WO2014200189A1

WO2014200189A1 - Laser device having wavelength stabilizer

Info

Publication number: WO2014200189A1
Application number: PCT/KR2014/004203
Authority: WO
Inventors: 김정수
Original assignee: 주식회사 포벨
Priority date: 2013-06-10
Filing date: 2014-05-12
Publication date: 2014-12-18
Also published as: CN104350652B; CN104350652A

Abstract

The present invention relates to a TO-type laser device capable of long-distance transmission having reduced laser light line width. The laser device according to the present invention comprises: a laser diode chip (100) for emitting laser light; a wavelength-selective filter; a collimating lens (200) provided on an optical path between the laser diode chip (100) and the wavelength-selective filter to collimate the light emitted from the laser diode chip (100); a 45° partial reflective mirror (300) provided on the optical path between the laser diode chip (100) and the wavelength-selective filter to redirect laser light traveling horizontally with respect to a package bottom surface to laser light traveling vertically with respect to the package bottom surface; and an optical wavelength-monitoring photodiode (500) arranged on to an optical path on which a laser light reflected from the wavelength-selective filter after being emitted from the laser diode chip (100) penetrates the 45° partial reflective mirror (300). In addition, the temperature of a thermoelectric device having a laser diode chip attached thereto is adjusted or the temperature of an etalon filter is adjusted to maintain a constant relationship between the wavelength of laser light and the wavelength of the etalon filter, and a "0" signal of the laser light is reduced to more than a "1" signal of the laser light to reduce the line width of a laser signal, thereby allowing longer-distance transmission of a high-speed modulation optical signal. In the present invention, a laser device using a low-price TO-type package is provided wherein parts are arranged around the 45° partial reflective mirror to obtain a laser signal which can be modulated at a high speed and can be communicated at a long distance by using a low-price TO-type package, and laser light modulated at a high speed can be transmitted up to a long distance when the laser light wavelength is maintained at a constant value; when the laser light wavelength is changed to a desired wavelength; and when the laser light wavelength is not adjusted.

Description

Laser device with wavelength stabilization device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser device, and more particularly, to a laser device having a wavelength stabilization device and having a wavelength stabilization device which can be manufactured in a very small size and has a line width of laser light emitted from a package, thereby allowing long distance transmission.

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. As a method of greatly increasing the communication capacity, a method of increasing the bit rate used for optical communication and simultaneously applying optical signals of various wavelengths to one optical fiber A wavelength division multiplexing (WDM) method is used. In the WDM method, two wavelengths of 1310 um band optical signal and 1550 um band optical signal, which are widely used in the past, a very dense WDM (Dense WDM) having a frequency interval of 100 GHz and 50 GHz is currently adopted. Furthermore, in order to further increase optical communication capacity, a method of increasing the bit rate of an optical signal having one wavelength and a WDM method for passing various wavelengths of light through one optical fiber are being applied simultaneously.

However, the semiconductor laser diode modulates the light intensity by flowing the current corresponding to the "1" signal and the "0" signal, and interprets the signal according to the change of the light intensity as the "1" and "0" signals. In the optical communication method, a chirp phenomenon occurs in which the wavelength of the laser light generated by the semiconductor laser diode chip changes depending on the magnitude of the injection current. Here, the signal "1" typically indicates a signal having a strong light intensity, and a signal having light with low light intensity is called a "0" signal. Since the semiconductor laser diode chip generates a larger light output when the amount of injected current is large, the "1" signal described above corresponds to a case where a large current flows in the laser diode chip, and the "0" signal is a laser diode. This corresponds to the light output when a relatively small current flows through the chip. For example, at a modulation rate of 10 Gbps, a wavelength change of approximately 5 GHz to 10 GHz occurs between a "1" signal and a "0" signal, and the difference in wavelength is referred to as chirp. In a typical DFB-LD, the "1" signal has a frequency greater by 5 GHz to 10 GHz than the "0" signal. Accordingly, the wavelength of the "1" signal has a shorter wavelength than the "0" signal. In optical fibers, dispersion speed causes light transmission speed to vary according to the wavelength of light. This dispersion phenomenon depends on the chirp characteristics generated when driving semiconductor lasers to "1" and "0". The transmission speed of the 0 "signal is changed. As a result, when the optical signal arrives at the optical receiver, the" 1 "signal and the" 0 "signal are mixed, which makes it difficult to separate the signal.

This phenomenon is particularly acute when the bit rate is high and when the transmission distance is too long. For optical signals generated at 1550 nm band semiconductor lasers running at 10 Gbps, the transmission of more than 10 km is not only very difficult, even 5Km optical transmission is also difficult.

In order to operate a semiconductor laser diode chip at a high speed of 10Gbps, a bias current corresponding to a "0" signal and a modulation current corresponding to a "1" signal must be flowed. In a "0" signal, a bias current is applied to the semiconductor laser diode chip. For the "1" signal, a current is added to the bias current plus the modulation current. For the high speed communication of 10Gbps, the optical response of the semiconductor laser diode chip should have a fast response to the radio frequency (RF) frequency signal of 10Gbps, but to increase the optical response of the RF laser signal of the semiconductor laser diode chip, It is desirable to increase the current. The magnitude of the modulation current is determined by the characteristics of the electronic circuit driving the semiconductor laser diode chip. In order for the electronic circuit to have a high frequency response characteristic, it is desirable to reduce the magnitude of the modulation current. Therefore, when the bias current flowing to the semiconductor laser diode chip is improved to improve the RF response characteristics of the semiconductor laser diode chip, and the modulation current magnitude of the low current is increased to improve the RF characteristics of the driving circuit of the semiconductor laser diode chip, the " 1 The difference between the intensity of the optical signal corresponding to "" and the intensity of the optical signal corresponding to "0" becomes small. The ratio of the intensity of the optical signal corresponding to "1" and the optical signal corresponding to "0" is called ER (extinction ratio). If the ER is low, the "1" and "0" signals are mixed at the optical receiver due to the chirp phenomenon of the semiconductor laser diode chip and the dispersion of the optical fiber, making it difficult to decode the optical signal at the optical receiver. The occurrence of crosstalk of the optical signal due to the chirp phenomenon of the semiconductor laser diode chip and the dispersion of the optical fiber can be reduced by increasing the ER. However, in order to increase the ER, the bias current must be reduced and the modulation current must be increased. However, if the bias current is reduced, the optical response speed of the electrical signal of the semiconductor laser diode chip is decreased, and if the modulation size is increased, the response speed of the driving circuit for driving the semiconductor laser diode chip is decreased.

