KR101040709B1 - Optical transmitting system for transmitting a broadcasting signal and a digital signal, optical transmitter included in the same and optic transmitting method - Google Patents

Abstract

The present invention relates to an optical transmitter included in an optical transmission system that transmits at least one of a broadcast signal and a digital signal while controlling to avoid mode partition noise while using a multi-mode light source. The optical transmitter includes a light source unit generating a multi-mode light source, a demultiplexer connected to the light source unit, and a noise controller connected to the demultiplexer. Here, the broadcast signal is modulated by the light source unit to output a first broadcast optical signal having multiple wavelengths from the light source unit, and the demultiplexer divides the output first broadcast optical signal for each wavelength to generate second broadcast optical signals. The noise controller amplifies and outputs at least one of the output second broadcast optical signals to a predetermined level.

Optical transmission, mode partition noise, multi-mode

Description

OPTICAL TRANSMITTING SYSTEM FOR TRANSMITTING A BROADCASTING SIGNAL AND A DIGITAL SIGNAL, OPTICAL TRANSMITTER INCLUDED IN THE SAME AND OPTIC TRANSMITTING METHOD}

The present invention relates to an optical transmission system, an optical transmitter and an optical transmission method included therein, and more particularly, to control a mode partition noise from occurring while using a multi-mode light source and to transmit at least one of a broadcast signal and a digital signal. An optical transmission system, an optical transmitter and an optical transmission method included therein.

The optical transmission system generally consists of a central base station, a local base station, and a subscriber end, and uses a multi-mode light source having multiple wavelengths in consideration of economics.

The central base station modulates a broadcast signal to light generated from the light source to generate a first broadcast optical signal, and transmits the generated first broadcast optical signal to the local base station through one optical fiber.

The local base station divides the broadcast optical signal by wavelength to generate second broadcast optical signals, and transmits the generated second broadcast optical signals to the subscriber end. That is, the second broadcast optical signals are implemented in a single mode each having one wavelength.

In this way, the second broadcast optical signal having a single wavelength should always be input to the subscriber end with a certain size in order to guarantee broadcast service quality, but in reality, the size of the second broadcast optical signal is changed. This is a phenomenon caused by the multi-mode light source. In detail, the multi-mode light source may branch into a multi-mode to output light having multiple wavelengths, but the light may not be constant in the branching process. For example, the size of the light when transmitting the first broadcast data and the size of the light when transmitting the second broadcast data may be different. As a result, the magnitude of the second broadcast signal was not kept constant, and the change in magnitude of the second broadcast signal acted as noise. This noise is called Mode Partition Noise.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical transmission system for controlling at least one of a broadcast signal and a digital signal while controlling a mode partition noise while using a multi-mode light source in consideration of economics, an optical transmitter, and an optical transmission method included therein. It is.

In order to achieve the above object, an optical transmitter according to an embodiment of the present invention includes a light source unit for generating a multi-mode light source; A demultiplexer connected to the light source unit; And a noise controller connected to the demultiplexer. Here, the broadcast signal is modulated by the light source unit to output a first broadcast optical signal having multiple wavelengths from the light source unit, and the demultiplexer divides the output first broadcast optical signal for each wavelength to generate second broadcast optical signals. The noise controller amplifies and outputs at least one of the output second broadcast optical signals to a predetermined level.

An optical transmission method according to an embodiment of the present invention comprises the steps of generating a first broadcast optical signal by modulating a broadcast signal to multi-mode light having a multi-wavelength; Dividing the first broadcast optical signal by wavelength to generate second broadcast optical signals; And amplifying at least one of the generated second broadcast optical signals to a predetermined size.

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Since the optical transmitter of the optical transmission system according to the present invention, in particular, the optical transmitter in the central base station uses an amplifying unit that amplifies to a certain level while using a multi-mode light source, the size of a broadcast optical signal having a single wavelength input to the subscriber end is increased. The advantage is that it remains constant so that no mode partition noise occurs. As a result, the optical transmission system can be economically implemented and can not generate mode partition noise.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. Like reference numerals are used for like elements in describing each drawing.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that no other component exists in the middle.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art, and are not construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

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

1 is a block diagram illustrating an optical transmission system according to an embodiment of the present invention.

Referring to FIG. 1, the optical transmission system of the present embodiment is a system for transmitting a specific signal, for example, a broadcast signal using light, and may be used for an IPTV service, a CATV service, an Internet service, and the like. ), Local base station 102 and subscriber end 104.

In such an optical transmission system, the central base station 100 uses a multi-mode light source having multiple wavelengths in consideration of economy.

In particular, when the multi-mode light source is used, a mode partition noise (a phenomenon in which the magnitude of the broadcast optical signal input to the subscriber station 104 is not constant and changes in the process of branching the multi-wavelength light source) may be caused. Since it is possible, the central base station 100 is implemented to have a function of controlling so that the mode partition noise does not occur.

