KR20030050851A - Optical communication device, method for manufacturing the same and module of the optical communication device - Google Patents

Abstract

PURPOSE: An optical communication device, a method for manufacturing the same and a module for the same are provided to reduce the manufacturing cost by simplifying the structure thereof, to maintain the optical intensity distribution uniformly, to have an excellent polarization characteristics and to reduce the optical loss. CONSTITUTION: An optical communication device includes an N-contact layer(51) formed on the top of the compound semiconductor substrate(50), an N-wave guide layer(52) formed on the top of the N-contact layer(51), an activation layer(53) for emitting the light by forming on the top of the N-wave guide layer(52), a P-wave guide layer(54) formed on the top of the activation layer(53), a P-contact layer(55) formed on the top of the P-wave guide layer(55), a P-metal layer formed on the top of the P-contact layer(55) and an N-metal layer(60) formed on the bottom of the compound semiconductor substrate(50).

Description

Optical communication device, method for manufacturing the same and module thereof

The present invention relates to an optical communication device, a manufacturing method, and a module thereof, and more particularly, to simplify the structure, to lower the manufacturing cost, to reduce light loss, to have excellent polarization, and to maintain a constant light quantity distribution. The present invention relates to an optical communication device, a manufacturing method, and a module thereof, which can facilitate fiber coupling, and at the same time realize light weight, short weight, and low cost.

In general, an optical communication network for optical communication may be classified into a transmitter, an optical transmission line, and a receiver.

The transmitting end generates a desired optical signal and transmits it to the optical transmission line, and the transmission line performs a function of transmitting to the receiving end while suppressing occurrence of loss, distortion and crosstalk of the optical signal transmitted from the transmitting end.

The receiving end performs a function of receiving the optical signal transmitted from the transmitting end through the transmission line and restoring the original optical signal.

The light source generating the optical signal transmitted from the transmitter is the most important element for optical communication.

Conventional light sources mainly used LD (Laser diode) and LED (Light emitting diode) which can emit light in the wavelength range of 1.55㎛, 1.3㎛, 850nm and 650nm depending on the transmission distance and transmission speed.

For long-distance high speed transmission, glass fiber used 1.55㎛ and 1.3㎛ light sources. For short distance low speed transmission, 850nm and 650nm wavelength light sources using plastic fiber were used. It was.

Recently, in short-range communication, a semiconductor vertical cavity surface emitting laser (hereinafter referred to as 'VCSEL') has been applied.

FIG. 1 is a diagram illustrating a VCSEL structure used in conventional short-range communication, and includes a distributed Bragg reflector in which a plurality of pairs of semiconductor layers are stacked on top of a compound semiconductor substrate 20 such as GaAs, GaInAs, InP, and InGaPAs. A lower mirror stack 18 having a distributed bragg reflector (hereinafter referred to as 'DBR') structure is formed, and an N-GaAs layer 17 and a P-GaAs layer 15 are formed on the lower mirror stack 18. The stack is stacked to form an active layer 16 between the N-GaAs layer 17 and the P-GaAs layer 15, and an upper mirror stack having a distributed Bragg reflector structure on the P-GaAs layer 15 ( 10) is formed.

In the VCSEL structure configured as described above, the laser light generated from the active layer 16 is emitted in the vertical direction of the compound semiconductor through the upper mirror stack 10.

The VCSEL structure is easy to assemble and is driven at low power, has a relatively low temperature sensitivity, and can implement a DBR structure by thinning the AlAs and GaAs layers, but is used as a light source in the 850 nm wavelength range, but is used in the 650 nm wavelength range. In this case, there is no material having a large difference in refractive index, and it is difficult to form a DBR structure and thus it is not used as a light source of 650 nm.

On the other hand, in order to emit light of the 650nm wavelength, a laser diode (LD) may be used, but the laser diode requires a lot of manufacturing cost.

In particular, the laser diode has a low coupling yield due to serious coupling problems with the optical fiber, and thus is only used as a light source in the 850 nm wavelength band.

In such a light source for short-range low-speed transmission, using a light source of 850nm wavelength band has a large light loss in plastic fibers, and when using a light source of 650nm wavelength band, manufacturing cost is high and performance is problematic.

Accordingly, the present invention has been made to solve the problems described above, and an object thereof is to provide an optical communication device that can reduce the manufacturing cost by simplifying the structure.

Another object of the present invention is to provide a method for manufacturing an optical communication device which reduces the light loss generated by using plastic fibers, is excellent in polarization and has a constant light amount distribution.

Another object of the present invention is to form a cut surface formed by removing a portion of the upper surface of the silicon optical bench (Si Optical Bench, SiOB), the groove is formed on the cut surface, the upper surface of the silicon optical bench adjacent to the groove An optical communication device is mounted on the optical fiber, and an optical fiber is inserted into the groove to align the optical communication device with the optical fiber, thereby providing a module of the optical communication device that can be easily coupled with the fiber and can be reduced in size and cost.

