KR102559100B1 - A optical signal transmitting apparatus including a wavelength tunable laser that is temperature independent and wavelength tunable method using the optical signal transmitting apparatus - Google Patents

Abstract

An optical signal transmission device including a temperature-independent wavelength tunable laser is disclosed. An optical signal transmission device includes a DBR laser including a DBR mirror region for converting a wavelength of a laser output based on a first supply current and an optical gain region for controlling a gain of the output laser based on a second supply current; a semiconductor optical amplifier for amplifying laser output from the DBR laser based on a third supply current; and a processor supplying a compensation current to the optical gain region in order to suppress a wavelength overshoot due to a carrier effect generated through a first supply current provided to the DBR mirror region according to a wavelength conversion request.

Description

Optical signal transmission device including temperature-independent wavelength tunable laser and wavelength tunable method using optical signal transmission device

The present invention relates to an optical signal transmission device including a temperature-independent wavelength tunable laser and a wavelength tunable method using the optical signal transmission device, and more particularly, to an optical signal transmission device that suppresses a wavelength drift phenomenon by compensating for the temperature of a DBR mirror that increases due to a current supplied when the wavelength is tunable.

Due to the recent surge in traffic occurring in data centers, problems with electrical switch-based data center networking such as high power consumption, network delay, limitations in networking scalability, and increased networking costs continue to occur. In order to solve these problems, data center networking based on optical switches having characteristics of low power consumption, low delay, and scalability has been considered.

A key element in an optical switching-based system is a tunable laser. In order to minimize the loss of information when optical switching is performed, the wavelength of the tunable laser must be converted at high speed. Among various wavelength tunable lasers, a DBR (Distributed Bragg Reflector) laser can have its wavelength controlled at high speed using opto-electronic conversion. However, a phenomenon in which the temperature increases occurs due to the current supplied to the DBR mirror region for wavelength tuning. This temperature increase causes a problem in that the oscillation wavelength of the tunable laser deviates from the target wavelength and causes a wavelength drift phenomenon.

The present invention provides an apparatus and method for maintaining the temperature of an entire optical signal transmission device constant by supplying a compensation current to an optical gain region and a semiconductor optical amplifier in response to the temperature increased by the current supplied to the DBR mirror region in a DBR wavelength tunable laser.

An optical signal transmission apparatus according to an embodiment of the present invention includes a DBR mirror region for converting a wavelength of a laser output based on a first supply current and an optical gain region for controlling a gain of the output laser based on a second supply current; a semiconductor optical amplifier for amplifying laser output from the DBR laser based on a third supply current; and a processor supplying a compensation current to the optical gain region in order to suppress a wavelength overshoot due to a carrier effect generated through the first supply current supplied to the DBR mirror region according to a wavelength conversion request.

The processor may supply a compensation current having an opposite sign to the first supply current to the optical gain region based on a wavelength switching time required by an application to which the DBR laser is applied.

The processor may adjust the level of the compensating current to be proportional to the level of the first supply current.

An optical signal transmission apparatus according to an embodiment of the present invention includes a DBR mirror region for converting a wavelength of a laser output based on a first supply current and an optical gain region for controlling a gain of the output laser based on a second supply current; a semiconductor optical amplifier for amplifying laser output from the DBR laser based on a third supply current; and a processor supplying a compensation current to the semiconductor optical amplifier in order to suppress a wavelength drift phenomenon due to a thermal effect generated through a first supply current provided to the DBR mirror region according to a wavelength conversion request.

The processor may supply a compensation current having an opposite sign to the first supply current to the semiconductor optical amplifier based on a wavelength holding time required by an application to which the DBR laser is applied.

The processor may adjust the level of the compensating current to be proportional to the level of the first supply current.

An optical signal transmission apparatus according to an embodiment of the present invention includes a DBR mirror region for converting a wavelength of a laser output based on a first supply current and an optical gain region for controlling a gain of the output laser based on a second supply current; a semiconductor optical amplifier for amplifying laser output from the DBR laser based on a third supply current; and a processor supplying a first compensation current and a second compensation current to each of the optical gain region and the semiconductor optical amplifier in order to suppress wavelength overshoot and wavelength drift caused by a carrier effect and a temperature effect generated through the first supply current provided to the DBR mirror region according to a wavelength conversion request.

The processor may supply a first compensation current having a sign opposite to the first supply current to the optical gain region based on a wavelength switching time required by an application to which the DBR laser is applied, and supply a second compensation current having a sign opposite to the first supply current to the semiconductor optical amplifier based on a wavelength holding time required by an application to which the DBR laser is applied.

The processor may adjust the magnitudes of the first compensation current and the second compensation current in proportion to the magnitude of the first supply current.

