KR100705436B1 - Wavelength division multiplexing system for preventing deteriorating optical signal quality - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wavelength division multiplexing (WDM) system, and more particularly to a wavelength division multiplexing system having an optical transmission performance deterioration prevention function that prevents performance degradation of optical transmission to a change in external temperature environment of an optical path section. .

To this end, the present invention transmits a light source having a wide wavelength line width so that a change in grid characteristics does not affect the optical transmission performance due to a change in external temperature of an optical path section, and thus does not include a temperature correction circuit and a controller separately. The result is a simple and inexpensive system.

Description

WAVELENGTH DIVISION MULTIPLEXING SYSTEM FOR PREVENTING DETERIORATING OPTICAL SIGNAL QUALITY}

1 is a block diagram of a system for preventing deterioration of optical transmission performance according to an embodiment of the present invention;

2 is a graph showing the change in the light spectrum after performing the multiplexing and demultiplexing,

3 is a graph illustrating a comparison of optical transmission performance according to changes in external temperature environment.

Explanation of Symbols for Major Parts of Drawings>

11-19: light path section

100-1 to 100-8, 140-1 to 140-8: optical transmitter and receiver

110: wavelength multiplexer 120: wavelength demultiplexer

130: temperature change unit

The present invention relates to a wavelength division multiplexing (WDM) system, and more particularly, to a wavelength division multiplexing system having an optical transmission performance degradation prevention function for preventing performance degradation of optical transmission due to a change in temperature environment of an optical path section.

In general, a WDM (Wavelength Division Multiplexing) network is an optical transmission network that provides a next generation multimedia service because it can easily increase transmission capacity and accept various types of dependent signals. Technology.

The PON (Passive Optical Network) system, which is one of the wavelength division multiplexing systems, has optical transceivers and wavelength multiplexers installed at the telephone station, wavelength demultiplexers are installed at the optical path section, and subscribers correspond to optical transceivers installed at the telephone station. Optical transmitter is installed.

At this time, the light path section is exposed to the outside, so in the summer and winter when the temperature change is large, the light transmission is not performed accurately, resulting in light loss.

Specifically, the light source of the optical transceiver on the telephone station side uses a laser diode (LD) light source having a narrow wavelength line width. The grid characteristics of the wavelength demultiplexer installed in the optical path section exposed to the outside change in response to the temperature change. The grid characteristics change when the temperature change occurs in the demultiplexer in the optical path section. That is, the grid characteristics change toward the long wavelength at the high temperature and the short wavelength at the low temperature. As can be seen, there occurs a case in which optical transmission with little optical power appears to be impossible.

Therefore, the temperature control circuit and the controller are installed in each of the wavelength multiplexer on the telephone station side and the wavelength demultiplexer on the optical path section so that the optical transmission is accurately performed by always matching the grid characteristics.

That is, the temperature control circuit and the controller installed in each of the wavelength multiplexer and the wavelength demultiplexer composed of the AWG (Arrayed Waveguide Grating) elements are used to change the external temperature of the demultiplexer in the optical path section in order to always match the grid characteristics according to the temperature change. The grid characteristics were detected at the telephone station so that the multiplexer could adjust the temperature to match the grid characteristics of the demultiplexer in the optical path section.

However, the installation of the temperature regulating circuit and controller described above not only complicates the configuration of the system but also is economically inefficient due to the high cost.

The present invention has been made to solve the above-described problem, an object of the present invention is to transmit a light source having a wide wavelength band to prevent the degradation of optical transmission performance in a low-cost system that does not require a temperature control circuit and controller without loss of optical power The present invention provides a wavelength division multiplexing system having an optical transmission performance degradation prevention function for optical transmission.

The present invention for achieving the above object, in the wavelength division multiplexing system having an optical transmission performance degradation prevention function for enhancing the optical transmission performance in the optical path section between the telephone station and the subscriber side, the transmission from the telephone station side to the subscriber side The light source may be a light source having a wide wavelength band, and the wavelength demultiplexer installed in the optical path section may demultiplex an optical signal generated from the light source and transmit the demultiplexed signal to the subscriber.

Hereinafter, with reference to the accompanying drawings will be described in detail the operation of the preferred embodiment according to the present invention.

