WO2014163449A1 - Wavelength-tunable laser - Google Patents

Abstract

The present invention relates to a wavelength-tunable laser, which can tune an oscillating laser wavelength and can be manufactured in a small size, comprising: a laser diode chip (100) for emitting a laser beam; a partial reflection mirror (500) for optical feedback, which partially reflects the beam emitted from the laser diode chip (100) so as to enable the reflected beam to be fed back to the laser diode chip (100); a collimation lens (200) provided on an optical path between the laser diode chip (100) and the partial reflection mirror (500) for optical feedback so as to collimate the beam emitted from the laser diode chip (100); a wavelength-tunable selective filter (300) for converting the wavelength transmitted according to the temperature; a phase compensator (350) of which a refractive index is changed according to the temperature and which offsets a change in the refractive index according to the temperature of the semiconductor laser diode chip (100) or the wavelength-tunable selective filter (300); and a 45 degree reflection mirror (400) for switching the direction of the laser beam from the laser beam traveling in the horizontal direction with respect to a bottom surface of a package, to the laser beam traveling in the vertical direction with respect to the bottom surface of the package, wherein the laser diode chip (100), the wavelength-tunable selective filter (300), and the phase compensator (350) are disposed at an upper part of a thermoelectric element (900) so as to change the wavelength oscillating according to a change in the temperature of the thermoelectric element (900).

Description

Tunable laser device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser device, and more particularly, to a tunable laser device that can be manufactured in a small size capable of varying a laser wavelength to oscillate.

Recently, communication services with a large communication capacity, including video services such as smartphones, have been released. Accordingly, there is a need to greatly increase the conventional communication capacity, and has adopted a DWDM (Dense Wavelength Division Multiplexing) communication method as a method of increasing communication capacity by using an optical fiber that is already conventionally installed. In the DWDM communication method, laser light having different wavelengths does not interfere with each other, and thus, even when light signals of different wavelengths are transmitted through one optical fiber at the same time, there is no interference between signals. It refers to the method of transmitting at the same time.

Currently, NG-PON2 (Next Generation-Passive Optical Network version 2) standard is globally agreed, and this NG-PON2 standard is a standard of optical communication module to be installed in subscribers and can accommodate 4 channels of 100GHz frequency interval. Variable laser is adopted. The subscriber optical module of NG-PON2 has a transceiver module called Small Form Factor Pluggable (SFP) as a standard. The SFP module package is small in volume, and the size of the 4channel tunable laser module must be miniaturized.

There are many different wavelength tunable lasers currently being developed and marketed, but in most cases they have a very bulky optical device in the form of a butterfly packet, which makes it impossible to embed this large volume into an SFP transceiver module. An optical device package having a size that can be embedded in an SFP transceiver is a TO (transistor outline) type package. Currently, there is no proposal for a wavelength variable TO optical device having a variable wavelength in the TO type.

[Preceding technical literature]

[Patent Documents]

(Patent Document 1) Republic of Korea Patent Publication No. 10-1124171 (2012.02.29)

The present invention has been proposed in order to solve the problems of the prior art, and an object of the present invention is to provide a tunable extended resonator laser device that can be manufactured in the form of a small (TO) transistor (Transistor Outline) package with a low manufacturing cost. .

In particular, the present invention uses a low-cost TO-type package, but the size of the TO-type package can be manufactured in a smaller size than the conventional butterfly-type package through the arrangement of the laser diode package to be mounted on the conventional SFP transceiver case It is an object of the present invention to provide a tunable laser device that can be manufactured as.

Laser device according to the present invention for achieving the above object is a laser diode chip for emitting a laser light; A partial reflection mirror for light feedback reflecting part of the light emitted from the laser diode chip and returning it back to the laser diode chip; A collimating lens disposed on an optical path between the laser diode chip and the partial reflecting mirror for optical feedback, the collimating lens for collimating light emitted from the laser diode chip, a tunable variable filter whose wavelength is transmitted according to temperature; Refractive index changes with temperature to compensate for the change in refractive index according to the temperature of the semiconductor laser diode chip or the tunable selective filter, and the laser light traveling horizontally with respect to the package bottom surface perpendicular to the package bottom surface. 45 degree reflective mirror for changing the direction of the laser light to proceed; and the laser diode chip, the tunable selective filter and the phase compensation are disposed on the thermoelectric element is a wavelength that is oscillated in accordance with the temperature change of the thermoelectric element Will change.

In addition, the light reflecting partial reflection mirror is preferably arranged on top of the 45 degree reflection mirror.

On the other hand, the 45-degree reflection mirror is made of a partial reflection mirror having a partial reflection / partial transmission characteristics, and one side of the 45-degree reflection mirror is emitted from the laser diode chip to transmit the laser light of the component that transmits the 45 degree reflection mirror A photodiode for monitoring light is further arranged to receive and monitor the light intensity of the laser light.

In addition, the 45-degree reflection mirror is made of a partial reflection mirror having a partial reflection / partial transmission characteristics, one side of the 45-degree reflection mirror is emitted from the partial reflection mirror for the light feedback to transmit the 45 degree reflection mirror The light monitoring photodiode receiving the laser light and monitoring the light intensity of the laser light may be further disposed.

In addition, the 45-degree reflection mirror is made of a partial reflection mirror having a partial reflection / partial transmission characteristics, the light path of the component emitted from the laser diode chip on one side of the 45-degree reflection mirror and transmitted through the 45 degree reflection mirror A wavelength filter and a photodiode, the transmittance of which is changed according to the wavelength, are disposed on the upper surface of the 45-degree reflective mirror, and a photodiode is disposed on the optical path that is emitted from the partial reflection mirror for light feedback and passes through the 45-degree reflective mirror. It is arranged, it is possible to determine the transmittance of the wavelength filter and the wavelength of the laser light through the comparison of the light current flowing through the photodiode.

Meanwhile, the tunable selective filter is manufactured to transmit light having a specific wavelength using a Ga (x1) Al (1-x1) As / Ga (x2) Al (1-x2) As compound semiconductor on a GaAs substrate. The composition is preferably between 1 and 0.1. The wavelength tunable selective filter may be fabricated by alternately depositing amorphous silicon (a-Si) and SiN (silicon nitride) layers on a transparent substrate.

Further, the tunable selective filter is composed of an etalon filter having a plurality of transmission wavelength bands, and the optical feedback partial reflecting mirror has a predetermined reflectance in the wavelength band to be oscillated and reflectance in the other wavelength bands. Silver may be formed to 80% or less, preferably 25% or less, compared to the reflectance of the oscillating wavelength band. Here, the variable wavelength selective filter is preferably a reflective film is formed by alternately depositing dielectric thin films having different refractive indices on both surfaces of a semiconductor substrate including any one of silicon, GaAs, and InP to have a plurality of transmission wavelength bands.

