KR101191236B1 - Multi-wavelength laser diode, multi-wavelength laser diode module, and wavelength division multiplexing optical communication system - Google Patents

Abstract

The multiwavelength laser diode includes first optical amplifiers, a second optical amplifier, a wavelength selector, and a photo detector. The first optical amplifiers generate and amplify the first to n th wavelengths (where n is a natural number of two or more). The second optical amplifier generates and amplifies the monitor wavelength signal. The wavelength selector selects and outputs the amplified first through n-th wavelength signals and the amplified monitor wavelength signal. The photo detector detects the reflected wavelength signal of the monitor wavelength signal output from the wavelength selector.

Description

Multi-wavelength laser diode, multi-wavelength laser diode module, and wavelength division multiplexing optical communication system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to semiconductor lasers, and more particularly, to a multi-wavelength laser diode (multi-wavelength laser).

The present invention is derived from the research conducted as part of the IT source technology development of the Ministry of Knowledge Economy and the Ministry of Information and Telecommunications Research and Development.

A passive optical network (PON) communication system of wavelength division multiplexing (WDM) provides a unique wavelength (a specific wavelength signal) to each subscriber and gives the Inherent wavelength is used to provide high speed broadband communication services.

WDM optical communication systems can keep communications secret. And when a new subscriber is added to the WDM optical communication system, only the unique wavelength to be given to that subscriber can be added to the WDM optical communication system. Therefore, the WDM optical communication system has an advantage of easily expanding the number of subscribers.

The WDM optical communication system may include a multi-wavelength light source. Examples of multi-wavelength light sources include distributed feedback lasers, distributed feedback laser arrays, multi-frequency laser diodes or multi-wavelength laser diodes, and ultra-short pulses ( picosecond pulse).

The technical problem to be solved by the present invention is a multi-wavelength laser diode that is used to align the output wavelength of the multi-wavelength laser diode with an external reference wavelength (external standard wavelength) of the multi-wavelength laser diode. A multi-wavelength laser diode module including the multi-wavelength laser diode, and a wavelength division multiple optical communication system capable of matching the output wavelength of the multi-wavelength laser diode with an external reference wavelength of the multi-wavelength laser diode.

In order to achieve the above technical problem, a multi-wavelength laser diode according to an embodiment of the present invention, the first to n-th (where n is a natural number of two or more) wavelength signals, respectively generating and amplifying; A second optical amplifier for generating and amplifying the monitor wavelength signal; A wavelength selector for selecting and outputting the amplified first to nth wavelength signals and the amplified monitor wavelength signal; And a photo detector for detecting a reflected wavelength signal of the monitor wavelength signal output from the wavelength selector.

The multi-wavelength laser diode may further include a power splitter connecting the second optical amplifier, the photo detector, and an output channel of the wavelength selector to each other.

The wavelength selector may comprise an arrayed waveguide grating or a planar echelle grating.

The wavelength selector may be formed on a silica substrate, and the first optical amplifiers, the second optical amplifier, and the photo detector may be formed on an indium phosphorus (InP) substrate.

When the center wavelength of the optical gain of the second optical amplifier is shorter than the center wavelength of the monitor wavelength signal, the current value of the photodetection current detected by the photodetector may decrease with increasing temperature of the multi-wavelength laser diode. Can be.

In order to achieve the above technical problem, a multi-wavelength laser diode module according to an embodiment of the present invention, the first to n (n is a natural number of two or more) wavelength signal and a wavelength selector for selectively outputting a monitor wavelength signal; A multi-wavelength laser diode comprising a photo detector for detecting a reflected wavelength signal of the output monitor wavelength signal; A wavelength filter transmitting the first to n-th wavelength signals and reflecting the reflected wavelength signal of the monitor wavelength signal to the multi-wavelength laser diode; A control circuit for receiving a photodetection current from the photodetector and generating a temperature control signal corresponding to a value of a control current among the received photodetection currents; And a temperature adjusting device configured to adjust a temperature of the multi-wavelength laser diode in response to the temperature control signal, wherein the value of the control current coincides with the reflected wavelength signal of the monitor wavelength signal. The first to nth wavelength signals outputted from the multi-wavelength laser diode by the temperature control device have a current value that is relatively larger than an adjacent current value and are output from the multi-wavelength laser diode. Can be matched to wavelength signals.