To solve this problem, Chang-Hee Lee et al. Optically filter the laser light output from a distributed feedback laser diode (DFB-LD) light source at CLEO '95 (CLEO 1995, CTuI10) to filter out a "0" signal. By improving or eliminating the ER, it has been shown that longer transmissions can be achieved than without optically filtering the laser light output from the semiconductor laser diode chip. This is because when the transmission band wavelength of the optical filter is set to "1", the "0" signal, which is longer in wavelength than the "1" signal, is blocked by the optical filter, so it is transmitted to the optical fiber.

The "0" signal has a weaker strength than the "1" signal, which increases the ER, thereby facilitating the reception of the optical signal at the optical receiver, thereby allowing the optical signal to be sent over longer distances. Therefore, the line width of the transmission band of the optical filter should have a significant level of transmittance difference according to the wavelength difference between the "1" signal and the "0" signal, and this difference in transmittance can be adjusted to the transmission band line width of the optical filter. As described above, since the "1" signal and the "0" signal have a frequency difference of about 5 GHz to 10 GHz, the line width of the transmission wavelength band of the optical filter should be set to show a meaningful transmittance difference with respect to this wavelength difference. do.

The aforementioned reference by Chang-Hee Lee et al. In CLEO '95 (CLEO 1995, CTuI10) sets the -3dB bandwidth of the transmission band of such an optical filter to 12 GHz. However, the transmission bandwidth of the optical filter has an appropriate value at 5 GHz to 30 GHz. It is preferable to use. The optical filter may use an optical filter having a transmission wavelength band peak in a wavelength band of at least 10 nm to 100 nm, but a filter having a plurality of transmission wavelength bands in the wavelength band may be used. In the case of an optical filter having a plurality of transmission wavelength bands, the aforementioned -3 dB bandwidth is defined as -3 dB bandwidth of any one transmission wavelength peak. In the case of having a plurality of transmission wavelength bands, the frequency difference between the plurality of transmission wavelength bands should be at least larger than the -3 dB width of the transmission wavelength band.

On the other hand, in the case of the DFB-LD type of semiconductor laser wavelength varies depending on the operating temperature, typically has a wavelength change rate of about 0.1nm / ℃. Therefore, the semiconductor laser diode chip has a wavelength change of about 12.5 nm according to the environmental temperature change of -40 ° C to 85 ° C. Therefore, when adjacent wavelengths are separated by about 20 nm, crosstalk of each wavelength can be eliminated without adjusting the temperature of the semiconductor laser diode chip. Therefore, in general, an optical signal having a wavelength interval of 20 nm or more is used without adjusting the temperature of the semiconductor laser diode chip. However, when the wavelength gap between adjacent wavelengths is within 10 nm, the semiconductor laser diode chip must maintain a constant temperature of the semiconductor laser diode chip using a thermoelectric element in order to suppress the temperature change.

In the case of 10Gbps high speed optical communication, the chirp phenomenon of the DFB-LD chip and dispersion of optical fiber occur regardless of the operating temperature of the semiconductor laser diode chip. Therefore, the wavelength used for optical communication is required to transmit 10Gbps high speed optical communication over a long distance. Regardless of the wavelength gap between them, it is necessary to optically filter the optical signal output from the semiconductor laser diode chip.

In addition, a small form factor pluggable (SFP) type, an optical communication module that is currently being standardized around the world, requires a miniaturized optical device because its internal size is very small. Currently, packages equipped with semiconductor laser chips include TO (transistor outline) type, mini flat type, and butterfly type package housings. Among them, the TO type package is very small in volume and relatively low in price. It is actively used in optical communication networks for subscribers who need a lot. However, an optical filter for optically filtering the laser light emitted from the DFB-LD chip and the DFB-LD chip in an existing TO type package to increase the ER which is the ratio of the "1" signal to the "0" signal. Packages with built-in types have not been reported.

Since the oscillation wavelength varies depending on the operating temperature, the semiconductor laser diode chip transmits the "1" signal among the laser light signals emitted from the semiconductor laser diode chip effectively, and the "0" signal effectively blocks the change in the external environment temperature. A predetermined constant relationship must be maintained between the wavelength of the laser light emitted from the semiconductor laser diode chip and the wavelength of the transmission band of the optical filter. Otherwise, a signal of "1" to be transmitted is blocked and a problem of "0" signal to be blocked is transmitted well, which makes optical communication difficult.

[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 to solve the problems of the prior art, and the present invention optically filters the laser light emitted from the DFB-LD chip to increase the ER, which is the relative intensity ratio of the "1" signal and the "0" signal. It is an object of the present invention to provide an ultra-compact and inexpensive TO type laser device that emits laser light having a reduced oscillation line width by reducing the line width of an optical signal.

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

In addition, the present invention provides a constant relative wavelength position between the wavelength of the laser light emitted from the semiconductor laser diode chip and the transmission wavelength band of the optical filter when performing high-speed optical communication using a distributed feedback laser diode (DFB-LD). It is an object of the present invention to provide a laser device incorporating a wavelength stabilization device for providing a method of fixing.

In the case of the DFB-LD used for high-speed optical communication, adjacent optical communication wavelength channel spacing may be more than 20 nm, and optical communication wavelength channel spacing may be converted into frequency and have a wavelength gap of 50 GHz or 100 GHz. In particular, when the wavelength channel spacing of optical communication is 50 GHz or 100 GHz, it is a variable wavelength light source that uses one DFB-LD chip as a light source module corresponding to the optical wavelength of multiple DWDM-class optical communication by using the wavelength change according to the temperature of DFB-LD. Can be used.

In order to reduce the cost of the optical module in the 10Gbps high-speed, long-distance optical communication, it is preferable to use a TO-type package. Therefore, even when the wavelength of the optical communication is 20 nm or more and the wavelength of the DFB-LD is not adjusted, It is necessary to optically filter the laser light signal in order to increase it, and to increase the ER of the optical signal even when adjacent wavelength channels have DWDM-level wavelength spacing to keep the temperature of the DFB-LD constant. There is a need for a method of filtering optically. In addition, in the case of a wavelength tunable laser type that can be applied to wavelengths of multiple channels with one optical element by varying the wavelength of the DFB-LD by varying the temperature of the semiconductor laser diode chip in DWDM-class optical communication, There is a need for a method of optically filtering a laser light signal to increase it.

In the present invention, in the high-speed optical communication, a method of optically filtering the laser light emitted from the semiconductor laser diode chip in the process of packaging the DFB-LD using a TO-type package to provide long-term optical communication, DFB -Optical filtering method in case that the operating temperature of LD does not need to be kept constant, and the temperature of DFB-LD is kept constant by using thermoelectric element regardless of temperature change of external environment. In the case of adjustment, optically filtering the laser light inside the TO-type package, and changing the wavelength of the DFB-LD by using a thermoelectric element, and using the DFB-LD as a wavelength tunable laser in DWDM-class optical communication. We present an optical filter in a package that enables long-range communication.

