TWI696355B - Optical fiber dispersion monitoring device - Google Patents

Abstract

An optical fiber dispersion monitoring device includes an optical delay interferometer, a signal processing module, and a control module. The optical delay interferometer is controlled by a delay control signal so that the position of one of the multiple orthogonal points of an amplitude response waveform corresponds to a center wavelength of an optical feedback signal of an optical communication system, and Generating first and second delayed interference signals with a phase difference of 180 degrees from each other according to the delay control signal and the optical feedback signal, the signal processing module generates at least one error signal according to the first and second delayed interference signals, The control module generates the delay control signal to the optical delay interferometer, and generates and outputs a control signal to the optical communication system according to the at least one error signal to adjust the dispersion of the optical communication system.

Description

Optical fiber dispersion monitoring device

The invention relates to a monitoring device, in particular to an optical fiber dispersion monitoring device.

In optical fiber communication systems, dispersion or optical dispersion is a phenomenon in which light waves are dispersed into spectral components of different wavelengths due to the dependence of wave speed on its wavelength. When an optical signal or pulse is projected into, for example, a fiber channel, its wave envelope propagates along the fiber channel at the wave group velocity. Since this pulse contains a series of spectral components, each spectral component advances at different wave group velocities, resulting in group velocity dispersion (GVD), intramodal dispersion, or simply fiber dispersion. This dispersion phenomenon is often referred to as pulse spreading. As the pulse advances along the fiber, the spectral components continue to spread in space and time until the pulse becomes too wide, so that the optical receiver cannot distinguish the difference between the "0" bit and the "1" bit.

As the demand for network bandwidth grows, the transmission rate continues to increase, and the time interval between adjacent bits continues to decrease. If the advance distance is large enough, the leading edge of one pulse overlaps the trailing edge of the previous pulse, intersymbol interference will occur. (Inter symbol interference, ISI) and cause bit ambiguity. That is to say, as the optical communication link is upgraded to a higher transmission speed (such as the urban link is upgraded from 2.5Gbits/s to 10Gbits/s, the new 40Gbits/s link, etc.), the dispersion becomes the influence of optical fiber communication One of the important factors of signal quality. Therefore, in order to avoid the serious impact of dispersion on the optical fiber communication system, how to accurately compensate for dispersion becomes a very important issue.

However, when the conventional fiber dispersion monitoring device is used to monitor high-speed transmission optical signals, it is disadvantageous that it can only monitor a relatively short optical transmission distance (that is, the monitoring range is limited) and the monitoring accuracy is poor, resulting in inconvenience use. Therefore, there is still room for improvement in conventional fiber dispersion monitoring devices.

Therefore, an object of the present invention is to provide an optical fiber dispersion monitoring device that can overcome the shortcomings of the prior art.

Therefore, the optical fiber dispersion monitoring device of the present invention is suitable for monitoring the dispersion of an optical communication system. The optical fiber dispersion monitoring device includes an optical delay interferometer, a signal processing module, and a control module.

The optical delay interferometer receives a delay control signal indicating an adjustable delay time, and is suitable for receiving an optical feedback signal divided by an optical splitter of the optical communication system. The optical delay interferometer is subjected to the delay control signal Control of one of the multiple orthogonal points of an amplitude response waveform corresponding to the optical feedback signal And a first delayed interference signal and a second delayed interference signal according to the delay control signal and the optical feedback signal. The first and second delayed interference signals have a phase difference of 180 degrees from each other.

The signal processing module is coupled to the optical delay interferometer to receive the first and second delayed interference signals, and generates at least one error signal based at least on the first and second delayed interference signals.

The control module is electrically connected to the optical delay interferometer and the signal processing module for generating and outputting the delay control signal to the optical delay interferometer, and receiving the at least one error signal from the signal processing module, the The control module generates and outputs a control signal to the optical communication system according to the at least one error signal to adjust the dispersion of the optical communication system.

Therefore, another object of the present invention is to provide an optical fiber dispersion monitoring device that can overcome the shortcomings of the prior art.

Therefore, the optical fiber dispersion monitoring device of the present invention is suitable for monitoring the dispersion of an optical communication system. The optical fiber dispersion monitoring device includes an optical delay interferometer, a signal processing module, and a control module.