The wavelength filter may include an optical fiber Bragg grating (FBG).

In order to achieve the above technical problem, a wavelength division multiplexing optical communication system according to an embodiment of the present invention, the first to n-th (where n is a natural number of two or more) wavelength signal and the monitor wavelength signal selectively A central station including a multi-wavelength laser diode including a wavelength selector for outputting a light beam and a photo detector for detecting a reflected wavelength signal of the output monitor wavelength signal; And a wavelength divider configured to receive the outputted first to nth wavelength signals and the outputted monitor wavelength signal through an optical fiber and to distribute the received first to nth wavelength signals to corresponding optical terminals. And a remote node comprising a reflective terminal for reflecting the received monitor wavelength signal and transmitting it to the photo detector, wherein the central station receives a photo detection current from the photo detector and receives the received light. A control circuit for generating a temperature control signal corresponding to the value of the control current among the detected currents; And a temperature adjusting device for adjusting a temperature of the multi-wavelength laser diode in response to the temperature control signal, wherein the value of the control current coincides with the reflected wavelength signal of the monitor wavelength signal. Is a value at the time of having a current value that is relatively larger than an adjacent current value, and wherein the first to nth wavelength signals output from the multi-wavelength laser diode are output from the wavelength divider by the temperature adjusting device. Can be matched to the 1 th to n th wavelength signals.

The multiwavelength laser diode according to the invention has relatively simple components and can be used to match the output wavelength of the multiwavelength laser diode with an external reference wavelength of the multiwavelength laser diode. As a result, the optical loss in the WDM filter (ie, the wavelength divider of the remote node) connected to the outside of the multi-wavelength laser diode can be reduced, thereby improving optical communication efficiency.

In addition, since the multi-wavelength laser according to the present invention has relatively simple components, the multi-wavelength laser of the present invention can be manufactured by a simple fabrication process, and the yield can be improved as compared with a distributed feedback laser. have. As a result, the cost of constructing the WDM system can be reduced.

The multi-wavelength laser diode module according to the present invention can match the output wavelength of the multi-wavelength laser with an external reference wavelength of the multi-wavelength laser, thereby increasing the efficiency of the WDM optical communication.

The wavelength division multiple optical communication system according to the present invention can match the output wavelength of the multi-wavelength laser diode included in the central station with the output wavelength of the wavelength divider included in the remote node, which is an external reference wavelength. Can be increased.

In order to fully understand the present invention and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings which illustrate embodiments of the present invention and the contents described in the accompanying drawings.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail by explaining embodiment of this invention with reference to attached drawing. Like reference numerals in the drawings denote like elements.

1 is a diagram illustrating a multi-wavelength laser diode 100 according to an embodiment of the present invention. The multi-wavelength laser diode 100 may also be referred to as a multi-wavelength semiconductor laser.

Referring to FIG. 1, the multi-wavelength laser diode 100 includes first optical amplifiers 110, a second optical amplifier 120, a power splitter 130, and a photo detector. detector 140, wavelength selector 150.

The first optical amplifiers 110 are semiconductor optical amplifier arrays and include a plurality of semiconductor optical amplifiers 111, 112, 113. The first optical amplifiers 110 generate and amplify the first to nth wavelength signals, where n is a natural number of two or more. The center wavelengths of the first to nth wavelength signals are λ 1 to λ n, respectively. Wavelength signals may also be referred to as wavelengths, light of wavelengths, wavelength channels, or light outputs. For convenience of description, in the present specification, the first to nth wavelength signals are denoted by λ1 to λn, respectively.

The first optical amplifiers 110 generate an optical gain by current injection by a current source. The current source may be disposed outside the multi-wavelength laser diode 100.

The second optical amplifier 120 is a monitor semiconductor optical amplifier and generates and amplifies a monitor wavelength signal. The center wavelength of the monitor wavelength signal is lambda m. For convenience of description, the monitor wavelength signal is denoted by λm in this specification.