To this end, the laser device according to the present invention includes a laser diode chip that emits laser light; Wavelength selective filters; A collimation lens disposed on an optical path between the laser diode chip and a wavelength selective filter to collimate the light emitted from the laser diode chip; 45 degree partial reflection mirror installed on the optical path between the laser diode chip and the wavelength selective filter to redirect the laser light traveling horizontally with respect to the package bottom surface to the laser light traveling perpendicular to the package bottom surface. ; And an optical wavelength monitoring photodiode disposed on an optical path through which the laser light emitted from the laser diode chip and reflected by the wavelength selective filter passes through the 45 degree partial reflection mirror.

When using a semiconductor laser diode chip having a DWDM-class wavelength stability, an optical element is used only at a specific wavelength, or a wavelength tunable laser corresponding to various wavelengths at intervals of 50 GHz or 100 GHz by changing the temperature of the semiconductor laser diode chip. In use, the laser diode chip and the wavelength selective filter are preferably disposed on one thermoelectric element. Therefore, in the case of controlling the temperature of the laser diode chip using the thermoelectric element, the oscillation wavelength of the laser diode chip is controlled using the thermoelectric element so that the "1" signal is relatively transmitted through the wavelength selective filter, and "0". The signal is relatively poorly transmitted by the wavelength selective filter so that the ER of the laser light transmitted to the optical fiber is larger than the ER of the state emitted from the laser diode chip, thereby enabling long-distance transmission.

If the temperature of the laser diode chip is not controlled, the temperature of the wavelength selective filter may be changed so that the wavelength band of the wavelength selective filter transmits the "1" signal better and the "0" signal is relatively more blocked, thereby increasing the ER. In this process, high-speed signals can be transmitted over long distances. In addition, when the temperature of the laser diode chip is not controlled, a method of maintaining a constant wavelength interval between the wavelength of the laser light and the transmission wavelength of the wavelength selective filter by controlling the temperature of the wavelength selective filter by using a heater is a thermoelectric element. Compared to the method of maintaining a constant relationship with the wavelength of the laser light and the wavelength band of the wavelength selective filter using the advantage that the electricity consumption is less. In the case of the thermoelectric element, when the cooling mode is used, the electricity consumption increases, but when the temperature of the laser diode chip is kept constant and the predetermined wavelength is emitted, the temperature of the laser diode chip is changed to the heating mode or It should be used in the cooling mode, but the temperature of the wavelength selective filter does not change the wavelength of the laser light but only the relative intensity of the "1" and "0" signals can be controlled so that the temperature of the wavelength selective filter can always be controlled in the heating mode. have.

In addition, it is preferable that the wavelength selective filter is an FP type etalon filter. The wavelength selective filter may be manufactured by stacking a dielectric film having a high refractive index and a low refractive index on a transparent substrate with respect to a wavelength of laser light to be considered. The wavelength selective filter may be a filter having one transmission peak or several transmission peaks in the wavelength range of the temperature change of the laser diode chip.

As described above, when the wavelength selective filter has several transmission wavelength peaks, the relationship between the several transmission peaks of the wavelength selective filter is variously applied according to the application form.

Particularly, in the case where the wavelength of the semiconductor laser diode chip is changed according to the external environmental temperature because the temperature of the semiconductor laser diode chip is not controlled, and the semiconductor laser diode chip is driven only by a predetermined specific wavelength, the transmission wavelength of the wavelength selective filter The peak may be any wavelength interval or singular or plural.

However, in the optical device having a wavelength tunable characteristic by controlling the temperature of the semiconductor laser diode chip by using a thermoelectric device, the wavelength selective filter has a transmission frequency interval determined by Equation 1 below.

[Equation 1]

Transmission Mode Frequency Spacing of Etalon Filters = (Ff-Ff × Ffilter / Flsaser) GHz

(Ff is the frequency interval of the transmission wavelength to be obtained, Ffilter is the transmission frequency mobility according to the temperature of the etalon filter, and Flaser is the frequency mobility according to the temperature of laser light emitted from the laser diode chip.)

On the other hand, a light diode for monitoring the light intensity is disposed on an optical path through which the laser light emitted from the laser diode chip passes through the 45 degree partial reflection mirror, or an optical path through which the laser light emitted from the rear surface of the laser diode chip proceeds. It is preferable that a photodiode for monitoring light intensity is disposed on the phase.

In addition, the 45-degree partial reflection mirror is coupled to the through-hole of the stand made of a rectangular parallelepiped silicon substrate formed by a dry etching method, the through-hole having an angle of 45 degrees with respect to one side, the angle of 45 degrees with respect to the floor It is preferable to be installed to have.

When the temperature of the semiconductor laser diode chip is not controlled, the temperature of the semiconductor laser diode chip is adjusted so that the wavelength of the laser light emitted from the semiconductor laser diode chip is constant, and the wavelength of the laser light emitted from the semiconductor diode chip is adjusted. Irrespective of the variable use, the heater temperature of the thermoelectric element or the wavelength selective filter is adjusted so that a value obtained by dividing the current flowing through the light wavelength monitoring photodiode by the current flowing through the light intensity monitoring photodiode is a constant value. Thus, the oscillation wavelength of the laser has a constant relationship with the wavelength selective filter and the transmission wavelength band, so that the laser light emitted from the laser diode chip performs filtering having different transmittances for the "1" signal and the "0" signal.

On the other hand, the sub-mount for the photodiode may be formed in a shape in which a metal pattern is continuously applied to a silicon {100} plane and a {111} plane based on silicon.

In addition, the thermoelectric element is measured temperature by the thermistor attached to the upper portion, the thermistor is preferably separated from the thermistor and electrically connected to the electrode pin via a thermistor connection submount attached to the thermoelectric element.

Here, the thermistor may be coated with a nonconductive polymer material such as epoxy.

Preferably, the 45 degree partial reflection mirror has a thickness of 0.1 mm to 0.25 mm.

In addition, the optical wavelength monitoring photodiode may be directly attached on the thermoelectric element.

In the present invention, for example, in a laser light for optical communication having a high speed modulation signal of 2.5 Gbps or more or 10 Gbps or more, a signal corresponding to a "1" signal has a high transmittance, and a laser light corresponding to a "0" signal. Manufacture of optical device for high speed long distance by inserting wavelength selective filter which selects small transmittance to enable high speed long distance communication, but effectively use low cost TO type package compared to butterfly type or mini flat package housing This lowers the cost.

In addition, the present invention does not control the temperature of the laser diode chip using the TO-type package, the case where the laser diode chip has a specific wavelength irrespective of the external environment temperature, and the laser diode regardless of the external environment. Regardless of the case where the wavelength of the laser light emitted from the chip is changed and controlled, there is an effect of transmitting a high speed optical signal to a long distance.

