KR20150075823A - Apparatus and method for forming of wavelength division multiplexing passive optical network optical signal - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical transmission apparatus and a method in which a complex wavelength control circuit is not required by using a broadband light source in a wavelength division multiplexing passive optical network (WDM-PON). The optical transmission apparatus of the present invention is characterized in that the broadband light source emits a broadband optical signal, a multi-channel optical wavelength filter generates a channel-specific optical signal corresponding to a center wavelength of each channel using a broadband optical signal, Modulates the optical signal for each channel to form a digital signal for each channel, and the multiplexing AWG multiplexes the digital signal for each channel to form an output optical signal.

Description

TECHNICAL FIELD [0001] The present invention relates to a WDM-PON optical signal forming apparatus and a method for forming a WDM-PON optical signal,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of optical communication, and more particularly, to a wavelength division multiplexing passive optical network (WDM-PON) in which a broadband light source is used, Forming apparatus and method.

A WDM-PON (wavelength division multiplexing passive optical network) optical communication is a technology that can simultaneously transmit optical signals of dozens of different wavelengths through a single optical fiber, and provides a point-to-point It is recognized as a technology that can lead future communication technology by securing superior technical superiority than other optical communication technologies such as providing independent wavelength channel by connection and high-speed access network configuration.

In such a WDM-PON optical communication, an optical line terminal (OLT) plays a role as an optical transceiver in a national office or a central office (CO). FIG. 1 is a view illustrating an optical transmitter part of an OLT structure using injection seeding technology that is currently commercialized. 1, a structure of a WDM-PON optical transmitter used in the prior art includes a broadband light source (BLS) 103, 106 for injection seeding, a laser diode 101, And an arrayed waveguide grating (AWG) 102 serving as a multiplexer / demultiplexer. In this case, a laser diode (laser diode) 101 mainly uses a fabry-perrot laser diode (FP-LD) or a reflective semiconductor optical amplifier (RSOA). In such a structure, a seeding optical signal having a certain wavelength is supplied to the laser diode 101 through a circulator (not shown) and a filter 104 through the AWG 102 in the broadband light source 103, In the LD, a light signal having a specific wavelength is stimulated and emitted. Optical signals of different wavelengths emitted from a plurality of FP-LDs are multiplexed through a corresponding channel of the AWG 102 and transmitted through one optical fiber 105. The C-BLS 106 is for supplying an optical signal to the laser diode on the subscriber side. Such a technique has an excellent effect in terms of generation of precise wavelength laser light which is essentially required in WDM-PON. However, expensive BLS (103, 106) and laser diode are used for optical signal generation to weaken price competitiveness .

Meanwhile, FIG. 2 is a view illustrating the structure of an OLT using a vertical cavity surface emitting laser (VCSEL). The optical signals (? 1,? 2,? 3, ...,? N) emitted from the VCSELs 201 having different wavelengths are multiplexed while passing through the AWG 208, ≪ / RTI > A multiplexed optical signal is separated from a certain portion of the optical signals through an optical power separator 203 connected to the common port 202 and is connected to a monitor AWG (mAWG: monitor AWG) 204 and a monitor photodiode (mPD: monitor PD, and 205 to the light-wavelength control unit 206. That is, the optical signal demultiplexed by the optical power splitter 203 is demultiplexed by a demultiplexer monitor AWG (mAWG) 204 and demultiplexed by a monitor photodiode (mPD) The optical power of the optical signal is measured. Thereafter, the control part 206 analyzes the optical power to control the bias current of the VCSEL 201 or the input current of the TEC (thermo-electric cooler) 207 to control the light wavelength. The use of the VSCEL 201 has the advantage that the VCSEL 201 is relatively inexpensive compared to the FP-LD and does not use the broadband light sources 103 and 106 (as in FIG. 1) It has the advantage of securing competitiveness. However, there is a problem that a circuit for monitoring and controlling the optical wavelength of the VCSEL 201 must be provided. That is, elements for controlling the optical wavelength by using the bias current of the VSCEL 201 or the input current of the TEC 207 are required as well as separate elements for monitoring the optical wavelength of the optical signal. Such a circuit configuration for monitoring and control has an economical advantage over the configuration using the BLSs 103 and 106 and the laser diode as shown in FIG. 1, but it is not easy to ensure accurate wavelength control technology I have a problem.

