KR102546248B1 - Wavelength tunable optical sub-assembly for bi-directional fiber optic telecommunication - Google Patents

Abstract

The wavelength tunable optical subassembly for bi-directional optical communication according to the present invention uses an optical path separator that separates the optical paths of the transmission light and the reception light, so that there is no need to separately provide an optical fiber for transmitting light and an optical fiber for receiving light. Since bi-directional optical communication is possible with just this, the efficiency of communication network operation can be improved. In addition, in the wavelength tunable optical subassembly for bidirectional optical communication according to the present invention, since the second etalon filter, the second temperature sensing element, and the second temperature control element are housed inside the housing, the number of receiving wavelength bands is fixed. Credit photodiodes and receiving TOs can also be used. That is, according to the present invention, the range of elements that can be utilized in the receiving end side is widened, and the stock burden of the receiving photodiode or the receiving TO at the receiving end side is reduced.

Description

Wavelength tunable optical subassembly for bidirectional optical communication {WAVELENGTH TUNABLE OPTICAL SUB-ASSEMBLY FOR BI-DIRECTIONAL FIBER OPTIC TELECOMMUNICATION}

The present invention relates to a wavelength tunable optical subassembly for bi-directional optical communication provided at a subscriber side or a central office side and enabling bi-directional communication by transmitting and receiving light between a subscriber and a central office.

In order to meet the demand for various multimedia services such as smartphones, high-performance televisions (HDTV, 3D TV, smart TV), e-commerce and Video On Demand (VOD), capacity expansion of existing optical communication networks is required. For these reasons, Wavelength-Division Multiplexing (WDM) technology is being recognized as the ultimate alternative.

WDM technology is a technology that bundles and transmits light having different wavelengths through a single optical fiber. WDM technology provides each subscriber with a dedicated, point-to-point channel with unique and independent wavelength assignments, and because each subscriber uses its own assigned optical signal wavelength, it is the highest technology to date. speed can be provided.

For example, WDM-PON (PON: Passive Optical Network) technology uses more wavelengths than Time-Division Multiplexing (TDM)-PON, which is a time-division method, so it guarantees bidirectional symmetric service, allocates bandwidth independently, Since the corresponding subscriber receives optical signals of different wavelengths, it has an advantage of excellent security.

In order to effectively implement such a WDM-PON technology, it is necessary to improve network operation efficiency by enabling bi-directional transmission and reception of light in an optical subassembly provided on the subscriber side or the central office side. In addition, the wavelength of the transmission light output from the laser diode included in the transmission terminal of the optical subassembly must be lockable and variable, and the photodiode included in the reception terminal of the optical subassembly must be able to receive only light of a specific wavelength as reception light. . In addition, the manufacturing efficiency of the optical subassembly can be applied to the optical subassembly regardless of the wavelength of the receiving light, rather than separately manufacturing the receiving TO (transistor outline package) according to the wavelength of the receiving light. also needs to be improved.

Meanwhile, Patent Document 1 discloses a tunable optical receiver including a wavelength tunable filter through which laser light emitted from an optical fiber passes, and a photodiode for receiving the laser light passing through the wavelength tunable filter.

Korean Registered Patent Publication No. 10-1950733 (2019.02.15.)

An object of the present invention is to provide a wavelength tunable optical subassembly for bi-directional optical communication capable of improving the efficiency of communication network operation.

In addition, the present invention is a wavelength tunable optical sub for bidirectional optical communication capable of locking and varying the wavelength of transmission light output from a laser diode included in a transmitter and receiving only light of a specific wavelength as reception light in a photodiode included in a receiver. Its purpose is to provide an assembly.

In addition, an object of the present invention is to provide a wavelength tunable optical subassembly for bi-directional optical communication that eliminates the need to utilize a separately manufactured reception TO according to the wavelength of received light.

However, the technical problem to be solved by the present invention is not limited to the above-mentioned problem, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

In order to achieve the above object, an optical module for communication according to the present invention includes a laser diode outputting transmission light; a first monitoring photodiode that detects the transmission light output to the rear of the laser diode; an optical diverter splitting the transmitted light output to the front of the laser diode into reflected light and transmitted light; a first etalon filter that transmits the reflected light in a first wavelength band; a second monitoring photodiode to detect the reflected light passing through the first etalon filter; a first temperature sensing element for sensing temperatures of the laser diode and the first etalon filter; a first temperature control element for controlling temperatures of the laser diode and the first etalon filter; an optical path separator disposed in the optical path of the transmitted light to separate the optical path of the transmitted light and the received light; an optical fiber into which the transmitted light passing through the optical path splitter is incident; a second etalon filter for transmitting the received light in a second wavelength band after passing through the optical path splitter after being emitted from the optical fiber; a second temperature sensing element for sensing a temperature of the second etalon filter; a second temperature control element for controlling the temperature of the second etalon filter; and a receiving photodiode for detecting the received light passing through the second etalon filter.