The optical delay interferometer is suitable for receiving an optical feedback signal divided by an optical splitter of the optical communication system and receiving a delay control signal. The optical delay interferometer operates at least for a first predetermined period and a continuous A second predetermined period after the first predetermined period, during the first predetermined period, the delay control signal indicates a first delay Time so that the position of the kth orthogonal point among the orthogonal points of an amplitude response waveform of the optical delay interferometer corresponds to a central wavelength of the optical feedback signal, and is controlled according to the delay The signal and the optical feedback signal generate a first delayed interference signal, and during the second predetermined period, the delay control signal indicates a second delay time to cause the orthogonality of the amplitude response waveforms of the optical interferometer The position of the (k+1)th orthogonal point in one of the points corresponds to the center wavelength of the optical feedback signal, and a second delayed interference signal is generated according to the delay control signal and the optical feedback signal. The first and second delayed interference signals have a phase difference of 180 degrees from each other, and k is any positive odd number.

The signal processing module is coupled to the optical delay interferometer to sequentially receive the first and second delayed interference signals, and accordingly generates an error signal when receiving the first and second delayed interference signals.

The control module is electrically connected to the optical delay interferometer and the signal processing module for generating and outputting the delay control signal to the optical delay interferometer, and receiving the error signal from the signal processing module, and according to the The error signal generates and outputs a control signal to the optical communication system to adjust the dispersion of the optical communication system.

Therefore, another object of the present invention is to provide an optical fiber dispersion monitoring device that can overcome the shortcomings of the prior art.

Therefore, the optical fiber dispersion monitoring device of the present invention is suitable for monitoring the dispersion of an optical communication system. The optical fiber dispersion monitoring device includes an optical delay interferometer, a signal processing module, and a control module.

The optical delay interferometer receives a delay control signal indicating an adjustable delay time, and is suitable for receiving an optical feedback signal divided by an optical splitter of the optical communication system. The optical delay interferometer is subjected to the delay control signal Control of one of the multiple orthogonal points of an amplitude response waveform corresponding to a center wavelength of the optical feedback signal, and a delay is generated according to the delay control signal and the optical feedback signal Interference signal.

The signal processing module is coupled to the optical delay interferometer to receive the delayed interference signal, and generates a first power detection signal and a second power detection signal according to the delayed interference signal.

The control module is electrically connected to the optical delay interferometer and the signal processing module for generating and outputting the delay control signal to the optical delay interferometer and receiving the first and second signals from the signal processing module The power detection signal generates and outputs a control signal to the optical communication system according to one of the first and second power detection signals to adjust the dispersion of the optical communication system.

The effect of the present invention is that, by cooperating with the optical delay interferometer and the control module, the monitoring range of the optical fiber dispersion monitoring device can be made larger, and the control module generates the control signal according to the error signal to adjust the light The dispersion of the communication system can achieve the purpose of improving the monitoring accuracy of the optical fiber dispersion monitoring device.