Korean Patent Publication No. 10-2007-0068084 (published on June 29, 2007)

The present invention provides an optical signal forming apparatus and method that does not require a complicated wavelength control circuit by using a broadband light source in a wavelength division multiplexing passive optical network (WDM-PON) .

A method of forming an optical signal in a wavelength division multiplexing passive optical network (WDM-PON) of the present invention includes the steps of emitting a broadband optical signal in a broadband light source, using the broadband optical signal as a multi-channel optical wavelength filter Generating an optical signal for each channel corresponding to a central wavelength of each channel; modulating the optical signal for each channel with an optical modulator to form a digital signal for each channel; And multiplexing the signals to form an output optical signal.

In addition, the WDM-PON (wavelength division multiplexing passive optical network) optical signal forming apparatus of the present invention includes: a broadband light source that emits a broadband optical signal; A light modulator for modulating the optical signal for each channel to form a digital signal for each channel and a multiplexing AWG for multiplexing the digital signal for each channel to form an output optical signal do.

According to the present invention, a broadband light source (BLS) and a passive optical wavelength filter are used to fabricate an optical transmitter used in a WDM-PON (wavelength division multiplexing passive optical network) Since no separate circuit or module is required, the system operation can be simplified and the cost can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an exemplary diagram illustrating an optical transmitter portion of an optical line terminal (OLT).
FIG. 2 is a view showing the structure of an OLT using a vertical cavity surface emitting laser (VCSEL). FIG.
FIG. 3 and FIG. 4 are views showing the configuration of an optical signal forming apparatus according to an embodiment of the present invention. FIG.
5 is a flowchart illustrating a procedure of an optical signal forming method 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. In the following description, well-known functions or constructions will not be described in detail if they obscure the subject matter of the present invention.

3 is an exemplary view showing a configuration of an optical signal forming apparatus according to an embodiment of the present invention.

3, when a broadband optical signal is emitted from a broadband light source 301 included in the optical signal forming apparatus 300, a multi-channel optical wavelength filter 302 uses a broadband optical signal to generate a It is possible to generate optical signals (? 1,? 2,? 3, ...,? N) for each channel coinciding with the central wavelength. In one embodiment, the multi-channel optical wavelength filter 302 may include an arrayed waveguide grating (AWG), and the AWG may demultiplex the broadband optical signal to generate an optical signal for each channel. In fabricating the multi-channel optical wavelength filter 302, each wavelength of an optical signal for each channel generated by the multi-channel optical wavelength filter 302 is transmitted through a light source of a fabry-perrot laser diode (FP-LD) or a vertical cavity surface emitting laser (VCSEL) (For example, several (1 to 9) MHz or less) linewidths as the wavelength of the optical signal generated by the optical fiber. An optical signal for each channel having a specific wavelength for each channel generated by the multi-channel optical wavelength filter 302 is input to an optical modulator 303. The optical modulator 303 modulates the inputted optical signal for each channel, Signal can be formed. The AWG 304 for multiplexing multiplexes the digital signals for each channel to form an output optical signal and can transmit the signals through a common port 305. In one embodiment, the common port 305 may include, but is not limited to, optical fibers, optical waveguides, and the like.

The optical wavelength characteristic of the optical signal for each channel according to the present embodiment is as shown in the bottom of Fig. 3, for example. Reference symbol a denotes a wavelength or a loss profile of a broadband optical signal emitted from the broadband light source 301, reference symbol b denotes a wavelength of an optical signal for each channel generated by the multi-channel optical wavelength filter 302, reference symbol c Represents the optical wavelength of the output optical signal formed by the AWG 304 for multiplexing.

