JPH0669169B2 - Switching the optical line without interruption - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for switching a line portion of a switching target section in a working optical line to a switching optical line without interruption.

"Prior art" As is known, tens of percent or more of the communication cables in urban areas have experienced changes to the laying route due to obstacles to this, or due to relocation, there is a high demand for switching to detour routes. .

By the way, when the working optical line is switched, the working information transmission should not be hindered, and therefore, line switching without interruption is required.

As such a non-instantaneous interruption switching method, a novel method shown in FIGS. 7 to 9 has been proposed.

The method will be briefly described below.

In FIG. 7, the working optical line 1 consisting of an optical cable is
It is laid across one station and the other station (not shown).

A beam splitter 2 required for line switching is inserted at each connection point of the optical line 1, and therefore the beam splitters 2 are located at both ends of the section line portion 1x to be switched of the active optical line 1.

Further, the variable optical attenuator 3 is inserted in the section line portion 1x.

In the above, insertion of the beam splitter 2 at the connection point of the working optical line 1 causes an insertion loss of 3 dB, but in order to reduce or eliminate this, the folding terminal 4 is connected to the beam splitter 2. .

Further, a variable optical attenuator 5 is inserted in the folding terminal 4.

The return terminal 4 does not affect the current information signal by keeping it short.

By the way, the transmission speed of the light in the optical cable is as high as 100 Mbps, and the pulse width at this time is 2 m, so that a bit error occurs when the difference in the optical path length exceeds the pulse width.

Therefore, in FIG. 8, when the switching optical line 6 is connected across the beam splitters 2 at both ends of the section line portion 1x and the section line portion 1x is switched to the switching optical line 6 without interruption, these sections are The phase difference caused by the optical path length difference between the line portion 1x and the switching optical line 6 must be compensated.

Therefore, the following measures are taken in FIG.

That is, in FIG. 8, the switching optical line 6 connected as described above is provided with a variable optical attenuator 7, a variable optical wavelength transmission type optical filter 8, and a variable delay device 9.

Further, the folding terminal 4 is separated from each beam splitter 2, and one beam splitter 2 has an electric / optical converter.
10, a pulse generator 11 is connected, and an optical / electrical converter 12 and a pulse monitor 13 are connected to the other beam splitter 2.

At this time, as the optical filter 8, a filter that does not transmit the currently used wavelength is used.

Then, an optical signal having a wavelength other than the working wavelength is sent from the pulse generator 11, the phase difference of the optical signal passing through the predetermined system is measured by the pulse monitor 13, and the phase difference is compensated by the variable delay device 9.

Next, the optical filter 8 is replaced with a working wavelength transmission type to disconnect the switching target section line section 1x, and further, the electric / optical converter 10, the pulse generator 11, the optical / electrical converter 12, the pulse monitor 13, etc. Each beam splitter 2 after removing
The turn-back terminal 4 is connected to and the predetermined non-interruption switching is completed in the state of FIG.

[Problems to be Solved by the Invention] In the method of FIGS. 7 to 9 described above, a signal having a wavelength different from the working wavelength is used when measuring the phase difference, and therefore a pulse generator, an optical filter, or the like is used. Although it must be equipped, and the phase difference is compensated, a wavelength different from the working wavelength is used, so that the phase difference-compensated wavelength may deviate from the working wavelength.

In addition, a beam splitter 2 is provided at each connection point of the working optical line 1.
Since it is necessary to insert the switch, the cost becomes high, and the optical filter 8 and the variable delay device 9 and the like remain in the switching optical line 6 after the switching is completed, which also causes a cost increase. Extra connection loss due to

In view of the above problems, the present invention is to provide a method for switching the optical line without interruption without causing a change in connection loss due to switching at a slight additional cost.