In addition, the phase compensation box is preferably manufactured based on a polymer material containing any one of PMMA, polyvinyl, polyethylene, polycarbonate, epoxy.

It is preferable that the length of the laser resonator including the semiconductor laser diode chip and the light reflecting partial reflection mirror is 5.8 mm to 6.2 mm when converted into an effective refractive index 1.

Meanwhile, the stand for fixing the flat reflective mirror to 45 degrees with respect to the horizontal is formed of a silicon substrate in the form of a rectangular parallelepiped, and the silicon substrate has a through hole having an angle of 45 degrees with respect to one side to form a flat reflective mirror. It is configured to be inserted and fixed, the through hole formed in the silicon substrate is preferably formed by a dry etching method.

The tunable selective filter is fabricated by alternately depositing GaAs / GaAlAs layers on a GaAs semiconductor substrate. The temperature dependence of the transmission wavelength of the tunable selective filter is approximately 90 pm / ° C. The laser proposed in the present invention is determined in a Fabry-Perot mode in which the oscillation wavelength is determined by a resonator composed of a semiconductor laser diode chip and a partial reflection mirror within a wavelength range passing through such a tunable selective filter. In the present invention, since the variable wavelength selective filter and the phase compensation based on the semiconductor laser diode chip and GaAs are disposed on the thermoelectric element, the semiconductor laser diode chip, the tunable selective filter and the phase compensation are arranged in the resonator by changing the temperature of the thermoelectric element. The temperature of the ruler will change. The tunable selective filter composed of a semiconductor laser diode chip and a GaAs-based semiconductor material exhibits a refractive index change of + that increases with increasing temperature, and a phase compensation exhibits a refractive index change of-with increasing temperature. Therefore, the semiconductor laser diode chip, the tunable selective filter, and the phase compensator are disposed on one thermoelectric element, and thus all experience the same temperature change. When the polymer material having a thickness capable of offsetting the refractive index change of the semiconductor laser diode chip and the tunable wavelength selective filter is placed in the laser resonator, the total effective refractive index change of the laser resonator is eliminated even if the thermoelectric element changes in temperature. The Fabry-Perot mode determined by the laser resonator is fixed at a constant wavelength regardless of the temperature of the thermoelectric element. When the temperature of the thermoelectric element is changed, the wavelength selected by the tunable selective filter is changed, and thus the laser oscillation wavelength oscillated by the laser resonator is changed, thereby making it possible to make the tunable laser cheaply and simply.

In addition, in the present invention, a resonator composed of a laser diode chip and a feedback reflecting mirror is manufactured in a fold type, and a feedback partial reflecting mirror is disposed above the 45 degree reflecting mirror so that the laser light emitted horizontally from the laser diode chip is vertical. Since the direction is changed, the light path is adjusted to be suitable for the TO-type package having a through hole through which the laser light escapes on the vertical surface of the TO-type package, thereby enabling the use of a low-cost TO-type package. Compared with the conventional laser package, there is an advantage that the manufacturing cost is low.

In addition, in the present invention, since the laser diode chip and the light reflection partial reflection mirror are manufactured in a fold type and the light reflection partial reflection mirror is disposed on the 45 degree reflection mirror, the bottom area of the resonator can be minimized. By minimizing the floor area, it can be mounted in a small TO package with a diameter of 7 mm or less, which makes it possible to manufacture an SFP transceiver using the TO package.

1 is an external view showing a schematic view of a TO-type package,

2 is a conceptual diagram illustrating an operating principle of an extended resonator laser diode package according to the present invention;

3 is a conceptual diagram showing the determination of the oscillation wavelength in the extended resonator laser type, Figure 3 (a) is an example of the transmittance curve of the tunable selective filter, Figure 3 (b) of the Fabry-Perot mode is determined in the expansion resonator 3 (c) shows an example of wavelength characteristics of laser light oscillated by an expansion resonator and a tunable wavelength selective filter.

FIG. 4 is a conceptual diagram illustrating determination of an oscillation wavelength in an extended resonator type wavelength tunable laser. FIG. 4A illustrates an example of a curve in which transmittance of the tunable selective filter changes with temperature. FIG. In the example in which the Fabry-Perot mode is determined to change with temperature, Fig. 3 (c) shows the laser light oscillated by the Fabry-Perot mode of the expansion resonator that changes with temperature and the wavelength tunable selective filter that changes with temperature. An example of the characteristic of changing wavelength,

FIG. 5 is a conceptual diagram illustrating a state in which a laser wavelength oscillating changes according to a temperature change of a resonator in the laser resonator structure of FIG. 2;

6 is a conceptual diagram illustrating the installation of a laser device having a resonator structure having a phase compensation according to the present invention;

FIG. 7 is a conceptual diagram illustrating determination of an oscillation wavelength in an extended resonator type tunable laser having a phase compensation according to the present invention. FIG. 7A illustrates an example of a curve in which transmittance of the tunable selective filter changes with temperature. (B) is an example in which the Fabry-Perot mode determined in the expansion resonator has a constant wavelength according to the temperature, and FIG. 7 (c) shows the Fabry-Perot mode and the temperature change which are kept constant regardless of the temperature change. An example of the wavelength change characteristic of the laser light oscillated by the tunable selective filter

8 is a conceptual diagram illustrating a state in which a laser wavelength oscillating changes according to a temperature change of a resonator in a laser resonator structure according to the present invention;

9 is a conceptual diagram illustrating the installation of a laser device having a clamshell resonator structure according to an embodiment of the present invention;

10 is a conceptual diagram of installation of a laser device according to another embodiment of the present invention;

11 is a conceptual diagram illustrating the installation of a laser device including a photodiode for monitoring light according to the present invention;

12 is another installation conceptual diagram of a laser device in which a photodiode for monitoring light according to an embodiment of the present invention is disposed;

13 is a conceptual diagram of installation of a laser device according to another embodiment of the present invention;

14 is a conceptual diagram of installation of a laser device according to another embodiment of the present invention;

15 is an example of a tunable selective filter consisting of an etalon filter according to the present invention,

16 is an example of transmittance according to the wavelength of light passing through the etalon filter manufactured by the method of FIG. 15;

FIG. 17 shows an example of an oscillation laser wavelength when a tunable selective filter having a plurality of transmission wavelength bands is applied to the external resonator laser shown in FIG. 2;

18 is a conceptual diagram illustrating an installation of an external resonator type laser package to which a tunable selective filter having a plurality of transmission wavelength bands and a partial reflection mirror in which reflection occurs only for a specific wavelength according to the present invention;

19 is a conceptual view illustrating a laser operating principle in the external resonator laser structure of FIG. 18;

20 is a conceptual diagram illustrating a process of varying a wavelength in the external resonator laser structure of FIG. 18;

21 is a conceptual view illustrating the installation of a stand for fixing a 45 degree reflective mirror according to the present invention.