1: Optical communication system

11: Light emitter

12: Optical amplifier

13: Optical link

14: Adjustable dispersion compensator

15: beam splitter

16: Optical receiver

2, 7, 8: Fiber optic dispersion monitoring device

3. 71, 81: optical delay interferometer

4: Signal processing module

41: Photoelectric conversion unit

411: The first photoelectric converter

412: Second photoelectric converter

42, 42a: signal amplification unit

421, 423: the first signal amplifier

422, 424: second signal amplifier

43, 43a: band-pass filter unit

431, 433: The first band-pass filter

432, 434: second bandpass filter

435: Third band-pass filter

436: Fourth band-pass filter

44, 44a: Power detection unit

441, 443: the first power detector

442, 444: second power detector

445: Third power detector

446: Fourth power detector

45, 45a: comparison unit

5, 73, 83: control module

6, 72, 82: signal processing module

61: Optical switch

62: Photoelectric converter

63: Signal amplifier

64: The first band-pass filter

65: Second band-pass filter

66: The first power detector

67: Second power detector

68: Comparator

721: Photoelectric converter

722: Signal amplifier

723: band-pass filter

724: Power detector

725: Comparator

821: Photoelectric converter

822: Signal amplifier

823: First band-pass filter

824: Second band-pass filter

825: the first power detector

826: Second power detector

A1, A4: the first amplified signal

A2, A5: second amplified signal

A3, A6: amplified signal

Ao1: the first amplified signal output

Ao2: second amplified signal output

As1: the first optical amplification signal

As2: second optical amplification signal

Cl: compensated optical signal

Cs: control signal

Dc1~Dc3: Delay control signal

E1~E5: error signal

Es: error signal

Et1, Et4: the first conversion signal

Et2, Et5: second conversion signal

Et3, Et6: Conversion signal

F1, F2: the first and second filtered signals

F3, F4: first and second filtered signals

F5, F6: first and second filtered signals

F11, F12: the first and second filtered signals

F21, F22: third and fourth filtered signals

Fo1: the first filtered signal output

Fo2: second filtered signal output

FSR: free spectrum range

Ld1, Ld3: the first delayed interference signal

Ld2, Ld4: second delayed interference signal

Ld5: delayed interference signal

Lf: optical feedback signal

Lo: optical signal output

Ls: optical signal

Os: output signal

P1, P3, P5: the first power detection signal

P2, P4, P6: second power detection signal

Po1: the first power detection signal output

Po2: second power detection signal output

P11: First power detection signal

P12: Second power detection signal

P21: Third power detection signal

P22: Fourth power detection signal

Q1~Q13: orthogonal points

Sc: switch signal

Other features and functions of the present invention will be clearly presented in the embodiment with reference to the drawings, in which: FIG. 1 is a block diagram illustrating a first embodiment of an optical fiber dispersion monitoring device of the present invention together with an optical communication system Use; FIG. 2 is a spectrogram illustrating the change of the frequency of an optical feedback signal of one of the first embodiment; FIG. 3 is a waveform diagram illustrating an amplitude response waveform of an optical delay interferometer of the first embodiment Changes in frequency; FIG. 4 is a waveform diagram illustrating the change of the first and second power detection signal outputs to a residual dispersion amount when the first embodiment operates in a specific frequency band; FIG. 5 is a waveform diagram, Explain the change of the residual dispersion of an error signal when the first embodiment operates in the specific frequency band; FIG. 6 is a waveform diagram illustrating the first and second when the first embodiment operates in another specific frequency band Power detection signal output changes to the residual dispersion amount; FIG. 7 is a waveform diagram illustrating the change of an error signal to the residual dispersion amount when the first embodiment operates in the other specific frequency band; FIG. 8 is a A block diagram illustrating a second embodiment of the optical fiber dispersion monitoring device of the present invention; FIG. 9 is a block diagram illustrating a third embodiment of the optical fiber dispersion monitoring device of the present invention; 10 is a block diagram illustrating a fourth embodiment of the optical fiber dispersion monitoring device of the present invention; FIG. 11 is a block diagram illustrating a fifth embodiment of the optical fiber dispersion monitoring device of the present invention; and FIG. 12 is a waveform diagram, The change of the residual dispersion amount of the first and second power detection signals of the fifth embodiment will be described.

Before the present invention is described in detail, it should be noted that in the following description, similar elements and signals are denoted by the same numbers.

Referring to FIG. 1, an embodiment of the optical fiber dispersion monitoring device 2 of the present invention is suitable for coupling to the optical communication system 1 to receive an optical feedback signal Lf, and generate a control signal Cs according to the optical feedback signal Lf to monitor and compensate the Chromatic dispersion of the optical communication system 1 to optimize the link transmission performance of the optical communication system 1.

The optical communication system 1 is a single wavelength optical transmission system, and includes an optical transmitter 11, an optical amplifier 12, an optical link (optical link) 13, and a tunable dispersion compensation with a tunable dispersion compensation value ( Tunable Dispersion Compensation (TDC) device 14, an optical splitter 15, and an optical receiver 16.

The optical transmitter 11 is used to emit an optical signal Ls. The optical amplifier 12 is coupled to the optical transmitter 11 to receive the optical signal Ls, and amplifies the optical signal Ls to generate a first optical amplified signal As1. The optical link 13 is coupled to the optical amplifier 12 to receive the first optical amplification signal As1 and accordingly output a second optical amplification signal As2 with dispersion. The TDC device 14 is coupled to the optical link 13 to receive the second optical amplification signal As2, and performs dispersion compensation on the second optical amplification signal As2 according to the adjustable dispersion compensation value to generate a compensated optical signal Cl. The optical splitter 15 is coupled to the TDC device 14 to receive the compensated optical signal Cl, and divides the compensated optical signal Cl into an optical signal output Lo sent to the optical receiver 16 and sent to the optical fiber dispersion monitoring device The light feedback signal of 2 is Lf. In this embodiment, the optical splitter 15 divides the compensated optical signal C1 in a ratio of 90:10 (the optical signal output Lo is larger than the optical feedback signal Lf, Lo:Lf). The following describes the optical fiber dispersion monitoring device 2 with the first to fifth embodiments.

