KR100841210B1 - Transistor outline type laser diode package controlled reflectivity of tilt mirror, and method for manufacturing the tilt mirror - Google Patents

Abstract

A transistor outline type laser diode package having a tilt mirror having a controlled rear reflectance and a method for manufacturing the same tilt mirror are provided to radiate laser light to a monitoring light receiving element without loss by reducing a reflectance of a rear surface of the tilt mirror. A laser diode chip, a tilt mirror(100) having a tilt angle of 45 degrees, a monitoring light receiving element are arranged in a line. A single dielectric thin film or a double dielectric thin film having different reflective indexes is coated on a reflective surface of the tilt mirror so that the laser light emitted from the laser diode chip is reflected on a reflective surface of the tilt mirror. A rear surface of the tilt mirror has a reflectance lower than a reflectance of a tilt mirror preform and a reflectance of an air layer. The monitoring light receiving element is installed at a monitoring light receiving element sub-mount in order to receive the laser light emitted through the rear surface of the tilt mirror.

Description

Transistor outline type laser diode package controlled reflectivity of tilt mirror, And Method for manufacturing the tilt mirror}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of fabricating a transistor outline type (hereinafter, abbreviated as "TO or thio") laser diode package and its inclined mirror. By arranging a partial inclined mirror having a reflecting surface of 45 ° in front of the chip, a part of the light emitted from the laser diode chip is reflected from the reflecting surface, and the traveling direction is 90 °, and the outside of the TO package is opened through a window provided on the upper part of the TO package. Of the inclined mirror so that the remaining light that is not reflected from the inclined mirror and goes straight through the rear of the inclined mirror is irradiated to the monitoring light receiving element without loss. On the fabrication method of thio type laser diode package with controlled rear reflectance and its inclined mirror A.

In order to precisely control the intensity of the light emitted from the laser diode package, it is common to have a monitoring light receiving element for monitoring the operating state of the laser diode chip inside the semiconductor laser diode package.

The semiconductor laser diode is divided into a structure of an edge emitting laser diode and a vertical cavity surface emitting laser (VcSEL) according to the direction of light emission. In general, edge emitting laser diodes emit laser light from both the front and the back of the laser diode chip. Therefore, conventional edge emitting laser diodes do not monitor the intensity of light from the front of the laser diode chip facing out of the TO package. Backside monitoring is often used to monitor the intensity of light from the back of the chip. In order to monitor the intensity of light emitted from the front of the laser diode chip by using the laser light emitted from the back of the laser diode chip, the ratio of the intensity of light emitted to the front and the back of the laser diode chip must be constant.

In general Fabry-Perot type semiconductor laser diode, the emission ratio of the front and rear of the laser diode chip is constant regardless of the laser diode driving current, so the rear emission light is used to monitor the intensity of the front emission light. The purpose is easily achieved. However, in a semiconductor laser diode chip such as a reflective semiconductor optical amplifier, the light output ratio of the front to the back varies according to the laser diode driving current, so that the light intensity monitoring at the rear of the laser diode chip is performed by the laser. It does not happen to accurately indicate the intensity of light emitted from the front of the diode chip. Therefore, a function of monitoring the light output intensity by using the front light output of the laser diode chip is required.

In a conventional laser diode package such as VcSEL, a window glass through which light emitted from the laser diode chip passes is attached at a certain angle to the optical axis, and then the laser diode chip is reflected light of a portion of the laser light from the window. A method of monitoring the intensity of the light emitted from is being used. However, this method, as mentioned in the applicant's patent application No. 2007-0108008, causes a disadvantage that the package becomes bulky because the distance between the laser emission point and the monitoring light receiving element is far.

In this patent application proposed by the present applicant to solve this problem, the reflecting surface of the 45 ° reflecting surface is formed by alternately depositing a reflective surface of an inclined mirror having a 45 ° inclination or a plurality of dielectric thin films having different heights of dielectric constant. By adjusting some of the light to pass through the inclined mirror, a method of effectively monitoring the laser light emitted from the front surface of the laser diode chip by using the light transmitted through the reflecting surface of the 45 ° tilt mirror.