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

Figure 2 is a conceptual diagram of a laser for emitting a laser light of a narrow line width to the optical fiber by reducing the transmittance of the "0" signal compared to the "1" signal according to the present invention.

3 is a conceptual diagram illustrating the role of the wavelength selective filter in the narrow linewidth laser according to the present invention, and FIG. 3 (a) shows an example of a transmittance curve of the wavelength selective filter, and FIG. 3 (b) shows a reflectance of the wavelength selective filter. 3C is an example of the photocurrent generated by the light reflected by the wavelength selective filter and incident on the photodiode for optical wavelength monitoring.

4 is a conceptual diagram of a narrow linewidth laser according to the present invention, a conceptual diagram of a structure having a light wavelength monitoring photodiode and a light intensity monitoring photodiode.

5 is a conceptual diagram of a narrow linewidth laser according to the present invention, which is a conceptual diagram of another structure including a photodiode for light wavelength monitoring and a photodiode for light intensity monitoring.

6 is a conceptual diagram illustrating an operating principle of a narrow linewidth laser according to the present invention, in which FIG. 6A is an example of the transmittance of the wavelength selective filter, and FIG. 6B is a laser when the laser diode chip is modulated at high speed. An example of the frequency characteristics of the laser light of the "1" signal and the "0" signal emitted from the diode chip, Figure 6 (c) is the frequency characteristic of the laser light emitted from the laser diode chip multiplied by the transmittance of the wavelength selective filter Compared with the "1" signal of the laser light passing through the wavelength selective filter, the "0" signal is relatively reduced, thereby showing the frequency characteristic of the laser light with narrow line width.

7 is a conceptual diagram showing how the frequency characteristic of the wavelength selective filter used in the present invention changes with temperature.

8 is a view illustrating a laser device in which laser light emitted from a laser diode variably emits laser light corresponding to a plurality of ITU channels using an FP type etalon filter having periodic transmission characteristics according to an embodiment of the present invention. 8A is an example in which the frequency characteristic through which the wavelength selective filter transmits varies according to the temperature of the thermoelectric element, and in FIG. 8B, the emission wavelength characteristic of the laser diode chip which is modulated at high speed is shown. FIG. 8C illustrates an example in which the wavelength characteristics of the laser light emitted through the wavelength selective filter vary depending on the temperature of the thermoelectric element.

FIG. 9 illustrates a case in which a thermoelectric element is not mounted in a TO-type package and a submount to which a laser diode chip is attached is directly disposed on a stem bottom surface according to another exemplary embodiment of the present invention.

10 is a conceptual view illustrating the installation of a stand for easily fixing a 45 degree reflective mirror according to an exemplary embodiment of the present invention.

FIG. 11 is a conceptual diagram illustrating the installation of a photodiode for measuring the intensity of laser light emitted from a laser diode. FIG.

12 is an example of a rectangular parallelepiped photodiode submount having a rectangular cross section.

13 is an example of metal pattern deposition of a submount for a photodiode according to an embodiment of the present invention.

14 is an example of a conventional general thermistor placement method.

15 shows an example of a thermistor placement method according to an embodiment of 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 outside the TO-type package 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 wavelength selective filter mounted on the optical path of the laser light emitted from the semiconductor laser diode chip and the semiconductor laser diode chip in the TO-type package according to the present invention, for example, 10Gbps optical signal can be transmitted over a long distance It is a conceptual diagram showing the operation principle of the optical device.

In the following description, for convenience of description, the wavelength selective filter is described as an FP type etalon filter having a plurality of transmission peaks to explain the characteristics of the present invention. However, the wavelength selective filter has a line width of 0.5 instead of the FP type etalon filter. Thin film filters of less than nm can also be used. The thin film filter refers to a filter having only one transmission peak within a possible wavelength band of laser light generated from a laser diode chip, for example, a wavelength band of 10 nm to 50 nm. Typically, such a thin film filter may also have a structure of an FP etalon filter.

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 collimating lens 200 for collimating the light, a 45 degree partial reflection mirror 300 reflecting only a predetermined ratio of light collimated through the collimation lens 200, and the 45 degree partial reflection mirror Among the laser beams reflecting the 300, the FP-type etalon filter 400, which is a wavelength selective filter for transmitting some laser light and reflecting the remaining light, is included. The light reflected by the FP-type etalon filter 400 is returned to the 45-degree partial reflection mirror 300 again, and passes through the 45-degree partial reflection mirror 300 by a predetermined ratio to the 45-degree partial reflection mirror 300. The light incident to the light wavelength monitoring photodiode 500 is disposed below.

On the other hand, when the light reflected by the etalon filter 400 is reflected back from the 45-degree partial reflection mirror 300 and returned to the laser diode chip 200, the operating characteristics of the laser diode chip 200 becomes unstable. In order to prevent this, as shown in FIG. 2, the etalon filter 400 is attached to have a reflection angle of at least 1 degree with respect to the laser light incident to the etalon filter 400 and is reflected by the etalon filter 400. It is desirable to prevent light from returning to the laser diode chip 200.

In addition, in FIG. 2, when the reflectivity of the 45 degree partial reflection mirror 300 is high, the intensity of light incident on the optical wavelength monitoring photodiode 500 becomes weak, and thus it is difficult to perform the function of wavelength monitoring. Too low reflectivity decreases the intensity of the laser light emitted from the laser diode chip 100 and reaches the etalon filter 400. Therefore, the reflectance of the 45-degree partial mirror 300 should be adjusted to an appropriate level. According to a test result according to an embodiment of the present invention, the reflectivity of the 45-degree partial mirror 300 is about 80% to 97%. It is preferable.

Figure 3 (a) shows an example of the transmission characteristics according to the frequency of the FP-type etalon filter. The etalon filter has a characteristic that the transmission and reflection characteristics are periodically repeated. The fact that the FP-type etalon filter has periodic transmission characteristics means that it simultaneously has periodic reflection characteristics as shown in FIG. Therefore, among the laser light emitted from the laser diode chip in FIG. 2 and reaching the FP type etalon filter 400, the laser light reflecting the laser light has a specific reflection ratio according to the frequency of the laser light and passes through the 45 degree partial reflection mirror 300. To enter the light wavelength monitoring photodiode 500 under the 45-degree partial reflection mirror (300). Since the reflectance of the light reflected by the FP-type etalon filter 400 has a specific reflection ratio according to the frequency of the laser light as shown in FIG. 3 (b), the laser light incident on the photo-wavelength monitoring diode 500 The frequency dependence of the intensity is shown in (b) of FIG. 3, and thus the photocurrent in the optical wavelength monitoring photodiode 500 is shown in FIG. 3 (c) according to the frequency of the laser light. Accordingly, by measuring the photocurrent flowing in the optical wavelength monitoring photodiode 500 it is possible to determine the frequency characteristics of the laser light. For example, when the intensity of the photocurrent flowing to the optical wavelength monitoring photodiode 500 changes with respect to the intensity of the laser light emitted from the laser diode chip 100 at a constant intensity, this is the center of the wavelength of the laser light and the etalon peak. It means that the relative wavelength of the wavelength is changing.