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

1 is an external view showing a schematic view of a TO-type package applied to the present invention.

As shown in FIG. 1, the TO-shaped package is largely composed of a stem 1 and a cap 2, in which parts are placed on the bottom of the stem 1 and sealed with a cap 2. Is produced. In this structure, the laser light is emitted to the TO-type package extension through the through hole drilled in the upper portion of the cap (2). Typically a through-hole of the cap 2 is formed with a lens or sealed with a flat glass window. In FIG. 1, a horizontal direction and a vertical direction to be used in the following description of the present invention are defined as arrow directions.

2 is a conceptual diagram illustrating an operating principle of an extended resonator laser diode package according to the present invention.

As shown in FIG. 2, the laser diode package according to the present invention includes a laser diode chip 100 installed in a submount 110 for a laser diode chip, and parallel light of laser light emitted from the laser diode chip 100. A collimated lens 200 for collimating with a wavelength, and a variable wavelength selective filter that selectively transmits the light of a specific wavelength of the laser light collimated through the collimating lens 200, the wavelength selected according to the temperature ( 300 and a partial reflection mirror 500 for light feedback reflecting some laser light of the laser light passing through the tunable selective filter 300 and transmitting the remaining light. The laser diode chip 100 and the tunable selective filter 300 are disposed on a thermoelectric element (not shown) for controlling temperature.

The laser diode chip 100 is an edge emitting type laser diode chip, and the edge emitting type laser diode chip 100 emits laser light at both incision surfaces. The laser diode chip 100 has a semiconductor laser fabricated on an InP substrate, and may have an oscillation wavelength of 1100 nm to 1700 nm. The incision surface of the laser diode chip 100 facing the partial reflection mirror 500 for the light feedback of both incision surfaces becomes an antireflective coating surface (reflective surface) having a reflectance of 1% or less. This antireflection surface has a reflectance of 1% or less, preferably 0.1% or less, and more preferably 0.01% or less. The incision surface opposite the antireflective surface of the laser diode chip 100 typically has a reflectance of 1% or more, preferably 10% or more, more preferably 80% or more. Since the laser diode chip 100 having one side of the incision is antireflectively coated, no light is fed back from the laser diode chip 100 itself, so that the Fabry-Perot mode using the laser diode chip 100 as a resonator is not formed. . The light emitted from the laser diode chip 100 exhibits a wavelength of light having a very wide wavelength band (typically, a half width of 20 nm or more). Light of a wide wavelength band emitted through the non-reflective surface of the laser diode chip 100 is collimated by parallel light by the collimating lens 200. The light of the wide wavelength band collimated by the collimation lens 200 is incident on the wavelength variable selectivity filter 300 having a narrow transmission wavelength bandwidth, and the wavelength variable selectivity filter among the light incident on the wavelength variable selectivity filter 300 ( Except for the light passing through 300, the rest is reflected by the tunable selective filter 300 and sent to another path that cannot be fed back to the laser diode chip 100. The light of the component transmitted from the laser diode chip 100 through the collimation lens 200 and the tunable selective filter 300 arrives at the partial reflection mirror 500 for light feedback. The light reflected from the light feedback partial reflection mirror 500 among the light reaching the light reflection partial reflection mirror 500 passes through the wavelength variable selectivity filter 300 and then passes through the collimation lens 200 and the laser diode. The chip 100 is fed back. Therefore, an extended resonator type laser including a laser diode chip 100, a collimating lens 200, a tunable wavelength selective filter 300, and a light reflecting partial reflection mirror 500 is completed.

If the transmission bandwidth of the tunable selective filter 300 is too narrow, the insertion loss of light passing through the tunable selective filter 300 becomes large, and if the transmission bandwidth of the tunable selective filter 300 is too wide, one effectively Difficult to choose Fabry-Perot mode Therefore, it is preferable that the transmission bandwidth of the tunable selective filter 300 is appropriately set for insertion loss of light and effective Fabry-Perot mode selection. In the embodiment of the present invention, the transmission bandwidth of the tunable selective filter 300 is It is preferably set to 10 nm or less, more preferably about 0.25 nm to 3 nm. The tunable selective filter 300 effectively transmits light only at a predetermined wavelength using a compound semiconductor of Ga (x1) Al (1-x1) As / Ga (x2) Al (1-x2) As on a GaAs substrate. In addition, other wavelengths are produced to reflect light. The Ga composition of Ga (x) Al (1-x) As is preferably about 1 to about 0.1. More preferably, the tunable wavelength selective filter 300 may be manufactured by sequentially stacking GaAs / AlGaAs based on a GaAs substrate. The GaAs / AlGaAs-based tunable selective filter 300 is changed in refractive index according to temperature, and thus the wavelength band transmitted is changed by about 90 pm/°C to 100pm / ° C, and thus the oscillation selected by the extended resonator laser The wavelength will change. In addition, the tunable selective filter 300 may be fabricated by alternately depositing amorphous silicon (a-Si) and silicon nitride (SiN) layers on a transparent substrate having a wavelength considered to be glass or quartz. have.

Even in the case of the light reflection partial reflection mirror 500, if the reflectance is too low, the amount of light fed back to the laser diode chip 100 is too small to lock the wavelength, so that wavelength locking of the laser does not occur easily. If the reflectance of the partial reflection 500 mirror is too high, a problem may occur that the signal to be used for the light transmission is too weak to pass through the partial reflection mirror 500 for light feedback. Therefore, it is preferable that the reflectance of the light reflection partial reflection mirror 500 is also appropriately set. In the embodiment of the present invention, the reflectance of the light feedback partial reflection mirror 500 is set to about 20% to 80%.

FIG. 3 is a conceptual diagram illustrating the determination of the oscillation wavelength in the extended resonator laser type. FIG. 3 (a) shows an example of a transmission curve of the tunable selective filter, and FIG. 3 (b) shows a Fabry-Perot determined in the extended resonator. 3 (c) shows an example of the wavelength characteristics of the laser light oscillated by the expansion resonator and the tunable wavelength selective filter. The wavelength determined by the extended resonator laser includes a transmission band of a wavelength tunable selective filter having one transmission wavelength band in the wavelength band considered as shown in FIG. 3A, and as shown in FIG. 3B. It is determined by two factors of the periodic and discontinuous Fabry-Perot mode determined by the expansion resonator length, so that a specific wavelength determined as shown in FIG.

That is, in the above-described resonator structure of FIG. 2, only the mode within the transmission band of the wavelength tunable selective filter of FIG. 3 (a) among the discontinuous Fabry-Perot allowable modes capable of laser oscillation by the expansion resonator of FIG. 3 (b). This expansion resonator is resonated and leads to laser oscillation, so that laser light having a specific wavelength is generated as shown in FIG.

