KR100871017B1 - Optical modulator package for triplexer type bi-directional data communication, and method for manufacturing the beam splitter/filter - Google Patents

Abstract

An optical modulator package for triplexer type is provided to integrate a laser diode, photo diode and 45-degree filter into one board and use a triplexer type duplex optical communications module, so there is no need to use high price waveguide photo diode chip. In an optical modulator package for bidirectional data communication, an inclined front side of 45 degree-slope beam spliter/ filter(250) passes laser light from the laser diode chip(100) and reflects laser light of the wavelength for the digital signal from the external optical fiber. An inclined backplane passes laser light of the wavelength for the digital signal from the laser light and optical fiber radiated from the laser diode chip and is coated with the reflective metal material or the dielectric thin film in order to reflect the laser light of the wavelength for the analog signal from the optical fiber under the inclined backplane of 45 degree-slope beam spliter/ filter(250), a photodiode chip(400), for the digital reception receiving the laser light of the wavelength for the digital signal, and a photodiode chip(500), for the analog reception receiving the laser light of the wavelength for the analog signal, are arranged.

Description

Optical modulator package for triplexer type bi-directional data communication, and method for manufacturing the beam splitter / filter}

The present invention relates to a triplexer optical module package for transmitting and receiving signals through a single optical fiber using three wavelengths of laser light, and in particular, a laser diode chip and a 45 ° inclined beam splitter / filter and The photodiode chip for digital signal reception and the photodiode chip for analog signal reception are built in one package housing to transmit and receive three wavelength optical signals of optical signal for transmission, optical signal for analog reception and optical signal for digital reception. The present invention relates to a triplex optical module package for bidirectional communication having one beam splitter / filter performing simultaneously and a method of manufacturing the beam splitter / filter.

Background Art In recent years, optical communication using light as a medium for information transmission has become common for large-capacity information transmission and high-speed information communication. In recent years, a semiconductor laser diode chip having a horizontal length and a vertical length of about 0.3 can be used to easily convert a 10 Gbps (giga bit per sec) electric signal into a laser light. The transmitted optical signal can be easily converted into an electrical signal. Light is an energy wave with very peculiar characteristics. In order for several lights simultaneously in one region to interact with each other, the light to be interacted with must have the same wavelength or have the same phase. In addition, the direction of travel must match. Therefore, light is very inferior to each other, and the wavelength division multiplexing (WDM) optical communication that transmits light having various wavelengths simultaneously through one optical fiber by using the characteristics of the light is preferred. Such WDM optical communication is a very economical communication method in that the optical fiber, which is a signal transmission medium, can be shared, thereby reducing the cost of laying the optical fiber.

In recent years, fiber to the home (FTTH), which connects optical fiber to the inside of a subscriber's home, is becoming more common. In the FTTH method, the optical fiber is drawn inside the subscriber's home for optical communication, and the optical signal is generated inside the subscriber's home and the optical signal transmitted from the base station of the optical communication is converted into an electrical signal. Downlink optical communication is required. As a method of performing the uplink and downlink optical communication, there is a method of separately installing and using an optical fiber for processing an uplink optical signal and an optical fiber for processing a downlink optical signal, but this method causes waste of optical fibers. Therefore, recently, a bidirectional optical communication method for transmitting an uplink optical signal and a downlink optical signal through one strand of optical fiber has been widely adopted. At present, the global trend in optical communication is calling for triple play, which combines data, voice and analog video (catalog). ITU.T G983.3, an international standard for communication, assigns frequencies of 1260 to 1360 nm as an uplink data signal, 1480 to 1500 nm as a downlink data signal, and 1550 to 1560 nm as a downlink video signal. Accordingly, an optical module capable of transmitting an optical signal of 1300 nm wavelength band upward through one optical fiber and simultaneously transmitting and receiving a downlink data signal of 1480-1500 nm wavelength band and a downlink video signal of 1550-1560 nm wavelength band is required. Optical modules with these functions are collectively called triplexer modules.

1 is a conceptual diagram illustrating a structure of a conventional general triplexer module.