Therefore, it can be seen that the wavelength of the laser light and the relative wavelength of the transmission wavelength band of the etalon filter 400 change by monitoring the change of the current flowing through the optical wavelength monitoring photodiode 500, and using this, the wavelength of the laser light May have a relatively constant wavelength spacing relationship with respect to the transmission wavelength of the etalon filter 400. Typically, the glass etalon filter 400 has a temperature dependence of a wavelength as small as 10 pm / ℃ while DFB-LD has a temperature dependency of a wavelength as large as 100 pm / ℃. Therefore, when assembling the optical device, the peak of the etalon filter 400 is set to the frequency set by the ITU, the wavelength emitted from the laser diode chip 100 is set to the peak of the etalon filter 400, and then the laser diode chip. When the temperature of the laser diode chip 100 is adjusted in a direction to offset the change by grasping the change in the wavelength of the laser light emitted from the light wavelength monitoring photodiode 500 as a current flowing in the laser diode chip ( The oscillation wavelength of 100) is stabilized at the frequency set in the ITU. In addition, the wavelength of the "1" signal of the laser light relatively passes through the etalon filter 400, and the "0" signal of the laser light is relatively poorly transmitted through the etalon filter 400. When the wavelength and the transmission wavelength band of the etalon filter 400 are set, the attenuation of the "0" signal is larger than that of the "1" signal, so that the light passing through the etalon filter 400 is emitted from the laser diode chip 100. Since the ER is larger than the signal of the laser light, it is easy to distinguish the signal from the optical receiver.

The photocurrent flowing to the optical wavelength monitoring photodiode 500 is changed not only by the difference between the reflectance wavelength band of the etalon filter 400 and the wavelength of the laser light, but also by the light emitted from the laser diode chip 100. Even when the intensity changes, the photocurrent flowing to the optical wavelength monitoring photodiode 500 is changed. The change of the photocurrent in the optical wavelength monitoring photodiode 500 due to the change in the intensity of the laser light emitted from the laser diode chip 100 does not change the correlation between the wavelength of the laser beam and the etalon filter 400. The effect by the variation in the intensity of the laser light emitted from the laser diode chip 100 should be removed.

4 illustrates a method of directly determining a change in light wavelength by directly measuring the intensity of laser light emitted from a laser diode chip in an embodiment of the present invention.

As shown in FIG. 4, the laser light emitted from the laser diode chip 100 reaches the 45 degree partial reflection mirror 300 after being collimated by the collimation lens 200. Since the 45 degree partial reflection mirror 300 has a predetermined ratio of transmission / reflection ratio, the 45 degree partial reflection mirror of the laser light emitted from the laser diode chip 100 and reaching the 45 degree partial reflection mirror 300 is obtained. The light component passing through 300 is incident on the light intensity monitoring photodiode 600 disposed on one side of the 45 degree partial reflection mirror 300. Therefore, the light intensity monitoring photodiode 600 can determine the intensity of the laser light emitted from the laser diode chip 100 by giving a photocurrent signal in proportion to the intensity of the laser light emitted from the laser diode chip 100. Therefore, when the value obtained by dividing the magnitude of the photocurrent flowing through the optical wavelength monitoring photodiode 500 by the current flowing through the photodiode monitoring photodiode 600 is maintained at a constant value, the center frequency of the laser light is a wavelength selective filter. The talon filter 400 is in a constant relationship with the center frequency of the transmission mode, thereby attenuating the " 0 " signal relatively more than the " 1 " signal to enable long distance communication. In FIG. 4, the relationship between the transmission band center frequency of the etalon filter 400 and the center frequency of the laser light is obtained by comparing the photocurrent flowing through the optical wavelength monitoring photodiode 500 and the light intensity monitoring photodiode 600. When the temperature of the thermoelectric element 900 is changed in a direction that cancels the change in the optical wavelength of the laser light based on the transmission wavelength of the etalon filter 400, the laser light is transmitted to the transmission wavelength band of the etalon filter 400. It can be made to have a relatively constant wavelength for.

At this time, the center frequency of the transmission mode of the etalon filter 400, which is the wavelength selective filter, is set to be the ITU set frequency, and then the magnitude of the light current flowing through the optical wavelength monitoring photodiode 500 is measured by the light intensity monitoring photodiode 600 When the temperature of the thermoelectric element 900 is changed so that the value divided by the current flowing in the constant state is constant, the center frequency of the oscillating laser light can be stabilized to be the ITU set frequency. The thermoelectric element 900 whose temperature is controlled is disposed above the stem 1000.

The light intensity monitoring photodiode 600 may be implemented in other configurations. The intensity of the laser light emitted from the laser diode chip 100 is emitted from the back of the laser diode chip 100 as shown in FIG. 5. The measurement is possible by arranging the photodiode 700 for photo-sensing intensity to measure the intensity of the light.

6A is a transmission characteristic according to the frequency of the FP type etalon filter. 6B is a frequency characteristic of the laser light of the "1" signal and the "0" signal emitted from the laser diode chip. The laser light of the " 1 " signal and the " 0 " signal emitted from the laser diode chip 100 passes through the FP-type etalon filter 400 and the frequency characteristics of the FP-type etalon filter 400 are multiplied. As shown in (c) of FIG. 6, laser light whose intensity of the “0” signal is reduced compared to the “1” signal is transmitted through the FP-type etalon filter 400 to be focused on the optical fiber. Therefore, the line width of the laser light transmitted through the optical fiber is less affected by the dispersion characteristics of the optical fiber because the "0" signal has a narrower line width than the "1" signal compared to the laser light emitted from the laser diode chip 100. By using the FP-type etalon filter 400 it is possible to transmit a longer distance than the laser light does not narrow the line width.

Typically, the FP type etalon filter 400 is made of glass having a parallel plane. In the case of such a glass material, the refractive index varies depending on the temperature. Accordingly, when the temperature of the FP-type etalon filter 400 is changed, the transmission frequency of the etalon filter 400 periodically changes as shown in FIG. 7. do.