An optical module for communication according to the present invention has a first etalon filter supporting the first etalon filter and provided with a reflective light passage hole so that the reflected light passing through the first etalon filter can be incident to the second monitoring photodiode. The apparatus may further include an etalon filter support member, wherein the second monitoring photodiode is disposed behind the first etalon filter support member so that reflected light passing through the first etalon filter passes through the reflected light passage hole. It may be incident on the second monitoring photodiode.

An optical module for communication according to the present invention supports the second etalon filter and is provided with a receiving light passage hole so that the receiving light passing through the second etalon filter can be incident to the receiving photodiode. It may further include a second etalon filter support member, wherein the reception photodiode is disposed behind the second etalon filter support member so that reflected light passing through the second etalon filter passes through the reception light passage hole. It can be incident on the photodiode for reception.

The transmitted light is input to a first port of the optical path splitter, the transmitted light is output to the second port of the optical path splitter and enters the optical fiber, and the received light emitted from the optical fiber is input. The received light may be output to a third port of the optical path separator and may be incident to the second etalon filter.

An optical module for communication according to the present invention includes the laser diode, the first monitoring photodiode, the optical diverter, the first etalon filter, the second monitoring photodiode, the first temperature sensing element, and the first temperature sensor. The control element, the optical path separator, the second etalon filter, the second temperature sensing element and the second temperature control element may further include an enclosure accommodating therein, wherein the optical fiber is outside the enclosure and , It may be disposed on a path along which the transmitted light passing through the optical path separator proceeds, and the receiving photodiode is outside the enclosure and disposed along a path along which the received light passing through the second etalon filter proceeds. It can be.

The first temperature control element and the second temperature control element may be in direct contact with the enclosure.

An optical module for communication according to the present invention includes a first window provided on a path of the transmitted light passing through the optical path separator and sealing one side of the enclosure; and a second window disposed on a path through which the received light passing through the second etalon filter proceeds, and sealing the other side of the enclosure.

An optical module for communication according to the present invention includes a first collimated light lens disposed between the first window and the optical fiber and coupled to one side of the enclosure; and a second parallel light lens disposed between the second window and the receiving photodiode and coupled to the other side of the enclosure.

An optical module for communication according to the present invention includes a transistor outline package (TO) accommodating the receiving photodiode; And it may further include a fixing member mounted outside the TO, and the fixing member may be fixed to the enclosure by laser welding.

An optical module for communication according to the present invention controls the first temperature control element based on the temperatures of the laser diode and the first etalon filter sensed by the first temperature sensing element, and the second temperature sensing element The controller may further include a controller for controlling the second temperature control element based on the temperature of the second etalon filter sensed by the temperature of the second etalon filter.

According to the present invention, due to the optical path separator that separates the optical paths of transmitted light (i.e., transmitted light) and received light, there is no need to separately provide an optical fiber for transmitted light (i.e., transmitted light) and an optical fiber for received light, Since bi-directional optical communication is possible with only one optical fiber, it is possible to improve the efficiency of communication network operation.

In addition, according to the present invention, the wavelengths of light detected by the first monitoring photodiode and the second monitoring photodiode and the transmission light output from the laser diode through the first etalon filter can be locked and varied, and the second etalon Through the filter, only light of a specific wavelength can be received as receiving light from the receiving photodiode, so that the accuracy and efficiency of bidirectional optical communication can be improved.

In addition, according to the present invention, since the second etalon filter, the second temperature sensing element, and the second temperature control element are accommodated inside the enclosure, a receiving photodiode or a receiving TO having a fixed receiving wavelength band can also be used. Anything can be used. That is, according to the present invention, the range of devices that can be utilized in the receiving terminal side is widened, and the burden of inventory of receiving photodiodes or TOs for reception having a fixed receiving wavelength band is reduced.

1 is a cross-sectional view of a wavelength tunable optical subassembly for bi-directional optical communication according to an embodiment of the present invention.
2 to 6 are three-dimensional views of a wavelength tunable optical subassembly for bidirectional optical communication according to an embodiment of the present invention.
FIG. 7 is a diagram illustrating a path of transmission light in the wavelength tunable optical subassembly for bidirectional optical communication of FIG. 1 .
FIG. 8 is a diagram illustrating a path of received light in the wavelength tunable optical subassembly for bidirectional optical communication of FIG. 1 .
9 is a diagram schematically illustrating transmitted light reflected and transmitted by an optical diverter.
10 is a diagram showing a transmission spectrum of an etalon filter by way of example.
11 is a diagram for explaining how the controller stabilizes the wavelength of transmission light.
12 is a diagram for explaining how the controller locks and varies the wavelength of transmission light.
13 is a diagram for explaining how the controller changes the wavelength transmitted through the second etalon filter.