The second optical amplifier 120 generates the optical gain by current injection by the current source. The current source may be disposed outside the multi-wavelength laser diode 100. Since the monitor wavelength signal λm may be lost during the power splitter 130, the amount of current injected into the second optical amplifier 120 may be greater than the amount of current injected into each of the first optical amplifiers 110. have. The monitor wavelength signal lambda m is a wavelength signal different from the first to nth wavelength signals lambda 1 to lambda n.

The power splitter 130 divides one channel of the output waveguide 151 of the wavelength selector 150 and one channel of the output waveguide 151 and the second optical amplifier 120. The photo detectors 140 are connected to each other.

The photodetector 140 is a monitor photodetector and detects the reflected wavelength signal λmr or λf of the monitor wavelength signal λm output from the wavelength selector 150. The current value of the photodetector current detected by the photodetector 140 is short when the center wavelength of the optical gain of the second optical amplifier 120 is shorter than the center wavelength λm of the monitor wavelength signal. As a result, the temperature of the multi-wavelength laser diode 100 (or the wavelength selector 150) may decrease. The reflected wavelength signal λmr is a wavelength signal in which the monitor wavelength signal λm is reflected by the first facet 160 of the multi-wavelength laser diode 100 and detected by the photodetector 140. The reflected wavelength signal [lambda] f is a wavelength signal detected by the photodetector 140 by the monitor wavelength signal [lambda] m being reflected by a wavelength filter disposed outside the multi-wavelength laser diode 100.

The photo detector 140 may be implemented with, for example, a photodiode. The photodiode may be manufactured by the same process as a semiconductor optical amplifier, and may be operated by applying a backward bias voltage or by applying a very low forward bias voltage.

The second optical amplifier 120, the power splitter 130, and the photodetector 140 monitor the output wavelength signals of the multi-wavelength laser diode 100 and the external reference wavelength signals of the multi-wavelength laser diode 100. Perform a wavelength monitoring function.

 The wavelength selector 150 selects the amplified first to n-th wavelength signals λ1 to λn and the amplified monitor wavelength signals λm and outputs them to the outside through the first cut plane 160.

Wavelength selector 150 may be, for example, an arrayed waveguide grating (AWG) that is a planar waveguide, as shown in FIG. 1. Hereinafter, the wavelength selector 150 will be described using an arrayed waveguide grating (AWG) as an example.

The wavelength selector 150 includes output waveguides 151, a first slab waveguide 152, an arrayed waveguide 153, a second slab waveguide 154, and an input waveguide. (input waveguide) 155.

The wavelength selector 150 may be used as a wavelength multiplexer or a wavelength demultiplexer that performs a wavelength selection function. When the wavelength selector 150 is used as the wavelength demultiplexer, the wavelength selector 150 outputs an optical signal input to the input waveguide 155 to one of the output waveguides 151 according to the center wavelength of the wavelength signal. It is a wavelength division element, and is an important element in a WDM optical communication system.

When the wavelength selector 150 is used when the number of channels of the WDM optical communication system increases, the insertion loss is small, the wavelength selector 150 is easy to mass-produce, and the wavelength selector 150 is The cost of packaging is also low. The wavelength selector 150 may be used for a multiwavelength laser diode, as shown in FIG. The wavelength selector 150 may also be used for an integrated wavelength switch.

An embodiment of the operation of the multiwavelength laser diode 100 is described as follows.

The first to nth wavelength signals λ1 to λn are generated by the semiconductor optical amplifiers 111, 112, and 113 of the first optical amplifiers 110, respectively. The second optical amplifier 140 also generates a monitor wavelength signal [lambda] m.

The generated first to nth wavelength signals λ1 to λn and the monitor wavelength signal λm are selected through the corresponding output waveguides 151 and the arrayed waveguide 153 to correspond to the first cut plane 160. To reach. The first to nth wavelength signals λ1 to λn have a constant wavelength spacing Δλ according to a difference in the length of the arrayed waveguide 153.

The first to n th wavelength signals λ1 to λn and the monitor wavelength signal λm reaching the first cut plane 160 are reflected at the first cut plane 160 and are again reflected by the first light through the wavelength selector 150. Return to the amplifiers 110 and the second optical amplifier 120. The first to nth wavelength signals λ1 to λn and the monitor wavelength signal λm returned to the first optical amplifiers 110 and the second optical amplifier 120 selected by the wavelength selector 150 are the first optical amplifier. Amplified by the light emitting diodes 110 and the second optical amplifier 120, and reflected back at the second cutting surfaces 170.