FIG. 1 schematically shows a structure for performing a light monitoring function using front emission light in a patented laser diode package proposed by the present applicant.

As shown in FIG. 1, the patent application is emitted through the laser diode chip 10 and the light transmitted through the 45 ° inclined mirror 60 proceeds to the bottom surface of the 45 ° inclined mirror according to Snell's law. Then, the light reflected upward by the total reflection from the bottom surface is directed toward the monitoring light receiving element 20 through the rear surface of the 45 ° inclined mirror. However, the light that passes through the 45 ° inclined mirror 60 and proceeds to the monitoring light receiving element 20 undergoes reflection at the interface between the rear of the 45 ° inclined mirror and the air. That is, the patent application proposes a single silicon semiconductor as the base material of the reflecting mirror, and the light passing through the 45 ° inclined mirror 60 at the interface between the back of the 45 ° inclined mirror 60 and the air made of silicon. Will be reflected.

The silicon used as the base material of the 45 ° inclined mirror 60 has a refractive index of about 3.5 for a wavelength of 1.55 µm, which is a wavelength band mainly used for optical communication. Light propagating into the air inside the mirror has a reflectance calculated at the following equation (1) at the silicon / air interface.

Here, Rs represents the refractive index experienced by the light passing through inside the silicon, and Ra represents the refractive index experienced by the light passing through inside the air layer.

When the refractive index of silicon and the refractive index of air are substituted for the light having the wavelength of 1.55 占 퐉 in Equation 1, the reflectance at the silicon / air interface is about 31%. As described above, part of the laser light transmitted through the reflecting surface of the 45 ° inclined mirror is reflected at the interface between the rear surface of the inclined mirror formed of silicon and the air layer according to the reflectance at the silicon and air interface. The light intensity is reduced.

As a method of not reducing the intensity of the laser light incident to the monitoring light receiving element, a method of increasing the transmittance into the inclined mirror by lowering the reflectance of the reflecting surface of the laser diode chip of the 45 ° inclined mirror may be proposed. The method results in a reduction in light output escaping out of the TO package. Therefore, in order not to reduce the intensity of the laser light incident to the monitoring light receiving element without reducing the light intensity extracted out of the TO package, it is necessary to reduce the reflectance at the rear side of the monitoring light receiving element of the 45 ° inclination mirror or to prevent reflection from occurring. Need to be done.

An object of the present invention is a thio type laser diode package equipped with a 45 ° tilting mirror reflecting a part of the laser light emitted from the laser diode chip to extract it out of the TO package and transmit the remaining laser light to the monitoring light receiving element. The thio type laser diode package having a rear reflectance of the inclined mirror and the inclined mirror of which the inclined mirror is controlled to lower the reflectance at the rear of the 45 ° inclined mirror to prevent the loss of laser light incident to the monitoring light receiving element. To provide a way to build.

In order to achieve the above object, the thio type laser diode package in which the rear reflectance of the inclined mirror is adjusted according to the present invention is a thio type laser diode package in which a laser diode chip, a 45 ° inclined mirror, and a light receiving element for monitoring are arranged in a line. The reflective surface of the 45 ° inclined mirror is coated with a single layer of a dielectric thin film or a multilayer dielectric thin film having a different refractive index so that a part of the laser light emitted from the laser diode chip is reflected and emitted to the outside of the package. The rear surface of the inclined mirror has a reflectance lower than that of the 45 ° inclined mirror base material and the air layer so that the remaining laser light not reflected from the reflecting surface passes through the reflecting surface and is emitted through the rear surface. Is installed on the monitoring light receiving element submount, spaced apart from the rear of the 45 ° inclined mirror. It receives laser light emitted through the rear of the 45 ° tilt mirror.

The base material of the 45 ° inclined mirror is formed of silicon or glass, and the rear surface of the 45 ° inclined mirror is coated with a material containing any one of oil, gel, and epoxy having low absorption to the laser beam passing therethrough. It is preferable that this coating substance has a refractive index of 1.4-1.9.