Hereinafter, a wavelength tunable optical subassembly for bidirectional optical communication according to the present invention will be described in detail with reference to the accompanying drawings. The accompanying drawings are provided as examples to sufficiently convey the spirit of the present invention to those skilled in the art, and the present invention may be embodied in other forms without being limited to the drawings presented below.

1 is a cross-sectional view of a wavelength tunable optical subassembly for bidirectional optical communication according to an embodiment of the present invention, and FIGS. 2 to 6 are three-dimensional views of the wavelength tunable optical subassembly for bidirectional optical communication according to an embodiment of the present invention. FIG. 7 is a view showing a path of transmission light in the wavelength tunable optical subassembly for bidirectional optical communication of FIG. 1 , and FIG. 8 is a view showing a path of reception light in the wavelength tunable optical subassembly for bidirectional optical communication of FIG. 1 .

1 to 8, the wavelength tunable optical subassembly 1000 for bi-directional optical communication according to an embodiment of the present invention can be provided on the subscriber side and the central office side, and thus the subscriber and the central office can interact with each other. Two-way optical communication can be performed between them.

A wavelength tunable optical subassembly 1000 for bidirectional optical communication according to an embodiment of the present invention may include a housing 100, an optical fiber 200, and a photodiode 300 for reception.

The enclosure 100 includes a laser diode 11, a first monitoring photodiode 12, an optical diverter 13, a first etalon filter 14, a second monitoring photodiode 15, and a first temperature sensing element. (16), a first temperature control element 17, an optical path separator 18, a second etalon filter 19, a second temperature sensing element 20 and a second temperature control element 21, etc. Acceptable.

The laser diode 11 serves to output transmission light, and at this time, the transmission light may be output to the front and rear of the laser diode 11, respectively.

Transmission light output to the rear of the laser diode 11 (a direction from the laser diode 11 to the first monitoring photodiode 12 in FIG. 1 ) may be detected by the first monitoring photodiode 12 . The first monitoring photodiode 12 may detect the transmitted light in the form of a photocurrent, and information on the detected transmitted light may be transmitted to the controller 600 to be described later. In this case, the controller 600 may obtain the intensity of the transmitted light through information on the transmitted light detected by the first monitoring photodiode 12 .

Transmitted light output to the front of the laser diode 11 (in the direction from the laser diode 11 to the optical diverter 13 in FIG. 1) can be converted into parallel light by the collimated light lens 22 for the transmitted light. there is. Transmitted light converted into parallel light by the collimated light lens 22 for the transmitted light may pass through the isolator 23 and be incident to the optical splitter 13 . Here, the isolator 23 serves to allow light to travel from the laser diode 11 only toward the optical diverter 13 and to prevent light from traveling in the opposite direction.

The light splitter 13 splits the transmitted light output forward of the laser diode 11 into reflected light and transmitted light. Here, the optical diverter 13 may correspond to a beam splitter capable of partially transmitting and partially reflecting incident light.

FIG. 9 is a diagram schematically showing transmitted light reflected and transmitted by the optical diverter 13. Referring to FIG. As shown in FIG. 9, the optical splitter 13 transmits 90 to 99% of the transmitted light output from the laser diode 11 and reflects the remaining 1 to 10% toward the wavelength locker. can be designed to Here, the wavelength stabilizer may include an optical diverter 13, a first etalon filter 14, and a second monitoring photodiode 15, and a first temperature sensing element 16 and a first temperature control element ( 17) is essential for wavelength stabilization of transmitted light, so the first temperature sensing element 16 and the first temperature control element 17 may also correspond to the components of the wavelength stabilizer.

The first etalon filter 14 serves to selectively transmit the reflected light split by the light diverter 13 in a first wavelength band. The first etalon filter 14 may be formed by filling a transmissive material such as glass between reflective surfaces positioned at both ends. Here, the first wavelength band means a wavelength band that can pass through the first etalon filter 14 .

10 is a diagram showing a transmission spectrum of the first etalon filter 14 as an example. The free spectral range (FSR) and transmission bandwidth of the first etalon filter 14 shown in FIG. 10 are influenced by the material of the first etalon filter 14, its thickness, multilayer thin film coating, and the incident angle of reflected light. As shown in FIG. 10, the transmission spectrum of the first etalon filter 14 exhibits a cyclic characteristic in which transmittance increases at regular intervals, where the period of the transmission spectrum is referred to as FSR, and the transmission bandwidth is It can be determined based on the peak transmittance. Meanwhile, the first wavelength band of the first etalon filter 14 may be adjusted by changing the temperature of the first etalon filter 14 .