A wavelength tuning method of an optical transmission device including a temperature-independent DBR laser according to an embodiment of the present invention includes providing a first supply current to a DBR mirror region of the DBR laser to convert a wavelength of an output laser; The method may include supplying a compensation current to an optical gain region of the DBR laser to suppress a wavelength overshoot due to a carrier effect generated through a first supply current provided to the DBR mirror region.

In the supplying of the compensation current, a compensation current having a sign opposite to that of the first supply current may be supplied to the optical gain region based on a wavelength switching time required by an application to which the DBR laser is applied.

In the step of supplying the compensating current, the amount of the compensating current may be adjusted in proportion to the amount of the first supply current.

A wavelength tuning method of an optical transmission device including a temperature-independent DBR laser according to an embodiment of the present invention includes providing a first supply current to a DBR mirror region of the DBR laser to convert a wavelength of an output laser; and supplying a compensation current to the semiconductor optical amplifier in order to suppress a wavelength drift phenomenon due to a temperature effect generated through the first supply current provided to the DBR mirror region.

Supplying the compensating current A compensating current having a sign opposite to that of the first supply current may be supplied to the semiconductor optical amplifier based on a wavelength retention time required by an application to which the DBR laser is applied.

In the step of supplying the compensating current, the amount of the compensating current may be adjusted in proportion to the amount of the first supply current.

A wavelength tuning method of an optical transmission device including a temperature-independent DBR laser according to an embodiment of the present invention includes providing a first supply current to a DBR mirror region of the DBR laser to convert a wavelength of an output laser; The method may include supplying a first compensation current and a second compensation current to the optical gain region and the semiconductor optical amplifier, respectively, in order to suppress a wavelength overshoot due to a carrier effect and a wavelength drift due to a temperature effect generated through the first supply current provided to the DBR mirror region.

The supplying of the first compensation current and the second compensation current may include supplying a first compensation current having an opposite sign to the first supply current to the optical gain region based on a wavelength switching time required by an application to which the DBR laser is applied, and supplying a second compensation current having a sign opposite to the first supply current to the semiconductor optical amplifier based on a wavelength holding time required by an application to which the DBR laser is applied.

In the step of supplying the first compensation current and the second compensation current, the magnitudes of the first compensation current and the second compensation current may be adjusted in proportion to the magnitudes of the first supply current.

According to an embodiment of the present invention, the temperature of the entire optical signal transmission device can be kept constant by supplying a compensation current to the optical gain region and the semiconductor optical amplifier in response to the temperature increased by the current supplied to the DBR mirror region in the DBR wavelength tunable laser.

1 is a diagram showing the configuration of an optical signal transmission device including a DBR laser according to an embodiment of the present invention.
2 is a diagram showing a conceptual diagram of a wavelength drift phenomenon for a DBR laser according to an embodiment of the present invention.
FIG. 3 is a conceptual diagram showing suppression of a wavelength drift phenomenon caused by a temperature change of a DBR laser according to an embodiment of the present invention.
4 is a diagram showing a result of suppressing a wavelength drift phenomenon through embodiments according to an embodiment of the present invention.
5 is a diagram showing a hardware embodiment for suppressing a wavelength drift phenomenon caused by a temperature change of a DBR laser according to an embodiment of the present invention.
6 is a diagram showing a software embodiment for suppressing a wavelength drift phenomenon caused by a temperature change of a DBR laser according to an embodiment of the present invention.

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

1 is a diagram showing the configuration of an optical signal transmission device including a DBR laser according to an embodiment of the present invention.

An optical signal transmission device may include a DBR laser that outputs an optical signal of a variable wavelength, a semiconductor optical amplifier that amplifies an optical signal output through the DBR laser, and a processor that controls supply currents supplied to the DBR laser and a semiconductor optical amplifier (SOA).

The DBR laser may include two DBR mirrors. In this case, the two DBR mirrors may be of the same type or different types of DBR mirrors. For example, when the DBR laser is a Digital Supermode (DS)-DBR laser, one DBR mirror has a property of having multiple reflection spectra depending on the wavelength, and the other DBR mirror has a multi-contact chirped grating. It may have a form. In contrast, when the DBR laser is a sampled grating (SG)-DBR laser, both DBR mirrors may include properties having multiple reflection spectra. However, the structure of the DBR laser provided in the present invention is not limited to any one, and the properties or shape of the DBR mirror may vary according to the type of the DBR laser.

Referring to FIG. 1 , an optical signal transmission apparatus 100 according to an embodiment of the present invention may include a DBR laser 110 that outputs an optical signal of a variable wavelength, a semiconductor optical amplifier 120 that amplifies an optical signal output through the DBR laser 110, and a processor 130 that controls supply current supplied to the DBR laser 110 and the semiconductor optical amplifier 120. At this time, the DBR laser 110 may include a front grating (FG) region 111 having a multi-contact chirp grating shape, a rear grating (RG) region 112 having a multi-reflection spectrum property, an optical gain region 113, and a phase region 114. And as an example, the processor may be a Field Programmable Gate Array (FPGA).