The 45 ° tilt mirror and the laser diode chip are fixed on the submount, which may be installed on the same horizontal plane as the submount to which the monitoring light receiving element is attached. In addition, the laser diode chip is fixedly installed on the upper part of the first submount, the first submount is fixedly installed on the upper part of the second submount 45 ° inclined mirror is installed on the upper part, the second submount is receiving light for monitoring The device is preferably installed on the same horizontal plane as the submount in which the device is mounted. The laser diode chip is mounted on the submount by the p-side down mount method.
On the other hand, in order to achieve the above object of the present invention, the method of manufacturing the inclined mirror having the rear reflectance is controlled to cut the silicon wafer from the silicon ingot so as to tilt 9.74 ° from the (001) plane, and a part of the upper surface of the silicon wafer is photoresisted. Applying with; Removing the photoresist of the portion to be etched of the silicon wafer by a photolithography method; Etching the portion of the photoresist removed using an anisotropic etching solution to form an exposed surface as an inclined surface having an inclination angle of 54.74 ° with the (001) surface; Alternately depositing a single layer of a dielectric thin film or a plurality of dielectric thin films having different refractive indices on a lower surface of the silicon wafer to form a partially reflective surface; Alternately depositing a single layer of a dielectric thin film or a plurality of dielectric thin films having different refractive indices on an upper surface of the silicon wafer including the inclined surface to form a reflectance of the upper surface lower than that of the inclined mirror base material and the air layer; And cutting the silicon wafer deposited on the upper and lower surfaces of the dielectric thin film to a 45 ° mirror.

The thio type laser diode package in which the rear reflectance of the inclined mirror is controlled according to the present invention, and the method of manufacturing the inclined mirror reduces the rear reflectance of the 45 ° inclined mirror, thereby monitoring the light receiving element for monitoring the laser light incident through the reflective surface without loss. There is an effect that can be made to enter.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In order to facilitate understanding in describing the embodiments of the present invention, patent application No. 2007-0026558 proposed by the present applicant in connection with the present invention will first be briefly described.

Figure 2 shows the process of manufacturing a 45 ° inclined mirror using the silicon base material proposed in the applicant's patent application No. 2007-0026558.

In the patent application, the silicon wafer 2 is sliced from a silicon ingot and coated with a photoresist 3, and then a 45 ° inclined surface 111 is formed by a wet etching method, and the polished original silicon wafer 2 A metal having a high reflectance or a plurality of layers of dielectric thin films having different levels of refractive index are coated on the lower surface 4 of the c), and the silicon wafer 2 having the reflecting layer formed thereon is cut by a method such as sawing or scribing and inclined at 45 °. The mirror 10 will be produced.

Figure 3 shows the changing shape of the 45 ° inclined mirror according to the size of the cut when separating the individual 45 ° inclined mirror from the silicon wafer through the above process, Figure 4 is cut to different sizes in one silicon wafer An example of a 45 ° inclined mirror of three shapes is shown.

In the 45 ° inclined mirror shown in Fig. 4, ① surface represents the polished lower surface of the original silicon wafer, ② surface is the sawing or scribing surface of the original silicon wafer, ③ surface is the etching surface of the original silicon wafer, Shows the polished top surface of the original silicon wafer.

The laser light emitted from the laser diode chip and proceeding to the 45 ° inclined mirror passes through the interior of the 45 ° inclined mirror, and has a different path of propagation depending on the shape of the 45 ° inclined mirror and the point of reaching the 45 ° inclined mirror.

5 is a conceptual diagram illustrating an example of a path through which laser light passes through a 45 ° inclined mirror manufactured through the above process.

As shown in FIG. 5, the laser light emitted from the laser diode chip and incident on the 45 ° inclination mirror passes through the total reflection at the bottom of the 45 ° inclination mirror to reach the rear of the 45 ° inclination mirror and then escapes into the air. . At this time, the back of the laser light escapes the 45 ° inclined mirror becomes a surface appearing during the sawing or scribing process for manufacturing the silicon wafer as an individual inclined mirror. Thus, this backside is the face that appears after the 45 ° mirror is individually separated from the silicon wafer.