The laser diode chip 100 typically produces a frequency shift on the order of 10-12 GHz / ° C. In contrast, the FP type etalon filter 400 brings about a frequency shift of 1 to 3 GHz / ° C. In the optical communication, communication must be made by using laser light of specific frequency specified in ITU-T. Therefore, in order to perform optical communication by changing the laser light, the wavelength should be changed only at the frequency set by ITU-T. In ITU-T, laser light with 50 GHz and 100 GHz frequency intervals is set for communication. Accordingly, the laser light frequency should be changed in 50 GHz and 100 GHz intervals. When the laser diode chip 100 changes to 10 GHz / ° C. and the FP-type etalon filter 400 changes to 2 GHz / ° C., the laser diode chip 100 and the FP-type etalon filter 400 may be thermoelectric elements. When it is adjusted to the same temperature by the 900, if the temperature of the thermoelectric element 900 is changed to control the wavelength of the laser light, the transmission wavelength band itself of the etalon filter 400 is also moved. Therefore, when the wavelength of the laser light 100 undergoes a temperature change of 50 GHz and 100 GHz, the etalon filter 400 must pass through this temperature change, and the transmission wavelength must match the ITU set frequency band.

Assume that the frequency mobility of the laser diode chip 100 is changed to Flaser GHz / ° C and the frequency of the etalon filter is changed to Ffilter GHz / ° C according to the temperature. In this case, when the frequency interval of the transmission wavelength band of the etalon filter 400 becomes the following Equation 1, the transmission mode of the laser diode chip 100 and the etalon filter 400 as shown in FIG. When the frequency matches the ITU set frequency at one temperature and then the frequency of the laser light emitted from the laser diode chip 100 at another temperature is changed to another ITU set frequency, the etalon filter 400 for this temperature change. ) And the light passing through the etalon filter 400 is set to the ITU set frequency in accordance with the ITU set frequency.

[수학식 1][Equation 1]

Transmission Mode Frequency Spacing of Etalon Filters = (100-100 × Ffilter / Flsaser) GHz

Here, Ffilter is the transmission frequency mobility according to the temperature of the etalon filter, Flaser is the frequency mobility according to the temperature of the laser light emitted from the laser diode chip.

Equation 1 is the transmission mode frequency interval of the etalon filter 400 in the wavelength tunable laser using the ITU set frequency of 100GHz interval, if the communication using the frequency of 50GHz interval etalon filter 400 The transmission mode frequency interval of is to be implemented by the following equation (2).

[수학식 2][Equation 2]

Transmission Mode Frequency Spacing of Etalon Filters = (50-50 × Ffilter / Flsaser) GHz

As such, the transmission mode interval of the etalon filter 400 may be arbitrarily determined, and may be changed to 25 GHz, 50 GHz, 100 GHz, 200 GHz, etc., but other arbitrary frequency intervals may also be adopted.

2 to 9 illustrate a case where a wavelength selective filter having a relatively small change in transmission wavelength is used as compared with laser light oscillated by the laser diode chip 100 according to a change in temperature. That is, a method of changing the temperature of the laser diode chip 100 so that the wavelength of the laser light has a constant relationship with the transmission wavelength band of the wavelength selective filter is described. Accordingly, a method of arranging the laser diode chip 100 on the thermoelectric element 900 is required, and the etalon filter 400 is also attached to the thermoelectric element 900 to attach the laser diode chip 100 and the etalon filter 400. Shows a method of controlling the temperature of the same with the same thermoelectric element (900). However, the method of using the thermoelectric element 900 is a method that consumes a lot of energy. In particular, when the thermoelectric element 900 is used in the cooling mode, a lot of energy is consumed. The method of controlling the wavelength of the laser light emitted from the laser diode chip 100 by adjusting the temperature of the laser diode chip 100 using the thermoelectric element 900 includes the wavelength of the laser light and the etalon filter 400. By extending the ER of the "1" signal and the "0" signal emitted from the laser diode chip 100 by making the correlation with the wavelength constant, not only enables the long-distance transmission of the high speed modulated optical signal, but also the wavelength of the laser light. This is a fixed way, so it is a proper way of DWDM method.

However, when it is not necessary to adjust the wavelength of the laser light, if you want to transmit a high-speed modulation signal over a long distance, it is not necessary to adjust the temperature of the laser diode chip 100, and adjust the temperature of the etalon filter 400 to filter the etalon filter. If the transmission wavelength band of 400 maintains a constant wavelength interval with the wavelength of the laser light, the "0" signal is attenuated more than the "1" t signal, thereby making the laser light having a narrow line width to enable long-distance transmission. can do. For this purpose, it is preferable to use an etalon filter coated with a heater as the etalon filter 400.

FIG. 9 illustrates a case in which the TO-type package is not equipped with a thermoelectric element and a submount to which a laser diode chip is attached is disposed directly on the stem bottom surface. The temperature of the laser diode chip 100 is exposed to an external environmental temperature. Accordingly, when the external environmental temperature is changed, the temperature of the laser diode chip 100 is changed to change the wavelength of the laser light that is oscillated. In this case, when the etalon filter 450 is manufactured in a form with a heater, the transmission wavelength peak of the etalon filter 450 is adjusted in advance by adjusting the temperature of the etalon filter 450. In this case, the "0" signal of the laser light passing through the etalon filter 450 is attenuated more strongly than the "1" signal, thereby transmitting a high-speed modulated optical signal over a longer distance. . In the structure of FIG. 9, it is preferable that the transmission wavelength of the etalon filter 450 is easily changed according to temperature. For this purpose, the etalon filter 450 is made of Silicon or InP such that the wavelength of the transmission wavelength is changed to about 0.09 nm / ° C. It is suitable to be made of a semiconductor material such as GaAs. In addition, in order to adjust the temperature of the etalon filter 450, a resistor of a metal thin film is attached to the surface of the etalon filter 450, and the etalon filter is generated by a current flowing through the metal thin film attached to the etalon filter 450. It is preferable that the temperature of 450 be adjusted. Attaching the metal thin film to the etalon filter 450 can be easily manufactured by the photolithography method and the metal deposition method. In addition, the etalon filter 450 preferably has a plurality of transmission peaks, and the etalon filter 450 in consideration of the ease of manufacturing an optical device and the plurality of transmission peak wavelengths of the etalon filter 450. ), The thickness of about 200um to 500um is appropriate.

Figure 10 shows the appearance of a 45-degree reflective mirror stand for easily mounting a 45-degree reflective mirror in the TO-type package according to an embodiment of the present invention.