Meanwhile, when the resonator structure of FIG. 2 is mounted on the thermoelectric element and the temperature of the thermoelectric element is changed, the temperatures of the semiconductor laser diode chip 100 and the tunable selective filter 300 disposed on the thermoelectric element are changed. The tunable selective filter 300 fabricated based on the semiconductor laser diode chip 100 and the GaAs substrate fabricated using an InP substrate may bring about a refractive index change of about 2 × 10 ⁻⁴ depending on temperature.

FIG. 4 is a conceptual diagram illustrating determination of an oscillation wavelength in an extended resonator type tunable laser according to such a temperature change. FIG. 4A illustrates an example of a curve in which transmittance of the tunable selective filter changes with temperature. b) is an example in which the Fabry-Perot mode determined in the expansion resonator changes with temperature, and FIG. 4 (c) shows the tunable-Perot mode and the wavelength-variable selective filter in the expansion resonator that changes with temperature. Shows an example in which the wavelength of the laser light oscillated changes.

As shown in FIG. 4A, the transmission band of the tunable selective filter 300 shifts about 90 pm/°C to about 100pm / ° C. In this case, since the refractive indices of the laser diode chip 100 and the tunable selective filter 300 which constitute the resonator are changed, the Fabry-Perot mode of the entire resonator is also changed as shown in FIG. Therefore, the wavelength of the actual oscillation of the laser light emitted from the laser resonator is generated by the oscillation of the Fabry-Perot mode, which is within the transmission band of the wavelength variable selectivity filter 300, among the conversion Fabry-Perot modes. The wavelength is variable.

As described above, when the temperature of the thermoelectric element is changed in the laser resonator structure of FIG. 2, the oscillation wavelength is characterized by continuously changing the Fabry-Perot mode of the resonator and the discontinuous Fabry-Perot mode selection of the tunable wavelength selective filter 300. According to this changing characteristic, discontinuous wavelength changes appear simultaneously. 5 shows an example of the wavelength change of the laser resonator according to the temperature change of the thermoelectric element. When the temperature of the laser resonator is changed in the expansion resonator type laser, a portion where the oscillation wavelength of the laser continuously changes and a portion that changes discontinuously are shown. Since they exist at the same time, it is difficult to keep the oscillation wavelength constant in the laser resonator. Referring to FIG. 5, since the laser oscillation wavelength is changed about 60 to 70 pm / ° C. in the section in which the oscillation wavelength is continuously changed, the temperature of the thermoelectric element must be adjusted very precisely in order to precisely control the wavelength of the laser light.

That is, in the laser resonator structure of FIG. 2, when the temperature of the laser resonator is changed, the laser oscillation wavelength is continuously changed in accordance with the temperature of the laser resonator within a section in which the oscillation wavelength is discontinuously changed, thereby causing difficulty in controlling the oscillation wavelength. Done. In the present invention, in order to solve such a problem that it is difficult to control the oscillation wavelength is arranged a phase compensation box to offset the change in refractive index according to the temperature of the semiconductor laser diode chip 100 and the GaAs / AlGaAs wavelength variable selectivity filter 300 in the laser resonator Present the structure.

6 is a conceptual diagram illustrating a laser device having a clamshell resonator structure having a phase compensation according to an exemplary embodiment of the present invention. The phase compensation 350 is a wavelength variable selective filter 300 and a light feedback module. Disposed on the optical path between the partially reflective mirrors 500.

In the embodiment of the present invention, the phase compensation box 350 is manufactured based on a polymer material such as polyvinyl, polyethylene, polycarbonate, PMMA, epoxy, and the like, and the polymer material changes the refractive index of (-) as the temperature increases. Will be imported. When light is reflected from the phase compensator 350, the laser beam may be disturbed. Therefore, the surface through which the laser light passes through the phase compensator 350 is preferably anti-reflective coating.

On the other hand, the Fabry-Perot mode of the laser resonator is determined by the optical length of the laser resonator. The semiconductor laser diode chip 100 and the GaAs / AlGaAs wavelength tunable filter 300 have a positive refractive index as the temperature increases. It becomes visible. A glass lens or the like may be added in the laser resonator, but this material is also weak, but shows a positive refractive index with increasing temperature. Therefore, in the resonator structure of FIG. 2, since the effective refractive index of the entire laser resonator is changed to (+) as the temperature increases, the FAbry-Perot mode causes a positive oscillation wavelength change as the temperature of the laser resonator increases. .

On the contrary, since the above-described polymer materials such as polyvinyl, polyethylene, and PMMA exhibit negative refractive index changes with increasing temperature, the refractive index according to the temperatures of the semiconductor laser diode chip 100 and the tunable selective filter 300 are varied. When the phase compensator 350 made of a polymer material having an appropriate thickness is disposed in the resonator to compensate for the change, the semiconductor laser diode chip 100, the tunable selective filter 300, and the phase compensator 350 are the same. Since the thermoelectric element exhibits the same temperature change, the effective refractive index of the entire resonator can maintain a constant value regardless of the temperature change of the thermoelectric element. Therefore, the Fabry-Perot mode, which is determined by the effective refractive index of the resonator, has a constant value regardless of the temperature of the thermoelectric element.

FIG. 7 is a conceptual diagram illustrating variation of an oscillation wavelength according to temperature change in an extended resonator type tunable laser having a phase compensation. FIG. 7A illustrates an example of a curve in which transmittance of a tunable selective filter changes with temperature. 7B is an example in which the Fabry-Perot mode determined in the expansion resonator has a constant wavelength according to temperature, and FIG. 7C is a Fabry-Perot mode and temperature maintained constant regardless of temperature change. An example of the wavelength change characteristic of the laser light oscillated by the wavelength variable selectivity filter which changes with a change is shown.

Since the wavelength-selective selective filter 300 is transmitted and selected wavelengths change according to the temperature change, as shown in FIG. 7A, the transmission wavelength band of the wavelength-selective selective filter changes with temperature. On the other hand, in the resonator structure of FIG. 6 having a phase compensator inserted therein, the Fabry-Perot mode of the entire resonator does not change, so that the Fabry-Perot mode is determined at an independent wavelength according to the temperature as shown in FIG. . Therefore, the laser oscillation wavelength determined in the Fabry-Perot mode in the tunable selective filter 300 is determined as shown in FIG.

8 is a conceptual diagram illustrating a state in which a laser wavelength oscillating changes according to a temperature change of a resonator in a laser resonator structure according to an exemplary embodiment of the present invention.

As shown in FIG. 8, when the semiconductor laser diode chip 100, the tunable selective filter 300, and the phase compensation 350 of the polymer material are disposed on one thermoelectric element according to the resonator structure of FIG. 6, As the temperature of the thermoelectric element changes, the laser wavelength oscillated in the laser resonator changes in a form in which the oscillation laser wavelength is kept constant and then suddenly changes in wavelength, unlike in the case of FIG. 5.