A preferred aspect for achieving the above object of the present invention is an N-contact layer formed on the compound semiconductor substrate;

An N-wave guide layer formed on the N-contact layer;

An active layer formed on the N-wave guide layer and emitting light;

A P-wave guide layer formed on the active layer;

A P-contact layer formed on the P-wave guide layer;

A P-metal layer formed on the P-contact layer;

There is provided an optical communication device comprising an N-metal layer formed under the compound semiconductor substrate.

According to another aspect of the present invention, there is provided a N-contact layer, an N-wave guide layer, an active layer, a P-wave guide layer, and a P-contact layer formed on an upper surface of a compound semiconductor substrate. Sequentially stacking;

A P-metal layer is formed on the upper portion of the P-contact layer, and an N-metal layer is formed on the lower portion of the compound semiconductor substrate.

According to another aspect of the present invention, there is provided a preferred embodiment comprising: an optical bench having a cut surface formed by removing a portion of an upper surface thereof;

Grooves on the cut surface;

An optical fiber inserted into the groove;

A module of an optical communication device is provided, comprising an optical communication device formed in alignment with the optical fiber on an upper surface of an optical bench neighboring the groove.

1 is a diagram illustrating a VCSEL structure used in conventional short-range communication.

2A and 2B are flowcharts of a manufacturing process of an optical communication device according to the present invention.

3A and 3B are views illustrating a state in which light is emitted by varying the size of forming the P-metal layer according to the first embodiment of the present invention.

4 is a perspective view showing a state in which light is emitted only to one side of the optical communication device according to the second embodiment of the present invention.

5 is a diagram illustrating a state in which an optical communication device according to the present invention is packaged in a module.

<Description of the symbols for the main parts of the drawings>

50 compound semiconductor substrate 51 N-contact layer

52: N-wave guide layer 53: active layer

54: P-wave guide layer 55: P-contact layer

60: N-metal layer 61: P-metal layer

100: silicon optical bench 110: step surface

120: groove 200: optical communication element

300: optical fiber

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

Figure 2a and 2b is a manufacturing process flow chart of the optical communication device according to the present invention, the metal organic chemical vapor deposition (MOCVD) process, the molecular beam epitaxy (MBE, Molecular) on the compound semiconductor substrate 50 The N-contact layer 51 is formed using any one of a beam epitaxy (LPE) process and a liquid phase epitaxy (LPE) process (FIG. 2A), and is formed on top of the N-contact layer 51. The N-wave guide layer 52, the active layer 53, the P-wave guide layer 54 and the P-contact layer 55 are sequentially formed (FIG. 2B).

Here, the compound semiconductor substrate 50 may be manufactured by applying any one compound semiconductor selected from GaAs, GaInAs, InP, and InGaPAs to manufacture an optical communication device, and most preferably, apply a GaAs compound semiconductor.

In addition, the N-wave guide layer 52 and the P-wave guide layer 54 may be formed of AlGaInP.

In particular, the N-wave guide layer 52 and the P-wave guide layer 54 may be formed of a material having a larger energy band gap than the material of the active layer 53.

The active layer 53 is preferably AlGaInP or GaInP, and the N-contact layer 51 and the P-contact layer 55 are preferably formed of the same compound semiconductor as the substrate.

3A and 3B are diagrams illustrating a state in which light is emitted by varying a size of forming a P-metal layer according to a first embodiment of the present invention. An N-contact layer 51 formed on the semiconductor substrate 50; An N-wave guide layer 52 formed on the N-contact layer 51; An active layer 53 formed on the N-wave guide layer 52 and emitting light; A P-wave guide layer 54 formed on the active layer 53; A stack structure formed of a P-contact layer 55 formed on the P-wave guide layer 54 is formed, and a P-metal layer 61 is formed on the P-contact layer 55. When the N-metal layer 60 is formed below the compound semiconductor substrate 50 (FIG. 3A), the light generated in the active layer 53 is emitted to the side of the optical communication device having a square pillar shape.

Such an optical communication device of the present invention is implemented in the form of LED, has the advantage of excellent polarization of light, constant light distribution.

As shown in FIG. 3B, when the P-metal layer 61 is formed only on the upper portion of the P-contact layer, light generated in the active layer 53 is emitted to the upper surface as well as the side of the optical communication device. .

4 is a perspective view illustrating a state in which light is emitted only to one side of an optical communication device according to a second exemplary embodiment of the present invention, in which light is emitted to one side of the optical communication device manufactured and cut at the wafer level. Doing.

Here, in order to implement an edge emitted LED emitting light only to one side of the optical communication device, at least 95% of high-reflection mirror facet coating on the side where no light is emitted. When the HR coating reflecting film 70 is formed by performing a 'HR coating', the light is emitted only to the side where the active layer is exposed, as shown in FIG. 4.

