CN118915245A - Optical fiber coupling structure and optical fiber and chip welding method thereof - Google Patents

Abstract

The invention discloses an optical fiber coupling structure and an optical fiber and chip welding method thereof, belonging to the technical field of optical fiber and wavelength division multiplexer chip coupling structures. The optical fiber coupling structure comprises a wavelength division multiplexer chip, a metal seat, an optical fiber fixer, an optical fiber sleeve, a chip base, optical fibers and an optical fiber array; the optical fiber fixer and the chip base are placed on the upper surface of the metal base, the optical fiber fixer and the metal base are connected through laser welding, a wavelength division multiplexer chip is arranged above the chip base, an opening of the optical fiber fixer is opposite to the output end of the chip, the bottom of the optical fiber fixer is propped against the bottom of the chip base, the optical fiber and the optical fiber sleeve are coaxially arranged, the optical fiber sleeve passes through the optical fiber fixer to realize limiting, and the optical fiber array is fixed on the chip base. The invention fixes the optical fiber sleeve by means of laser welding, and ensures the transverse and longitudinal alignment of the optical fiber and the wavelength division multiplexer chip. Finally, the chip base is adjusted again, and the chip base is fixed by using laser welding, so that stable and accurate connection of the optical fiber and the wavelength division multiplexer chip is realized.

Description

Optical fiber coupling structure and optical fiber and chip welding method thereof

Technical Field

The invention relates to the technical field of optical fiber and wavelength division multiplexer chip coupling structures, in particular to an optical fiber coupling structure and an optical fiber and chip welding method thereof.

Background

Multimode interferometer type, arrayed waveguide grating type, mach-Zehnder interferometer type and other wavelength division multiplexing devices are indispensable parts in optical fiber communication networks. In the radio frequency subsystem, the application requirement of the energy-efficient high-power broadband wireless system under the Sub15GHz golden spectrum will be rapidly increased in the future. The related technology of breaking through the microwave photon core device of the high-power high-efficiency analog radio frequency forwarding network and the direct-drive antenna of the photoelectric detector becomes particularly important. High input optical power requires a stable connection between the optical chip and the optical fiber, while high efficiency requires efficient coupling of the optical chip and the optical fiber to reduce losses. Conventional optical chip and fiber coupling is fixed using a curing agent. As described in "Ranno,L.,et al.(2022)."Integrated Photonics Packaging:Challenges and Opportunities."ACS Photonics 9(11):3467-3485.", the method is poor in the stability of the curing agent for connecting the optical fiber and the device under high power input, and affects the coupling quality, which results in increased input loss, and serious damage to the optical chip, which makes it impossible to operate normally. Much research on optical fiber coupling has focused on laser-to-optical fiber coupling, such as that disclosed in patent application publication number CN108879318a entitled "a semiconductor laser package structure and method of soldering thereof. As also described in document "Yi-Cheng,H.,et al.(2005)."A novel fiber alignment shift measurement and correction technique in laser-welded laser module packaging."Journal of Lightwave Technology 23(2):486-494.". Because of the working characteristics of the laser, the optical chip and the optical fiber only need single-end-face coupling, and compared with a wavelength division multiplexer which needs to couple two input and output end faces, the coupling difficulty is lower. On the other hand, the coupling difficulty is increased due to the miniaturization of the device, and the insertion loss of the optical device can be reduced by adopting the input/output coupling technology of the precise optical fiber, the wavelength division multiplexer and other passive optical chips. Although the proposal of the patent application with publication number CN103323919A and the invention name of optical component and optical fiber accurately aligned can accurately align the optical component and the optical fiber, the procedures are complex, the coupling requires special devices to finish, and the operation is difficult. There is therefore a need for a new chip and fiber coupling method for wavelength division multiplexing devices that is simple to operate and simple in structure.

Disclosure of Invention

The invention aims to provide a coupling structure of an optical fiber and a wavelength division multiplexer chip and a coupling method thereof, wherein the coupling structure has the advantages of low loss, stable coupling and high coupling precision under the application scene of high power input based on actual requirements.