The first to n th wavelength signals λ 1 to λ n and the monitor wavelength signal λ m reflected from the second cut surfaces 170 are again amplified by the first optical amplifiers 110 and the second optical amplifier 120. Is input to the wavelength selector 150. Laser oscillation occurs only in the wavelength signal (eg, λ 1) selected by the internal resonance of light between the first cut plane 160 and the second cut planes 170 described above. As a result, in the input waveguide 155 of the wavelength selector 150, wavelength signals λ1 to λn and λm having a predetermined wavelength interval as many as the number of the first and second optical amplifiers 110 and 120. It is output as this light output. The wavelength signals λ1 to λn may be used for WDM optical communication including an optical signal included in the wavelength signals λ1 to λn and transmitted. That is, the wavelength signals λ1 to λn are used as carriers.

The wavelength characteristic of the wavelength selector 150 reacts very sensitively with temperature. That is, the spacing between each of the wavelength signals is kept constant, but the center wavelengths of the wavelength signals vary with the change in temperature of the refractive index of the material used to fabricate the wavelength selector 150. In the case of the wavelength selector 150 made of a semiconductor, the center wavelength of the wavelength selector 150 changes by 0.1 (nm) as the temperature changes by 1 ⁰ C. In the case of the wavelength selector 150 made of silica (SiO ₂ ), the center wavelength of the wavelength selector 150 changes by 0.01 (nm) as the temperature changes by 1 ⁰ C.

In the multi-wavelength laser diode 100 according to the embodiment of the present invention, the second optical amplifier 120, the power splitter 130, and the photo detector 140, which perform a wavelength monitoring function, have a single wavelength laser diode chip ( chip, it can be used to match the output center wavelengths of the multi-wavelength laser with the external reference center wavelengths of the multi-wavelength laser when the output wavelength signals of the wavelength selector 150 change with temperature. As a result, the optical loss in the WDM filter connected to the outside of the multi-wavelength laser diode can be reduced to improve the optical communication efficiency.

In addition, the multi-wavelength laser of the present invention includes relatively simple components (eg, the second optical amplifier 120, the power splitter 130, and the photo detector 140), and thus the multi-wavelength laser of the present invention. Can be manufactured by a simple fabrication process, and the yield can be improved compared to DFB laser. As a result, the cost of constructing the WDM system can be reduced.

The multi-wavelength laser diode according to the embodiment of the present invention may be formed on a single substrate (eg, indium phosphorus (InP) substrate). In a multi-wavelength laser diode according to another embodiment of the present invention, the wavelength selector 150 is formed on a silica substrate, and the first optical amplifiers 110, the second optical amplifier 120, and the power splitter 130 are formed. And the photo detector 140 may be formed on an InP substrate. That is, in another embodiment of the present invention, a hybrid substrate bordering the line 180 shown in FIG. 1 may be used.

In another embodiment of the invention, the wavelength selector 150 may be a planar echelle grating. The planar Echel grating includes an input waveguide corresponding to the input waveguide 155, an output waveguide corresponding to the output waveguide 151, and a reflective diffraction grating connected through the slab waveguide to the input waveguide and the output waveguide. Include. The input waveguide and the output waveguide are disposed on the same side. The nature of the wavelength generated in the planar echel grating varies with temperature, and the planar echel grating can be used as a multiplexer or demultiplexer.

2 is a diagram illustrating a multi-wavelength laser diode module 200 according to an embodiment of the present invention.

Referring to FIG. 2, the multi-wavelength laser diode module 200 may include a multi-wavelength laser diode 100, a wavelength filter 220, a control circuit 240, and a temperature control unit ( 260).

The multiwavelength laser diode 100 corresponds to the multiwavelength laser diode shown in FIG. 1. The multi-wavelength laser diode 100 includes a wavelength selector 150 for selectively outputting first to nth wavelength signals λ1 to λn, a monitor wavelength signal λm, and the output monitor wavelength signal λm. And a photo detector 140 for detecting the reflected wavelength signal [lambda] f. Wavelength selector 150 may be, for example, an arrayed waveguide grating or a planar echel grating.