In the look-up table of the processor 130, supply currents to be provided to each region of the DBR laser 110 and the semiconductor optical amplifier 120 may be set for each wavelength. Supply currents may be provided to passive tuning regions such as the FG region 111, RG region 112, and the phase region 114, which are sensitive to current changes, using a high-performance DAC such as a 16-bit digital-to-analog converter (DAC). On the other hand, since active tuning regions such as the optical gain region 113 and the semiconductor optical amplifier 120 are relatively less sensitive to current changes, supply currents may be provided using a low-performance DAC such as a 14-bit DAC. The supply current provided to the FG region 111 must be provided to the contacts of adjacent FG regions for single-wavelength operation, whereby the number of DACs required to drive eight FG regions 111 can be reduced to two by using two additional 1x4 electrical switches.

In this case, the processor 130 may simultaneously provide the analog current provided through the DAC to the RG region 112, the optical gain region 113, and the semiconductor optical amplifier 120 by controlling the current driver. The wavelength drift suppression method of the optical signal transmission device 100 provided by the present invention can be applied to general DBR lasers such as SG-DBR lasers as well as DS-DBR lasers. Accordingly, the processor 130 may adjust supply currents provided to the optical gain region 113 and the semiconductor optical amplifier 120 in consideration of supply currents provided to other regions (FG region 111, phase region 114, etc.) when the output wavelength of the DBR laser 110 is converted. Two ThermoElectric Cooler (TEC) drivers can maintain the temperature of internal components and provide long-term wavelength stability.

Describing a process of providing supply currents to each region of the optical signal transmission device 100, the processor 130 may first output a digital signal by referring to the lookup table. In this case, the lookup table may include information on supply current supplied to each region of the optical signal transmission apparatus 100 necessary for the DBR laser 110 to output optical signals of various wavelengths. For example, first supply currents provided to the RG region 112 for each output wavelength may be stored in the lookup table, and constant values of the second supply current provided to the optical gain region 113 and the third supply current supplied to the semiconductor optical amplifier 120 may be stored regardless of the wavelength.

Then, the output digital signal is converted into an analog current at the DAC corresponding to each area of the DBR laser 110, and the converted analog current is supplied as a supply current to each area of the corresponding optical signal transmission device 100 through each current driver (DR).

2 is a diagram showing a conceptual diagram of a wavelength drift phenomenon for an optical signal transmission device according to an embodiment of the present invention.

Referring to FIG. 2 , the concept of wavelength drift occurring in the optical signal transmission apparatus 100 can be confirmed. In order for the DBR laser 110 to output an optical signal having a wavelength converted in a wide wavelength band, a current of several tens of mA must be applied to the DBR mirror region (corresponding to the RG region in FIG. 1 ) of the DBR laser 110 . That is, the optical signal transmission apparatus 100 may provide a first supply current to the RG region 112 of the DBR laser 110 by referring to the look-up table of the processor 130 to change the wavelength of the output optical signal. Here, if the oscillation wavelength of the optical signal currently output through the DBR laser 110 is λ _{Start Channel,} a current of several tens of mA is supplied and the target wavelength of the output optical signal is determined as λ _{Destination Channel} .

When a first supply current of several tens of mA is provided to the RG region 112 of the DBR laser 110 in order to convert the output wavelength of the output optical signal from the λ _{Start Channel} to the λ _{Destination Channel} , the wavelength of the optical signal output through the DBR laser 110 shows the form shown in FIG. 2. That is, when a first supply current of several tens of mA is provided to the RG region 112 of the DBR laser 110, a wavelength overshoot in which the wavelength of an output optical signal is misaligned may occur in a time domain where a carrier effect occurs.

Thereafter, the temperature of the DBR laser 110 increases due to the first supply current provided to the RG region 112, and as a result, the refractive index of the DBR laser 110 decreases and the wavelength of an output optical signal may increase. A phenomenon in which the output wavelength of the optical signal output through the DBR laser 110 deviates from the target wavelength λ _{destination channel} due to such a temperature increase is referred to as a wavelength drift phenomenon due to a temperature effect. Since the wavelength drift phenomenon due to the temperature effect occurs in a time domain of several hundred milliseconds or more, a problem in that information cannot be transmitted/exchanged occurs in an optical switching-based system during that time.

FIG. 3 is a conceptual diagram showing suppression of a wavelength drift phenomenon caused by a temperature change of a DBR laser according to an embodiment of the present invention.