1, the wavelength of light emitted from the TO-type laser diode module 6 installed in the preplexer housing 1 and transmitting an optical signal upward to the optical fiber 2 is 1300 nm. The wavelength of the analog video light transmitted downward in (2) is assumed to be 1550 nm, and the wavelength of the data light transmitted downward in the optical fiber 2 is assumed to be 1490 nm. In FIG. 1, the 45 ° filter (3) (4) is fabricated by alternately depositing a dielectric film having a relatively high refractive index and a low refractive index into a plurality of layers, and transmits 1300 nm and 1490 nm wavelengths, and transmits a wavelength of 1550. The A filter 3 is made to reflect silver, or the D filter 4 is made to transmit 1300 nm wavelength and reflect the 1490 nm wavelength. In this case, since 1550 nm is blocked by the A filter 3 and does not enter the D filter 4, it is irrelevant whether it has a characteristic of transmitting the 1550 nm wavelength or not. Both of these A and D filters 3 and 4 have a characteristic of transmitting a 1300 nm wavelength. Therefore, the laser light having a wavelength of 1300 nm emitted from the TO-type laser diode module 6 passes through all of the A and D filters 3 and 4, which are 45 ° filters, to be focused on the optical fiber 2 and the optical fiber ( The downward light of 1550 nm wavelength emitted by 2) enters the TO-type light-receiving element 5 for analog reception while the traveling direction of the A filter 3 is turned upward by 90 °, and 1490 nm emitted by the optical fiber 2. After passing through the A filter (3), the downward digital signal of D is incident on the TO-type light-receiving element (7) for the digital signal by turning the filter 90 degrees downward in the D filter (4). Therefore, by using the triplexer module, not only the up / down transmission of the data signal but also the reception of the analog video downlink signal is performed by using one optical fiber 2. However, the conventional triplexer module is bulky by mounting two TO-type modules such as a TO-type laser diode module 6 and two TO-type light receiving elements 5 and 7 therein, and the optical fiber 2 And optical alignment of the optical fiber 2 and the two TO-type light-receiving elements 5 and 7 as well as the precise optical alignment of the TO-type laser diode module 6 had a problem in that the assembly time and cost for the alignment were increased. . In addition, the conventional triplexer module requires about 40 parts such that each TO type module needs to be aligned independently x, y, z so that each TO type module needs to move its position. Sumitomo's triplexer module, which is reported to be the smallest volume in the world, has a volume of 12 mm * 10.5 mm * 5.6 mm, which is about 700 mmW.

In order to reduce the shortcomings of the conventional triplexer module as shown in FIG. 1, a laser diode chip using two silicon planar light circuit (PLC) technologies, two photodiode chips for analog and digital, and two filters are integrated. There was research and development on PLC type triplexer module.

2 is a conceptual diagram of a triplex module using a typical PLC technique shown in the data published by Park Jung-woo (Electronic Telecommunication Trend Analysis Vol. 20 No. 6, p77, 2005). In this conceptual diagram, it is difficult to focus the laser diode light having a wavelength of 1300 nm directly into a silicon waveguide. A photodiode chip does not use a general planar photodiode chip and is called a waveguide photo diode. There is a problem that a very expensive photodiode chip, which is not common, must be used. In addition, there is a problem that a very precise passive optical alignment is required to optically connect the silicon waveguide and the waveguide type photodiode chip, which has not been commercialized until now.

Accordingly, an object of the present invention is to solve the problems of the prior art, and an object of the present invention is to integrate a laser diode chip, a general planar photodiode chip, and a 45 ° filter onto a single substrate, thereby enabling bidirectional optical communication having a triple play function. In manufacturing the triplexer type bidirectional optical communication module, it is possible to reduce the number of assembly parts and the assembly process compared to the conventional 3 TO type triplexer and reduce the cost, and to use the expensive waveguide type photodiode chip used in the conventional PLC type. By using a general planar photodiode chip without using it, it is possible to manufacture an optical module package for bidirectional communication at a low price. Also, compared to the existing 3 TO triplexer, a laser diode chip, a photodiode chip, and a 45 ° filter mounting volume can be reduced. Small form factor pluggable by minimizing To provide an optical module package and a beam splitter / filter for bidirectional communication that can be easily applied to a small package such as).

In the present invention, a 45 ° inclined beam splitter / filter for a very small 45 ° filter is fabricated, and a laser diode chip, a general planar digital and analog reception photodiode chip, and a plurality of 45 ° inclination filters are disposed. By presenting the method, a laser diode chip, a photodiode chip for digital and analog reception, and a plurality of 45 ° inclined beam splitters / filters are assembled on a single substrate to provide a low cost implementation of bidirectional optical communication.

The triplex optical module package for bidirectional communication according to the present invention can be assembled with the laser diode chip and the photodiode chip for analog and digital reception lying on the floor so that the position adjustment of the laser diode chip and the photodiode chip for reception is very easy. Compared with the conventional commercially available 3 TO triplexer structure, the assembly volume is small and the parts used are small, thereby reducing the assembly cost. In addition, it is possible to reduce the cost by using a low-cost photodiode chip compared to the conventionally proposed PLC type.

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

3 is an overall structural diagram of an optical module package for bidirectional communication according to an embodiment of the present invention.

As shown in FIG. 3, in the triplex optical module package for bidirectional communication according to the present invention, a laser diode submount 110 is installed at an upper side of the base submount 600, and the laser diode submount 110 is installed. The laser diode chip 100 is installed on the top.

In addition, one side of the base submount 600 is provided with a lens 700 for making horizontal light of the 1300 nm wavelength band for transmission emitted from the laser diode chip 100, the base sub on the side of the lens 700 The upper part of the mount 600 is provided with a wedge-shaped 45 ° bevel beam splitter / filter (hereinafter, abbreviated as “45 ° bevel filter”) 250 having an inclined surface having an inclination angle of 45 ° with respect to the bottom surface. An optical fiber (not shown) is provided on the side of the 45 ° gradient filter 250.

Two or more dielectric thin films having a relatively high refractive index and a low refractive index such that the front inclined surface of the 45 ° gradient filter 250 toward the laser diode chip 100 have antireflective characteristics for 1300 nm and high reflection for 1490 nm Alternately deposited. In addition, a plurality of dielectric thin films are coated so that the rear rear inclined surface of the 45 ° inclined filter 250 toward the optical fiber has an anti-reflective transmission for 1300 nm and 1490 nm wavelengths and high reflection for 1550 nm wavelengths.