In one aspect, the invention discloses an optical fiber coupling structure comprising a metal seat, an optical fiber holder, an optical fiber sleeve, a chip base, a wavelength division multiplexer chip, an optical fiber and an optical fiber array;

the optical fiber fixer and the chip base are arranged on the upper surface of the metal seat, the optical fiber fixer and the chip base are both in a similar shape and are respectively fixed on the upper surface of the metal seat through the bottom of the optical fiber fixer and the bottom of the chip base, the height of the optical fiber fixer is larger than that of the chip base, and a wavelength division multiplexer chip is arranged above the chip base;

The optical fiber and the optical fiber sleeve are coaxially arranged, the inner diameter of the optical fiber sleeve is not smaller than the outer diameter of the optical fiber, the optical fiber sleeve penetrates through the optical fiber fixer to be opposite to the wavelength division multiplexer chip, and the optical fiber sleeve positioned in the optical fiber fixer is fixedly connected with the optical fiber fixer;

The chip input end of the wavelength division multiplexer chip is connected with the optical fiber array fixed on the chip base, and the chip output end of the wavelength division multiplexer chip is connected with the optical fibers in the optical fiber sleeve passing through the optical fiber fixer.

Further, the size of the upper surface of the chip base is larger than that of the wavelength division multiplexer chip, the chip output end face of the wavelength division multiplexer chip is flush with the edge of the upper surface of the chip base, and the distances between the two sides of the wavelength division multiplexer chip and the two edges of the upper surface of the chip base are equal.

Furthermore, the connection of the optical fiber and the optical fiber array with the wavelength division multiplexer chip can be exchanged, the opening of the optical fiber fixer is opposite to the chip input end face of the wavelength division multiplexer chip, the chip input end of the wavelength division multiplexer chip is used for being connected with the optical fiber passing through the optical fiber fixer, and the chip output end of the wavelength division multiplexer chip is used for being connected with the optical fiber array.

Further, the length of the upper surface of the chip base is 5-7 mm longer than the length of the chip.

Further, the height of the optical fiber fixer is 4-5 mm greater than the height of the chip base.

Further, the metal seat, the optical fiber fixer, the optical fiber sleeve and the chip base are made of a vaive alloy.

Further, windows are formed on the side surface of the chip base and/or the extension surface of the side surface, which is positioned on the upper surface of the metal base, so that the adjustment welding spots are added, and the adjustment welding dimension is increased.

Furthermore, the side surface of the chip base is shaped like a Chinese character 'ji', and two groups of welding fixing points are respectively arranged at the left side and the right side of the side surface of the Chinese character 'ji', so that the chip base is welded on the upper surface of the metal base.

On the other hand, the invention also discloses an optical fiber and chip welding method for the optical fiber coupling structure, which comprises the following steps:

a) Mounting the wavelength division multiplexer chip on a chip base;

b) Trimming the fiber splice so that the fiber splice does not exceed a defined length of the fiber cladding, the defined length being 1-5 mm;

C) Permanently connecting the optical fiber with the optical fiber sleeve by adopting a curing agent;

D) Fixing the optical fiber fixer to the metal seat by laser welding;

E) The chip base is propped against the optical fiber fixer by using a clamp, the optical fiber sleeve passes through the optical fiber fixer by using a precision regulator, the transverse distance between the optical fiber and the output end of the wavelength division multiplexer chip is observed by using a microscope, the position of the chip base is adjusted, and after the optical axis of the optical fiber is aligned with the output waveguide of the chip, the wavelength division multiplexer chip attached to the chip base is pressed down to temporarily fix the optical fiber;

f) Connecting the other end of the optical fiber with a laser, and placing a near infrared imaging microscope on the input end face of the wavelength division multiplexer chip;

G) Opening laser, observing output conditions through a near infrared imaging microscope, adjusting the position of the optical fiber sleeve, and welding the optical fiber sleeve and the optical fiber fixer by using two symmetrical lasers when the emergent channel of the wavelength division multiplexer chip displays light spots so as to realize permanent connection of the optical fiber sleeve and the optical fiber fixer;

H) Releasing the pressure on the wavelength division multiplexer chip, adjusting a chip base by observing the output of the near infrared imaging microscope, and pressing down the temporarily fixed wavelength division multiplexer chip when the near infrared imaging microscope displays the emergent channel light spots;

I) One path of the optical fiber array is connected into an optical power meter, a precise regulator is used for clamping the optical fiber array, and when the output optical power is maximum, the optical fiber array and the wavelength division multiplexer chip are fixed;

J) And (3) using two symmetrical lasers to weld the chip base on the metal base by laser, and releasing the pressure on the wavelength division multiplexer chip.