When a first supply current of several tens of mA is provided to the RG region 112 of the DBR laser 110 to change the wavelength of an output optical signal, a wavelength overshoot due to a carrier effect and a wavelength drift due to a temperature effect may occur. In order to suppress this wavelength drift phenomenon, the present invention provides a method for maintaining the overall temperature of the optical signal transmission device 100 constant by supplying a first compensation current to the optical gain region 113 of the DBR laser 110 in response to the carrier effect of the DBR laser 110 or supplying a second compensation current to the semiconductor optical amplifier 120 in response to the temperature effect. At this time, the first compensation current supplied to the optical gain region 113 and the first compensation current supplied to the semiconductor optical amplifier 120 may be adjusted in proportion to the magnitude of the first supply current supplied to the RG region 112 of the DBR laser 110. The reason for the difference between the optical gain region 113 and the semiconductor optical amplifier 120 is that the optical gain region 113 is a section constituting the resonator of the DBR laser 110, and the semiconductor optical amplifier 120 is only thermally coupled outside the resonator of the DBR laser 110.

For example, referring to FIG. 3 , the first supply current supplied to the RG region 112 of the DBR laser 110 in the start channel is almost zero (I _RG = 0 mA), and the optical gain region 113 and the semiconductor optical amplifier 120. The second supply current (I' _Gain ) and the third supply current (I' _SOA ) supplied to each of them may have a constant size.

At this time, the optical signal transmission apparatus 100 may increase the first supply current I _RG of several tens of mA to the RG region 112 of the DBR laser 110 in order to convert the wavelength of the output optical signal (that is, to switch the wavelength to the destination channel). As mentioned above, in response to the wavelength drift phenomenon caused by the first supply current I _RG provided to the RG region 112, the optical signal supply apparatus 100 of the present invention uses the processor 130 to generate ΔI Gain and ΔI _Gain and Wavelength drift can be suppressed by supplying the first compensation current and the second compensation current as much as ΔI _SOA .

4 is a diagram showing a result of suppressing a wavelength drift phenomenon through embodiments according to an embodiment of the present invention.

4 is an experimental result showing that the wavelength drift phenomenon of the entire optical signal transmission apparatus 100 is suppressed when a compensation current is supplied to the optical gain region 113 of the DBR laser 110 and the semiconductor optical amplifier 120. For example, I' _Gain , that is, the second supply current and I' _SOA , that is, the third supply current of a predetermined size are continuously provided to the optical gain region 113 and the semiconductor optical amplifier 120 in the start channel.

Graph ① shows a change in wavelength over time when a first supply current of 0 mA to 60 mA is provided to the RG region 112 of the DBR laser 110 without supplying any compensation current. In other words, supply currents provided to the optical gain region 113 and the semiconductor optical amplifier 120 in the start channel and the destination channel may be unchanged (I' _Gain =I _Gain and I' _SOA =I _SOA ). Referring to the resulting graph of output wavelengths, both the time domain 410 in which the carrier effect occurs and the time domain 420 in which the temperature effect occurs are far outside the wavelength tolerance range 400 allowed by the Optical Internetworking Forum (OIF) standard.

In response to the wavelength overshoot due to the carrier effect, the optical signal transmission apparatus 100 of the present invention may supply a first compensation current having a size of ΔI _Gain to the optical gain region 113 in the start channel. At this time, the supplied first compensation current may have a sign opposite to that of the first supply current and be adjusted in proportion to the magnitude of the first supply current.

Graph ② shows a change in wavelength with time when the first compensation current is supplied to the optical gain region 113 as described above. Referring to the output wavelength graph, the carrier effect is reduced through the first compensation current supplied to the optical gain region 113 of the start channel, so that the output wavelength in the time domain 410 meets the wavelength tolerance range 400 allowed by the OIF standard. It can be seen that it satisfies. Since the temperature of the laser is slightly changed through the supply of the first compensation current, it can be seen in the time domain 420 that not only the carrier effect but also the wavelength drift caused by the temperature effect is suppressed to some extent.

However, it can be confirmed that the temperature compensation of the DBR laser 110 is not completely compensated despite the supply of the first compensation current to the optical gain region 113, so that the wavelength drift phenomenon due to the temperature effect still occurs.

In response to the wavelength drift caused by the temperature effect, the optical signal transmission apparatus 100 of the present invention may supply a second compensation current having a magnitude of ΔI _SOA to the semiconductor optical amplifier 120 in the start channel. At this time, the supplied second compensation current has a sign opposite to that of the first supply current and may be adjusted in proportion to the magnitude of the first supply current.