As an effective anti-reflective treatment on such a back surface, there is a method of applying a material having a low refractive index with respect to transmitted light and having a refractive index having a median value between silicon and air. The reflectance at the back surface coated with a material having a refractive index corresponding to the median value of silicon and air is given by Equation 2 below.

Rs: the refractive index experienced by the transmitted light inside the silicon

Ri: refractive index experienced by the light passing through inside the intermediate layer

Ra: refractive index experienced by the light passing through inside the air layer

6 shows the total reflectance according to the refractive index of the interlayer material calculated according to Equation 2 above.

As shown in Fig. 6, when the refractive index of the intermediate layer has a value of 1.8 to 1.9, the reflectance at the rear of the 45 ° inclined mirror drops to about 18%, which is about 39% compared to when silicon and air are directly adjacent to each other. Will be reduced. As various materials that can be used as the intermediate layer are commercially available in the form of oil, gel, epoxy, etc., the use of such intermediate layer material can significantly lower the reflectance on the rear surface of the 45 ° inclined mirror. Interlayer materials having these properties are commonly referred to as optical refractive index matching oils, gels, and epoxys. Optical refractive index matching oils, gels, and epoxy resins that are readily available on the market range from 1.4 to 1.9. Therefore, the use of optical refractive index matching oil and gel epoxy with a refractive index of about 1.4 to 1.9 can improve the reflectance on the rear surface of the 45 ° mirror by 18 to 21%. Figure 7 shows an example in which the optical refractive index matching oil, gel, epoxy and the like is applied to the back of the 45 ° tilt mirror.

The above method is an effective method for lowering the reflectance of the rear surface exposed by the sawing or scribing method of 45 ° inclined mirror. However, if the size of the 45 ° inclined mirror changes and the point where the laser light arrives at the inclined mirror changes, the exit of the laser light may be the top of the original silicon substrate rather than the sawed or scribed back.

FIG. 8 is a conceptual diagram illustrating various propagation paths of light that proceed according to the position of the light arriving at the 45 ° inclined mirror.

As shown in FIG. 8, when the length of the polished silicon top surface is cut relatively longer than that of FIGS. 5 and 7 in the process of cutting individual 45 ° mirrors from the silicon substrate, the position of the laser light is incident. The path of the laser light is formed differently. That is, the laser light incident to the A ″ region of the 45 ° inclined mirror is totally reflected from the lower surface of the mirror (③) and then emitted through the sawing rear surface (②) of the upper portion of the inclined mirror. After the total reflection at the bottom surface (③) of the inclined mirror is totally reflected at the side (④) that was the upper surface of the original silicon wafer of the rear surface of the inclined mirror and escapes through the sawing rear surface (②) of the upper portion of the inclined mirror. The laser light entering the C "region proceeds directly to the side surface (④), which was the upper surface of the silicon wafer, and escapes the reflection mirror. The laser light entering the D" region of the inclined mirror is sawing the rear surface (②) After reflection, it is emitted through the side (④) which was originally the top of the silicon wafer. As such, the laser light traveling in the inclined mirror according to the size of the 45 ° inclined mirror and the position of incidence of the laser light has various propagation paths.

As described above with reference to FIG. 2, the present applicant forms a reflective surface of a 45 ° inclined mirror on a flat lower surface of a semiconductor wafer such as silicon, and has a refractive index with a material and a structure for forming the reflective surface in the patent application No. 2007-26558. These different multilayer dielectric thin films are presented. The technique of controlling reflectance and transmittance for specific wavelengths by depositing a dielectric thin film on a flat surface is a very general and well managed process, and thus the transmittance of the 45 ° mirror can be easily controlled. The same discussion applies to the top surface of the patterned silicon wafer, so that antireflection deposition on the flat top surface of the silicon wafer can be made very easily.