The local base station 100 is connected to the central base station 100 through one optical fiber (or optical cable), and the subscriber station 104 is connected to the local base station 102 through a plurality of optical fibers (or optical cables).

Hereinafter, a detailed configuration and function of the central base station 100 will be described with reference to the accompanying drawings.

2 is a diagram illustrating a configuration of a central base station according to the first embodiment of the present invention.

2, the central base station 100 of the present embodiment is an optical transmitter for transmitting a broadcast optical signal to the local base station 102 or the subscriber station 104, the light source unit 200, the demultiplexer (202), A noise controller 204 and a multiplexer 206.

The light source unit 200 may be implemented as a multi-mode light source having multiple wavelengths. For example, the light source unit 200 may be implemented as a Fabry-Perot Laser Diode (FP-LP) having low cost and excellent characteristics.

As shown in FIG. 2, the analog broadcast signal is modulated to the light output from the light source unit 200, that is, the broadcast signal is modulated by the light source unit 200 to output the first broadcast optical signal from the light source unit 200.

As shown in FIG. 2, the first broadcast optical signal is implemented in a multi mode having multiple wavelengths. For example, a double sideband (DSB) in which broadcast signals BS are positioned on both sides of a carrier wave (CW). It may be implemented in the form. That is, one mode may include one carrier wave CW and broadcast signals BS arranged at both sides thereof. Of course, the first broadcast optical signal may be implemented as a single sideband (SSB).

The first broadcast optical signal of the multi mode output from the light source unit 200 is demultiplexed by the demultiplexer 202. As a result, the first broadcast optical signal is separated by wavelength, that is, by mode, as shown in FIG. do. Hereinafter, a signal separated for each wavelength will be referred to as a second broadcast optical signal.

The second broadcast optical signals have different wavelengths and include broadcast signals BS as shown in FIG. 2.

The second broadcast optical signals output from the demultiplexer 202 are provided to the noise controller 204.

The noise controller 204 may include a plurality of amplifiers 210, and the number of amplifiers 210 may match the number of the second broadcast optical signals. That is, the second broadcast optical signals are respectively input to the corresponding amplifiers 210.

The amplifier 210 amplifies and outputs the second broadcast optical signal to a predetermined level (constant level). As a result, the size of the third broadcast optical signal output from the amplifier 210 is always constant.

According to an embodiment of the present invention, the amplifier 210 may be formed of a semiconductor optical amplifier (SOA) having a saturation gain.

The third broadcast optical signals output from the respective amplification units 210 are multiplexed by the multiplexer 206, and as a result, the fourth broadcast optical signal having the multi mode is output from the multiplexer 206 as shown in FIG. do.

The fourth broadcast optical signal output from the multiplexer 206 is transmitted to the subscriber station 104 through the local base station 102.

In short, the central base station 100 of the present embodiment uses a multi-mode light source having a multi-wavelength, preferably FP-LP, but maintains a constant level of the second broadcast optical signal using the noise controller 204. Let's do it. As a result, the fourth broadcast optical signal transmitted to the subscriber end 104 maintains a constant level unlike in the prior art, and thus mode partition noise may not be generated.

That is, the central base station 100 of the present embodiment uses a multi-mode light source in consideration of economical efficiency, but uses a noise control unit 204 to amplify to a predetermined level in order to prevent the generation of mode partition noise.

3 is a diagram showing the configuration of a central control station according to the second embodiment of the present invention.

Referring to FIG. 3, the central control station 100 of the present embodiment includes a light source unit 300, a demultiplexer 302, a noise controller 304, and a multiplexer 306.

Since the remaining components except for the noise controller 304 are the same as in the first embodiment, detailed description of the same components will be omitted.

The noise controller 304 includes a plurality of sub-noise controllers 310, and second broadcast optical signals are input to each sub-noise controller 310 in a one-to-one correspondence.

Each sub noise controller 310 includes an amplifier 312 and a modulator 314.

The amplifier 312 amplifies the input second broadcast optical signal to a predetermined level and may be, for example, SOA.

The modulator 314 modulates the digital data D to the amplified second broadcast optical signal, and the third broadcast optical signal having digital data D according to the modulation as shown in FIG. 3. Output

According to an embodiment of the present invention, the optical transmission system of the present invention can be used for an interactive TV service, in which case it is highly likely that the data provided to each user is different from each other, so that at least one of the digital data (D) is used. One is different data from the other data.

The multiplexer 306 having received the third broadcast optical signals transmits the fourth broadcast optical signal to the subscriber station 104 through the local base station 102.

In short, the central base station 100 of the present embodiment uses a multi-mode light source having a multi-wavelength, preferably FP-LP, but maintains a constant level of the second broadcast optical signal using the noise controller 304. Control to avoid the mode partition noise. In addition, the central base station 100 outputs the fourth broadcast optical signal in which the analog broadcast signal and the digital data are simultaneously modulated.