<First embodiment>

The optical fiber dispersion monitoring device 2 includes an optical delay interferometer 3, a signal processing module 4, and a control module 5.

The optical delay interferometer 3 receives a delay control signal Dc1 indicating an adjustable delay time, and is suitable for coupling to the optical splitter 15 to receive the optical feedback signal Lf. By adjusting the adjustable delay time, the optical delay interferometer 3 can be controlled by the delay control signal Dc1 to make the position of one of the orthogonal points of an amplitude response waveform correspond to the light A central wavelength of the feedback signal Lf, so that the light delays interference The waveform of any signal output by the instrument 3 has symmetry. The optical delay interferometer 3 generates a first delayed interference signal Ld1 and a second delayed interference signal Ld2 according to the delay control signal Dc1 and the optical feedback signal Lf, the first and second delayed interference signals Ld1, Ld2 are mutually It has a phase difference of 180 degrees. A free spectrum range (Free Spectral Range, FSR) of the optical delay interferometer 3 changes with the change of the adjustable delay time. In this embodiment, the free spectrum range is the reciprocal of the adjustable delay time (ie, FSR=1/τ, and the parameter τ is the adjustable delay time).

Further referring to FIG. 2 and FIG. 3, FIG. 2 is a spectrum diagram of the optical feedback signal Lf, and FIG. 3 is a waveform diagram of a waveform obtained by the amplitude response of the optical delay interferometer 3 versus frequency change. It should be noted that in FIG. 2, the frequency represented by the horizontal axis is the frequency relative to the center wavelength of the optical feedback signal Lf, and the position where the frequency of the horizontal axis is zero corresponds to the center wavelength of the optical feedback signal Lf, The intensity represented by the vertical axis is the relative light intensity, and the maximum light intensity of the optical feedback signal Lf is set to 0 dB. In FIG. 3, the parameters Q1~Q13 are the orthogonal points, but not limited to this, the value of each orthogonal point Q1~Q13 is equal to the maximum value of the amplitude response waveform divided by 2 ^1/2 . By adjusting the adjustable delay time, the free spectral range FSR can be changed, so that the amplitude response waveform changes, so that the position of one of the orthogonal points Q1 to Q13 corresponds to the optical feedback signal Lf Center wavelength. For example, the position of the orthogonal point Q7 in FIG. 3 corresponds to the frequency at which the horizontal axis of FIG. 2 is zero (ie, corresponds to the center wavelength of the optical feedback signal Lf), but it is not limited thereto.

The signal processing module 4 is coupled to the optical delay interferometer 3 to receive the first and second delayed interference signals Ld1, Ld2, and generates an error signal Es according to the first and second delayed interference signals Ld1, Ld2 . In this embodiment, the signal processing module 4 includes a photoelectric conversion unit 41, a signal amplification unit 42, a band pass filter unit 43, a power detection unit 44, and a comparison unit 45.

The photoelectric conversion unit 41 is coupled to the optical delay interferometer 3 and includes first and second photoelectric converters 411 and 412. The first and second photoelectric converters 411 and 412 are respectively coupled to the optical delay interferometer 3 to receive the first and second delayed interference signals Ld1 and Ld2, respectively, and respectively delay the first and second delays The interference signals Ld1 and Ld2 undergo photoelectric conversion to generate a first conversion signal Et1 and a second conversion signal Et2, respectively.

The signal amplifying unit 42 is electrically connected to the photoelectric conversion unit 41 and includes first and second signal amplifiers 421 and 422. The first and second signal amplifiers 421 and 422 are electrically connected to the first and second photoelectric converters 411 and 412 of the photoelectric conversion unit 41 to receive the first and second conversion signals Et1 and Et2, respectively. And amplify the first and second conversion signals Et1 and Et2, respectively, to generate a first amplified signal output Ao1 and a second amplified signal output Ao2, respectively.