[Means for Solving the Problems] In order to achieve the intended purpose, the present invention is one in which a plurality of section line portions are optically connected between these adjacent terminals with a separation gap interposed therebetween. A method for switching a section line section to be switched in an optical line in the order of a temporary optical line and a switching optical line, and a means for measuring a phase difference of optical wavelengths when switching a predetermined optical line. And a means for compensating for the phase difference and a beam splitter. More specifically, in the above, the light incident terminal of the section line section to be switched is set to t _02, and the light emission terminal of the section line section to be switched is set to t _02.
03 , the light emitting terminal of the section line portion adjacent to the light incident terminal t ₀₂ is t ₀₁ , the light incident terminal of the section line portion adjacent to the light emitting terminal t ₀₃ is t _04, and the light incident on the temporary optical line Terminal t ₁₁
, The light emitting terminal of the temporary optical line is t ₁₂ , the light incident terminal of the switching line is t _21, and the light emitting terminal of the switching optical line is t 12.
_In the case of ₂₂ , the light emitting terminal t ₀₃ is provided between the light emitting terminal t ₀₁ and the light incident terminal t ₀₂ in the first switching step.
A beam splitter between the optical input terminal t ₀₄ and the optical input terminal t ₀₄ , and the optical input terminal t ₁₁ of the temporary optical line is connected to both terminals t _04.
01 , t ₀₂ connected to the beam splitter, and the phase difference measuring means, the light emitting terminal t ₁₂ of the temporary optical line, and,
After connecting to the beam splitter between both terminals t ₀₃ and t ₀₄ , the phase difference of the pulse of the working optical signal passing through the working optical line and the temporary optical line respectively is measured by the phase difference measuring means, and the phase difference is measured. The light emitting terminal t ₁₂ of the temporary optical line that has been compensated by the phase difference compensating means attached to the temporary optical line and has completed the compensation of the phase difference is connected to the beam splitter between both terminals t ₀₃ , t _04. That, in the next switching step, the section line section of the switching target is removed from the working optical line, and the light input terminal t ₂₁ and the light emitting terminal t ₂₂ of the switching optical line are
After connecting to the beam splitter and the phase difference measuring means on the side of the light emitting terminal t ₀₁ , respectively, the phase difference of the pulse of the working optical signal passing through the working optical line and the switching optical line is measured by the phase difference measuring means, and The phase difference is compensated by the phase difference compensating means attached to the temporary optical line, and the light emitting terminal t ₂₂ of the switching optical line that has completed the compensation of the phase difference is changed to both terminals t ₀₃ , t _04.
It is characterized in that the temporary optical line, the beam splitter, and the phase difference measuring means are removed from the working optical line in the subsequent switching step.

[Examples] Examples of the method of the present invention will be described below with reference to the drawings.

FIG. 1 shows a working optical line 20 according to the present invention.

This working optical line 20 is composed of an optical cable and is laid across one station and the other station (not shown).

Each connection point of the optical line 20, that is, the section line portions 20L, 2
Rod lenses 21a, 21b, 21c, on both ends of 0M, 20N ...
21d ... are respectively attached, and rod lenses 21a and 21b and 21c and 21d adjacent to each other are opposed to each other with an appropriate interval.

Furthermore, in each section line section (see 20M), a variable optical attenuator 2
2 is inserted.

FIG. 6 shows a phase difference measuring means, which comprises a pulse monitor 30 and optical input terminals 31a, 31b connected to the pulse monitor 30 and having the same length. Rod lenses 32a and 32b are connected to the tip of 31, and optical / electrical converters 33a and 33b are interposed between them.

In the working optical line 20, for example, when the section line section 20M is switched to a switching line described later, the section line section 20M
As shown in FIG. 2, beam splitters 23M and 23N are inserted between the rod lenses 21b and 21c at both ends of the rod lens and the rod lenses 21a and 21d adjacent to the rod lenses 21b and 21c.

Further, as the temporary optical line 24 that bypasses the section line portion 20M, one provided with a variable optical attenuator 25, a variable delay device 26, etc. is used.