The wavelength filter 220 passes (transmits) the first to nth wavelength signals λ1 to λn and reflects the reflected wavelength signal λf of the monitor wavelength signal λm to the multi-wavelength laser diode 100. That is, the wavelength filter 220 reflects only a specific wavelength. The wavelength filter 220 may include an optical fiber Bragg grating (FBG). The wavelength filter 220 may be connected to the multiwavelength laser diode 100 through an optical fiber.

The control circuit 240 receives the photodetection current ID from the photodetector 140 and generates a temperature control signal TC corresponding to the value of the control current among the received photodetection currents ID. The value of the control current is a value when the monitor wavelength signal [lambda] m and the reflection wavelength signal [lambda] f of the monitor wavelength signal [lambda] m coincide with each other and have a current value that is relatively larger than an adjacent current value.

The temperature regulating device 260 adjusts (controls) the temperature of the multi-wavelength laser diode 100 (or the wavelength selector 150) in response to the temperature control signal TC. The thermostat 260 includes a thermistor and a thermoelectric cooler (TE) that sense the temperature.

By the temperature controller 260, the first to nth wavelength signals λ1 to λn output from the multiwavelength laser diode 100 are external reference wavelength signals λ1 to λn of the multiwavelength laser diode 100. Can be matched with The external reference wavelength signals λ 1 to λ n of the multi-wavelength laser diode 100 are standard wavelength signals used in a WDM optical communication system.

The photo detector 140, the control circuit 240, and the temperature controller 260 form a feedback loop.

2 and 3, an embodiment of a method of matching output wavelength signals of the multi-wavelength laser diode 100 and external reference wavelength signals λ 1 to λ n of the multi-wavelength laser diode 100 is as follows. It is explained.

The multi-wavelength laser diode 100 outputs the first to nth wavelength signals λ1 to λn and the monitor wavelength signal λm. The wavelength filter 220 passes the first through n-th wavelength signals λ1 to λn, reflects the monitor wavelength signal λm, and outputs the reflected wavelength signal λf of the monitor wavelength signal λm. The reflected wavelength signal λf of the monitor wavelength signal λm is transmitted to an input port of the photo detector 140.

The photo detector 140 detects the reflected wavelength signal [lambda] f of the monitor wavelength signal [lambda] m. In addition, the photo detector 140 also detects the reflected wavelength signal [lambda] mr reflected by the cut surface (160 in FIG. 1) toward the input waveguide side of the wavelength selector 150.

The light detection current ID generated by the wavelength signals detected at the photo detector 140 is shown in FIG. 3. That is, FIG. 3 is a graph showing the change of the photodetection current ID according to the temperature of the multi-wavelength laser diode 100 shown in FIG. 2.

In FIG. 3, the dotted line is the light detection current when the wavelength filter 220 is not present, and the solid line in FIG. 3 is the light detection current when the wavelength filter 220 is present. The photodetection current corresponding to the dotted line is a current due to the light output λmr reflected from the cut surface (160 in FIG. 1) toward the input waveguide side of the wavelength selector 150 and input to the photodetector 140.

When the center wavelength of the optical gain of the second optical amplifier 120 is longer than the center wavelength λ m of the monitor wavelength signal, the photodetection current corresponding to the dotted line increases with increasing temperature. When the center wavelength of the optical gain of the second optical amplifier 120 is shorter than the center wavelength λm of the monitor wavelength signal, as illustrated in FIG. 3, light detection corresponding to the dotted line with increasing temperature is shown. The current decreases.

When the monitor wavelength signal [lambda] m coincides with the selection wavelength signal [lambda] f of the wavelength filter 220 according to the wavelength change according to the temperature of the wavelength selector 150, the photodetection current corresponding to the solid line is shown in FIG. As shown, it forms a convex curve. The temperature at which the monitor wavelength signal λm coincides with the selection wavelength signal λf is T1, and the photodetection current value when the monitor wavelength signal λm coincides with the selection wavelength signal λf is the control current value ( IC).