The band-pass filter unit 43 is electrically connected to the signal amplifying unit 42 and includes first and second band-pass filters 431 and 432. The first and second band-pass filters 431 and 432 are electrically connected to the first and second signal amplifiers of the signal amplifying unit 42, respectively 421 and 422 respectively receive the first and second amplified signal outputs Ao1 and Ao2, and perform bandpass filtering on the first and second amplified signal outputs Ao1 and Ao2 respectively to generate a first filtered signal output Fo1 and a second filtered signal output Fo2. In this embodiment, the band-pass filtering unit 43 allows waves of a specific frequency band to pass, that is, the first and second band-pass filters 431, 432 each allow waves of the specific frequency band to pass. The specific frequency band is n times the free spectrum range of the optical delay interferometer 3, n=N+0.5, N≧0, and N is an integer. For example, when N=0, Fr=0.5×FSR, the parameter Fr is the specific frequency band, when N=1, Fr=1.5×FSR, and so on.

The power detection unit 44 is electrically connected to the band-pass filter unit 43 and includes first and second power detectors 441 and 442. The first and second power detectors 441 and 442 are electrically connected to the first and second band-pass filters 431 and 432 of the band-pass filter unit 43 to receive the first and second filtered signals, respectively Output Fo1, Fo2, and respectively detect the power of the first and second filtered signal outputs Fo1, Fo2 to generate a first power detection signal output Po1 and a second power detection signal output Po2, respectively.

It should be noted that in this embodiment, the first and second power detectors 441 and 442 first detect the respective powers of the first and second filtered signal outputs Fo1 and Fo2, and then apply them Logarithmic calculation of the power detected by each to obtain the corresponding first and second power detection The measured signal outputs Po1 and Po2 (that is, log(Power), and Power represents the respective power of the first and second filtered signal outputs Fo1 and Fo2), but is not limited thereto.

The comparison unit 45 is electrically connected to the first and second power detectors 441 and 442 of the power detection unit 44 to receive the first and second power detection signal outputs Po1 and Po2, respectively, and convert the The first and second power detection signal outputs Po1 and Po2 are compared to generate the error signal Es. In this embodiment, the comparison unit 45 subtracts the second power detection signal output Po2 from the first power detection signal output Po1 to obtain the error signal Es.

The control module 5 is electrically connected to the optical delay interferometer 3 and the comparison unit 45 of the signal processing module 4 for generating and outputting the delay control signal Dc1 to the optical delay interferometer 3 and receiving from the comparison unit The error signal Es of 45. The control module 5 generates and outputs the control signal Cs to the TDC device 14 of the optical communication system 1 according to the error signal Es, so that the TDC device 14 adjusts its own tunable dispersion compensation value according to the control signal Cs, Furthermore, the dispersion of the second optical amplification signal As2 related to the optical signal Ls sent by the optical communication system 1 is adjusted.

51.7 ps)，該自由頻譜範圍為19.33GHz(即，FSR

1/51.7e-12)，及該等第一及第二帶通濾波器431、432各自 的該特定頻段為0.5×FSR的情況下，該等第一及第二功率偵測信號輸出Po1、Po2，及該誤差信號Es隨不同殘餘色散量變化之波形圖。圖4及圖5之橫軸為該已補償光信號Cl所具有的殘餘色散量。 Referring to FIGS. 4 and 5, the optical fiber dispersion monitoring device 2 operates when the optical signal Ls is a 58GBd 4th order pulse amplitude modulation (PAM4) optical signal, and the delay control signal Dc1 is delayed by 3 bits and indicated by the Adjustable delay time is about 51.7ps (ie, τ=3×1/58e9

51.7 ps), the free spectral range is 19.33 GHz (ie, FSR

1/51.7e-12), and when the specific frequency band of each of the first and second band-pass filters 431, 432 is 0.5×FSR, the first and second power detection signals output Po1 Po2, and the waveform of the error signal Es with different residual dispersion. The horizontal axis of FIGS. 4 and 5 is the amount of residual dispersion that the compensated optical signal Cl has.