Graph ③ shows the change in wavelength with time when the compensation current is supplied to both the optical gain region 113 and the semiconductor optical amplifier 120 as described above. Referring to the output wavelength graph, the carrier effect is reduced through the first compensation current supplied to the optical gain region 113 of the start channel, so that the output wavelength in the time domain 410 meets the wavelength tolerance range 400 allowed by the OIF standard. It can be seen that it satisfies. In addition, it can be seen that the temperature effect is reduced through the second compensation current supplied to the semiconductor optical amplifier 120 of the start channel, so that the output wavelength satisfies the wavelength tolerance range 400 allowed by the OIF standard in the time domain 420.

5 is a diagram showing a hardware embodiment for suppressing a wavelength drift phenomenon caused by a temperature change of a DBR laser according to an embodiment of the present invention.

Referring to FIG. 5 , the optical signal transmission apparatus 100 of the present invention can suppress a wavelength drift phenomenon due to a temperature change due to wavelength conversion through a simple change of internal hardware without modifying a laser process. Specifically, the optical signal transmission device 100 may supply the first supply current to the RG region 112 by controlling the current driver (DR) 140 having a differential output corresponding to the RG region 112 of the DBR laser 110. The temperature of the RG region 112 may increase due to the first supply current supplied in this way, and this temperature increase may cause a wavelength overshoot due to a carrier effect and a wavelength drift due to a temperature effect. Therefore, there is an advantage in that the existing laser module can be simply upgraded through a change in the driving circuit.

<First Embodiment>

The optical signal transmission apparatus 100 may suppress a wavelength overshoot due to a carrier effect by providing a first supply current to the RG region 112 of the DBR laser 110 according to a wavelength conversion request. In other words, the first embodiment may be suitable for an application that outputs an optical signal having a stabilized wavelength by completion of wavelength switching in the time domain 410 .

Specifically, the optical signal transmission apparatus 100 controls the current driver 140 corresponding to the RG region 112 in the start channel to supply a first compensation current having a sign opposite to that of the first supply current to the optical gain region 113 of the DBR laser 110. In this case, the optical signal transmission device 100 may adjust the size of the first compensation current using a separate current controller 150a, and the current controller 150a may adjust the size of the compensation current in proportion to the size of the first supply current. Here, the current regulator 150a may be a device capable of amplifying or attenuating the gain of an electrical signal (G/A, Electrical Gain/Attenuation). The first compensation current whose size is adjusted as described above may be supplied to the optical gain region 113 after being combined with the second supply current continuously supplied to the optical gain region 113 through the electric adder 160a.

Thereafter, the optical signal transmission apparatus 100 provides the first supply current to the RG region 112 to perform wavelength switching and simultaneously reduces the magnitude of the second supply current provided to the optical gain region 113 by the amount of the first compensation current. Through this operation, the optical signal transmission apparatus 100 can reduce the carrier effect and suppress a wavelength drift phenomenon with respect to the output wavelength in the time domain 410 .

<Second Embodiment>

The optical signal transmitting apparatus 100 may suppress a wavelength drift phenomenon caused by a temperature effect by providing a first supply current to the RG region 112 of the DBR laser 110 according to a wavelength conversion request. In other words, the second embodiment may be suitable for an application that maintains the wavelength of an optical signal whose wavelength has been switched in the time domain 420 .

Specifically, the optical signal transmission apparatus 100 controls the current driver 140 corresponding to the RG region 112 to supply a second compensation current having a sign opposite to that of the first supply current to the semiconductor optical amplifier 120. At this time, the optical signal transmission device 100 may adjust the size of the second compensation current using a separate current controller 150b, and the current controller 150b may adjust the size of the second compensation current in proportion to the size of the first supply current. Here, the current controller 150b may be a device capable of amplifying or attenuating a gain of an electrical signal. The second compensation current whose size is adjusted in this way can be supplied to the semiconductor optical amplifier 120 after being combined with the third supply current continuously supplied to the semiconductor optical amplifier 120 through the electric adder 160b.

Thereafter, the optical signal transmission apparatus 100 provides the first supply current to the RG region 112 to perform wavelength switching and simultaneously reduces the magnitude of the third supply current supplied to the semiconductor optical amplifier 120 by the amount of the second compensation current. Through this operation, the optical signal transmission apparatus 100 can reduce the temperature effect and suppress the drift phenomenon of the output wavelength in the time domain 420 .

<Third Embodiment>

The optical signal transmission apparatus 100 provides a first supply current to the RG region 112 of the DBR laser 110 according to a wavelength conversion request, thereby suppressing wavelength overshoot due to the carrier effect and wavelength drift caused by the temperature effect. In other words, the third embodiment outputs an optical signal having a stabilized wavelength after the wavelength is switched in the time domain 410 and maintains the wavelength of the optical signal whose wavelength has been switched in the time domain 420. It may be suitable for applications.