Hereinafter, a method of manufacturing a 45 ° inclined mirror according to an embodiment of the present invention will be described.

9 is a conceptual diagram illustrating a process of manufacturing a 45 ° inclined mirror using a semiconductor silicon wafer according to an embodiment of the present invention.

First, (a) to (d) of FIG. 9 which is a process of causing the (111) surface of the silicon wafer to appear appear in the same manner as the process of (a) to (d) of FIG. 2 described above. As follows.

The silicon wafer 2 is cut out from the semiconductor silicon ingot not shown in FIG. 9A so as to be tilted 9.74 ° on the (001) surface, and a part of the upper surface of the cut semiconductor wafer 2 is coated with the photoresist 3. do.

After removing the photoresist 3 of the portion to be etched in FIG. 9B by the photolithography method, the portion of the photoresist 3 removed in FIG. 9C is etched using an anisotropic etching solution. The exposed surface is formed with an inclined surface ((111) surface) having an inclination angle of (001) and 54.74 °. In this case, since the etched exposed surface and the (001) plane have an inclination angle of 54.74 °, the etched exposed surface has an inclination angle of 45.00 ° and 64.48 ° with the horizontal plane of the silicon wafer 2, respectively.

In FIG. 9D, the residual photoresist 3 of the inclined surface-etched semiconductor wafer 2 is removed, and dielectric materials having different refractive indices are alternately deposited on the lower flat bottom surface of the silicon wafer 2. The dielectric thin film is deposited to have reflectance and transmittance.

Meanwhile, in FIG. 2, the dielectric thin film layer in which the reflectance is controlled is deposited only on the flat lower surface of the silicon wafer. However, in the present invention, as shown in FIG. 9E, the silicon wafer 2 including the inclined surface (111) surface is formed. The dielectric film layer having a controlled reflectance is deposited on the upper surface. In the case of the silicon wafer 2, the upper and lower sides of the silicon wafer may be polished at the fabrication stage to make the upper and lower surfaces both as mirror surfaces, and the mirror surface formed by polishing is very smooth so that no diffuse reflection occurs. Therefore, since the top surface of the silicon wafer 2 is also manufactured with very good smoothness, it is very easy to deposit a dielectric thin film of which the reflectance is controlled in this aspect. At this time, if the thickness and refractive index of the dielectric thin film are adjusted to have a reflectance of 30% or less on the upper surface of the silicon wafer 2 or preferably 5% or less, the antireflection deposition on the upper surface of the silicon wafer 2 is completed. .

When the silicon wafer 2 thus produced is cut out to an appropriate size as shown in FIG. 9 (f), a desired 45 ° inclined mirror can be completed as shown in FIG. 9 (g). If the inclined mirror of the wedge shape is inverted as shown in FIG. 9 (h), and the inclined surface (111) surface shown by etching is placed downward, the reflectance of the polished silicon wafer corresponds to the reflectance through the controlled reflecting surface. Some light paths are changed at right angles, and the light passing through the remaining reflecting surfaces can escape the inclined mirror without reflection from the rear of the inclined mirror.

In the above discussion, only the components of the laser light incident in the 45 ° tilt mirror proceed in the horizontal direction have been described. However, the light emitted from the semiconductor laser diode chip is dispersed and emitted in a range of angles. In general, light emitted from a semiconductor laser diode chip emits with a full width at half maximum divergence angle in the vertical direction.

FIG. 10 illustrates an example of a path when laser light corresponding to each angular component passes through the inclined mirror when the laser light emitted from the laser diode chip is distributed at a predetermined angle. As shown in FIG. 10, when the horizontal distance between the laser divergence point of the laser diode chip 200 and the reflecting surface of the 45 ° tilt mirror 100 is short, the size of the laser light according to the divergence angle of the laser light is large. Since it is not enlarged, even a small inclination mirror may reflect and transmit all of light emitted from the laser diode chip 200.