The reflected light passing through the first etalon filter 14 may be detected by the second monitoring photodiode 15 . Like the first monitoring photodiode 12 , the second monitoring photodiode 15 may also detect reflected light in the form of a photocurrent, and information on the detected reflected light may be transmitted to the controller 600 . In this case, the controller 600 may obtain the intensity of the reflected light through information on the reflected light detected by the second monitoring photodiode 15 .

The first etalon filter 14 may be supported by the first etalon filter support member 24 . More specifically, the first etalon filter 14 may be fixed to the front side of the first etalon filter support member 24 (the side on which the reflected light is incident on the first etalon filter support member 24).

In the first etalon filter support member 24, a reflected light passage hole (through which the reflected light is emitted from the first etalon filter support member 24) passes through the front and rear sides of the first etalon filter support member 24. 25) is provided, and a second monitoring photodiode 15 may be disposed behind the first etalon filter support member 24. In this case, the reflected light passing through the first etalon filter 14 may be incident to the second monitoring photodiode 15 through the reflected light passage hole 25 . When the first etalon filter 14, the first etalon filter support member 24, and the second monitoring photodiode 15 have such an arrangement relationship, the optical subassembly 1000 according to the present invention is relatively compact. be able to produce.

The first temperature sensing element 16 serves to sense the temperatures of the laser diode 11 and the first etalon filter 14 . To this end, the first temperature sensing element 16 may be formed of a thermistor or may include the thermistor. Although only one first temperature sensing element 16 is shown in FIG. 1 and the like, the first temperature sensing element 16 is used to separately sense the temperature of the laser diode 11 and the temperature of the first etalon filter 14 may be two. That is, the first temperature sensing element 16 may be attached to the laser diode 11 and the first etalon filter 14 (or the first etalon filter support member 24), respectively.

The first temperature control element 17 serves to control the temperatures of the laser diode 11 and the first etalon filter 14 . The first temperature control element 17 may be formed of or include a Thermo-Electric Cooler (TEC) to change the temperatures of the laser diode 11 and the first etalon filter 14 . The controller 600 may apply a voltage to both electrodes of the first temperature control element 17 to allow current to flow, and the temperature of the laser diode 11 and the first etalon filter 14 may be adjusted according to the direction in which the current flows. can be raised or lowered. Although only one first temperature control element 17 is shown in FIG. 1 and the like, in order to separately control the temperature of the laser diode 11 and the temperature of the first etalon filter 14, the first temperature control element 17 may be two.

The first temperature control element 17 controls the temperatures of the laser diode 11 and the first etalon filter 14 through an exothermic action or an endothermic action. At this time, if the heat generated by the temperature control of the first temperature control element 17 is not smoothly discharged to the outside of the optical subassembly 1000, the temperature of the laser diode 11 and the first etalon filter 14 is properly controlled. can't be Accordingly, by directly contacting the first temperature control element 17 with the enclosure 100, the heat generated by the temperature control of the first temperature control element 17 is smoothly discharged to the outside of the light subassembly 1000. It is desirable to do That is, when the first temperature control element 17 is in direct contact with the enclosure 100, heat generated by temperature control of the first temperature control element 17 can be discharged to the outside through the enclosure 100. Because of this, the temperature of the laser diode 11 and the first etalon filter 14 is precisely controlled, and as a result, the wavelength of the transmission light output from the laser diode 11 can be accurately varied and locked to a specific wavelength. .

Meanwhile, a first base plate 26 may be disposed above the first temperature control element 17 . In addition, the above-described laser diode 11, the first monitoring photodiode 12, the collimated light lens 22 for transmitting light, the isolator 23, the optical splitter 13, A first etalon filter 14 , a first etalon filter support member 24 , a second monitoring photodiode 15 , and a first temperature sensing element 16 may be disposed.

In particular, the first temperature sensing element 16 may directly contact the first base plate 26 at an upper portion of the first base plate 26 . When the first temperature control element 17 controls temperature by exothermic action or heat absorbing action, the temperature of the first base plate 26 is the temperature of the laser diode 11 and the temperature of the first etalon filter 14 temperature can be Accordingly, when the first temperature sensing element 16 is in direct contact with the first base plate 26, the first temperature sensing element 16 is a laser diode disposed on the first base plate 26 ( 11) and the temperature of the first etalon filter 14 can be sensed simultaneously.

11 is a diagram for explaining how the controller 600 stabilizes the wavelength of transmission light.