Currently, since optical communication is implemented at 100 GHz wavelength interval or 50 GHz wavelength interval, the mode interval of the laser resonator according to the present invention is represented by the following Equation 1 according to the length of the laser resonator.

Equation 1

From here,

ω: the frequency of the oscillating laser light

λ: wavelength in the air of the oscillating laser light

C: luminous flux in vacuum

m: integer

nd: Laser resonator length when the refractive index of laser resonator is converted to 1

When the Fabry-Perot mode of the laser resonator is 100 GHz interval, the resonator converted to refractive index 1 is about 24 mm. When the Fabry-Perot mode is 50 GHz interval, the resonator converted to refractive index 1 is about 12 mm long. When the mode is 25GHz interval, the length of the resonator converted into refractive index 1 is about 6mm.

The resonator length of 24 mm or 12 mm is difficult to be embedded in a small TO can package, and there is a problem of uneven temperature inside the thermoelectric element due to the increase in the resonator length. In addition, a frequency difference of 12.5 GHz requires a resonator length of 3 mm. In this short resonator length, it is very difficult to arrange the collimation lens 200, the tunable selective filter 300, and the phase compensator 350. Therefore, the length of the resonator converted into refractive index of 6mm is suitable to make a laser having a wavelength interval of 50GHz or 100GHz, which is an international communication protocol, and to secure wavelength accuracy (+/- 12.5GHz) required by international communication standards. It is preferable that the length of the laser resonator converted into the refractive index 1 is adjusted within 5.8 mm to 6.2 mm.

In general, a TO-type package mounted on an SFP transceiver should have all components mounted in the inner diameter of the cap 2 in FIG. 1, and the light escaping from the TO-type package should be emitted from the center portion of the TO-type package. Therefore, in order to emit the horizontally moving laser light to the outside of the TO package cap 2 in FIG. 2, a 45 degree reflective mirror for converting the horizontal laser light into the vertical laser light is required. The reflecting mirror should be located underneath the cap 2 of the TO package.

FIG. 9 is a conceptual diagram illustrating a laser device having a clamshell resonator structure according to an exemplary embodiment of the present invention, wherein a 45-degree reflecting mirror converts a direction of laser light vertically on one side of the light reflecting partial reflection mirror 500 ( A structure in which 400 is disposed is shown.

In general, the inner diameter of the cap (2) of the TO-type package mounted on the SFP transceiver is about 4.4 mm, and in order for the light to escape from the center of the cap (2) of the TO-type package, the laser diode chip 100 and the 45 degree reflection mirror ( The length to the center of 400) shall be physically within 2.2mm.

The laser diode chip 100 of the extended resonator type laser currently used is at least about 400 μm, and considering the heat dissipation of the laser diode chip 100, the length of the submount 110 of the laser diode chip 100 is about 700 μm. . At present, the thickness of the collimation lens 200 that provides a beam size of an appropriate size is about 400 μm, and the thickness of the tunable selective filter 300 is considered in consideration of the stress caused by the dielectric thin film deposited on the tunable selective filter 300. At least 500um. In addition, the light reflection partial reflection mirror 500 has a thickness of about 300um to about 500um, and the size of the 45 degree reflective mirror 400 is about 1000um. In order to align each component, a minimum of 150um of free space is required between each component. Therefore, as shown in FIG. 6, when these parts are arranged in a line on the thermoelectric element 900 of the TO-type package, the length from the laser diode chip 100 to the center point of the 45 degree reflective mirror 400 is equal to the length of each part. Considering the required space, it is about 2.7mm long, which causes light to escape from the center of the TO-type package.

In addition, when the refractive index of the laser diode chip 100 is considered to be about 3.5 and the refractive index of the collimating lens 200, the tunable selective filter 300, and the light reflecting partial reflection mirror 500 of glass material is considered to be 1.5. The effective optical resonator length (in terms of refractive index 1) of the expansion resonator including the laser diode chip 100 and the light reflection partial reflection mirror 500 is about 4 mm. When the optical resonator length is 4 mm, the interval between the resonator Fabry-Perot modes in FIG. 3B becomes about 300 pm. When the laser is unstable, the oscillation wavelength may exceed the adjacent Fabry-Perot mode. This is called mode hopping. Including this mode hopping, DWDM recommends that the wavelength be within +/- 100pm from a wavelength predefined by the international organization. Therefore, it is preferable that the optically effective resonator length of the expansion resonator is at least about 5.8 mm to 6.2 mm so that the wavelength is within the range of 100 pm at the predetermined wavelength even during mode hopping. However, when the resonators have a one-dimensional arrangement as shown in FIG. 6, increasing the effective resonator length of the expansion resonator inevitably increases the horizontal length of the resonator. The problem of moving away from the center occurs.

In order to solve this problem, the present invention introduces a folding type resonator type laser structure as shown in FIG. When the resonator is arranged as shown in FIG. 9, there is no direct relationship between the length of the resonator and the escape point of the TO package of the laser light, and thus, an extended resonator type laser having a long resonator structure can be manufactured using a small TO can package. Will be produced. In the structure of FIG. 9, the variable wavelength selective filter 300 is directly attached and fixed to the thermoelectric element, and the phase compensation box 350 is disposed on the 45 degree reflective mirror 400.

10 is a conceptual diagram illustrating a laser device according to another embodiment of the present invention, and includes a variable wavelength selective filter 300, a phase compensation 350, and a partial reflection for light feedback on a 45 degree reflective mirror 400. The structure in which the mirror 500 is arrange | positioned is shown. In this arrangement, the horizontal length of the resonator can be within 1.5 mm, and the optical length of the resonator can be 6 mm or more.

FIG. 11 is a conceptual diagram illustrating an installation of a laser device in which a photodiode for monitoring light according to an embodiment of the present invention is disposed.

In FIG. 11, the 45 degree reflective mirror 400 is manufactured as a partial reflection mirror, and the photo-monitoring photo diode 600 attached to the photodiode submount 610 is arrange | positioned at the rear end of this 45 degree reflective mirror 400. FIG. Thus, a portion of the light incident on the 45 degree reflective mirror 400 is transmitted through the 45 degree reflective mirror 400 to be incident on the photodiode 600 for light monitoring so that the intensity of the laser light can be monitored. In this arrangement, since the light intensity monitoring photodiode 600 is disposed on the opposite side of the laser resonator with respect to the center point of the TO package, the internal space of the TO-type package can be efficiently utilized.

As shown in FIG. 11, although a part of the light emitted from the laser diode chip 100 and incident on the 45 degree reflective mirror 400 is transmitted, the light intensity may be monitored by entering the photodiode 600 for light monitoring. A light monitoring photodiode 600 may be installed below the island reflection mirror 400 to monitor light intensity.