Below the 45 ° gradient filter 250, a digital receiving photodiode chip 400 reacting to a wavelength of 1490 nm and an analog receiving photodiode chip 500 reacting to a wavelength of 1550 nm are located, respectively. The digital reception photodiode chip 400 and the analog reception photodiode chip 500 are respectively installed on the digital reception submount 410 and the analog reception submount 510.

When the 45 ° gradient filter 250 having such a structure is used, laser light having a wavelength of 1300 nm emitted from the laser diode chip 100 is antireflectively coated on both sides of the 45 ° gradient filter 250 with respect to 1300 nm. The 45 ° slope filter 250 passes through and goes straight to the optical fiber. Laser light having a wavelength of 1550 nm emitted from the optical fiber is reflected from the rear inclined surface of the optical fiber side of the gradient filter 250 and is incident on the vertically downward 1550 nm analog photodiode chip 500 to generate a photocurrent signal.

Meanwhile, the laser light having a wavelength of 1490 nm emitted from the optical fiber passes through the rear inclined plane of the 45 ° slope filter 250 and is reflected from the front slope, and then goes straight down to the 45 ° slope filter 250 through the rear slope. .

4 is a conceptual diagram illustrating a laser light path having a wavelength of 1490 nm traveling through the 45 ° gradient filter.

As shown in FIG. 4, laser light having a wavelength of 1490 nm emitted from the optical fiber passes through the rear slope of the optical fiber side of the gradient filter 250 and then from the front slope of the laser diode chip 100 side of the gradient filter 250. Will be reflected. The laser light of 1490 nm passing through the gradient filter 250 has an angle of 11.7 ° with respect to the repair of the rear inclined surface and is incident on the front inclined surface of the laser diode chip 100 side, so that the laser diode chip 100 side according to the law of reflection. At the front slope, it reflects at an angle of 11.7 ° to the inclination of the slope. The 1490 nm wavelength reflected from the front slope of the laser diode chip 100 and reaching the rear slope of the optical fiber is incident on the vertically downward 1490 nm digital reception photo diode chip 400 to generate a photocurrent signal.

Applicant in the patent application No. 2007-0026558 to form an inclined surface of 45 ° inclined mirror on the flat lower surface of the semiconductor wafer, such as silicon, and present a multilayer dielectric thin film having a different refractive index as a material and structure for forming the reflective surface It was. 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. In addition, the applicant of the Patent Application No. 2007-0120602, the anti-reflective deposition on the upper surface of the patterned silicon wafer to prevent the laser light emitted from the laser diode chip embedded in the module to escape into the air without reflection from the rear of the 45 ° tilt mirror. Explained.

The 45 ° gradient filter 250 applied to the present invention is manufactured through a process similar to the 45 ° slope mirror. Hereinafter, a method of manufacturing the 45 ° slope filter 250 according to the embodiment of the present invention will be described. .

5 is a conceptual diagram illustrating a process of fabricating a 45 ° gradient filter having wavelength selectivity using a semiconductor silicon wafer according to an embodiment of the present invention.

First, the process of causing the (111) surface of the semiconductor silicon wafer to appear as shown in FIG. 5A is described in detail in the above-described patent applications Nos. 2007-0026558 and 2007-0120602, but the present invention will be briefly described. . First, the semiconductor silicon wafer is cut out at an angle of 9.74 ° from the semiconductor silicon ingot to the (001) plane (not shown), and a part of the upper surface of the cut semiconductor silicon wafer is coated with photoresist, and then the photoresist of the portion to be etched. Is removed by the photolithography method, and the semiconductor silicon of the portion where the photoresist is removed is etched using the anisotropic etching solution, and the etch exposed side of the semiconductor silicon wafer becomes the (111) plane. At this time, since the (111) plane has an inclination angle of 54.74 ° with the (001) plane, when the semiconductor silicon wafer is cut out from the ingot with the (001) plane having an inclination angle of 9.74 °, the (111) plane is etched and exposed. The silicon wafer has a horizontal plane and an inclination angle of 45.00 ° and 64.48 °, respectively.

Thereafter, as shown in (b) of FIG. 5, a laser diode chip mounted in the module on the lower surface of the exposed wafer having two (111) planes having an inclination angle of 45.00 ° and 64.48 ° with respect to the bottom surface of the semiconductor silicon wafer. A dielectric thin film having a characteristic of transmitting through 1300 nm, which is a wavelength emitted from (100), and reflecting with respect to 1490 nm, which is a wavelength for a digital signal emitted from an optical fiber, is deposited. The dielectric thin film having the wavelength selectivity may be obtained by alternately depositing materials having different refractive indices, but in general, the dielectric thin film may be formed by alternately depositing TiO2 having a refractive index of about 2.2 to 2.8 and SiO2 having a refractive index of 1.35. Thin films can be deposited. Filters having wavelength selectivity, which are fabricated by alternately depositing heterogeneous materials having different refractive indices on glass substrates, have been widely adopted in bidirectional optical communication modules having an existing structure.