One end of the temporary optical line 24 is connected to the beam splitter 23M on the incident side via a rod lens 21e as shown in FIG. 2, and the other end of the temporary optical line 24 has a rod lens 21f.
And the light input terminal 31a is connected via the rod lens 32a and the rod lens 32a.

Next, the optical input terminal 31b is the beam splitter 23N on the output side.
The optical attenuators 22 and 25 of the working optical line 20M and the temporary optical line 24 are kept to a minimum at the time of the connection.
The phase difference between the working optical signals passing through the working optical line 20M and the temporary optical line 24 is measured by the pulse monitor 30, and the phase difference is compensated by the variable delay device 26.
The maximum amount of attenuation is maintained via the variable optical attenuator 25, and the rod lens 21f of the temporary optical line 24 is connected to the beam splitter 23N on the emission side.

Thus, the temporary optical line 24 is connected to a predetermined portion of the working optical line 20 so as to bypass the section line portion 20M, but at this point,
Since the amount of attenuation of the temporary optical line 24 is the maximum, the optical signal of the working wavelength split by the incident side beam splitter 23M is not bypassed to the temporary optical line 24 side.

After that, the variable optical attenuator 25 keeps the amount of attenuation of the temporary optical line 24 to a minimum, and the temporary optical line 24 becomes ready for optical transmission. As a result, the working optical signal split by the incident side beam splitter 23M is The temporary optical line 24 and the exit side beam splitter 23N can also be passed through the detour route.

At this point, the variable optical attenuator 22 holds the maximum attenuation of the switching target section line section 20M, and the section line section 20M is separated from the working optical line 20 as shown in FIG.

Thus, the non-instantaneous switching from the section line section 20M to the temporary optical line 24 is completed.

Next, as shown in FIG. 4, a switching optical line having an optical variable attenuator 40 in the line and rod lenses 41b and 41c at both ends.
42 is connected across the beam splitter 23M and the optical input terminal 32a of the pulse monitor 30, and similarly to the above, after the phase difference between the temporary optical line 24 and the switching optical line 42 is measured and compensated by the optical signal of the working wavelength, The maximum amount of attenuation is maintained via the variable attenuator 40 of the switching optical line 42, and the rod lens 41c is connected to the emission side beam splitter 23N, and then the switching is performed via the variable attenuator 40. The amount of attenuation of the optical line 42 is kept to a minimum, which allows the switching optical line to be switched.
An optical signal of the working wavelength is transmitted to 42.

After that, the temporary optical line 24 maximizes the amount of attenuation of the temporary optical line 24, and when the working wavelength is opaque, the beam splitter
23M and 23N are separated from each other, and the pulse monitor 30 having the optical input terminal 31a and the optical input terminal 31b, the beam splitters 23M and 23N, and the like are also separated, and thus the predetermined non-interruption switching is completed. A state, that is, a state equivalent to that of FIG. 1 is obtained.

[Effects of the Invention] As described above, according to the method of the present invention, the temporary optical line is connected in a bypass shape over the desired switching section of the working optical line to remove the section line section to be switched, and then the switching line is used. Since the optical line is connected and then the temporary optical line is also removed, it is possible not only to perform the predetermined non-interruptible switching, but also to measure the phase difference by the working wavelength at the time of the switching and to compensate for the phase difference. Compared with the case where these measurements and compensations are performed at wavelengths different from the working wavelength, the use of pulse generators, optical filters, etc. can be omitted, switching facility costs are saved, and the optical line after switching is expensive. Since no optical parts remain and the optical line status before and after switching the line does not change, there is no waste of expensive optical parts in the optical line after switching and no increase in connection loss due to remaining parts. The set of temporary optical lines and equipment required for switching can be used repeatedly.

Therefore, according to the method of the present invention, it is possible to perform the non-instantaneous switching of the optical line with a slight additional cost and without causing problems such as connection loss and connection space.