Furthermore, if the light-dropping phenomenon occurs, the chip base is adjusted by using the adjusting solder to find the optimal coupling position.

Because the wavelength division multiplexer is a passive optical device, light waves can be transmitted in two directions, and therefore, the optical fiber and the chip welding method are also applicable to the coupling of the wavelength division multiplexer with the optical fiber, wherein the optical fiber is used as an input end, and the optical fiber array is used as an output end.

Further, in step D), when the optical fiber holder is fixed to the metal base by laser welding, both sides of the bottom of the optical fiber holder are spot-welded at the same time, so as to ensure that the optical fiber holder has no offset in a direction perpendicular to the axial direction of the optical fiber, and a pair of front welding points are fixed and a pair of rear welding points are fixed after the front welding points are fixed.

Further, in step G), when the optical fiber sleeve is fixedly welded to the optical fiber holder by laser welding, both sides of the opening of the optical fiber holder are spot-welded at the same time, so as to ensure that the optical fiber holder is free from offset in a direction perpendicular to the axial direction of the optical fiber, and a pair of front welding points are fixed and a pair of rear welding points are fixed.

When the emergent channel of the wavelength division multiplexer chip displays light spots, the optical fiber sleeve and the optical fiber fixer are welded by using two symmetrical lasers, so that the permanent connection between the optical fiber sleeve and the optical fiber fixer is realized;

the technical scheme provided by the invention has at least the following beneficial effects:

Compared with the existing coupling structure, the optical fiber coupling structure of the application realizes coarse alignment in the horizontal direction by adjusting the transverse position of the chip base after fixing the optical fiber fixer, and then realizes fine alignment of the optical fiber and the chip by adjusting the height of the optical fiber sleeve on the optical fiber fixer. The optical fiber and the chip welding method provided by the application enable the obtained optical fiber coupling structure to complete the efficient butt joint of the chip and the optical fiber array only by adjusting the optical fiber array after the optical fiber is fixed. Compared with the optical fiber fixer, the chip base is larger in size, the offset of the chip after laser welding is smaller, the symmetrical laser welding mode is used, the limitation of the coupling structure to the chip base is combined, and the base welding process can be effectively prevented from generating displacement. In addition, after the chip base and the optical fiber sleeve are welded by laser, the offset caused by deformation can be adjusted by using the adjustment welding secondary, and the adjustment with higher precision than the adjustment of inputting the optical fiber by laser welding alone can be realized.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic diagram of an optical fiber coupling structure according to the present application.

FIG. 2 is a top view of the fiber holder of the present application.

FIG. 3 is a schematic view of a laser welded portion of a fiber sleeve and fiber holder of a fiber coupling structure according to the present application.

Fig. 4 is a schematic diagram of a chip base with an optical fiber coupling structure according to the present application.

Reference numerals: 1. a chip base; 2. an optical fiber holder; 3. an optical fiber sleeve; 4. a metal seat; 5. a wavelength division multiplexer chip; 6. an optical fiber; 7. an optical fiber array; 11 and 12 are respectively different fixed point pairs for welding the metal seat on the chip base, and 21 and 22 are respectively different fixed point pairs for welding the metal seat on the optical fiber fixer; 23 and 24 are respectively different pairs of fastening points on the fiber optic holder for welding the fiber optic ferrule.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be fully described in detail below with reference to the accompanying drawings in the practice of the present application. It will be apparent that the described embodiments are only some, but not all, embodiments of the application. In general, the components of the embodiments of the application described and illustrated in the figures can be arranged and designed using different configurations. Thus, the following detailed description of the embodiments of the application, as presented in the figures, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application.