Referring to FIG. 11 , the controller 600 is connected to the first monitoring photodiode 12 and the second monitoring photodiode 15, and thereby transmits light detected by the first monitoring photodiode 12. Information and information on reflected light detected by the second monitoring photodiode 15 may be obtained.

As described above, the intensity of the transmitted light output to the rear of the laser diode 11 is detected by the first monitoring port diode 12 . In addition, the transmission light output to the front of the laser diode 11 is branched in a small amount by the light splitter 13, and the reflected light split in a small amount passes through the first etalon filter 14 having a wavelength dependency, and then passes through the second etalon filter 14. The intensity is detected by the monitoring photodiode 15.

The controller 600 is connected to the first temperature sensing element 16, and thus the temperature of the laser diode 11 and the temperature of the first etalon filter 14 sensed by the first temperature sensing element 16 can be obtained. In addition, the controller 600 is connected to the first temperature control element 17, based on the temperature of the laser diode 11 and the temperature of the first etalon filter 14, the first temperature control element 17 can control.

12 is a diagram for explaining how the controller 600 locks and varies the wavelength of transmission light.

The upper graph of FIG. 12 shows the photocurrent (indicating light intensity) detected by the first monitoring photodiode 12 and the second monitoring photodiode 15 with respect to wavelength. According to the upper graph of FIG. 12 , the intensity of the transmitted light detected by the first monitoring photodiode 12 has a constant value regardless of the wavelength, whereas the intensity of the reflected light detected by the second monitoring photodiode 15 It can be seen that has a wavelength dependency due to the first etalon filter 14 that transmits only the light having the first wavelength band.

The lower graph of FIG. 12 shows the intensity of transmitted light detected by the first monitoring photodiode 12 and the second monitoring photodiode 15 through a comparator (not shown) provided therein by the controller 600. It represents a value obtained by comparing the intensity of the detected reflected light (ie, a comparison value).

The controller 600 controls the laser diode 11 sensed by the first temperature sensing element 16 and the first etalon filter (so that the comparison value becomes the locking wavelength shown in the lower graph of FIG. 12). Based on the temperature of 14), the first temperature control element 17 can be controlled. When the controller 600 controls the first temperature control element 17, the wavelength of the transmission light output from the laser diode 11 is changed, and the first wavelength band of the first etalon filter 14 is also changed. do.

The locking wavelength must be a wavelength exactly corresponding to the ITU-grid. To this end, the controller 600 controls the first temperature control element 17 so that the linear part of the slope of the photocurrent detected by the second monitoring photodiode 15 comes to the locking wavelength, and the controller 600 controls the The intensity of the photocurrent detected by the first monitoring photodiode 12 is minutely changed using an internal amplifier (not shown) so that the comparison value exactly matches the wavelength corresponding to the ITU-grid.

In this way, the controller 600 reads the change in wavelength by the photocurrent detected by the first monitoring photodiode 12 and the second monitoring photodiode 15, and the temperature of the laser diode 11 based on the change. By adjusting the current or the like, the wavelength of the transmission light output from the laser diode 11 is controlled. Whether to use temperature or current as a variable for controlling the wavelength of the transmission light output from the laser diode 11 is a matter to be individually selected according to the type of laser diode 11 used, and the DFB laser diode (distributed feedback In the case of a laser diode), temperature is generally used as a means for controlling the wavelength of transmitted light.

On the other hand, the optical path separator 18 is disposed in the optical path of the transmitted light diverged from the optical splitter 13 to separate the transmitted light from the optical path of the received light to be described later.

The optical path separator 18 shown in FIG. 1 and the like represents a circulator, and the optical path separator 18 includes a first port, a second port, and a third port. The transmitted light diverged from the optical splitter 13 is input to the first port of the optical path splitter 18 . The transmitted light is output and incident to the optical fiber 200 through the second port of the optical path separator 18, and the received light emitted from the optical fiber 200 is input. The received light is output to the third port of the optical path separator 18 and is incident to the second etalon filter 19 . As the optical path separator 18, in addition to the circulator, an optical rotator, an interleaver filter, etc. can be used, and the optical path separator 18 can separate transmitted light (here, transmitted light) and received light having a very fine wavelength interval. there will be

The optical fiber 200 is outside the enclosure 100 and is disposed on a path along which the transmitted light passing through the optical path splitter 18 travels, and the transmitted light passing through the optical path splitter 18 is incident. In addition, the optical fiber 200 emits received light toward the optical path splitter 18 .

The second etalon filter 19 selectively transmits received light in a second wavelength band after passing through the optical path separator 18 after being emitted from the optical fiber 200 . Like the first etalon filter 14, the second etalon filter 19 may be formed by filling a transmissive material such as glass between reflective surfaces located at both ends. Here, the second wavelength band means a wavelength band capable of passing through the second etalon filter 19 among wavelength bands of light incident on the second etalon filter 19 .