1 is a view showing the configuration of a wavelength division multiplexing system having a function of preventing optical transmission performance deterioration in a preferred embodiment of the present invention. In the telephone station, optical transceivers 100-1 to 100-8 and wavelength multiplexer 110 are shown. And a wavelength demultiplexer 120 are installed in the temperature change section 130 and the temperature change section 130 in the optical path section, and the subscriber side corresponds to the optical transceiver 100-1 to 100-8 at the telephone station. Optical transmitters 140-1 to 140-8 are provided.

At this time, the light sources of the optical transceivers 100-1 to 100-8 on the telephone station side and the optical transmitters 100-1 to 100-8 on the subscriber side are light emitting diode (LED) light sources having a wide wavelength line width. .

In addition, the wavelength multiplexer 110 and the wavelength demultiplexer 120 have a 1 × 8 structure, in which a free spectral range (FSR) indicating a wavelength interval of optical signals is 12.8 nm, a grid interval is 1.6 nm, and a 3 GHz bandwidth is 0.7. It is an element having the characteristic of nm.

Accordingly, the directly modulated LED light sources 100-1 to 100-8 are transmitted to the wavelength multiplexer 110 formed of the AWG elements, and the wavelength multiplexer 110 multiplexes the transmitted optical signals to the optical line 11. Through the transfer to the wavelength demultiplexer 120 installed in the temperature change unit 130.

The wavelength demultiplexer 120 installed in the optical path section demultiplexes the optical signal transmitted from the wavelength multiplexer 110 and exits to the ports having the respective grid characteristics, thereby providing light at the subscriber side through the optical paths 12 to 19. It is transmitted to the transceivers 140-1 to 140-8.

At this time, the temperature change unit 130 serves to determine whether the optical transmission is made correctly by giving a temperature change to the wavelength demultiplexer 120.

That is, the temperature change unit 130 is configured to change the temperature from -40 ° C to +70 ° C so that it is possible to know whether the light transmission is made without light loss through the temperature change periodically.

FIG. 2B illustrates the multiplexer 110 and the demultiplexer when the temperature change of the demultiplexer 120 in the optical path section is changed to a high temperature at a room temperature and through the temperature change unit 130 as described above. As an optical spectrum for the degree of change in optical power at 120, it can be seen that an optical signal is transmitted without optical loss.

3 is a graph showing a performance comparison of light transmission according to the temperature change of the temperature change unit 120.

That is, in consideration of the fact that the wavelength multiplexer 110 of the telephone station is fixed at 23 ° C. and the temperature change is applied to the wavelength demultiplexer 120 of the optical path section through the temperature change unit 130, for example, +23 It can be seen that there is no loss of transmission as a comparison of the transmission performance when the temperature is changed from ℃ to +70 ℃. Therefore, as can be seen in Figure 2b, it can be expected that the transmission loss does not occur even when the temperature change from +23 ℃ to -40 ℃, a separate temperature correction circuit and a controller as in the prior art is required There will be no.

As described above, the wavelength division multiplexing system having the optical transmission performance deterioration prevention function according to the present invention transmits a light source having a wide wavelength line width so that the grid characteristic is shifted toward the long wavelength or the short wavelength due to the change in the external temperature of the optical path section. It is configured not to affect performance.

Therefore, the present invention does not affect the optical transmission performance even if the grid characteristics change due to the external temperature change, so that a separate temperature correction circuit and a controller are not required as in the prior art, thereby simplifying the configuration of the system. The result is a low cost system that reduces production costs.

Claims (4)

A wavelength division multiplexing system having an optical transmission performance degradation prevention function for enhancing optical transmission performance in an optical path section between a telephone station and a subscriber side; A plurality of telephone station-side optical transceivers 100-1 to 100-8 installed at the telephone station and outputting a light source having a wide wavelength band; A wavelength multiplexer for multiplexing and outputting an optical signal generated from a light source output from the optical transceiver on the telephone station side; A wavelength demultiplexer for demultiplexing the light source output from the wavelength multiplexer and delivering the demultiplexer to the subscriber; And a temperature changer configured to periodically change a temperature of the wavelength demultiplexer and monitor a transmission performance of the optical signal in the optical path section. The method of claim 1, And a light source having a wide wavelength band generated from the optical transceiver at the telephone station side is an LED light source. delete The method according to claim 1 or 2, And the wavelength demultiplexer is installed in the temperature change section.

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