In order for the laser light to escape the inclined mirror through the top surface of the original silicon wafer as shown in FIG. 9 (h), the laser light is relatively higher than the case where the laser light escapes the inclined mirror through the sawing surface of the inclined mirror as shown in FIG. The laser light must be emitted at the location, thereby increasing the distance between the laser light emission point and the laser beam arrival point of the inclined mirror.

FIG. 11 is a conceptual diagram illustrating that a part of the laser light emitted from the laser diode chip may not arrive at the reflective surface of the inclined mirror when the distance between the laser diode chip and the 45 ° inclined mirror becomes far. As shown in FIG. 11, when the horizontal distance between the emission point of the laser diode chip 200 and the 45 ° tilt mirror 100 increases, the size of the laser light is enlarged according to the divergence angle of the laser light. Laser light components that go straight without reaching the slope are generated. Laser light that does not reach the reflective surface of the 45 ° inclined mirror 100 is not reflected in the inclined mirror and cannot effectively escape the TO package. Increasing the size of the inclined mirror to reflect all the scattered laser light makes the package large in size, making it impossible to manufacture a compact TO package.

This problem can be solved by floating the laser diode chip 200 on the bottom surface of the TO package and placing the laser diode chip 200 close to the reflective surface of the 45 ° inclined mirror 100. 12 shows an example of bringing the distance between the laser light emitting surface of the laser diode chip and the inclined mirror close to each other. A submount 400 is installed on the bottom surface of the TO package, and the laser is placed on the upper part of the submount 400. The diode chip 200 may be fixed to be positioned close to the reflective surface of the 45 ° tilt mirror 100.

Conventional semiconductor laser diode chip 200 is configured to have a thickness of approximately 50 ~ 150㎛. FIG. 13 illustrates a structure of a general semiconductor laser diode chip. The laser diode chip 200 is a p-n diode structure, which is a p-n junction structure, in which an n-doping layer and a p-doping layer are stacked in the height direction of the chip. In a conventional semiconductor laser diode chip 200, the thickness of the p-doping layer is about 3 to 5 mu m, and laser light is generated at the interface between the p-doping layer and the n-doping layer. Therefore, the portion of the laser diode chip 200 where the actual laser light is generated is very close to the surface of the p-doping layer of the chip.

The method of packaging the laser diode chip 200 with the p-doping layer above the n-doping layer is called a p-side up mount method, and the method of assembling the p-doping layer with the n-doping layer below is called p-side up mount method. This is called the side down mount method. 12 illustrates that the p-side up mount method is applied. In the case of the p-side up mount, the distance between the light emitting point of the laser diode chip 200 and the inclined mirror is far from the thickness of the laser diode chip 200. You lose.

Therefore, in order to minimize the divergence range of the laser light when the laser light reaches the 45 ° tilt mirror 100, it is more effective to assemble the p-side down mount method. An example of installation of a laser diode chip is shown. As shown in FIG. 14, in the p-side down mount assembly method, the active layer region in which the laser light is generated is closer to the submount 400 than in the p-side up mount assembly method. There is also a side effect that can effectively remove heat generated during operation.

Since the height of the laser diode chip 200 is about 50 to 150 μm in a small package such as a TO 56 type package, the laser light passing through the 45 ° inclined mirror 100 shown in FIGS. 10, 12, and 14 is The 45 ° inclined mirror 100 escapes to a height within approximately 100 to 200 μm from the bottom surface. Typically, the monitoring light receiving element has a size of about 500 μm, and has a height of about 250 μm from the end of the monitoring light receiving element to the center point of the light receiving area, and the monitoring light receiving element is removed from the floor due to problems such as electrical insulation. Since the assembly should be spaced about 100㎛, the center of the light receiving area of the monitoring light receiving element has a height of about 350㎛ from the bottom. Since the height of the laser beam penetrating the 45 ° inclined mirror 100 is lower than approximately 100 to 200 μm from the bottom, the central axis of the laser diode light transmitted through the 45 ° inclined mirror 100 is It does not coincide with the center point of the light receiving area, making it impossible to efficiently monitor the laser light intensity. This may be overcome by varying the height of the bottom surface on which the 45 ° mirror 100 is installed and the bottom surface on which the monitoring light receiving element is installed.