Specifically, the optical signal transmission apparatus 100 may control the current driver 140 corresponding to the RG region 112 to supply a first compensation current having a sign opposite to that of the first supply current to the optical gain region 113 of the DBR laser 110, and supply a second compensation current having a sign opposite to that of the first supply current to the semiconductor optical amplifier 120. At this time, the optical signal transmission apparatus 100 may adjust the size of the compensation currents using separate current controllers 150a and 150b, and the current controllers 150a and 150b may adjust the size of the compensation currents in proportion to the size of the first supply current. Here, the current controllers 150a and 150b may be devices capable of amplifying or attenuating a gain of an electrical signal. The first compensation current and the second compensation current whose magnitudes are adjusted as described above may be combined with the second supply current continuously supplied to the optical gain region 113 and the third supply current continuously supplied to the semiconductor optical amplifier 120 through the electric adders 160a and 160b, and then supplied to the optical gain region 113 and the semiconductor optical amplifier 120.

Thereafter, the optical signal transmission apparatus 100 provides a first supply current to the RG region 112 to perform wavelength switching, simultaneously reducing the magnitude of the second supply current supplied to the optical gain region 113 by the first compensation current, and reducing the magnitude of the third supply current supplied to the semiconductor optical amplifier 120 by the second compensation current. Through this operation, the optical signal transmission apparatus 100 can suppress the wavelength overshoot of the output wavelength in the time domain 410 by reducing the carrier effect, and suppress the wavelength drift phenomenon with respect to the output wavelength in the time domain 420 by reducing the temperature effect.

This hardware implementation method has an advantage in that time synchronization can be easily matched by supplying compensation current using a current driver having a differential output corresponding to the RG region 112 of the DBR laser 110. In addition, although the supply current ideally has a step function waveform, in reality, each driving driver may have a different waveform. However, when supplying current to the RG region 112 and supplying compensation current to the optical gain region 113 and the semiconductor optical amplifier 120 using only one differential driver, there is an advantage in that they can be driven with signals of similar waveforms because the same driving driver is used. Lastly, since the compensation current of the optical gain region 113 and the semiconductor optical amplifier 120 is supplied in proportion to the magnitude of the supply current supplied to the RG region 112 without modifying the lookup table, there is an advantage in that the magnitude of the compensation current can be automatically adjusted.

6 is a diagram showing a software embodiment for suppressing a wavelength drift phenomenon caused by a temperature change of a DBR laser according to an embodiment of the present invention.

Referring to FIG. 6 , the optical signal transmission apparatus 100 of the present invention can suppress the wavelength drift phenomenon using a software method. To this end, the optical signal transmission apparatus 100 may modify a lookup table of the processor 130 for driving the DBR laser 110 . In general, the processor 130 of the optical signal transmission apparatus 100 stores the first supply current of the RG region 112, the second supply current of the optical gain region 112, and the third supply current of the semiconductor optical amplifier 120, which are various for each wavelength of an optical signal to be output, in a look-up table.

Therefore, the optical signal transmission apparatus 100 of the present invention can modify supply currents supplied to each of the optical gain region 113 of the DBR laser 110 and the semiconductor optical amplifier 120 stored for each wavelength to be output in the look-up table in step 610. In this case, supply currents supplied to each of the optical gain region 113 and the semiconductor optical amplifier 120 to be corrected may be corrected based on the first compensation current and the second compensation current determined through the first supply current supplied to the RG region 112, respectively.

Such compensating currents can be empirically obtained through experiments. Typically, compensating currents supplied to the optical gain region 113 and the semiconductor optical amplifier 120 may be smaller than the value of the first supply current supplied to the RG region 112. More specifically, as the compensation current value, the maximum switching current value of the RG region 112 is applied, and after finding compensation currents of the maximum optical gain region 113 and the semiconductor optical amplifier 120 corresponding thereto, the compensation current values of the optical gain region 113 and the semiconductor optical amplifier 120 may be adjusted in proportion to the switching current value of the RG region 112. At this time, when the compensation current value is found, if the compensation current value is found in a large current unit, the compensation current value can be found quickly, but the wavelength stability (accuracy) due to this may be lowered. However, on the contrary, if you search in small current units, you can find the compensation current value with high wavelength stability (accuracy) although it is slow.

The optical signal transmission apparatus 100 may modify the lookup table by adding the determined compensation current value to the second supply current and the third supply current continuously supplied to the optical gain region 113 and the semiconductor optical amplifier 120 in the start channel.

In operation 620, the optical signal transmitting apparatus 100 may control and supply the first supply current of the RG region 112 corresponding to the wavelength to be converted through the processor 130 by referring to the modified lookup table.