As shown in fig. 1, the optical fiber coupling structure of the present application includes a metal base 4, an optical fiber holder 2, an optical fiber sleeve 3, a chip base 1, a wavelength division multiplexer chip 5, an optical fiber 6, and an optical fiber array 7; wherein, the optical fiber fixer 2 and the chip base 1 are respectively fixedly connected to the upper surface of the metal seat 4 through the bottoms thereof, and the height of the optical fiber fixer 2 is larger than the height of the chip base 1. Preferably, in the present embodiment, the optical fiber holder 2 and the bottom of the chip base 1 are welded and fixed to the upper surface of the metal base 4 based on the same. A wavelength division multiplexer chip 5 is arranged above the chip base 1, an opening of the optical fiber fixer 2 is opposite to the chip output end face of the wavelength division multiplexer chip 5, an optical fiber 6 and an optical fiber sleeve 3 are coaxially arranged, the inner diameter of the optical fiber sleeve 3 is not smaller than the outer diameter of the optical fiber 1, the optical fiber sleeve 3 passes through the optical fiber fixer 2 to be opposite to the wavelength division multiplexer chip 5, and the optical fiber sleeve 3 positioned in the optical fiber fixer 2 is fixedly connected with the optical fiber fixer 2; the chip input end of the wavelength division multiplexer chip 5 is connected with the optical fiber array 7 fixed on the chip base 1, and the chip output end of the wavelength division multiplexer chip 5 is connected with the optical fibers 6 in the optical fiber sleeve 3 passing through the optical fiber fixer 2. Preferably, the size of the upper surface of the chip base 1 is larger than the chip size of the wavelength division multiplexer chip 5, the chip output end face of the wavelength division multiplexer chip 5 is flush with the edge of the upper surface of the chip base 1, and the distances between the two sides of the wavelength division multiplexer chip 5 and the two sides of the upper surface of the chip base 1 are equal. In addition, in the concrete implementation, the materials of the metal seat 4, the optical fiber fixer 2, the optical fiber sleeve 4 and the chip base 1 are kovar alloy, and the kovar alloy is convenient to weld, high in thermal conductivity and small in thermal expansion coefficient, so that the position offset after laser welding can be reduced.

The optical fiber and chip welding method for the optical fiber coupling structure provided by the application comprises the following steps:

Mounting the wavelength division multiplexer chip 5 on the chip base 1, wherein the chip output end surface of the wavelength division multiplexer chip 5 is flush with the edge of the upper surface of the chip base 1, and the two sides of the wavelength division multiplexer chip 5 are equidistant with the two sides of the chip base 1;

the optical fiber 6 is inserted into the optical fiber sleeve 3 after trimming the optical fiber connector and fixed by using a curing agent;

The optical fiber holder 2 is fixed to the metal base 4 by laser welding, as shown in fig. 2, two symmetrical lasers are used to weld the fixed point pair 21 first and then the fixed point pair 22;

The chip base 1 is propped against the optical fiber fixing device 2 by using a clamp to prevent the chip base 1 from moving in the axial direction of the optical fiber, the optical fiber sleeve 3 passes through the optical fiber fixing device 2 by using a precise regulator, the transverse distance between the optical fiber 6 and the chip output end face of the wavelength division multiplexer chip 5 is observed by using a microscope, the chip base 1 is propped against the optical fiber fixing device 2, the position of the chip base 1 is adjusted at the same time, and after the optical axis of the optical fiber 6 is aligned with the output waveguide of the wavelength division multiplexer chip 5, the wavelength division multiplexer chip 5 which is pasted on the chip base 1 is pressed down to temporarily fix the optical fiber, so that the transverse distance deviation is prevented;

The other end of the optical fiber 6 is connected with a laser, a near infrared imaging microscope is placed on the chip input end face of the wavelength division multiplexer chip 5, then laser is turned on, the output condition is observed through the near infrared imaging microscope, the position of the optical fiber sleeve 3 is adjusted, when the emergent channel of the wavelength division multiplexer chip 5 displays light spots, the optical fiber sleeve 3 is permanently connected with the optical fiber fixer 2 by using two bundles of symmetrical laser welding, as shown in fig. 3, two fixed points are welded 23 first and then two fixed points are welded 24, the symmetrical laser is used for well inhibiting the movement of the optical fiber sleeve 3 in the horizontal direction, the subsequent adjustment difficulty is reduced, and the fixture is released after the optical fiber fixer 2 and the optical fiber sleeve 3 are fixed.