In the received light emitted from the optical fiber 200 and passing through the optical path splitter 18, the light of the wavelength band to be received by the receiving photodiode 300 and the light of the wavelength band corresponding to other noise are mixed. may have been At this time, the second etalon filter 19 transmits only the light corresponding to the second wavelength band and blocks light corresponding to other wavelength bands. Accordingly, the receiving photodiode 300 It is possible to receive only the light of the desired wavelength band.

Similar to the first etalon filter 14 described above, the FSR and transmission bandwidth of the second etalon filter 19 are influenced by the filter's material, thickness, multilayer thin film coating, incident angle of received light, and the like. Here, the angle of incidence of the received light to the second etalon filter 19 may be 90°, and the second wavelength band of the second etalon filter 19 may change the temperature of the second etalon filter 19. can be adjusted through

The received light passing through the second etalon filter 19 may be detected by the receiving photodiode 300 . The receiving photodiode 300 may detect received light in the form of a photocurrent.

The second etalon filter 19 may be supported by the second etalon filter support member 27 . More specifically, the second etalon filter 19 may be fixed to the front of the second etalon filter support member 27 (the side on which the received light is incident to the second etalon filter support member 27).

In the second etalon filter support member 27, received light passing through the front and rear sides of the second etalon filter support member 27 (the side where the received light is emitted from the second etalon filter support member 27) passes A hole 28 is provided, and a receiving photodiode 300 may be disposed behind the second etalon filter support member 27 . In this case, the received light passing through the second etalon filter 19 may be incident to the receiving photodiode 300 through the receiving light passage hole 28 . When the second etalon filter 19, the second etalon filter support member 27, and the receiving photodiode 300 have such an arrangement relationship, the optical subassembly 1000 can be manufactured in a relatively small size.

The second temperature sensing element 20 serves to sense the temperature of the second etalon filter 19 . To this end, the second temperature sensing element 20 may be formed of a thermistor or may include the thermistor. The second temperature sensing element 20 may be attached to the second etalon filter 14 or the second etalon filter support member 27 .

The second temperature control element 21 serves to control the temperature of the second etalon filter 19 . The second temperature control element 21 may be made of or include a TEC to change the temperature of the second etalon filter 19 . The controller 600 may apply a voltage to both electrodes of the second temperature control element 21 to allow current to flow, and the temperature of the second etalon filter 19 may increase or decrease depending on the direction in which the current flows. .

The second temperature control element 21 controls the temperature of the second etalon filter 19 through an exothermic action or an endothermic action. At this time, if the heat generated by the temperature control of the second temperature control element 19 is not smoothly discharged to the outside of the light sub-assembly 1000, the temperature of the second etalon filter 19 cannot be properly adjusted. Accordingly, by directly contacting the second temperature control element 21 with the housing 100, the heat generated by the temperature control of the second temperature control element 21 is smoothly discharged to the outside of the light subassembly 1000. It is desirable to do That is, when the second temperature control element 21 is in direct contact with the enclosure 100, heat generated by temperature control of the second temperature control element 21 can be discharged to the outside through the enclosure 100. Therefore, the temperature of the second etalon filter 19 is accurately adjusted, and thus, the wavelength band to be received by the receiving photodiode 300 can be accurately adjusted.

A second base plate 29 may be disposed above the second temperature control element 21 . In addition, the above-described second etalon filter 19 , the second etalon filter support member 27 , and the second temperature sensing element 20 may be disposed on the upper portion of the second base plate 29 .

Here, the second temperature sensing element 20 may directly contact the second base plate 29 at an upper portion of the second base plate 29 . Alternatively, the second temperature sensing element 20 may be disposed above the second base plate 29 and on the second etalon filter support member 27 as shown in FIG. 1 and the like. When the second temperature control element 21 controls the temperature by exothermic action or heat absorbing action, the temperature of the second base plate 29 or the second etalon filter support member 27 is the second etalon filter ( 19) can be. Accordingly, when the second temperature sensing element 20 directly contacts the second base plate 29 or is disposed on the second etalon filter support member 27, the second temperature sensing element 20 The temperature of the second etalon filter 19 can be sensed.

13 is a diagram for explaining how the controller changes the wavelength transmitted through the second etalon filter.

Referring to FIG. 13 , the controller 600 is connected to the second temperature sensing element 20, and thus obtains the temperature of the second etalon filter 19 sensed by the second temperature sensing element 20. can do. In addition, the controller 600 is connected to the second temperature control element 21, and thus can control the second temperature control element 21 based on the temperature of the second etalon filter 19. When the controller 600 controls the second temperature control element 21, the second wavelength band of the second etalon filter 19 is also changed.