4 is a diagram illustrating a configuration of a central base station according to the third embodiment of the present invention.

Referring to FIG. 4, the central base station 100 of this embodiment includes a light source unit 400 and a noise control unit 402.

That is, the central base station 100 of the present embodiment does not use the demultiplexer and the multiplexer, unlike in the second embodiment. In detail, the second embodiment required the demultiplexer 302 and the multiplexer 306 because the digital data provided to the users are different, but when the same digital data is provided to all users, one digital data is provided. Since only one is needed, there is no need for a demultiplexer and multiplexer for a plurality of digital data as in this embodiment.

Since the functions of the amplifier 404 and the modulator 406 of the noise controller 402 are the same as in the second embodiment, the description thereof will be omitted. In FIG. 4, the modulator 406 is illustrated, but in the optical transmission system in which digital data is not provided, the noise controller 402 may include only the amplifier 404.

5 is a diagram illustrating a configuration of a central base station according to the fourth embodiment of the present invention.

Referring to FIG. 5, the central base station 100 according to the present embodiment includes a light source unit 500, a demultiplexer 502, and a noise controller 504.

That is, the central base station 100 of this embodiment does not include a multiplexer unlike in the second embodiment.

In general, the local base station 102 is installed in consideration of economical efficiency because the distance between the central base station 100 and the subscriber station 104 is far, so the distance between the central base station 100 and the subscriber station 104 is close In such a case, the local base station 102 may not be installed.

In this case, since the central base station 100 and the subscriber station 104 are directly connected through a plurality of optical fibers, the multiplexer is not required and the sub-noise controllers 506 are directly connected to the subscriber station 104 via the corresponding optical fibers. . As a result, the third broadcast optical signal for each wavelength in which the analog broadcast signal and the digital data are modulated is transmitted to the subscriber station 104 through the corresponding optical fibers.

Summarizing the first to fourth embodiments, the optical transmission system of the present invention uses a multi-mode light source, but uses amplifiers such as SOA so that no mode partition noise is generated. Therefore, the configuration of the optical transmission system of the present invention can be variously modified as long as it uses a multi-mode light source and has a configuration capable of removing mode partition noise.

The embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art having ordinary knowledge of the present invention may make various modifications, changes, and additions within the spirit and scope of the present invention. Should be considered to be within the scope of the following claims.

1 is a block diagram illustrating an optical transmission system according to an embodiment of the present invention.

2 is a diagram illustrating a configuration of a central base station according to the first embodiment of the present invention.

3 is a diagram showing the configuration of a central control station according to the second embodiment of the present invention.

4 is a diagram illustrating a configuration of a central base station according to the third embodiment of the present invention.

5 is a diagram illustrating a configuration of a central base station according to the fourth embodiment of the present invention.

Claims (11)

A light source unit generating a multi-mode light source; A demultiplexer connected to the light source unit; And Including a noise control unit connected to the demultiplexer, The broadcast signal is modulated by the light source unit to output a first broadcast optical signal having multiple wavelengths from the light source unit, and the demultiplexer divides the output first broadcast optical signal for each wavelength to output second broadcast optical signals. And the noise controller amplifies and outputs at least one of the output second broadcast optical signals to a predetermined level. The mode partition of claim 1, wherein the light source unit comprises a Fabry-Perot Laser Diode (FP-LP), and the noise controller includes one or more semiconductor optical amplifiers (SOAs). And removes mode partition noise, wherein the first broadcast optical signal is implemented in a DSB type. The method of claim 1, wherein the noise control unit comprises a plurality of sub-noise unit, The sub noise unit, An amplifier for amplifying the second broadcast optical signal to a desired level; And And a modulator for modulating specific digital data on the second broadcast optical signal amplified by the amplifier and outputting the digital data as a third broadcast optical signal. 4. The optical transmitter of claim 3, wherein at least one of the digital data modulated by the sub-noise units is other data. The method of claim 3, wherein the optical transmitter, And a multiplexer for multiplexing the third broadcast optical signals output from the sub-noise units and outputting the third broadcast optical signals as a fourth broadcast optical signal. delete delete delete Generating a first broadcast optical signal by modulating a broadcast signal on multi-mode light having multiple wavelengths; Dividing the first broadcast optical signal by wavelength to generate second broadcast optical signals; And And amplifying at least one of the generated second broadcast optical signals to a predetermined size. The method of claim 9, wherein the optical transmission method, Modulating digital data on the amplified second broadcast optical signals, respectively, And the broadcast signal is an analog signal. The light source of claim 9, wherein the light source generating the multi-mode light is a Fabry-Perot Laser Diode (FP-LP), and the amplification is performed by a semiconductor optical amplifier (SOA). And the first broadcast optical signal is implemented in a DSB type.

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