The control circuit 240 generates the temperature control signal TC corresponding to the control current value IC in response to the photodetection current ID. The temperature adjusting device 260 adjusts the temperature of the multi-wavelength laser diode 100 (or the wavelength selector 150) to T1 based on the temperature control signal TC. Then, the monitor wavelength signal [lambda] m and the selection wavelength signal [lambda] f of the wavelength filter 220 coincide with each other. Therefore, the output wavelength signals λ1 to λn of the multiwavelength laser diode 100 and the external reference wavelength signals λ1 to λn of the multiwavelength laser diode 100 may coincide with each other.

The multi-wavelength laser diode module 200 according to the present invention, even if the output wavelength of the wavelength selector 150 of the multi-wavelength laser diode 100 changes with temperature, the output center wavelengths of the multi-wavelength laser, By matching external reference center wavelengths, it is possible to increase the efficiency of WDM optical communication.

4 is a diagram illustrating a wavelength division multiple optical communication system 300 according to an embodiment of the present invention.

Referring to FIG. 4, the wavelength division multiplexing optical communication system 300 includes a central office 400, an optical fiber 450, and a remote node 500. ), Optical fibers 531, 532, 533, and optical network terminals 541-543. The wavelength division multiple optical communication system 300 shown in FIG. 4 represents a downstream part. The wavelength division multiple optical communication system 300 may be, for example, a wavelength division multiplexing passive optical subscriber network (WDM PON) communication system.

The central station 400 includes a multi-wavelength laser diode 100, a control circuit 240, and a temperature control device 260. Each of the multi-wavelength laser diode 100, the control circuit 240, and the temperature regulating device 260 corresponds to the multi-wavelength laser diode, the control circuit, and the temperature regulating device shown in FIG. 2.

The central station 400 includes a multiwavelength laser diode 100 that includes a photo detector 140 and a wavelength selector 150. Wavelength selector 150 may be an arrayed waveguide grating or a planar shell grating. The characteristics of the wavelengths generated in an arrayed waveguide grating or planar echel grating vary with temperature.

The wavelength selector 150 selectively outputs the first to nth wavelength signals λ1 to λn and the monitor wavelength signal λm. The photo detector 140 detects the reflected wavelength signal [lambda] f of the output monitor wavelength signal [lambda] m.

The central station 400 further includes a control circuit 240 and a temperature regulating device 260. The control circuit 240 receives the photodetection current ID from the photodetector 140 and generates a temperature control signal TC corresponding to the value of the control current among the received photodetection currents ID. The temperature regulating device 260 adjusts the temperature of the multi-wavelength laser diode 100 in response to the temperature control signal TC.

The value of the control current is a value when the monitor wavelength signal [lambda] m and the reflection wavelength signal [lambda] f of the monitor wavelength signal [lambda] m coincide with each other and have a current value that is relatively larger than an adjacent current value.

The first to nth wavelength signals λ1 to λn outputted from the multi-wavelength laser diode 100 by the temperature adjusting device 260 are output to the first to nth wavelength signals λ1 to n outputted from the wavelength divider 510. λn).

The remote node 500 includes a wavelength splitter 510 and a reflection terminal 520. The remote node 500 may be, for example, a base station (BS).

The wavelength splitter 510 is configured to convert the first to nth wavelength signals λ1 to λn output from the multi-wavelength laser diode 100 and the monitor wavelength signal λm output from the multi-wavelength laser diode 100 into an optical fiber ( 450). The wavelength divider 510 distributes the received first to nth wavelength signals λ 1 to λ n to corresponding optical network terminals (optical terminals) 541, 542, and 543. The structure of the wavelength divider 510 is the same as that of the wavelength selector 150 included in the central station 400, and the interval of the wavelength signals in the wavelength divider 510 and the wavelength selector of the multi-wavelength laser diode 100 ( The spacing of the wavelength signals at 150 coincides.

Wavelength divider 510 may comprise an arrayed waveguide grating or a planar echel grating. The characteristics of the wavelengths generated in an arrayed waveguide grating or planar echel grating vary with temperature.

The reflective terminal 520 reflects the received monitor wavelength signal [lambda] m and transmits it to the photodetector 140 of the multi-wavelength laser diode. The reflective terminal 520 does not need a separate power supply.