15 is an example of the installation of the laser diode chip and the inclined mirror and the monitoring light receiving device according to an embodiment of the present invention, the second submount (on the bottom surface on which the submount 310 of the monitoring light receiving device 300 is installed; 420 is installed, the first submount 410 and the 45 ° inclined mirror 100 is installed on the second submount 420, the laser diode chip 20 is installed on the first submount 410 Is installed. In this arrangement, it is possible to effectively match the central axis of the laser light passing through the 45 ° inclined mirror 100 and the light receiving area of the monitoring light receiving element 300. The first and second submounts 410 and 420 on which the laser diode chip 200 is installed are made of aluminum nitride (AlN), berillium oxide (BeO), to effectively dissipate heat generated from the laser diode chip 200. It is preferably made of a material such as Silicon Carbide (SiC), Silicon, Alumina (Al2O3).

FIG. 16 is an example of installation of a laser diode chip, an inclined mirror, and a monitoring light receiving device according to another embodiment of the present invention, wherein the height of the bottom surface of the laser diode chip 200 and the bottom surface of the 45 ° inclined mirror 100 are When the same is the method of arranging the monitoring light receiving element (300). In this method, the submount 400 is installed on the floor where the submount 310 of the monitoring light receiving element 300 is installed, and the laser diode chip 200 and the 45 ° inclined mirror directly on the submount 400. 100 is installed. The arrangement of the laser diode chip 200, the 45 ° inclination mirror 100, and the monitoring light receiving element 300 is based on the central axis of the laser light passing through the 45 ° inclination mirror 100 and the monitoring light reception as shown in FIG. 15. It is possible to effectively match the light receiving area of the device.

In the above-described embodiment of the present invention, a 45 ° inclined mirror using silicon has been described as an example, but it is obvious that the 45 ° inclined mirror can be applied as it is even when the base material is glass.

1 is a schematic diagram of a structure for performing a light monitoring function using the front emission light in a laser diode package,

2 is a conceptual diagram showing a process of manufacturing a 45 ° tilt mirror using a silicon base material,

3 is a conceptual diagram showing the changing shape of the 45 ° inclined mirror according to the size of the cut when separating the individual 45 ° inclined mirror from the silicon wafer,

4 is an example of three shapes of 45 ° inclined mirrors cut to different sizes from one silicon wafer;

5 is a conceptual diagram illustrating an example of a path through which laser light passes through a 45 ° mirror;

6 is an example showing the total reflectance according to the refractive index of the interlayer material,

7 is an example in which an optical refractive index matching oil, gel, epoxy, or the like is applied to the rear surface of a 45 ° inclined mirror,

8 is a conceptual diagram showing various propagation paths of the light that proceeds according to the position of the light arriving at the 45 ° tilt mirror;

9 is a conceptual diagram illustrating a process of manufacturing a 45 ° tilt mirror using a semiconductor silicon wafer according to the present invention;

10 is an example of a path when the laser light corresponding to each angular component passes through the inclined mirror when the laser light emitted from the laser diode chip is distributed at a predetermined angle according to the present invention.

FIG. 11 is a conceptual diagram illustrating that a part of the laser light emitted from the laser diode chip may not arrive at the reflective surface of the inclined mirror when the distance between the laser diode chip and the 45 ° inclined mirror increases according to the present invention.

12 is an example of making the distance between the laser light emitting surface of the laser diode chip and the inclined mirror close according to the present invention;

13 is a structural conceptual diagram of a semiconductor laser diode chip;

14 shows an example of installation of a laser diode chip to which the p-side down mount method is applied;

15 is an example of installation of the laser diode chip and the inclined mirror and monitoring light receiving element according to an embodiment of the present invention,

16 is an example of installation of a laser diode chip and a tilting mirror and monitoring light receiving element according to another embodiment of the present invention.