Stand 350 according to an embodiment of the present invention is made of a rectangular parallelepiped, has a through hole 351 at an angle of 45 degrees to the base, the through-hole 351 is a flat 45-degree partial mirror ( 300 is inserted and mounted on the thermoelectric element. This structure allows the 45 degree partial reflection mirror 300 to be easily attached onto the thermoelectric element 900. The stand 350 may be a material having a good heat transfer rate, and a silicon substrate having a heat transfer rate of 170 W / m and an easy manufacturing of the through hole 351 by a dry etching process may be appropriate. In particular, since the silicon is very easy to adjust the width of the through hole 351 by the dry etching method, and the angle to the base is easy to adjust, the flat partial reflection mirror 300 of the silicon-type stand 350 is only the through hole 351. By simply inserting into the) flat plate reflection mirror 300 is placed at an angle of 45 degrees to facilitate the assembly process.

In general, when the external environment 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, a change in the external environmental temperature of the TO package can unevenly change the temperature of the internal component of the TO package. Since the independent temperature change of the resonator component material causes a non-uniform change in the effective optical length of the resonator, it is desirable to minimize heat exchange between the resonator component and the outer peripheral surface of the TO-type package. Therefore, it is preferable to keep the inside of the TO-type package in a vacuum, and in particular, the degree of vacuum is more preferably 0.2 atm or less.

On the other hand, the present invention can be modified in various forms. For example, the characteristics of the present invention can be driven by a laser driven at a specific wavelength without using a tunable laser. In this case, since the periodicity of the frequency interval of the etalon filter 400 is not necessary, the etalon filter 400 The periodicity of the frequency of does not need to follow the equation (1). In addition, when using the laser operating only at a specific wavelength of the characteristics of the present invention, instead of the FP type etalon filter 400, a plurality of high and low refractive index on the substrate transparent to the laser light of the wavelength considered, such as glass or quartz Any kind of filter having wavelength selectivity, such as a thin film filter manufactured by stacking a dielectric thin film, may be used.

Further, in the case of the flat 45 degree partial reflection mirror 300, if the thickness is too thick, it is difficult to be inserted into the limited standard of TO60, and if the thickness is too thin, there is a problem that the mechanical strength becomes weak. Therefore, the thickness of the flat 45 degree partial reflection mirror 300 is appropriately about 0.1 to 0.3mm, more preferably about 0.1 to 0.2mm to meet the standard of TO60.

FIG. 11 is a conceptual diagram illustrating a photodiode for measuring the intensity of laser light emitted from a laser diode chip. FIG. 11 is a cross-sectional view typically used to measure the intensity of laser light emitted horizontally from the laser diode chip 100. The

photodiodes

700 and 710 are shown attached to the

submounts

710 and 610 for the photodiode at right angles.

12 shows an example of a rectangular parallelepiped submount for photodiodes having a rectangular cross section.

In FIG. 12, a metal pattern for electrical connection of a photodiode is to be deposited on a rectangular submount made of a ceramic substrate such as alumina to form a metal thin film pattern. The metal pattern is formed on two consecutive surfaces curved at right angles. It is difficult to deposit all at once. Therefore, conventionally, there is a problem in that the cost is increased by depositing a metal pattern on each side of the metal pattern to be coated separately.

In accordance with this problem, the present invention provides a method of depositing a metal pattern on a photodiode submount at a time, and FIG. 13 shows an example of metal pattern deposition on such a photodiode submount.

As shown in FIG. 13, in the embodiment of the present invention, the silicon substrate is etched to expose the {100} plane and the {111} plane, and then an electrical insulating layer is deposited on the etched silicon substrate, and the {100} plane and { A method of fabricating the photodiode submounts 615 and 715 by simultaneously depositing a metal pattern on the surface 111} is provided. As described above, the photodiode submounts 615 and 715 are not only inexpensive to fabricate but also have a rectangular cross-section, whereas the photodiode submounts 610 and 710 have a flat 45 degree angle. Since the difference between the inclination angle and the placement angle of the partial reflection mirror 300 is small, it may be more closely disposed in the flat 45 degree partial reflection mirror 300, thereby helping to utilize the space inside the TO package.

On the other hand, in order to stabilize the wavelength of the laser device, the thermistor mounted on the thermoelectric element 900 inside the package and measuring the temperature should not be affected by temperature changes outside the TO package.

14 illustrates a conventional general thermistor disposition method. The thermistor 950 has an electrical connection with the electrode pin 1010 by Au wire 1020. At this time, since the electrode pin 1010 is not a temperature controlled portion by the thermoelectric element 900, the electrode fin 1010 has a temperature different from that of the thermoelectric element 900, and thus, the heat exchange between the electrode pin 1010 and the thermistor 950 is performed. This occurs, causing the thermistor 950 to be inaccurate in measuring the temperature of the thermoelectric element 900.

Figure 15 shows a thermistor placement method according to an embodiment of the present invention presented in accordance with this problem.

As shown in FIG. 15, in the embodiment of the present invention, the submount 980 for connecting the thermistor between the electrode pin 1010 and the thermistor 950 to suppress heat exchange between the electrode pin 1010 and the thermistor 950. And attach the electrode pin 1010 and thermistor connection submount 980 to the Au wire 1020 via the thermistor connection submount 980, and the Au wire 1030 to the submount for thermistor connection. 980 and the thermistor 950 are connected. Accordingly, since the heat flowing to the Au wire 1020 is absorbed by the thermistor connection submount 980 due to the temperature difference between the electrode pin 1010 and the thermoelectric element 900, the amount of heat flowing to the Au wire 1030 is minimized. The temperature measurement of the thermistor 950 can be more accurate. As described above, the thermistor 950 and the electrode pin 1010 are separated from the thermal path between the thermoelectric element 900 and the thermistor 950 through the thermistor connection submount 980 independently attached to the upper portion of the thermoelectric element 900. ) Is electrically connected to each other, the inaccuracy due to the change of the external environment temperature during the temperature measurement of the thermoelectric element 900 through the thermistor 950 can be alleviated.

In addition, the heat exchange between the thermistor 950 and the air inside the TO package also causes the thermistor 950 to be inaccurate in measuring the temperature of the thermoelectric element 900, so that the thermistor 950 is wrapped with non-conductive epoxy. In addition, the thermoelectric element 900 of the thermistor 950 increases the accuracy of the temperature measurement.

On the other hand, in the case of the 45-degree partial reflection mirror 300 is too thick, there is a disadvantage that the space in the package is reduced, if too thin, there is a risk of shaking in the vibration. In the present invention, the 45-degree partial reflection mirror 300 was produced by various tests, and according to the results of the experiment, the 45-degree partial reflection mirror 300 had a thickness of about 0.1 mm to 0.25 mm.