Meanwhile, a first window 30 may be provided in a path along which the transmitted light passing through the optical path separator 18 travels. The first window 30 corresponds to a path through which transmitted light moves from the optical path splitter 18 toward the optical fiber 200 and a path through which received light moves from the optical fiber 200 toward the optical path splitter 18 . In this case, the first window 30 may prevent an external material from entering the enclosure 100 by sealing one side of the enclosure 100 .

In addition, a first collimated light lens 400 may be disposed between the first window 30 and the optical fiber 200. At this time, the first collimated light lens 400 is coupled to one side of the enclosure 100 There may be. In this way, when the first collimated light lens 500 is coupled to the enclosure 100, since the optical fiber alignment for the transmitting end can be relatively easily performed, the efficiency of manufacturing the optical subassembly 1000 can be greatly improved. . The first collimated light lens 400 focuses the transmitted light moving from the optical path splitter 18 toward the optical fiber 200 and at the same time collimates the received light moving from the optical fiber 200 toward the optical path splitter 18. It plays a role in converting it into light form.

A second window 31 may be provided on a path along which the received light passing through the second etalon filter 19 travels. The second window 31 corresponds to a passage through which reception light moves from the second etalon filter 19 toward the reception port diode 300 . At this time, the second window 31 can prevent the penetration of external substances into the enclosure 100 by sealing the other side of the enclosure 100 .

In addition, a second collimated light lens 500 may be disposed between the second window 31 and the receiving photodiode 300. At this time, the second collimated light lens 500 is the other side of the housing 100 may be linked to The second collimated light lens 500 serves to focus the received light moving from the second etalon filter 19 toward the receiving port diode 300 .

The receiving photodiode 300 is outside the housing 100 and is disposed on the path of the receiving light passing through the second etalon filter 19, and is capable of passing through the second etalon filter 19. It plays a role in detecting new light. The receiving photodiode 300 may detect the received light in the form of a photocurrent, and information on the detected transmitted light may be transmitted to the controller 600 .

The receiving photodiode 300 may be accommodated inside the TO 310 . A transmission window 315 may be provided at an upper end of the TO 310 so that the received light transmitted through the second etalon filter 19 may move to the reception port diode 300 .

When the TO 310 is fixed to the enclosure 100, it is important that the received light transmitted through the second etalon filter 19 is transmitted to the photodiode 300 for reception with high efficiency. That is, in order to improve reception efficiency of the receiving photodiode 300, the second etalon filter 19 and the receiving photodiode 300 need to be optically aligned. To this end, a fixing member 320 may be mounted outside the TO 310 .

When fixing the fixing member 320 to the enclosure 100, an ultraviolet curing agent may be used, but in this case, optical alignment between the second etalon filter 19 and the receiving photodiode 300 is achieved while the ultraviolet curing agent is cured. There is a risk that this will slip off. Accordingly, when fixing the fixing member 320 to the enclosure 100, it is preferable to fix it by laser welding. Fixing by laser welding takes less time than fixing by hardener, the optical alignment of the second etalon filter 19 and the receiving photodiode 300 can be relatively sophisticated, and the fixing by laser welding After that, since the misalignment phenomenon is relatively small, the receiving photodiode 300 can receive the receiving light with relatively high efficiency.

Meanwhile, as described above, the enclosure 100 accommodates the second etalon filter 19, the second temperature sensing element 20, and the second temperature control element 21 therein. At this time, since the second temperature control element 21 can be controlled based on the temperature of the second etalon filter 19 sensed by the second temperature sensing element 20, the receiving photodiode 300 A wavelength band of light to be used may be varied.

As such, the present invention is a filter that transmits only the reception wavelength band because the second etalon filter 19, the second temperature sensing element 20, and the second temperature control element 21 are accommodated inside the enclosure 100 It is not necessary to separately equip the receiving terminal side, and a receiving photodiode having a fixed receiving wavelength band or a receiving TO (consisting of a receiving photodiode, a TO stem, and a cap) can be used as much as desired. In addition, according to the present invention, since the second collimated light lens 500 is coupled to the enclosure 100, TO alignment for the receiving end can be relatively easily performed, and thus the efficiency of manufacturing the optical subassembly 1000 is greatly increased. be able to improve

Although the present invention has been described with limited embodiments and drawings, the present invention is not limited to the above embodiments, and various modifications and variations from these descriptions can be made by those skilled in the art in the field to which the present invention belongs. Therefore, the technical spirit of the present invention should be grasped only by the claims, and all equivalent or equivalent modifications thereof will be said to belong to the scope of the technical spirit of the present invention.