※ Explanation of codes for main parts of drawing

100: 45 ° tilt mirror 200: laser diode chip

300: monitoring light receiving element 310: monitoring light receiving element submount

400: submount 410: first submount

420: second submount

Claims (9)

In the thio type laser diode package in which the laser diode chip 200, the 45 ° tilt mirror 100, and the monitoring light receiving element 300 are arranged in a line, The reflective surface of the 45 ° inclined mirror 100 is a dielectric thin film of a single layer or a multilayer dielectric thin film having a different refractive index so that a part of the laser light emitted from the laser diode chip 200 is reflected and emitted to the outside of the package. Coated, The rear surface of the 45 ° inclined mirror 100 has a reflectance lower than that of the 45 ° inclined mirror base material and the air layer so that the remaining laser light, which is not reflected from the reflective surface, passes through the reflective surface and is emitted through the rear surface. , The monitoring light receiving element 300 is installed in the monitoring light receiving element submount 310 in a state spaced apart from the rear of the 45 ° tilt mirror 100, the laser light emitted through the rear of the 45 ° tilt mirror (100). The thio type laser diode package with a rear reflectance of the inclined mirror being adjusted. The method according to claim 1, The thio-type laser diode package of the rear reflectance of the inclined mirror, characterized in that the base material of the 45 ° inclined mirror 100 is silicon or glass. The method according to claim 1 or 2, The rear surface of the inclined mirror 100 is a thio type with the rear reflectance of the inclined mirror 100, characterized in that the back surface of the inclined mirror 100 is coated with a material containing any one of oil, gel and epoxy low absorption Laser diode package. The method according to claim 3, The thio-type laser diode package of the back reflectance of the inclined mirror is characterized in that the material is applied to the back of the 45 ° tilt mirror 100 has a refractive index of 1.4 ~ 1.9. As a method of manufacturing the 45 ° inclined mirror 100 of claim 1 (a) cutting the silicon wafer 2 from the silicon ingot so that it is 9.74 ° tilted at the (001) plane and applying a portion of the upper surface of the silicon wafer 2 to the photoresist 3; (b) removing the photoresist 3 of the portion to be etched of the silicon wafer 2 by a photolithography method; (c) etching the portion where the photoresist 3 is removed using an anisotropic etching solution to form an exposed surface as an inclined surface (111) surface having an inclination angle of 54.74 ° with the (001) surface; (d) alternately depositing a single layer of a dielectric thin film or a plurality of dielectric thin films having different refractive indices on a lower surface of the silicon wafer 2 to form a partially reflective surface; (e) A single layer of dielectric thin film or a plurality of layers of dielectric thin films having different refractive indices are alternately deposited on the upper surface of the silicon wafer 2 including the inclined surface (111) surface to reflect the upper surface reflectivity on the inclined mirror base material and the air layer. Forming lower than the reflectance; (f) cutting the silicon wafer (2) deposited on the upper and lower surfaces of the dielectric thin film to form a 45 ° inclined mirror (100). The method according to claim 5, And a dielectric thin film is deposited such that an upper surface of the silicon wafer (2) including the inclined surface (111) surface has a reflectance of 0 to 30%. The method according to claim 1, The 45 ° inclined mirror 100 and the laser diode chip 200 are fixed on the submount 400, and the submount 400 is the same horizontal surface as the submount 310 to which the monitoring light receiving element 300 is attached. The thio type laser diode package with a rear reflectance of the inclined mirror being installed on. The method according to claim 1, The laser diode chip 200 is fixedly installed on the first submount 410, and the first submount 410 is on the second submount 420 on which the 45 ° inclined mirror 100 is installed. The thio type laser diode package with fixed rear reflectance of the inclined mirror, wherein the second submount 420 is fixed and installed on the same horizontal plane as the submount 310 in which the monitoring light receiving element 300 is installed. . The method according to claim 7 or 8, The laser diode chip 200 is a thio type laser diode package with a rear reflectance of the inclined mirror, characterized in that the p-side down mount method is installed on the submount (400, 410).

Images