FIG. 12 shows an installation conceptual view in which the photodiode for light monitoring is disposed below the 45 degree reflective mirror. As shown in FIG. 12, when the 45 degree reflecting mirror 400 has the function of a partial reflecting mirror, the 45 degree reflecting mirror 400 is reflected by the 45 degree reflecting mirror 400 and is incident on the upper part reflecting mirror 500 for light feedback. Among the lights, the light passing through the 45 degree reflection mirror 400 even when the light of the path reflected by the light feedback partial reflection mirror 500 and returned to the laser diode chip 100 reaches the 45 degree reflection mirror 400. Transmission occurs. In this way, the light passing through the 45 degree reflective mirror 400 from the partial reflection mirror 500 for light feedback and passes through the 45 degree reflective mirror 400 reaches the lower surface of the 45 degree reflective mirror 400, As described above, even if the photodiode 600 for light monitoring is disposed under the 45 degree reflective mirror 400, the light intensity monitoring function can be performed in the same manner. Since the 45 degree reflective mirror 400 underlay of the optical monitoring photodiode 600 does not increase the horizontal axis length of the expansion resonator, it is also a method that can make the best use of the internal area of the TO-type package.

FIG. 13 is a conceptual view illustrating the installation of a laser device according to still another embodiment of the present invention, and a method for determining the wavelength of laser light using light transmitted vertically and light vertically transmitted through the 45 degree reflective mirror 400. It is about.

As shown in FIG. 13, a wavelength filter 700 having a transmittance that is different depending on the wavelength is inserted into a path of light passing horizontally through the 45 degree reflective mirror 400, and on the path of light passing through the wavelength filter 700. The photodiode 650 for wavelength monitoring is attached. The photodiode 620 for output monitoring is disposed on a path of light that vertically passes through the 45 degree reflective mirror 400. By dividing the photocurrent of the wavelength monitoring photodiode 650 thus divided by the photocurrent flowing through the output monitoring photodiode 620, the ratio of permeation through the wavelength filter 700 can be determined and the wavelength of laser light can be determined from this ratio. have. In this case, it is preferable that the characteristics of the wavelength filter 700 do not change with temperature, or that the wavelength characteristics are changed within 15 pm / ° C. according to the temperature. More preferably, the wavelength characteristics are changed within 3 pm / ° C. according to the temperature.

FIG. 14 is a conceptual view illustrating the installation of a laser device according to another embodiment of the present invention, in which a wavelength filter 700 having a transmittance varying according to a wavelength is disposed on a path of light passing horizontally through a 45 degree reflective mirror 400. The photodiode 650 for wavelength monitoring is attached to a path of light passing through the wavelength filter 700. The photodiode 620 for output monitoring is disposed on a path of light reflected by the wavelength filter 700. By comparing the photocurrent of the wavelength monitoring photodiode 650 disposed as described above with the photocurrent flowing through the output monitoring photodiode 620, the ratio of the intensity of light passing through the wavelength filter 700 and the reflected light can be determined. From this ratio, the wavelength of the laser light can be determined.

Meanwhile, in the above-described embodiment, the wavelength tunable selective filter 300 has been described as selecting only one wavelength, and the tunable selective filter 300 is tunable even if it is configured to select a plurality of wavelengths. A laser device can be manufactured.

The tunable selective filter 300 that selects only one wavelength may be manufactured by alternately growing a GaAs layer and an AlGaAs layer on a GaAs substrate as described above, and may also be made of amorphous silicon on a substrate such as glass, quartz, silicon, or the like. And SiN can be produced by alternately depositing.

In contrast, the wavelength tunable selective filter capable of selecting a plurality of wavelengths is manufactured in a structure that allows a plurality of wavelengths to pass through the filter at a constant frequency interval, which can be easily manufactured as an etalon filter. The etalon filter may be manufactured by reflecting coating so as to have a predetermined reflectance on both sides of the substrate transparent to light in the wavelength band to be transmitted.

FIG. 15 illustrates an example of a tunable selective filter including an etalon filter. The etalon filter constituting the tunable selective filter 330 includes a semiconductor substrate 333 through which laser light, such as silicon, GaAs, or InP, passes. It is made of a structure in which the reflective film 335 is deposited so as to have a predetermined reflectance with a dielectric thin film having different refractive indices on both sides of the C). The method of manufacturing the reflective film 335 from the dielectric thin film is a method that is very widely applied to lens coating and optical filter fabrication and has a very high technical maturity. This method has the advantage of being very simple compared to the method of alternately growing a GaAs layer and an AlGaAs layer on a GaAs substrate or by depositing amorphous silicon and SiN on a substrate such as silicon.

FIG. 16 shows the transmittance according to the wavelength of light passing through the etalon filter manufactured by the method of FIG. 15. The etalon filter used for measuring the transmittance has reflectances on both sides of a 50 μm thick silicon substrate. It is a case where a reflecting film coating is performed using a dielectric thin film layer so that it may become 70%. As shown in FIG. 16, the silicon etalon filter having the above structure has a plurality of transmission wavelength bands having a wavelength interval of about 1000 GHz.

FIG. 17 illustrates the oscillation laser wavelength when the tunable selective filter having a plurality of transmission wavelength bands is applied to the external resonator laser shown in FIG. 2.

As shown in FIG. 17B, the Fabry-Perot mode of the external resonator laser is continuously distributed at a wavelength interval of about 0.1 nm to 1 nm. The light reflected directly from the tunable selective filter 330 by tilting at an angle with respect to the optical axis inside the laser resonator may not be fed back to the laser diode chip 100, whereas the tunable selective filter 330 may pass through the tunable selective filter 330. The light is reflected by the optical reflecting mirror 500 and is reversely transmitted through the tunable selective filter 330 to be fed back to the laser diode chip 100. Accordingly, the laser diode chip 100 has a tunable selective filter ( Wavelength locking and laser oscillation occur in the resonator Fabry-Perot mode of the wavelength band passing through 330. At this time, when the light passing through the tunable selective filter 330 has a plurality of wavelength bands as shown in (a) of FIG. 17, as shown in (c) of FIG. Oscillation is performed in the Fabry-Perot mode within the transmission wavelength band of), thereby generating laser light having a plurality of wavelengths.

These different wavelengths act as noise in communication, making DWDM communication impossible, especially based on very precise control of the wavelength. Therefore, even when the variable wavelength selective filter 330 having a plurality of transmission wavelength bands is used, a function of causing only one wavelength to oscillate in the laser resonator is required.