The next step is to align the wavelength division multiplexer chip 5 and the optical fiber array 7, firstly release the pressure on the wavelength division multiplexer chip 5, adjust the chip base 1 by observing the near infrared imaging microscope output, and when the near infrared imaging shows the emergent channel light spot, press down the temporarily fixed wavelength division multiplexer chip 55 to ensure that the alignment can be completed by inputting the laser signal at the chip input end. One path of the optical fiber array 7 is connected to an optical power meter, the optical fiber array 7 is clamped by using a precision regulator, and when the output optical power is maximum, the optical fiber array 7 and the wavelength division multiplexer chip 5 are fixed. The coupling efficiency from the output end of the wavelength division multiplexer chip 5 to the optical fiber array 7 can be improved by fixing the chip base 1 and adjusting the position of the optical fiber array 7.

After the optical fiber array 7 is fixed on the chip base 1, the relative position of the chip base 1 and the optical fiber fixer 2 is adjusted again to the position with the maximum output optical power, and the chip base 1 is welded to the metal base 4 by using two symmetrical lasers, as shown in fig. 4, the fixed point 11 is welded first and then the fixed point 12 is welded, because the size of the chip base is larger than that of the optical fiber fixer, the offset of the chip after laser welding is smaller, and the offset after laser welding can be corrected more accurately during subsequent adjustment welding. Because symmetrical lasers are used for two times of adjustment, the relative displacement of the optical fiber 6 and the wavelength division multiplexer chip 5 in the horizontal direction is greatly reduced, and therefore, the vertical direction of the optical fiber sleeve is only required to be adjusted by adjusting welding, the adjustment difficulty is reduced, and the alignment precision is improved.

In the application, an optical fiber fixer 2 and a chip base 1 are arranged on the upper surface of a metal seat 4, the optical fiber fixer 2 is connected with the metal seat 4 through laser welding, a wavelength division multiplexer chip 5 is arranged above the chip base 1, an opening of the optical fiber fixer 2 is opposite to the chip output end face of the wavelength division multiplexer chip 5, the bottom of the optical fiber fixer 2 is propped against the bottom of the chip base 1, an optical fiber 6 and an optical fiber sleeve 3 are coaxially arranged, the optical fiber sleeve 3 passes through the optical fiber fixer 2 to realize limit, and an optical fiber array 7 is fixed on the chip base 1. The optical fiber sleeve 3 is fixed by means of laser welding, so that the transverse and longitudinal alignment of the optical fiber 6 and the wavelength division multiplexer chip 5 is ensured. Finally, the chip base 1 is adjusted again, and the chip base 1 is fixed by using laser welding so as to realize stable and accurate connection between the optical fiber 6 and the wavelength division multiplexer chip 5.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

What has been described above is merely some embodiments of the present invention. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit of the invention.

Claims (10)

1. The optical fiber coupling structure comprises a metal seat, an optical fiber fixer, an optical fiber sleeve, a chip base, a wavelength division multiplexer chip, optical fibers and an optical fiber array, and is characterized in that the optical fiber fixer and the chip base are arranged on the upper surface of the metal seat, the optical fiber fixer and the chip base are in a similar shape and are respectively fixed on the upper surface of the metal seat through the bottom of the optical fiber fixer and the bottom of the chip base, the height of the optical fiber fixer is larger than the height of the chip base, and the wavelength division multiplexer chip is arranged above the chip base;

The opening of the optical fiber fixer is opposite to the chip output end face of the wavelength division multiplexer chip, the length of the bottom of the chip base is longer than that of the top of the chip base, and the bottom of the optical fiber fixer is propped against the bottom of the chip base;

The optical fiber and the optical fiber sleeve are coaxially arranged, the inner diameter of the optical fiber sleeve is not smaller than the outer diameter of the optical fiber, the optical fiber sleeve penetrates through the optical fiber fixer to be opposite to the wavelength division multiplexer chip, and the optical fiber sleeve positioned in the optical fiber fixer is fixedly connected with the optical fiber fixer;

The chip input end of the wavelength division multiplexer chip is connected with the optical fiber array fixed on the chip base, and the chip output end of the wavelength division multiplexer chip is connected with the optical fibers in the optical fiber sleeve passing through the optical fiber fixer.

