceiver module. The vertically upward laser beam emitted by the laser array is totally reflected on the oblique end face of the 45° end-face fiber array, and then bends to the horizontal direction and transmits in the fiber. In order to ensure the coupling efficiency of the beam, the optical fiber should be as close as possible to the surface of the laser array, so when making the optical fiber array, let the optical fiber protrude and position the substrate for a certain length, as shown in Figure 3.

The flat-end optical fiber array 4 and the photodetector array 7 are coupled through a rectangular prism 6 and a microlens array 5 to form a receiving component of the optical fiber transceiver module. As shown in FIG. 4 , the optical fiber array 4 with flat end face transmits the light beam output from the optical fiber along the horizontal direction, and is incident on the photodetector array 7 after being reflected by the oblique surface of the right-angled triangular prism 6 . Since the optical fiber emits divergent light beams, in order to ensure the coupling efficiency, a microlens array 5 is mounted on the incident right-angle surface of the triangular prism.

During the assembly process, the laser array 1 and the fiber array 2 are adjusted to be precisely aligned and fixed through the precision optical adjustment mount. The relative positioning accuracy between the 45° end face fiber array 2 and the flat end face fiber array 4 pasted back to back is not guaranteed by the process. On the premise that the fiber array 2 and the laser array 1 are precisely aligned, the fiber array 4 and the photodetector array 7 is not precisely aligned, and the alignment error between the two can be corrected by adjusting the inclination angle of the triangular prism 6.

The beam propagation process from the optical fiber array 4 to the photodetector array 7 via the microlens array 5 and the triangular prism 6 is shown in FIG. 5 . Since the end face of the fiber is placed on the focal plane of the microlens, the incident light on the photodetector is parallel light, and the beam diameter W depends on the numerical aperture NA of the fiber and the focal length f of the microlens, as shown in formula (1).

W=2f·NA(1)

As shown in Figure 6, the microlens array 5 is generally a single spherical lens array etched on the base material by microelectronics technology. The focal length f of the lens depends on the radius of curvature R of the spherical surface and the refractive index n of the base material, as shown in the formula (2); The arc height H of the spherical surface of the lens depends on the lens aperture D and the radius of curvature R of the spherical surface, such as formula (3).

$\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; R</span>}}{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

$\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; -</span>\sqrt{{\mathrm{<span\; class="notranslate">\; R</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; D.</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 4</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

It can be known from formula (2) that under the condition of a given refractive index n of the substrate material, the smaller the focal length f of the lens is, the smaller the radius of curvature R of the spherical surface is; , the smaller the lens curvature radius R is, the larger the spherical arc height H is. This constitutes a dimensional relationship: f decreases → R decreases → H increases.

According to formula (1), the spot size W is proportional to the focal length f of the lens, and in order to achieve high-density interconnection, the fiber spacing is required to be as small as possible (usually 250 microns), so the lens aperture D and spot size W are limited , and then require the lens focal length f to be as small as possible. This results in an increase in the arc height of the spherical surface of the lens according to the above dimensional relationships.

Since the microlens array is generally processed by microelectronic etching technology, the spherical arc height H cannot be made very large, and the actual process capability is in contradiction with the demand for high-density interconnection. Considering the above formula (2), corresponding to the same focal length f (corresponding to the same spot size W according to formula (1), when the refractive index n of the microlens base material increases, the radius of curvature R of the spherical surface also increases, thereby decreasing Requirements for lens spherical arc height H.

Microlens arrays are usually made of quartz glass or polysilicon. In the 850nm band where active optical cables usually work, the refractive index of quartz glass is 1.45, and the refractive index of polysilicon is 3.44. According to formula (2), corresponding to the same spot size, that is, the focal length of the lens, the microlens array made of polysilicon material, compared with quartz glass material, has a spherical curvature radius of the lens increased by 4.4 times, and the spherical arc height can be greatly reduced.

Those skilled in the art can easily understand that the above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements and modifications made within the spirit and principles of the utility model Improvements and the like should all be included within the protection scope of the present utility model.

Claims (4)

1. A fiber coupling module, characterized in that, the fiber coupling module comprises: a laser array, an optical fiber array of 45° end faces, an optical fiber connector, a flat end face optical fiber array, a microlens array, a rectangular prism, a photodetector array and base; The laser array and the photodetector array are arranged on the substrate; the microlens array is pasted on the incident rectangular surface of the rectangular prism; the optical fiber array of the 45° end face and the flat end optical fiber array Paste together back to back, the pigtails of the optical fiber array with the 45° end face and the pigtails of the flat end optical fiber array are both inserted into the optical fiber connector; The laser array is directly coupled with the 45° end-face fiber array to form a transmitting component in the fiber coupling module; The flat-end optical fiber array is coupled with the photodetector array through the rectangular prism and the microlens array to form a receiving component of the optical fiber coupling module. 2. The fiber coupling module according to claim 1, wherein the laser array is a VCSEL laser array. 3. The optical fiber coupling module according to claim 1, wherein the optical fiber connector is a 2×N core MPO optical fiber connector. 4. The optical fiber coupling module according to claim 1, wherein the microlens array is a microlens array made of polysilicon material.