This function can be implemented by changing the characteristics of the partially reflective mirror 500 for the light feedback shown in FIGS. That is, in FIG. 2 and FIG. 6, the light reflection partial reflection mirror 500 is described as a partial reflection mirror having a constant reflectance irrespective of the wavelength, but the wavelength variable selective filter 330 having a plurality of transmission wavelength bands is used. In order to fabricate a laser having a single wavelength, if the partial reflection mirror 500 for light feedback has a predetermined specific reflectance for a specific wavelength but is manufactured to have a completely transmissive characteristic for a wavelength band in which no oscillation should occur do.

FIG. 18 is a conceptual diagram illustrating an installation of an external resonator type laser package including a wavelength tunable selective filter having a plurality of transmission wavelength bands and a partial reflection mirror in which reflection occurs only for a specific wavelength, and FIG. 19 is an external resonator type laser structure of FIG. 18. Shows the laser operating principle in.

The variable wavelength selective filter 330 applied to FIGS. 18 and 19 has a plurality of transmission wavelength bands, and the optical feedback partial reflection mirror 550 reflects at a predetermined ratio only in a specific wavelength band and does not generate laser oscillation. For wavelengths in other bands, the wavelength-dependent optical feedback partially reflecting mirror transmits.

In such an external resonator type laser structure, the laser diode chip 100 emits light having a wide wavelength band suitable for gain characteristics of a semiconductor laser. The light emitted from the laser diode chip 100 reaches the tunable selective filter 330 having a plurality of transmission wavelength bands, and the plural wavelength bands of the tunable selective filter 330 are wavelengths. It is transmitted through the variable selectivity filter 330 and transmitted to the partial reflection mirror 550 for light feedback. On the other hand, the laser light that does not pass through the tunable selective filter 330 and reflects is reflected by the tunable selective filter 330 which is turned at a predetermined angle with respect to the laser optical axis and sent to another path to be fed back to the laser diode chip 100. I can't.

On the other hand, light corresponding to a plurality of wavelength bands transmitted through the tunable selective filter 330 (FIG. 20 (a)) passes through the phase compensation 350 and has a wavelength dependency partial reflection mirror 550. Is sent to. The reflectance characteristic curve of the light reflection partial reflection mirror 550 having the wavelength dependence is as shown in FIG. 20C, and the light reflection partial reflection mirror 550 having the wavelength dependence passes through the tunable filter 330. Among the plurality of wavelengths, only a specific wavelength is partially reflected and the remaining wavelengths are manufactured to show transmission characteristics. As described above, the laser light that does not pass through the tunable filter 330 among the light emitted from the laser diode chip 100 is reflected by the tunable filter 330 and cannot be fed back to the laser diode chip 100. Light having a plurality of wavelength bands passing through the filter 330 reaches the partial reflection mirror 550 having the wavelength dependency through the phase compensation 350.

The light reflected from the partial reflection mirror 550 among the light arriving at the light reflection partial reflection mirror 550 having the wavelength dependency is again passed through the phase compensation box 350 and the wavelength tunable selector filter 330. 100 and the light having a wavelength corresponding to the transmission band among the light arriving at the light reflection partial reflection mirror 550 passes through the light reflection partial reflection mirror 550 and is returned to the laser diode chip 100. You won't be. Therefore, the wavelength of the laser light finally oscillating in the external resonator type laser structure of FIG. 18 passes through the wavelength tunable selective filter 330 having a plurality of transmission wavelength bands as shown in FIG. Among the a)), the Fabry-Perot mode (Fig. 20 (d)) corresponding to the resonance mode of the wavelength band (Fig. 20 (c)) where reflection occurs in the light reflection partial reflection mirror 550 having wavelength dependence is do.

On the other hand, the light reflecting partial reflection mirror 550 having the wavelength dependence applied to FIGS. 18 and 19 does not have to be reflectance for wavelengths other than the reflection band without reflection, and at least 80% or less than the reflectance of the reflection band. Preferably, even when it is 50% or less, operation | movement is possible. However, most preferably, the reflectance of the transmission wavelength band of the partial reflection mirror 550 is 25% or less than the reflectance of the reflection band. In addition, it is preferable that the reflection band wavelength width of the partial reflection mirror 550 whose reflection characteristics vary depending on the wavelength is 1/2 or less of the interval between wavelengths of the tunable selective filter 330 having a plurality of transmission wavelength bands.

In particular, in FIG. 18 and FIG. 19, the tunable selective filter 330 having a plurality of transmission wavelength bands forms a reflective film by depositing a plurality of dielectric films having a high refractive index and low refractive index on both surfaces of a semiconductor substrate such as silicon, GaAs, or InP. It is preferable that it is an etalon filter manufactured in form. In the etalon filter using the semiconductor substrate, the refractive index of the semiconductor substrate is changed according to temperature. By using this characteristic, the wavelength band of transmission can be changed by changing the temperature of the etalon filter. Accordingly, FIGS. 2 and 6 It is possible to manufacture a wavelength tunable laser capable of varying the oscillating laser wavelength described in. This method is a highly industrial method by fabricating a tunable filter through a very well established dielectric thin film deposition.

FIG. 20 illustrates a process of varying a wavelength in the external resonator laser structures of FIGS. 18 and 19. As shown in FIG. 20A, in the case of an etalon filter in which a reflective film is formed of a dielectric thin film on both surfaces of a semiconductor substrate such as silicon, the refractive index of the semiconductor changes according to temperature change, and thus the wavelength band for transmission is changed.

The Fabry-Perot mode (FIG. 20B) in the reflection band (FIG. 20C) of the partial reflection mirror 550 for optical feedback among the transmission band wavelengths of the variable tunable selectivity filter 330 is As a result, since the oscillation is performed as shown in FIG. 20 (d), the oscillation wavelength of the laser is also changed as the oscillation wavelength of the laser is changed as the temperature of the tunable selective filter 330 having a plurality of transmission wavelength bands is changed.

Figure 21 shows the form of a stand for 45-degree reflective mirror for easily mounting the 45-degree reflective mirror in the TO-type package according to an embodiment of the present invention.

As shown in FIG. 21, the 45 degree reflective mirror stand 450 according to the present invention is made of a rectangular parallelepiped, and the 45 degree reflective mirror stand 450 has a through hole having an angle of 45 degrees with respect to the base. have. A flat 45 degree reflective mirror 400 is inserted into the through hole formed in the stand 450 and mounted on the thermoelectric element, and a partial reflective mirror 500 is attached to the upper part of the stand 450. The stand 450 having the above structure allows the 45 degree reflective mirror 400 and the partially reflective mirror 500 to be easily attached.

The stand 450 is preferably a material having a good heat transfer rate. The material is a silicon substrate having a heat transfer rate of 170 W / m and easy to manufacture through holes by a dry etching process. In particular, the silicon is very easy to adjust the width of the through hole by the dry etching method, and the angle to the base is easy to adjust, so the flat 45 degree reflective mirror 400 is simply inserted into the through hole of the silicon stand. Positioning the reflecting mirror 400 at a 45 degree angle facilitates the assembly process.