Each of the optical terminals 541, 542, 543 includes a receiver (REC) 551-552. The receiver REC is used by the optical subscriber.

Central station 400 is coupled to remote node 500 via optical fiber 450. Remote node 500 is connected to multiple optical terminals 541, 542, 543 via multiple optical fibers 531, 532, 533.

3 and 4, a method of matching output wavelength signals of the wavelength divider 510, which are output reference signals of the multi-wavelength laser diode 100 (or the wavelength selector 150) and external reference wavelength signals, is performed. An example is described as follows. The external reference wavelength signals lambda 1 to lambda n are standard wavelengths used in a WDM optical communication system.

The method of matching the output wavelength signals of the multi-wavelength laser diode 100 and the output wavelength signals of the wavelength divider 510 is similar to the wavelength signal matching method described with reference to FIGS. 2 and 3.

The multi-wavelength laser diode 100 transmits the wavelength signals λ 1 to λ n and λ m through the optical fiber 450 to the wavelength divider 510 of the remote node 500. The monitor wavelength signal [lambda] m output to one output port of the wavelength divider 510 is reflected by the reflection terminal 520 without being transmitted to the optical terminal.

The wavelength signal [lambda] f reflected by the reflective terminal 520 is transmitted to the multi-wavelength laser diode 100 and detected by the photo detector 140. The control circuit 240 generates the temperature control signal TC corresponding to the control current value IC in response to the photodetection current ID.

When the monitor wavelength signal [lambda] m coincides with the reflected wavelength signal [lambda] f at the reflection terminal 520 by the change of the wavelength according to the temperature of the wavelength selector 150 or the temperature of the wavelength divider 510, it is shown in FIG. As shown, the photodetection current forms a convex curve. The temperature when the monitor wavelength signal [lambda] m coincides with the reflection wavelength signal [lambda] f at the reflection terminal 520 is T1, and the monitor wavelength signal [lambda] m is the reflection wavelength signal [lambda] f at the reflection terminal 520. The photodetection current value when coinciding with is the control current value IC.

The temperature adjusting device 260 adjusts the temperature of the multi-wavelength laser diode 100 to T1 based on the temperature control signal TC. Then, the monitor wavelength signal [lambda] m and the reflection wavelength signal [lambda] f at the reflection terminal 520 coincide. Accordingly, the output wavelength signals of the wavelength selector 150 of the multi-wavelength laser diode 100 or the output wavelength signals of the wavelength divider 510 of the remote node 500 may change according to temperature change or the multi-wavelength laser diode 100 may change. Although the characteristics of the wavelength selector 150 deteriorate and the output wavelength signals of the wavelength selector 150 are changed, the output wavelength signals λ1 to λn of the multi-wavelength laser diode 100 and the outside at the remote node 510 are changed. The reference wavelength signals λ1 to λn may match.

The wavelength division multiple optical communication system according to the present invention can match the output center wavelengths of the multi-wavelength laser diode included in the central station with the output center wavelengths of the wavelength divider included in the remote node, which is an external reference wavelength. Communication efficiency can be increased.

As described above, the embodiments have been disclosed in the drawings and specification. Although specific terms are used herein, they are used for the purpose of describing the present invention only and are not used to limit the scope of the present invention described in the claims or the claims. Therefore, it will be understood by those skilled in the art that various modifications and equivalent embodiments are possible from the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

In order to more fully understand the drawings used in the detailed description of the invention, a brief description of each drawing is provided.

1 is a diagram illustrating a multi-wavelength laser diode 100 according to an embodiment of the present invention.

2 is a diagram illustrating a multi-wavelength laser diode module 200 according to an embodiment of the present invention.

FIG. 3 is a graph showing a change in photodetection current ID according to the temperature of the multi-wavelength laser diode 100 shown in FIG. 2.

4 is a diagram illustrating a wavelength division multiple optical communication system 300 according to an embodiment of the present invention.