11: laser diode 12: first monitoring photodiode
13: optical diverter 14: first etalon filter
15: second monitoring photodiode 16: first temperature sensing element
17: first temperature control element 18: optical path separator
19: second etalon filter 20: second temperature sensing element
21: second temperature control element 22: collimated light lens for transmission light
23: isolator 24: first etalon filter support member
25: reflected light passage hole 26: first base plate
27: second etalon filter support member 28: receiving light passage hole
29: second base plate 30: first window
31: second window 100: enclosure
200: optical fiber 300: photodiode for reception
310: TO 315: transmission window
320: fixing member 400: first parallel light lens
500: second parallel light lens 600: controller
1000: Wavelength tunable optical subassembly for bi-directional optical communication

Claims (10)

a laser diode that outputs transmission light;
a first monitoring photodiode that detects the transmission light output to the rear of the laser diode;
an optical diverter splitting the transmitted light output to the front of the laser diode into reflected light and transmitted light;
a first etalon filter that transmits the reflected light in a first wavelength band;
a second monitoring photodiode to detect the reflected light passing through the first etalon filter;
a first temperature sensing element for sensing temperatures of the laser diode and the first etalon filter;
a first temperature control element for controlling temperatures of the laser diode and the first etalon filter;
an optical path separator disposed in the optical path of the transmitted light to separate the optical path of the transmitted light and the received light;
an optical fiber into which the transmitted light passing through the optical path splitter is incident;
a second etalon filter for transmitting the received light in a second wavelength band after passing through the optical path splitter after being emitted from the optical fiber;
a second temperature sensing element for sensing a temperature of the second etalon filter;
a second temperature control element for controlling the temperature of the second etalon filter; and
A receiving photodiode for detecting received light passing through the second etalon filter,
the laser diode, the first monitoring photodiode, the optical diverter, the first etalon filter, the second monitoring photodiode, the first temperature sensing element, the first temperature control element, the optical path separator, the A second etalon filter, the second temperature sensing element and the second temperature control element further comprising a housing for receiving therein,
The wavelength tunable optical subassembly for bidirectional optical communication, characterized in that the first temperature control element and the second temperature control element are in direct contact with the enclosure.
According to claim 1,
a first etalon filter support member supporting the first etalon filter and having a reflective light passing hole through which the reflected light passing through the first etalon filter is incident to the second monitoring photodiode; ,
The second monitoring photodiode is disposed behind the first etalon filter support member, and reflected light passing through the first etalon filter is incident to the second monitoring photodiode through the reflected light passage hole. A wavelength tunable optical subassembly for bi-directional optical communication.
According to claim 1,
A second etalon filter supporting member supporting the second etalon filter and having a reception light passage hole so that the reception light passing through the second etalon filter is incident to the reception photodiode. and
The receiving photodiode is disposed behind the second etalon filter support member, and reflected light passing through the second etalon filter is incident to the receiving photodiode through the receiving light passage hole. Wavelength tunable optical subassembly for bi-directional optical communication.
According to claim 1,
The transmitted light is input to a first port of the optical path separator,
The transmitted light is output and incident to the optical fiber, and the received light emitted from the optical fiber is input to a second port of the optical path splitter.
The wavelength tunable optical subassembly for bi-directional optical communication, characterized in that the received light is output through a third port of the optical path separator and is incident to the second etalon filter.
According to claim 1,
The optical fiber is outside the enclosure and is disposed on a path along which the transmitted light passing through the optical path separator travels;
The receiving photodiode is outside the enclosure and is disposed on a path along which the receiving light passing through the second etalon filter travels.
delete According to claim 5,
a first window provided on a path of the transmitted light passing through the optical path separator and sealing one side of the enclosure; and
The wavelength tunable optical subassembly for bidirectional optical communication further comprising a second window disposed on a path of the received light passing through the second etalon filter and sealing the other side of the enclosure.
According to claim 7,
a first collimated light lens disposed between the first window and the optical fiber and coupled to one side of the enclosure; and
The wavelength tunable optical subassembly for bidirectional optical communication further comprising a second collimated light lens disposed between the second window and the receiving photodiode and coupled to the other side of the enclosure.
According to claim 5,
a TO accommodating the receiving photodiode; and
Further comprising a fixing member mounted outside the TO,
The fixing member is a wavelength tunable optical subassembly for bidirectional optical communication, characterized in that fixed to the enclosure by laser welding.
According to claim 1,
Controlling the first temperature control element based on the temperatures of the laser diode and the first etalon filter sensed by the first temperature sensing element, and the second etalon sensed by the second temperature sensing element. The wavelength tunable optical subassembly for bidirectional optical communication further comprising a controller for controlling the second temperature control element based on the temperature of the filter.

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