On the other hand, when the extended environmental temperature of the TO-type package varies, heat exchange occurs between the outer circumferential surface of the TO-type package and the internal components of the TO-type package. Since the distance between each internal component of the TO package and the outer circumferential surface of the TO package can vary widely, an extended environmental temperature change of the TO package can unevenly change the temperature of the internal components of the TO package. This independent change in temperature of the resonator material will result in a non-uniform change in the effective optical length of the resonator, so it is desirable to minimize heat exchange between the resonator component and the outer circumferential surface of the TO-type package. Therefore, it is preferable to keep the inside of the TO package in a vacuum, and the degree of vacuum is preferably 0.2 atm or less.

As described above, in the tunable laser device according to the present invention, the laser resonator is disposed by arranging the light reflecting partial reflection mirror 500 on the 45 degree reflection mirror 500 installed in the horizontal direction of the laser diode chip 100. By increasing the optical resonator length while minimizing the horizontal length, the internal area of the TO-type package can be maximized. In addition, the semiconductor laser diode chip 100, the tunable wavelength selective filter 300, and the phase compensation 350 are disposed on one thermoelectric element 900, so that the entire laser resonator due to the temperature change of the thermoelectric element 900 is effectively used. By offsetting the change in refractive index, the Fabry-Perot mode determined by the laser resonator can be fixed at a constant wavelength regardless of the temperature of the thermoelectric element 900.

The present invention is not limited to the above-described embodiments and various modifications and variations within the equivalent range of the technical spirit of the present invention and the claims to be described below by those skilled in the art to which the present invention pertains. Of course this can be done.

Claims (14)

1. In a semiconductor laser device,

   A laser diode chip 100 for emitting laser light;

   A partial reflection mirror (500) for light feedback reflecting part of the light emitted from the laser diode chip (100) and returning it back to the laser diode chip (100);

   A collimation lens 200 installed on an optical path between the laser diode chip 100 and the partial reflection mirrors 500 and 550 for optical feedback, and collimating the light emitted from the laser diode chip 100; The wavelength variable selectivity filters 300 and 330 whose wavelengths are transmitted according to temperature and the refractive index are changed according to temperature to change the refractive index according to the temperature of the semiconductor laser diode chip 100 or the variable wavelength selective filter 300. Comprising a phase compensation box 350 to compensate, and a 45-degree reflective mirror 400 for redirecting the laser light traveling horizontally with respect to the package bottom surface to the laser light traveling perpendicular to the package bottom surface; Lose,

   The laser diode chip 100, the tunable selective filters 300 and 330, and the phase compensation 350 are disposed on the thermoelectric element 900 to change the oscillation wavelength according to the temperature change of the thermoelectric element 900. Laser device, characterized in that.
2. The method of claim 1,

   The light reflecting partially reflective mirror (500, 550) is a laser device, characterized in that disposed on top of the 45 degree reflective mirror (400).
3. The method of claim 1,

   The 45 degree reflecting mirror 400 is made of a partial reflecting mirror having a partial reflection / partial transmission characteristics, the one side of the 45 degree reflecting mirror 400 is emitted from the laser diode chip 100 to the 45 degree reflecting mirror ( And a light monitoring photodiode (600) for receiving the laser light of the component passing through the 400 and monitoring the light intensity of the laser light.
4. The method of claim 1,

   The 45-degree reflective mirror 400 is made of a partial reflection mirror having a partial reflection / partial transmission characteristics, and one side of the 45-degree reflective mirror 400 is emitted from the light reflection partial reflection mirror 500 to the 45 degrees The laser device, characterized in that the light-monitoring photodiode 600 for receiving the laser light of the component passing through the reflective mirror 400 to further monitor the light intensity of the laser light.
5. The method of claim 1,

   The 45 degree reflecting mirror 400 is made of a partial reflecting mirror having a partial reflection / partial transmission characteristics, the one side of the 45 degree reflecting mirror 400 is emitted from the laser diode chip 100 to the 45 degree reflecting mirror ( A wavelength filter 700 and a photodiode 650 having a transmittance that is changed according to a wavelength are disposed on an optical path of a component that passes through 400, and a partial reflection mirror for light feedback is disposed below the 45 degree reflective mirror 400. A photodiode 620 is disposed on an optical path that is emitted from 500 and passes through the 45 degree reflective mirror 400.

   Laser device, characterized in that to determine the transmittance of the wavelength filter 700 and the wavelength of the laser light by comparing the light current flowing through the photodiode (650) (620).
6. The method of claim 1,

   The tunable selective filter 300 is manufactured to transmit light having a specific wavelength by using a Ga (x1) Al (1-x1) As / Ga (x2) Al (1-x2) As compound semiconductor on a GaAs substrate. And wherein said Ga composition is between 1 and 0.1.
7. The method of claim 1,

   The wavelength tunable selective filter (300) is a laser device, characterized in that the amorphous silicon (a-Si) and SiN (silicon nitride) layers are deposited alternately on a transparent substrate.
8. The method of claim 1,

   The tunable selective filter 330 is made of an etalon filter having a plurality of transmission wavelength bands,

   The light reflection partial reflection mirror 550 has a predetermined reflectance in the wavelength band to be oscillated, and the reflectance in the other wavelength bands is formed to be 80% or less than the reflectance of the oscillating wavelength band. Device.
9. The method of claim 8,

   In the light reflecting partial reflection mirror 550

   And a reflectance in a wavelength band other than the wavelength band to be oscillated is 25% or less than the reflectance in the wavelength band to be oscillated.
10. The method according to claim 1 or 8,

    The variable-wavelength selective filter 330 has a plurality of transmission wavelength bands, and dielectric films having different refractive indices are alternately deposited on both surfaces of the semiconductor substrate 333 including any one of silicon, GaAs, and InP so that the reflective film 335 is formed. Laser device, characterized in that formed.
11. The method of claim 1,

    The phase compensation box 350 is a laser device, characterized in that produced on the basis of a polymer material containing any one of PMMA, polyvinyl, polyethylene, polycarbonate, epoxy.
12. The method of claim 1,

    The laser resonator including the semiconductor laser diode chip (100) and the light reflecting partial reflection mirror (500) has a length of 5.8mm to 6.2mm when converted into an effective refractive index of 1.
13. In the stand which fixes a flat reflection mirror to 45 degrees with respect to the horizontal,

    The stand 450 is

    It is formed of a rectangular parallelepiped silicon substrate,

    The silicon substrate is a stand, characterized in that the through-hole (451) having an angle of 45 degrees with respect to any one side is formed so that the flat reflective mirror can be inserted and fixed.
14. The method of claim 13,

    The through hole 451 formed in the silicon substrate is characterized in that formed by a dry etching method.

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