2. The optical fiber coupling structure of claim 1, wherein the upper surface of the chip base has a size greater than the chip size of the wavelength division multiplexer chip, the chip output end face of the wavelength division multiplexer chip is flush with the edge of the upper surface of the chip base, and the two sides of the wavelength division multiplexer chip are equidistant from the two edges of the upper surface of the chip base.

3. The optical fiber coupling structure of claim 1, wherein the optical fibers and the optical fiber array are connected to the wavelength division multiplexer chip in a reciprocal manner, the opening of the optical fiber holder is opposite to the chip input end face of the wavelength division multiplexer chip, the chip input end of the wavelength division multiplexer chip is connected to the optical fibers passing through the optical fiber holder, and the chip output end of the wavelength division multiplexer chip is connected to the optical fiber array.

4. The optical fiber coupling structure of claim 1, wherein the upper surface of the chip base has a length greater than 5-7 mm of the chip length.

5. A fiber coupling structure according to claim 1, wherein the fiber holder has a height greater than 4-5 mm of the height of the chip base.

6. The optical fiber coupling structure of claim 1 wherein the metal base, the fiber holder, the fiber sleeve and the chip base are all made of a vaive alloy.

7. The optical fiber coupling structure according to claim 1, wherein the side surface of the chip base and/or the extension surface of the side surface on the upper surface of the metal base are/is provided with windows.

8. The optical fiber coupling structure of claim 1, wherein the open ends of the fiber holder are respectively provided with a pair of welding fixation points for welding the fiber optic ferrule disposed within the fiber holder.

9. The optical fiber coupling structure of claim 1, wherein the side surface of the chip base is shaped like a Chinese character 'ji', and a welding fixing point is respectively arranged at the left and right sides of the side surface of the Chinese character 'ji' to weld the chip base to the upper surface of the metal base.

10. A method of optical fiber and die bonding for an optical fiber coupling structure according to any one of claims 1 to 9, comprising the steps of:

a) Mounting the wavelength division multiplexer chip on a chip base;

b) Trimming the fiber splice so that the fiber splice does not exceed a defined length of the fiber cladding, the defined length being 1-5 mm;

C) Connecting the optical fiber with the optical fiber sleeve by adopting a curing agent;

D) Fixing the optical fiber fixer to the metal seat by laser welding;

E) The chip base is propped against the optical fiber fixer by using a clamp, the optical fiber sleeve passes through the optical fiber fixer by using a precision regulator, the transverse distance between the optical fiber and the output end of the wavelength division multiplexer chip is observed by using a microscope, the position of the chip base is adjusted, and after the optical axis of the optical fiber is aligned with the output waveguide of the chip, the wavelength division multiplexer chip attached to the chip base is pressed down to temporarily fix the optical fiber;

f) Connecting the other end of the optical fiber with a laser, and placing a near infrared imaging microscope on the input end face of the wavelength division multiplexer chip;

G) Opening laser, observing output conditions through a near infrared imaging microscope, adjusting the position of the optical fiber sleeve, and welding the optical fiber sleeve and the optical fiber fixer by using two symmetrical lasers when the emergent channel of the wavelength division multiplexer chip displays light spots;

H) Releasing the pressure on the wavelength division multiplexer chip, adjusting a chip base by observing the output of the near infrared imaging microscope, and pressing down the temporarily fixed wavelength division multiplexer chip when the near infrared imaging microscope displays the emergent channel light spots;

I) One path of the optical fiber array is connected into an optical power meter, a precise regulator is used for clamping the optical fiber array, and when the output optical power is maximum, the optical fiber array and the wavelength division multiplexer chip are fixed;

J) And (3) using two symmetrical lasers to weld the chip base on the metal base by laser, and releasing the pressure on the wavelength division multiplexer chip.