[Brief description of drawings]

1 to 5 are non-interruptible switching process steps of the optical line in the method of the present invention, FIG. 1 is an explanatory view showing a main part of the working optical switching line, and FIG. 2 is a predetermined diagram of the optical line. FIG. 3 is an explanatory view of a state in which a temporary optical line is connected to a section, FIG. 3 is an explanatory view of a state in which a section line portion to be switched is separated from the optical line,
FIG. 5 is an explanatory view showing a state in which a switching optical line is connected to a predetermined section of the optical line, FIG. 5 is an explanatory view showing a state in which a temporary optical line is separated from the optical line, and FIG. 6 is a phase difference in the method of the present invention. FIGS. 7 to 9 are explanatory views illustrating an example of the measuring unit, and FIGS. 7 to 9 are explanatory views showing the non-instantaneous interruption switching process of the optical line in the proposed example as the prior art of the present invention in the order of the switching. 20 …… Current optical line 20M …… Section line section to be switched 22 …… Variable optical attenuator 23M …… Beam splitter 23N …… Beam splitter 24 …… Temporary optical line 25 …… Variable optical attenuator 26 …… Variable Delay device 30 …… Pulse monitor 31a …… Optical input terminal 31b …… Optical input terminal 40 …… Variable optical attenuator 42 …… Switching optical line

Claims (1)

[Claims] 1. In a working optical line in which a plurality of section line sections are optically connected between these adjacent terminals with a separation gap interposed, the section line section to be switched is a temporary optical line and is switched. A method for switching in order of the optical lines for use, and a method of using a means for measuring the phase difference of the optical wavelength, a means for compensating the phase difference, and a beam splitter when switching a predetermined optical path. That is, in the above, the light incident terminal of the section line section to be switched is set to t _02, and the light emission terminal of the section line section to be switched is set to t _02.
03 , the light emitting terminal of the section line portion adjacent to the light incident terminal t ₀₂ is t ₀₁ , the light incident terminal of the section line portion adjacent to the light emitting terminal t ₀₃ is t _04, and the light incident on the temporary optical line Terminal t ₁₁
And the light emitting terminal of the temporary optical line is t ₁₂ , the light incident terminal of the switching optical line is t _21, and the light emitting terminal t ₂₂ of the switching optical line is Between the light emitting terminal t ₀₁ and the light incident terminal t ₀₂ , the light emitting terminal t ₀₃
A beam splitter between the optical input terminal t ₀₄ and the optical input terminal t ₀₄ , and the optical input terminal t ₁₁ of the temporary optical line is connected to both terminals t _04.
01 , t ₀₂ connected to the beam splitter, and the phase difference measuring means, the light emitting terminal t ₁₂ of the temporary optical line, and,
After connecting to the beam splitter between both terminals t ₀₃ and t ₀₄ , the phase difference of the pulse of the working optical signal passing through the working optical line and the temporary optical line respectively is measured by the phase difference measuring means, and the phase difference is measured. The light emitting terminal t ₁₂ of the temporary optical line that has been compensated by the phase difference compensating means attached to the temporary optical line and has completed the compensation of the phase difference is connected to the beam splitter between both terminals t ₀₃ , t _04. That, in the next switching step, the section line section of the switching target is removed from the working optical line, and the light input terminal t ₂₁ and the light emitting terminal t ₂₂ of the switching optical line are
After connecting to the beam splitter and the phase difference measuring means on the side of the light emitting terminal t ₀₁ , respectively, the phase difference of the pulse of the working optical signal passing through the working optical line and the switching optical line is measured by the phase difference measuring means, and The phase difference is compensated by the phase difference compensating means attached to the temporary optical line, and the light emitting terminal t ₂₂ of the switching optical line that has completed the compensation of the phase difference is changed to both terminals t ₀₃ , t _04.
An optical line non-interruption switching method characterized by connecting to a beam splitter between them and removing the temporary optical line, beam splitter, and phase difference measuring means from the working optical line in the subsequent switching process.