In order to protect the light emitting surface, an anti-reflection mirror facet coating (hereinafter referred to as an AR coating) of 10% or less may be selectively performed on the light emitting surface to form an AR coated antireflective film. You may.

Here, the HR coating reflective film 70 is formed of an insulator such as a silicon nitride film (SiN) or a titanium oxide film (TiO ₂ ), and the AR coating non-reflective film is a silicon oxide film (SiO ₂ ).

5 is a view showing a state of packaging an optical communication device according to the present invention, a portion of the upper surface 105 of the silicon optical bench (Si Optical Bench, SiOB) 100 is removed to form a cut surface 110, A groove 120 is formed on the cut surface 110, and the upper surface 105 of the silicon optical bench 100 adjacent to the groove 120 has the side emission type light emitting diode described above in the second embodiment of the present invention. An optical communication device 200 of the type (Edge emitted LED) is mounted.

Then, the optical fiber 300 is inserted into the groove 120, and the optical communication device 200 and the optical fiber 300 are aligned for optical transmission, thereby facilitating optical fiber coupling, and at the same time, reducing the size and cost of the optical fiber. The module of the optical communication element which can be harmonized can be manufactured.

Here, the silicon optical bench 100 may also apply an optical bench made of GaAs or InP.

As described in detail above, the optical communication device of the present invention can simplify the manufacturing cost, reduce light loss, have excellent polarization, and maintain a constant amount of light distribution. At the same time, the fiber coupling can be easily reduced in thickness and cost.

Although the invention has been described in detail only with respect to specific examples, it will be apparent to those skilled in the art that various modifications and variations are possible within the spirit of the invention, and such modifications and variations belong to the appended claims.

Claims (15)

An N-contact layer formed on the compound semiconductor substrate; An N-wave guide layer formed on the N-contact layer; An active layer formed on the N-wave guide layer and emitting light; A P-wave guide layer formed on the active layer; A P-contact layer formed on the P-wave guide layer; A P-metal layer formed on the P-contact layer; Optical communication device, characterized in that consisting of the N-metal layer formed on the lower portion of the compound semiconductor substrate. The method of claim 1, And the P-metal layer is formed on a portion of an upper portion of the P-contact layer. The method of claim 1, The N-contact layer and the P-contact layer is an optical communication device, characterized in that the same compound semiconductor as the substrate. The method of claim 1, And the N-wave guide layer and the P-wave guide layer are compound semiconductors of AlGaInP. The method of claim 1, And the N-wave guide layer and the P-wave guide layer are formed of a material having a larger energy band gap than the material of the active layer. The method of claim 1, The active layer is an optical communication device, characterized in that AlGaInP or GaInP. The method according to claim 1 or 3, The compound semiconductor is an optical communication device, characterized in that any one selected from GaAs, GaInAs, InP and InGaPAs. A GaAs N-contact layer formed on the GaAs substrate having a rectangular pillar shape; An AlGaInP N-wave guide layer formed on the N-contact layer; An AlGaInP active layer formed on top of the N-wave guide layer and having an energy band gap larger than that of the N-wave guide layer emitting light; An AlGaInP P-wave guide layer formed on the active layer; A GaAs P-contact layer formed on the P-wave guide layer; A P-metal layer formed on the P-contact layer; N-metal layer formed on the lower portion of the GaAs substrate, In order to emit light only to the side of the element of the square pillar, except for one side, HR coating reflective film is coated on the other side except for one side. The method of claim 8, The active layer is an optical communication device, characterized in that made of a material having a larger energy band gap than the material of the N-wave guide layer and the P-wave guide layer. The method of claim 8, The active layer is an optical communication device, characterized in that AlGaInP or GaInP. The method of claim 8, Optical communication device, characterized in that the AR coating non-reflective film is coated on the side of the optical communication device is not coated with the HR coating reflective film. Sequentially stacking an N-contact layer, an N-wave guide layer, an active layer, a P-wave guide layer, and a P-contact layer formed on the compound semiconductor substrate; Forming a P-metal layer on an upper portion of the P-contact layer and an N-metal layer on a lower portion of the compound semiconductor substrate. The method of claim 12, The compound semiconductor is any one selected from GaAs, GaInAs, InP, and InGaPAs; The N-wave guide layer and the P-wave guide layer are AlGaInP compound semiconductors; The active layer is AlGaInP or GaInP; The N-contact layer and the P-contact layer is a manufacturing method of the optical communication device, characterized in that the same material as the compound semiconductor. An optical bench having a cut surface formed by removing a portion of the upper surface; Grooves on the cut surface; An optical fiber inserted into the groove; And an optical communication element formed in alignment with the optical fiber on an upper surface of the optical bench neighboring the groove. The method of claim 14, The optical bench module of the optical communication device, characterized in that made of any one material selected from Si, GaAs and InP.