In operation 630, the optical signal transmission apparatus 100 may supply a second supply current of the optical gain region corresponding to the first supply current and a third supply current of the semiconductor optical amplifier under the control of the processor 130 by referring to the modified look-up table in order to suppress a wavelength drift phenomenon that may occur due to the first supply current.

In step 640, the optical signal transmitting apparatus 100 may check the wavelength of the output optical signal to determine whether a wavelength drift phenomenon has occurred.

If the wavelength drift phenomenon does not occur, the optical signal transmission apparatus 100 stores the modified lookup table in step 650, and if the wavelength drift phenomenon occurs, steps 610 to 630 are repeated to find an optimal compensation current. The process of finding can be repeated.

Meanwhile, the method according to the present invention is written as a program that can be executed on a computer and can be implemented in various recording media such as magnetic storage media, optical reading media, and digital storage media.

Implementations of the various techniques described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or combinations thereof. Implementations may be implemented as a computer program product, i.e. a computer program tangibly embodied in an information carrier, e.g. a machine readable storage device (computer readable medium) or radio signal, for processing by, or for controlling the operation of, a data processing device, e.g. a programmable processor, computer, or operation of multiple computers. Computer programs, such as the computer program(s) described above, may be written in any form of programming language, including compiled or interpreted languages, and may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program can be deployed to be processed on one computer or multiple computers at one site or distributed across multiple sites and interconnected by a communication network.

Processors suitable for processing a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from read only memory or random access memory or both. Elements of a computer may include at least one processor that executes instructions and one or more memory devices that store instructions and data. In general, a computer may include one or more mass storage devices that store data, such as magnetic, magneto-optical disks, or optical disks, or may be coupled to receive data from or transmit data to, or both. Information carriers suitable for embodying computer program instructions and data include, for example, semiconductor memory devices, for example, magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as compact disk read only memory (CD-ROM) and digital video disks (DVD), magneto-optical media such as floptical disks, read memory only (ROM), random access memory (RAM). , flash memory, EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), and the like. The processor and memory may be supplemented by, or included in, special purpose logic circuitry.

In addition, computer readable media may be any available media that can be accessed by a computer, and may include both computer storage media and transmission media.

While this specification contains many specific implementation details, they should not be construed as limiting as to the scope of any invention or claimables, but rather as a description of features that may be unique to a particular embodiment of a particular invention. Certain features that are described in this specification in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments individually or in any suitable subcombination. Further, while features may operate in particular combinations and be initially depicted as such claimed, one or more features from a claimed combination may in some cases be excluded from that combination, and the claimed combination may be modified as a subcombination or variation of a subcombination.

Similarly, while actions are depicted in the drawings in a particular order, it should not be construed as requiring that those actions be performed in the specific order shown or in the sequential order, or that all depicted actions must be performed to obtain desired results. In certain cases, multitasking and parallel processing can be advantageous. Further, the separation of various device components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the program components and devices described may generally be integrated together into a single software product or packaged into multiple software products.

On the other hand, the embodiments of the present invention disclosed in this specification and drawings are only presented as specific examples to aid understanding, and are not intended to limit the scope of the present invention. In addition to the embodiments disclosed herein, it is obvious to those skilled in the art that other modified examples based on the technical idea of the present invention can be implemented.

100: optical signal transmission device
110: DBR laser
111: DBR mirror area
112: optical gain area
113: phase area
120: semiconductor optical amplifier
130: processor

Claims (18)