In FIG. 5C, a dielectric thin film is deposited on the upper surface of the silicon wafer, having a characteristic of transmitting a wavelength of 1300 nm and a wavelength of 1490 nm, and reflecting a 1550 nm wavelength for an analog signal emitted from an optical fiber. Such deposition can be obtained by adjusting the thickness of the dielectric layer of TiO 2 / SiO 2 described above. Since the upper surface of the semiconductor silicon wafer is a very smooth surface by polishing, it is very easy to deposit a dielectric thin film on such a surface.

When the semiconductor silicon wafer thus manufactured is cut to an appropriate size as shown in (d) of FIG. 5 and placed so that the etched (111) surface is positioned downward, the laser diode chip embedded in the module as shown in (e) of FIG. 1300 nm laser light emitted from 100) is transmitted, and 1550 nm light for analog signal emitted from the optical fiber is reflected vertically downward from the rear slope, and 1490 nm light for digital signal emitted from the optical fiber passes through the rear slope. After reflecting from the front inclined surface, the 45 ° slope filter 250 which moves vertically downward through the rear inclined surface is completed.

In general, laser light emitted from a semiconductor laser diode chip is emitted with a divergence angle of approximately 30 to 40 degrees in both front and rear directions of the laser diode chip. Coating the dielectric thin film on the front of the laser diode chip can adjust the reflectivity of the front of the diode and thus the intensity of the laser light emitted to the front of the laser diode. In general, the surface where the laser light is strongly emitted is called the front surface, and the surface that is weakly emitted is called the rear surface. The laser light emitted strongly from the front side of the laser diode chip is used for signal transmission, and the laser light emitted from the back side with low intensity is incident on the photodiode for laser diode operation monitoring not shown in the drawing to check whether the laser diode chip is operating. Used to monitor. In general, laser light emitted from a laser diode chip has an angle of divergence of about 30 to 40 ° with a full width at half maximum (FWHM). In the wavelength selective filter, the wavelength selectivity is changed depending on the angle of incidence of the laser light as well as the wavelength of the laser light incident on the filter. In general, it is very easy to separate two wavelengths separated by a distance of several hundred nm or more, such as 1300 nm and 1550 nm, and the wavelength selection can be well performed even if the angle of incidence of the laser light varies considerably. However, when the distance between wavelengths, such as 1490 nm and 1550 nm, is close to several tens of nm, the incident angle of the laser light must be narrow within a number to effectively separate the wavelengths.

6 is a conceptual diagram illustrating a process in which laser light is focused through a lens.

As shown in FIG. 6, in order to optically connect the laser diode chip 100 in the optical module and the optical fiber outside the package, a lens 710 is provided between the laser diode chip 100 and the optical fiber to provide the laser diode chip 100. And laser light emitted from the optical fiber. Generally, in order to optically connect the laser diode chip 100 and the optical fiber, the laser diode chip 100 may be divided into one lens type using one lens 710 and two lens types using two lenses 720 and 730. . In the case of using one lens 710 as shown in FIG. 6A, the laser light emitted from the laser diode chip 100 converges to the optical fiber via the lens 710. The laser light proceeding has a convergence angle corresponding to the magnification of the lens 710. When the optical coupling efficiency between the optical fiber and the laser diode chip 100 is maximum, the laser light emitted from the optical fiber converges through the lens 710 toward the laser diode chip 100, and at this time, the laser diode chip in the lens 710. The convergence angle in the (100) direction is the same as the divergence angle emitted from the laser diode chip 100. In contrast, in the two-lens system, when the light emitted from the laser diode chip 100 is first balanced by one lens 720 and the second lens 730 has a lens that converges to the optical fiber, the two lenses 720 are provided. Between 730 the optical paths are in equilibrium with each other. As described above, since the reflection and transmission characteristics of the wavelength selective filter vary according to the incident angle as well as the wavelength of the laser light, the wavelength selective filter has the same incidence angle for wavelengths that do not have a wide interval between about 1490 nm and 1550 nm. Maximizes.

Accordingly, as shown in FIG. 3, a single lens 700 is provided on the front surface of the laser diode chip 100 to make the laser light emitted from the laser diode chip 100 into a balanced light, which is not shown in the drawing. When the optical coupling occurs to the optical fiber by using a lens, the laser lights have the same propagation angle in the section between the lens shown in the drawing and the lens not shown in the drawing, and the incident angle of the laser light when entering each filter The same will maximize the wavelength selectivity of the filter. As described above, the laser light emitted from the laser diode chip 100 is converted into a balanced light while passing through the lens 700 in front of the laser diode chip 100 and then incident on the digital 45 ° gradient filter 250. do. In the drawing, for the sake of convenience, since the light emitted from the laser diode chip 100 becomes the balanced light by the lens 700, only the balanced light component is simply displayed between the laser diode chip 100 and the lens 700. In the above description, since the front and rear surfaces of the 45 ° gradient filter 250 have anti-reflective characteristics with respect to 1300 nm, laser light incident on the 45 ° gradient filter 250 passes through the gradient filter 250 and then is again inclined filter. It is emitted through the rear inclined surface of (250). The laser light having a wavelength of 1300 nm that escapes the 45 ° gradient filter 250 is focused to the optical fiber outside the package through a lens not shown in the drawing.