As another embodiment, the optical signal forming apparatus 400 according to the present invention may be manufactured in the form of a PIC (photonics integrated chip) as shown in FIG. 4, in order to simplify the fabrication cost and packaging of the optical signal forming apparatus. In this case, at least two of the broadband light source 401, the multi-channel lightwave wavelength filter 402, the optical modulator 403, the multiplexing AWG 404, and the optical waveguide 405 can be integrated into one chip.

The present embodiment relates to a technique for generating an optical signal having a plurality of light wavelengths by using a single wideband light source, and can be applied to various fields where an optical signal having a plurality of light wavelengths is used.

5 is a flowchart illustrating a procedure of an optical signal forming method according to an embodiment of the present invention.

Referring to FIG. 3, a broadband optical signal may be emitted from a broadband light source 301 included in the optical signal forming apparatus 300 (S510). Thereafter, the multi-channel optical wavelength filter 302 demultiplexes the wideband optical signal to generate optical signals (lambda 1, lambda 2, lambda 3, ..., lambda N) for each channel coinciding with the center wavelength of each channel (S520). An optical signal for each channel having a specific wavelength for each channel generated by the multi-channel optical wavelength filter 302 is input to an optical modulator 303. The optical modulator 303 modulates an input optical signal for each channel, (S530). The multiplexing AWG 304 multiplexes the digital signals for each channel to form output optical signals (S540), and can transmit the signals through the common port 305. [

Although the method has been described through particular embodiments, the method may also be implemented as computer readable code on a computer readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and may be implemented in the form of a carrier wave (for example, transmission over the Internet) . In addition, the computer-readable recording medium may be distributed over network-connected computer systems so that computer readable codes can be stored and executed in a distributed manner. In addition, functional programs, codes, and code segments for implementing the above embodiments can be easily deduced by programmers of the present invention.

Although the present invention has been described in connection with some embodiments thereof, it should be understood that various changes and modifications may be made therein without departing from the spirit and scope of the invention as understood by those skilled in the art. something to do. It is also contemplated that such variations and modifications are within the scope of the claims appended hereto.

101: laser diode 102: AWG
103: broadband light source 104: filter
105: Fiber 106: C-BLS
201: VCSEL 202: Common port
203: optical power separator 204: monitor AWG
205: monitor photodiode 206:
207: TEC 300: Optical Transmitter
301: broadband light source 302: multi-channel light wavelength filter
303: Optical modulator 304 AWG for multiplexing
305: Common port

Claims (5)

A method of forming an optical signal in a WDM-PON (wavelength division multiplexing passive optical network)
In a broadband light source, emitting a broadband optical signal,
A multi-channel optical wavelength filter, comprising the steps of: generating an optical signal for each channel coinciding with a central wavelength of each channel using the wideband optical signal;
Modulating an optical signal for each channel with an optical modulator to form a digital signal for each channel;
And multiplexing the channel-specific digital signals with an AWG for multiplexing to form an output optical signal. The method according to claim 1,
The linewidth of the optical signal for each channel may be expressed as:
1 to 9 MHz. A WDM-PON (wavelength division multiplexing passive optical network) optical signal forming apparatus,
A broadband light source for emitting a broadband optical signal,
A multi-channel lightwave filter for generating an optical signal for each channel coinciding with a center wavelength of each channel using the wideband optical signal;
An optical modulator for modulating the optical signal for each channel to form a digital signal for each channel,
And a multiplexing AWG for multiplexing the digital signals for each channel to form an output optical signal. The method of claim 3,
The linewidth of the optical signal for each channel may be expressed as:
1 to 9 MHz. The method of claim 3,
Wherein at least two or more of the broadband light source, the multi-channel lightwave wavelength filter, the optical modulator, and the AWG for multiplexing are integrated in the form of a PIC (photonics integrated chip).

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