a DBR laser comprising a DBR mirror region for converting a wavelength of a laser output based on a first supply current and an optical gain region for controlling a gain of the output laser based on a second supply current;
a semiconductor optical amplifier for amplifying laser output from the DBR laser based on a third supply current; and
In order to suppress a wavelength overshoot due to a carrier effect generated through the first supply current provided to the DBR mirror region, a processor supplying a compensation current to the optical gain region during a time when the wavelength is changed to a requested wavelength according to a wavelength conversion request and maintained.
An optical signal transmission device comprising a. According to claim 1,
the processor,
An optical signal transmission device that supplies a compensation current having an opposite sign to the first supply current to the optical gain region based on a wavelength switching time required by an application to which the DBR laser is applied. According to claim 1,
the processor,
An optical signal transmission device that adjusts the amount of the compensating current in proportion to the amount of the first supply current. a DBR laser comprising a DBR mirror region for converting a wavelength of a laser output based on a first supply current and an optical gain region for controlling a gain of the output laser based on a second supply current;
a semiconductor optical amplifier for amplifying laser output from the DBR laser based on a third supply current; and
A processor supplying a compensation current to the semiconductor optical amplifier during a time when the wavelength is changed to a requested wavelength and maintained according to a request for wavelength conversion, in order to suppress a wavelength drift phenomenon caused by a temperature effect generated through the first supply current provided to the DBR mirror region.
An optical signal transmission device comprising a. According to claim 4,
the processor,
An optical signal transmission device for supplying a compensation current having an opposite sign to the first supply current to the semiconductor optical amplifier based on a wavelength holding time required by an application to which the DBR laser is applied. According to claim 4,
the processor,
An optical signal transmission device that adjusts the amount of the compensating current in proportion to the amount of the first supply current. a DBR laser including a DBR mirror region for converting a wavelength of a laser output based on a first supply current and an optical gain region for controlling a gain of the output laser based on a second supply current;
a semiconductor optical amplifier for amplifying laser output from the DBR laser based on a third supply current; and
A processor for supplying a first compensation current and a second compensation current to the optical gain region and the semiconductor optical amplifier, respectively, during a time when the wavelength is changed to a requested wavelength and maintained according to a wavelength conversion request, in order to suppress a wavelength overshoot due to a carrier effect and a wavelength drift caused by a temperature effect generated through the first supply current provided to the DBR mirror region.
An optical signal transmission device comprising a. According to claim 7,
the processor,
Supplying a first compensation current having an opposite sign to the first supply current to the optical gain region based on a wavelength switching time required by an application to which the DBR laser is applied;
An optical signal transmission device for supplying a second compensation current having an opposite sign to the first supply current to the semiconductor optical amplifier based on a wavelength holding time required by an application to which the DBR laser is applied. According to claim 7,
the processor,
An optical signal transmission device for adjusting the magnitudes of the first compensation current and the second compensation current in proportion to the magnitude of the first supply current. In the wavelength tuning method of an optical transmission device including a temperature-independent DBR laser,
providing a first supply current to a DBR mirror region of the DBR laser to convert a wavelength of an output laser;
Supplying a compensation current to an optical gain region of the DBR laser during a time when the wavelength is changed to a requested wavelength and maintained according to a wavelength conversion request, in order to suppress a wavelength overshoot due to a carrier effect generated through a first supply current provided to the DBR mirror region.
Wavelength tuning method of an optical signal transmission device comprising a. According to claim 10,
The step of supplying the compensation current,
A wavelength tuning method of an optical signal transmission device for supplying a compensation current having an opposite sign to the first supply current to the optical gain region based on a wavelength switching time required by an application to which the DBR laser is applied. According to claim 10,
The step of supplying the compensation current,
A wavelength tuning method of an optical signal transmission device for adjusting the magnitude of the compensating current in proportion to the magnitude of the first supply current. In the wavelength tuning method of an optical transmission device including a temperature-independent DBR laser,
providing a first supply current to a DBR mirror region of the DBR laser to convert a wavelength of an output laser;
supplying a compensation current to a semiconductor optical amplifier during a time when the wavelength is changed to a requested wavelength and maintained according to a wavelength conversion request, in order to suppress a wavelength drift phenomenon caused by a temperature effect generated through a first supply current provided to the DBR mirror region;
Wavelength tuning method of an optical signal transmission device comprising a. According to claim 13,
supplying the compensating current;
A wavelength tuning method of an optical signal transmission device for supplying a compensation current having an opposite sign to the first supply current to the semiconductor optical amplifier based on a wavelength holding time required by an application to which the DBR laser is applied. According to claim 13,
supplying the compensating current;
A wavelength tuning method of an optical signal transmission device for adjusting the magnitude of the compensating current in proportion to the magnitude of the first supply current. In the wavelength tuning method of an optical transmission device including a temperature-independent DBR laser,
providing a first supply current to a DBR mirror region of the DBR laser to convert a wavelength of an output laser;
Supplying a first compensation current and a second compensation current to an optical gain region of the DBR laser and a semiconductor optical amplifier, respectively, during a time when the wavelength is changed to a requested wavelength and maintained according to a wavelength conversion request, in order to suppress a wavelength overshoot due to a carrier effect and a wavelength drift phenomenon due to a temperature effect generated through the first supply current provided to the DBR mirror region.
Wavelength tuning method of an optical signal transmission device comprising a. According to claim 16,
The step of supplying the first compensation current and the second compensation current,
Supplying a first compensation current having an opposite sign to the first supply current to the optical gain region based on a wavelength switching time required by an application to which the DBR laser is applied;
A wavelength tuning method of an optical signal transmission device for supplying a second compensation current having an opposite sign to the first supply current to the semiconductor optical amplifier based on a wavelength holding time required by an application to which the DBR laser is applied. According to claim 16,
The step of supplying the first compensation current and the second compensation current,
A wavelength tuning method of an optical signal transmission device for adjusting the magnitudes of the first compensation current and the second compensation current in proportion to the magnitude of the first supply current.

Images