In addition, although the optical wavelength monitoring photodiode 500 disposed below the 45 degree partial reflection mirror 300 has been described as being fixedly arranged on one side of the upper portion of the optical wavelength monitoring photodiode submount 510, the optical wavelength The monitoring photodiode 500 may be disposed on the thermoelectric element 900. This is because the upper plate of the thermoelectric element 900 has a thermal expansion coefficient similar to that of the optical wavelength monitoring photodiode 500, thereby minimizing the mechanical stress applied to the optical wavelength monitoring photodiode 500 according to the temperature variation. The monitoring photodiode 50 can be assembled in such a way that it is directly attached to the top of the thermoelectric element 900. In this case, there is an advantage that the lower space of the 45 degree partial reflection mirror 300 can be used as efficiently as possible.

As described above, the present invention may be modified in various forms, and the present invention is not limited to the above-described embodiments, and the technical spirit of the present invention and the following by those skilled in the art to which the present invention pertains. Of course, various modifications and variations can be made within the equivalent scope of the claims to be described.

[Description of the code]

100: laser diode chip

110: submount for laser diode chip

200: collimation lens

300: 45 degree partial reflection mirror

350: 45 degree partially reflective mirror stand

351: through hole

400: FP type etalon filter

450: etalo filter with heater

500: Photodiode for light wavelength monitoring

510: Submount for photodiode for light wavelength monitoring

600: Photodiode for light intensity monitoring

610: Submount for photodiode for light intensity monitoring

700: photodiode for light intensity monitoring

710: submount for photodiode for light intensity monitoring

615, 715: submounts for photodiodes

900: thermoelectric element

950: Thermistor

960: submount for thermistor

980: submount for thermistor connection

1000: Stem

1010: electrode pin

1020, 1030: Au wire

Claims

In a semiconductor laser device,

A laser diode chip 100 for emitting laser light;

Wavelength selective filters;

A collimation lens (200) installed on an optical path between the laser diode chip (100) and a wavelength selective filter, for collimating light emitted from the laser diode chip (100);

Is installed on the optical path between the laser diode chip 100 and the wavelength selective filter, 45 degrees to redirect the laser light traveling horizontally with respect to the package bottom surface to the laser light traveling perpendicular to the package bottom surface Partial reflection mirror 300;

And a light wavelength monitoring photodiode 500 disposed on an optical path through which the laser light emitted from the laser diode chip 100 and reflected by the wavelength selective filter pass through the 45 degree partial reflection mirror 300. Laser device, characterized in that.
The method of claim 1,

The laser diode chip (100) and the wavelength selective filter is a laser device, characterized in that disposed on one thermoelectric element (900).
The method of claim 1,

The wavelength selective filter is a laser device, characterized in that the FP type etalon filter (400).
The method of claim 1,

The wavelength selective filter is a laser device, characterized in that the dielectric film is laminated with a high refractive index and low.
The method of claim 1,

Laser device, characterized in that the light intensity monitoring photodiode (600) is disposed on the optical path through which the laser light emitted from the laser diode chip (100) passes through the 45 degree partial reflection mirror (300).
The method of claim 1,

Laser device having a line width reduced wavelength stabilization device, characterized in that the light intensity monitoring photodiode 700 is disposed on the optical path through which the laser light emitted from the back of the laser diode chip (100).
The method of claim 3, wherein

The FP type etalon filter 400 is a laser device, characterized in that the transmission frequency interval is determined by the following equation (1).

[Equation 1]

Transmission Mode Frequency Spacing of Etalon Filters = (Ff-Ff × Ffilter / Flsaser) GHz

(Ff is the frequency interval of the transmission wavelength to be obtained, Ffilter is the transmission frequency mobility according to the temperature of the etalon filter, and Flaser is the frequency mobility according to the temperature of laser light emitted from the laser diode chip.)
The method of claim 7, wherein

The Ff is a laser device, characterized in that any one of 25, 50, 100, 200.
The method of claim 1,

The wavelength selective filter is a laser device, characterized in that the line width of the transmission wavelength band is 0.5nm or less.
The method of claim 1,

The 45 degree partial reflection mirror 300

A through hole 351 having an angle of 45 degrees with respect to one side is fixedly coupled to the through hole 351 of the stand 350 made of a rectangular parallelepiped silicon substrate formed by a dry etching method, thereby providing an angle of 45 degrees with respect to the floor. It is installed to have a laser device.
The method of claim 5 or 6,

The oscillation wavelength of the laser is adjusted by adjusting the temperature of the thermoelectric element 900 such that a value obtained by dividing the current flowing through the optical wavelength monitoring photodiode 500 by the current flowing through the light intensity monitoring photodiode 600 and 700 is minimized. Stabilizing a laser device characterized in that.
The method according to claim 5 or 6,

The photodiode submount (610) (710) is a laser device, characterized in that the metal pattern is applied to the silicon {100} plane and {111} plane in succession of silicon as a base material.
The method of claim 2,

The thermoelectric element 900 has a temperature measured by a thermistor 950 attached to an upper portion thereof, and the thermistor 950 is separated from a thermistor 950 so as to attach a thermistor connection submount attached to an upper portion of the thermoelectric element 900 ( Laser device, characterized in that electrically connected to the electrode pin 1010 via 980.
The method of claim 13,

The thermistor 950 is a laser device, characterized in that the coating with a non-conductive polymer material.
The method of claim 1,

The 45 degree partial reflection mirror 300 is a laser device, characterized in that the thickness of 0.1mm ~ 0.25mm.
The method of claim 1,

The optical wavelength monitoring photodiode 500 is a laser device, characterized in that attached to the thermoelectric element (900).
The method of claim 1,

The wavelength selective filter is a laser device, characterized in that the dielectric film is formed by laminating a high refractive index and a low refractive index on a glass or quartz substrate.
The method of claim 1,

The wavelength selective filter is a laser device, characterized in that the high refractive index and low dielectric film is laminated on a semiconductor substrate including any one of Silicon, InP, GaAs.
The method of claim 18,

And a thin film heater is further attached to the wavelength selective filter.
The method according to claim 5 or 6,

The laser diode chip 100 and the wavelength selective filter are disposed on one thermoelectric element 900.

The temperature of the thermoelectric element (900) is a laser device, characterized in that the value of the photocurrent flowing through the optical wavelength monitoring photodiode (500) and the photocurrent flowing through the light intensity monitoring photodiode (600) (700) is adjusted to be constant.
The method of claim 5 or 6,

The wavelength selective filter is manufactured by stacking a dielectric film having a high refractive index and a low refractive index on a semiconductor substrate including any one of silicon, inP, and GaAs.

The temperature of the wavelength selective filter is a laser device, characterized in that the value of the photocurrent flowing through the optical wavelength monitoring photodiode (500) and the photocurrent flowing through the light intensity monitoring photodiode (600) (700) is adjusted to be constant.
The method of claim 21,

The wavelength selective filter is attached to a resistor formed in a metal thin film pattern, the laser device, characterized in that the temperature is controlled by the current flowing through the metal thin film.