On the contrary, 1490 nm and 1550 nm downward laser light emitted from an optical fiber not shown in the figure is converted into a balanced light through a lens not shown in the figure. Since the laser light is a balanced light, each wavelength component is represented by one straight line in the drawing. Laser light of 1550 nm and 1490 nm descending from the optical fiber arrives at the 45 ° gradient filter 250. Since the rear slope of the optical fiber side of the 45 ° slope filter 250 reflects to 1550 nm and the 1490 nm wavelength transmits, the 1550 nm wavelength that reaches the 45 ° slope filter 250 has a traveling path of 90 degrees. The angle is turned to enter the 1550nm analog receiving photodiode chip 500 under the inclination filter 250 to be converted into a current signal. Meanwhile, the 1490 nm wavelength reaching the 45 ° slope filter 250 passes through the rear inclined surface as it is, passes through the interior of the gradient filter 250, and reaches the front slope, and the front slope of the 45 ° slope filter 250. Since the reflection characteristic is about 1490 nm, it is reflected and then proceeds back to the rear inclined plane, and then enters the lower 1490 nm digital reception photodiode chip 400 through the rear inclined plane to be converted into a current signal.

In FIG. 3 and FIG. 4, the propagation angle of the light passing through the 45 ° gradient filter 250 is slightly changed, which is caused by the refractive index of the gradient filter 250 being different from the air. Well organized.

The package module manufactured in the form of FIG. 3 is difficult to use as it is because parts such as the laser diode chip 100 are exposed, and the package housing which protects the components by mounting the entire package of FIG. 3 and makes an electrical connection with an external power source. This is necessary. These package housings include a package housing type where the optical axis of laser light exiting the package, such as minidill, miniflat, butterfly package housing, is horizontal to the package bottom and the package housing such as a TO (transistor outline) package housing. There is a package housing in which the optical axis of the incoming laser light is perpendicular to the bottom of the package.

7 is an example of a butterfly type package housing, and FIG. 8 is an example of a TO type package housing.

As shown in FIG. 7, the butterfly-type or mini-deal type and the mini-flat package housings are formed in the optical axis horizontally with the bottom surface of the package, so that the structure of FIG. It is desirable to.

In contrast, the TO-type package housing of FIG. 8 is a package package having a flat bottom surface of package (a) and a header of protruding vertically from the bottom surface as a header of (b). It can be divided into two package housing types. The package of FIG. 3 may be mounted on the header of the TO-type package housing having a header so that the optical axis direction as shown in FIG. 3 may escape to the outside of the package. Meanwhile, in order to mount the package module of FIG. 3 to the TO-type package housing having a flat bottom as shown in FIG. 8A, the optical axis needs to be bent in the vertical direction.

FIG. 9 is a conceptual view illustrating an example in which a package module is mounted on the TO-type package housing of FIG. 8A.

As shown in FIG. 9, when the package module is mounted in the TO-type package housing, the reflection having reflection characteristics for all wavelengths considered between the 45 ° gradient filter 250 and the optical fiber in order to bend the optical axis vertically. A 45 ° tilt mirror 800 is disposed. The reflective 45 ° inclined mirror 800 should be manufactured to have a high reflectance for all wavelengths of 1300 nm, 1490 nm, and 1550 nm. To this end, Au (gold) and Ag (silver) materials having high reflectance with respect to infrared rays are used. ), The inclined surface may be coated with a metal material such as aluminum (Al), Cu (copper), or may be coated to have a high reflectance for the entire wavelength range considered by using a dielectric film having a relatively high refractive index and a low refractive index.

In FIGS. 3 and 9, the laser light having a wavelength of 1300 nm passing through each of the 45 ° gradient filters 250 proceeds with a downward angle of 33.4 ° with respect to the horizontal plane inside the gradient filter 250 according to Snell's law. . Therefore, since the height of the laser light having a wavelength of 1300 nm decreases when passing through the gradient filter 250, the height of the gradient filter 250 must be increased to maintain an optical axis having a sufficient height even when passing through the gradient filter 250. There is this. If the height of the inclination filter 250 is high, there is a disadvantage in that stable assembly is difficult during assembly. In the present invention, as shown in Figures 3 and 9, by using a step of varying the upper height of the base submount 600, even using a relatively low inclination filter 250 to effectively 1300 It was made to maintain the nm optical axis height.

When the base submount 600 is made of silicon, which is a semiconductor substrate, as the base material, when the step of the silicon surface is manufactured by the semiconductor photolithography method, each step may be very parallel. When the 45 ° gradient filter 250 and the 45 ° gradient mirror 800 for reflection are assembled by engaging the walls of the parallel step, the gradient filter 250 and the gradient mirror 800 can be easily arranged in parallel. . Therefore, forming a step on the upper surface of the base submount 600 not only allows the size of the gradient filter 250 to be reduced, but also makes it possible to easily assemble the gradient filter 250 and the gradient mirror 800 in parallel.

Meanwhile, as the lens 700 illustrated in FIGS. 3 to 9, a transmission laser light having an angular characteristic emitted by using a spherical ball lens, an aspherical lens, a Fresnel lens, and the like, is balanced. It can be implemented to act as a collimating lens.