Description of the Related Art

120: second optical amplifier 130: power splitter

140: light detector 150: wavelength selector

220: wavelength filter 240: control circuit

260: thermostat 510: wavelength divider

520: reflective terminal

Claims (15)

delete delete delete delete delete delete In a multi-wavelength laser diode module, A multi-wavelength laser including first to nth (n is a natural number of two or more) wavelength signals, a wavelength selector for selectively outputting a monitor wavelength signal, and a photo detector for detecting a reflected wavelength signal of the output monitor wavelength signal diode; A wavelength filter transmitting the first to n-th wavelength signals and reflecting the reflected wavelength signal of the monitor wavelength signal to the multi-wavelength laser diode; A control circuit for receiving a photodetection current from the photodetector and generating a temperature control signal corresponding to a value of a control current among the received photodetection currents; And In response to the temperature control signal, the temperature control device for adjusting the temperature of the multi-wavelength laser diode, The value of the control current is a value when the monitor wavelength signal and the reflected wavelength signal of the monitor wavelength signal coincide, and have a current value that is relatively larger than an adjacent current value. And, by the temperature regulating device, first to nth wavelength signals output from the multiwavelength laser diode coincide with external reference wavelength signals of the multiwavelength laser diode. The method of claim 7, wherein The wavelength filter is a multi-wavelength laser diode module comprising an optical fiber Bragg grating (FBG). The method of claim 7, wherein And the wavelength selector comprises an arrayed waveguide grating. The method of claim 7, wherein The wavelength selector is a multi-wavelength laser diode module comprising a planar shell shell. A wavelength division multiplexing optical communication system, A multi-wavelength laser including first to nth (n is a natural number of two or more) wavelength signals, a wavelength selector for selectively outputting a monitor wavelength signal, and a photo detector for detecting a reflected wavelength signal of the output monitor wavelength signal A central station comprising a diode; And A wavelength splitter configured to receive the outputted first to nth wavelength signals and the outputted monitor wavelength signal through an optical fiber and to distribute the received first to nth wavelength signals to corresponding optical terminals; A remote node comprising a reflective terminal for reflecting and transmitting the received monitor wavelength signal to the photo detector, The central station, A control circuit for receiving a photodetection current from the photodetector and generating a temperature control signal corresponding to a value of a control current among the received photodetection currents; And In response to the temperature control signal, further comprising a temperature control device for adjusting the temperature of the multi-wavelength laser diode, The value of the control current is a value when the monitor wavelength signal and the reflected wavelength signal of the monitor wavelength signal coincide, and have a current value that is relatively larger than an adjacent current value. And, by the temperature regulating device, first to nth wavelength signals output from the multi-wavelength laser diode coincide with first to nth wavelength signals output from the wavelength divider. In a multi-wavelength laser diode module, First optical amplifiers for generating and amplifying first to nth wavelengths, wherein n is a natural number of two or more, a second optical amplifier for generating and amplifying monitor wavelength signals, and amplified first to nth wavelengths; A multi-wavelength laser diode comprising a wavelength selector for selecting and outputting a wavelength signal and the amplified monitor wavelength signal, and a photo detector for detecting a reflected wavelength signal of the monitor wavelength signal output from the wavelength selector; A wavelength filter transmitting the first to n-th wavelength signals and reflecting the reflected wavelength signal of the monitor wavelength signal to the multi-wavelength laser diode; A control circuit for receiving a photodetection current from the photodetector and generating a temperature control signal corresponding to a value of a control current among the received photodetection currents; And In response to the temperature control signal, the temperature control device for adjusting the temperature of the multi-wavelength laser diode, The value of the control current is a value when the monitor wavelength signal and the reflected wavelength signal of the monitor wavelength signal coincide, and have a current value that is relatively larger than an adjacent current value. And, by the temperature regulating device, first to nth wavelength signals output from the multiwavelength laser diode coincide with external reference wavelength signals of the multiwavelength laser diode. The method of claim 12, The multi-wavelength laser diode And a power splitter for coupling the second optical amplifier, the output channel of the photo detector, and the wavelength selector to each other. The method of claim 12, The wavelength selector is formed on a silica substrate, And the first optical amplifiers, the second optical amplifier, and the photo detector are formed on an indium inP substrate. The method of claim 12, When the center wavelength of the optical gain of the second optical amplifier is shorter than the center wavelength of the monitor wavelength signal, the current value of the photodetection current detected by the photodetector decreases with increasing temperature of the multi-wavelength laser diode. Multiwavelength Laser Diode Module.

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