10 is a perspective view of a base submount in accordance with an embodiment of the present invention.

As shown in FIG. 10, the base submount 600 has two “c” shaped grooves into which one side of the base submount 600 may be inserted, in which the photodiode chips 400 and 500 for digital and analog reception are inserted. The base submount 600 is preferably made of silicon which is inexpensive and can be easily manufactured in a "c" shape by a dry or wet etching process.

A 45 ° gradient filter 250 is installed on the “substrate” submount 600 having a “c” shape. The photodiode chip 400 for digital reception is formed in a “c” shaped groove of the base submount 600. The digital receiving submount 410 and the analog receiving submount 510, each of which has an analog receiving photodiode chip 500 attached thereto, are inserted into and coupled to each other.

In the embodiment of the present invention, the laser light having a wavelength of 1300 nm is typically a strong energy of 0 dBm or more for transmission, whereas the received laser light is typically a very weak signal of -10 dBm or less. Therefore, a part of the laser light having a wavelength of 1300 nm emitted from the embedded laser diode chip 100 may be diffusely reflected inside the module, and the diffusely reflected light is received by the photodiode chip 400 and 500 for digital and analog reception. Can be.

11 is a layout view of a receiving photodiode chip for preventing such diffusely reflected light from being received by the receiving photodiode chip.

In general, digital and analog photodiode chips 400 and 500 for detecting near infrared wavelength bands of 1490 nm and 1550 nm wavelengths use InGaAs lattice matched to InP as a light absorption layer on InP substrates 401 and 501. do. If a p-n junction is formed on a part of the InGaAs layer, only this p-n junction region serves as an effective light absorption layer. InGaAs layers without p-n junctions do not generate electrical signals when they absorb light. Accordingly, the active regions 402 and 502 of the receiving photodiode chips 400 and 500 become partial regions of the InGaAs light absorbing layer capable of absorbing light to generate an electrical signal. The bandgap energy of InGaAs lattice matched to InP is 0.75 eV and absorbs light having a wavelength of 1300 nm to 1550 nm. In contrast, the InP substrates 401 and 501 do not absorb light having a wavelength of 1300 nm to 1550 nm with an energy band gap of approximately 1.35 eV. Therefore, the active regions 402 and 502 of the receiving photodiode chips 400 and 500 are directed toward the bottom of the package, and the anode and cathode electrodes of the receiving photodiode chips 400 and 500 are the receiving photodiode chips. Receiving photodiode substrate surface to be electrically connected in a flip chip bonding method through the sub-mount 410, 510 and the metal balls 406, 506 located below the (400) (500) 403 and 503 react only with laser light of the required wavelength when the dielectric thin films 404 and 504 are transmitted so as to transmit only a specific wavelength band to be detected. The active thin films 402 and 502 of the photodiode chips 400 and 500 for receiving are disposed in an upward direction, and a dielectric thin film (or thin film) may transmit only a specific wavelength band to be detected above the active regions 402 and 502. The conventional method of metal ball wire bonding after the deposition of 404 and 504 may also be employed.

The substrate surface 503 of the analog receiving photodiode chip 500 manufactured as described above has a characteristic of transmitting 1550 nm wavelength through the dielectric thin film 504 and reflecting 1490 nm and 1300 nm wavelengths. In addition, the substrate surface 403 of the digital receiving photodiode chip 400 transmits 1490 nm wavelength through the dielectric thin film 403 and reflects 1550 nm and 1300 nm wavelengths.

In general, the active regions 402 and 502 of the photodiode chips 400 and 500 may display the active region through surface step etching or coating in the form of a metal ring for indicating the active region. It is common not to mark anything at (503). However, the substrate surface 403 of the photodiode chips 400 and 500 when optically aligning the photodiode chips 400 and 500 and the submount 410 and 510 blocks bonded using the flip chip bonding method. If the active layer region is not displayed at 503, light alignment is difficult. This can be prevented by depositing a metal thin film on the substrate surfaces 403 and 503 of the photodiodes 400 and 500 except for the same position as the active region. As shown in FIG. 11, the substrate surfaces 403 and 503 are deposited on the metal thin films 405 and 505, but the metal thin film is not deposited on the opposite side of the active regions 402 and 502. Due to the difference in reflectance between the 405 and 505 and the substrate surfaces 403 and 503, the active area position can be easily identified, thus making it easier to align the receiving photodiode chips 400 and 500. In addition, since the received light has a vertical downward component and is incident on the openings of the metal thin films 405 and 505 in the active region, the received light is easily directed to the active regions 402 and 502 of the photodiode chips 400 and 500. You will join. Since the laser light emitted from the laser diode chip 100 is diffusely reflected inside the module has various paths and angles, the diffuse reflection enters the metal thin films 405 and 505 of the photodiode chip substrate surface 403 and 503. Since the laser light does not enter the photodiode chips 400 and 500 and is reflected, the laser light mounted in the module is directly incident to the photodiode chip 400 and 500 for receiving, thereby reducing signal leakage. . The metal thin film material for coating the substrate surfaces 403 and 503 of the photodiode chips 400 and 500 may be titanium, platinum, gold, silver, aluminum, copper, or the like. Combinations also become possible metal thin films.

Meanwhile, as described above with reference to FIG. 6, light incident to the receiving photodiode chips 400 and 500 may be parallel light and thus may not be effectively focused on the light absorption region. This problem can be eliminated by attaching lenses 406 and 506 on the light absorbing regions of the substrate surfaces 403 and 503 of the photodiode chips 400 and 500, which are photodiode chips 400 and 500. A hemispherical lens is suitable when considering the bonding with the lens.

In FIGS. 3 to 10, the 1550 nm analog receiving photodiode chip 500 and the 1490 nm digital receiving photodiode chip 400 are separately manufactured, which may be manufactured as a single chip.

12 is a conceptual diagram illustrating a diode chip structure in which a 1490 nm photodiode chip and a 1550 nm photodiode chip are integrated into one photodiode chip according to an embodiment of the present invention.

In general, a photodiode chip in the near infrared region grows an InGaAs light absorbing layer on an n-InP substrate, grows a p-InP layer thereon, and installs metal pads for electrical contact in the p and n layers to complete the device. In this case, as shown in FIG. 17, when the p-InP layer and the InGaAs layer are etched to separate the light absorbing layer into two, each p-n junction structure becomes the same photodiode chip. Since the InGaAs light absorbing layer absorbs light within the wavelength range of 1000 nm to 1670 nm, both p-n photodiode chips 400 and 500 are in a state capable of absorbing 1490 nm and 1550 nm. In this case, if a transmission / reflection filter for selecting a wavelength for each photodiode chip is installed on the n-InP substrate, two photodiode chips 400 and 500 are independent photodiode chips that respond to 1490 nm and 1550 nm, respectively. Becomes The wavelength selective transmission / reflection filter installed on the n-InP substrate surface may be integrally coated on the n-InP substrate or coated on a glass substrate, and then attached to the bottom of the photodiode chip 400, 500.

The triplex optical module package for bidirectional communication of the present invention has been described for the convenience of description including laser diode chip 100, analog and digital photodiode chip 400, 500, which are main active components, but in addition, laser diode chip 100 A preamplifier such as a supervisory photodiode chip for monitoring the operation state of the electronic device and a trans impedance amplifier (TIA) for amplifying the photocurrent received from the digital receiver photodiode chip 400, and the corresponding capacitors are packaged. Can be added within. In addition, since the laser diode chip 100 is very sensitive to temperature, the laser diode chip 100 may include a thermo electric cooler to adjust the temperature of the laser diode chip 100.

1 is a conceptual diagram showing the structure of a conventional general triplexer module;

2 is a conceptual diagram of a triplexer module using a conventional PLC technique;

3 is an overall structural diagram of an optical module package for bidirectional communication according to the present invention;

4 is a conceptual diagram showing the laser light path characteristics of the wavelength 1490nm passing through the gradient filter in accordance with the present invention,

5 is a conceptual diagram illustrating a process of fabricating a 45 ° gradient filter having wavelength selectivity using a semiconductor silicon wafer according to the present invention;

6 is a conceptual diagram illustrating a process in which laser light is focused through a lens;

7 is an example of a butterfly type package housing,

8 is an example of a TO-type package housing,

9 is a conceptual diagram illustrating an example in which a package module is mounted on a TO-type package housing according to the present invention;

10 is a perspective view of a base submount in accordance with the present invention;

11 is a layout view of a receiving photodiode chip for preventing diffusely reflected light from being received by the receiving photodiode chip according to the present invention;

12 is a conceptual diagram illustrating a diode chip structure in which a 1490 nm photodiode and a 1550 nm photodiode are integrated in one photodiode chip according to the present invention.

※ Explanation of codes for main parts of drawing

100: laser diode chip

110: submount for laser diode

250: 45 ° sloped beam splitter / filter

400: Photodiode chip for digital reception

410: submount for digital reception

500: photodiode chip for analog reception

510: submount for analog reception

600: base submount

700: Lens

800: 45 ° mirror for reflection

Claims (16)

There is an optical module package for triplexer bidirectional communication in which a laser diode chip, a 45 ° incline beam splitter / filter and a receiving photodiode chip are housed in one package housing. The front inclined plane of the 45 ° inclined beam splitter / filter 250 transmits the laser light of the wavelength emitted from the laser diode chip 100 and reflects the laser light of the wavelength for the digital signal incident from an external optical fiber, and the rear inclined plane is The laser light of the wavelength emitted from the laser diode chip 100 and the laser light of the wavelength for the digital signal incident from the optical fiber are transmitted, and the laser light of the wavelength for the analog signal incident from the optical fiber is coated with a reflective metal material or a dielectric thin film. Become, A digital receiving photodiode chip 400 for receiving laser light of a wavelength for digital signals and an analog receiving photodiode for receiving laser light of an analog signal wavelength are disposed below the rear slope of the 45 ° inclined beam splitter / filter 250. Triplexer optical module package, characterized in that the chip 500 is disposed. The method according to claim 1, The 45 ° tilt beam splitter / filter 250, the base material of the triplex optical module package for bidirectional communication, characterized in that the silicon or glass. The method according to claim 1, The triplex optical module package for bidirectional communication Triplex optical module package for bidirectional communication, characterized in that the lens 700 for installing the laser light emitted from the laser diode chip 100 to parallel light is installed. The method according to claim 1, The back sloped side of the 45 ° sloped beam splitter / filter 250 reflects the laser light emitted from the laser diode chip 100 and transmitted through the 45 ° sloped beam splitter / filter 250 to the upper side, or from the optical fiber of the upper side. A triplex optical module package for bidirectional communication, characterized in that a reflective 45 ° inclined mirror 800 is installed to reflect the incident laser light to the rear inclined plane of the 45 ° inclined beam splitter / filter 250. The method according to claim 1, The laser diode chip 100 is fixedly installed on the laser diode submount 110, and the laser diode submount 110 and the 45 ° inclined beam splitter / filter 250 are on the base submount 600. It is fixed to the 45 ° bevel beam splitter / filter 250, the digital diode photodiode chip 400 and the analog diode photodiode chip 500 for the two-way communication is characterized in that the optical module is installed. package. The method according to claim 5, Steps are formed in the base submount 600 so as to have different heights, and the laser diode submount 110 and the 45 ° inclined beam splitter / filter 250 are respectively disposed on the base submount 600 having the step formed thereon. Triplex optical module package for bidirectional communication, characterized in that is installed. The method according to claim 5, The base submount 600 is a bi-directional communication, characterized in that the groove formed in the "c" shape that can accommodate the digital receiving photodiode chip 400 and the analog receiving photodiode chip 500 inside, respectively. Triplexer optical module package. The method according to claim 1, The photodiode chip 400 for digital reception and the photodiode chip 500 for analog reception are disposed such that the photoactive regions 402 and 502 face the bottom. A dielectric thin film 404 is deposited on the upper substrate surface 403 of the digital reception photodiode chip 400 to reflect laser light having a wavelength of 1300 nm and 1550 nm and transmit laser light having a wavelength of 1490 nm. A dielectric thin film 504 is deposited on the upper substrate surface 503 of the analog photodiode chip 500 so that laser light having a wavelength of 1300 nm and 1490 nm is reflected and laser light having a wavelength of 1550 nm is transmitted. Triplexer optical module package for bidirectional communication. The method according to claim 8, The digital receiving photodiode chip 400 and the analog receiving photodiode chip 500 may be coupled to each other through flip chip bonding on the digital receiving submount 410 and the analog receiving submount 510. Triplexer optical module package for bidirectional communication. The method according to claim 8, Lenses 406 and 506 are provided on the substrate surfaces 403 and 503 of the digital receiving photodiode chip 400 and the analog receiving photodiode chip 500 to focus the received laser light. Triplexer optical module package for bidirectional communication. The method according to claim 1, The digital receiving photodiode chip 400 and the analog receiving photodiode chip 500 have two active regions respectively corresponding to the wavelengths of the laser light for the digital signal and the wavelength of the laser signal for the analog signal. Triplexer optical module package for bidirectional communication, characterized in that the production. The method according to claim 11, A dielectric thin film is deposited on the back of the digital reception photodiode chip 400 so that laser light of 1300 nm and 1550 nm wavelengths is reflected and laser light of 1490 nm wavelength is transmitted. The rear surface of the analog receiving photodiode chip 500 is a laser diode of 1300nm and 1490nm wavelength is reflected and the dielectric thin film is deposited to transmit the laser light of 1550nm wavelength triplexer optical module package, characterized in that . The method according to claim 11, On the back of the digital receiving photodiode chip 400 is provided a glass or silicon substrate on which a dielectric thin film is deposited, which reflects laser light of 1300 nm and 1550 nm wavelength and transmits laser light of 1490 nm wavelength. The rear surface of the analog receiving photodiode chip 500 is provided with a glass or silicon substrate on which a dielectric thin film is deposited, which reflects laser light of 1300 nm and 1490 nm wavelength and transmits laser light of 1550 nm wavelength. Triplexer optical module package for bidirectional communication. A method of making the 45 ° sloped beam splitter / filter 250 of claim 1, (a) slicing the semiconductor wafer from the semiconductor ingot and coating it with a photoresist to form a 45 ° inclined surface ((111) surface) by a wet etching method; (b) forming a coating layer by depositing a dielectric thin film having wavelength selective transmission reflection on a lower surface of the semiconductor wafer not including the 45 ° inclined surface (111) surface; (c) forming a coating layer by depositing a dielectric thin film having wavelength selective transmission reflection on an upper surface of the semiconductor wafer including the 45 ° inclined surface (111) surface; (d) cutting the semiconductor wafer coated with the dielectric thin film and completing the 45 ° inclined beam splitter / filter (250). The method according to claim 14, A lower surface of the semiconductor wafer transmits laser light having a wavelength of 1300 nm and reflects laser light having a wavelength of 1490 nm. The top surface is coated to transmit the laser light of 1300nm and 1490nm wavelength and to reflect the laser light of 1550nm wavelength, the manufacturing method of the beam splitter / filter. The method according to claim 14 or 15, And the dielectric thin film is formed by alternately depositing dielectric thin films having different refractive indices.

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