，參數c為光速，參數λ為該光信號Ls的一波長，參數D為一光纖色散參數，參數L為一光纖長度，參數f為一特定頻段(該特定頻段f等於上述該特定頻段Fr)，在此實施例中，該光纖色散參數D約為16~17ps/nm/km，該特定頻段f為0.5×FSR，即~9.67GHz)。在此實施例中，為避免色散的錯誤監控，因此僅將每一第一及第二功率偵測信號輸出Po1、Po2波形中之其中一相鄰二波峰間的區間作為用來監控色散情況的監控範圍，且此相鄰二波峰間之一波谷所對應之一殘餘色散量約為零，例如，將圖4中相鄰二波峰且殘餘色散量在±640ps/nm(或光纖長度為±40km，該光信號Ls的波長為1550nm)的區間作為本案用來監控色散情況的監控範圍，而該等第一及第二功率偵測信號輸出Po1、Po2對應其餘殘餘色散量(即，殘餘色散量大於640ps/nm或小於-640ps/nm的部分)的變化則於圖4中省略。 It should be noted that the first and second power detection signal outputs Po1 and Po2 are each a periodic sine wave signal (

, Parameter c is the speed of light, parameter λ is a wavelength of the optical signal Ls, parameter D is a fiber dispersion parameter, parameter L is a fiber length, and parameter f is a specific frequency band (the specific frequency band f is equal to the specific frequency band Fr) In this embodiment, the fiber dispersion parameter D is about 16-17ps/nm/km, and the specific frequency band f is 0.5×FSR, which is ~9.67GHz). In this embodiment, in order to avoid the erroneous monitoring of dispersion, only the interval between one of the adjacent two peaks in each of the first and second power detection signal output Po1, Po2 waveforms is used as the monitor for the dispersion Monitoring range, and one of the valleys between the two adjacent peaks corresponds to a residual dispersion of about zero, for example, the adjacent two peaks in Figure 4 and the residual dispersion is within ±640ps/nm (or the fiber length is ±40km , The wavelength of the optical signal Ls is 1550 nm) is used as the monitoring range for monitoring the dispersion in this case, and the first and second power detection signal outputs Po1 and Po2 correspond to the remaining residual dispersion (ie, the residual dispersion Changes greater than 640ps/nm or less than -640ps/nm are omitted in FIG. 4.

As can be seen from FIG. 5, the error signal Es has a polarity. When the error value of the error signal Es is greater than zero, the control signal Cs generated by the control module 5 will cause the TDC device 14 to reduce its own tunable dispersion compensation value, so that the compensated optical signal Cl The amount of residual dispersion decreases; on the contrary, when the error value of the error signal Es is less than zero, the control signal Cs generated by the control module 5 will cause the TDC 14 to increase its own adjustable dispersion compensation value, so that The amount of residual dispersion of the compensated optical signal Cl rises. In this way, after multiple adjustments, the error value of the error signal Es will gradually approach zero, and the amount of residual dispersion corresponding to the compensated optical signal Cl will also gradually approach 0 ps/nm, thereby achieving monitoring and compensation. The dispersion of the optical communication system 1 is for the purpose of optimizing the link transmission performance of the optical communication system 1. It should be noted that, because the error signal Es has a polarity, and as long as the error signal Es changes, the control module 5 can learn how to adjust the control signal Cs generated by the corresponding adjustment of the TDC device 14 Tonal dispersion compensation value, therefore, the control module 5 does not need to make the output of the control signal Cs jitter and offset. In this way, the degradation of the link transmission performance of the optical communication system 1 can be avoided. In addition, as can be seen from FIGS. 4 and 5, the optical fiber dispersion monitoring device 2 has the advantages of a large monitoring range and a relatively long optical transmission distance (ie, ±40 km, the monitoring range is less limited).

6 and 7, the optical fiber dispersion monitoring device 2 operates when the optical signal Ls is the 58GBd fourth-order pulse amplitude modulation (PAM4) optical signal, the adjustable delay time is about 51.7 ps, and the free spectrum range is 19.33GHz, and these first and first When the specific frequency band of each of the two band-pass filters 431 and 432 is 1.5×FSR, the first and second power detection signals output Po1 and Po2, and the waveform of the error signal Es changes with different residual dispersion Figure. The horizontal axis of FIGS. 6 and 7 is the amount of residual dispersion that the compensated optical signal Cl has.

As can be seen from FIGS. 6 and 7 compared to FIGS. 4 and 5, respectively, the specific frequency bands of the first and second band-pass filters 431 and 432 are adjusted from 0.5×FSR to 1.5×FSR. The monitoring range Reduced to ±71ps/nm (or fiber length is ±4.4km, the wavelength of the optical signal Ls is 1550nm). It can be seen from FIG. 7 that the error signal Es varies greatly between the residual dispersion amount of ±10 ps/nm, and from FIG. 5 that the error signal Es varies greatly between the residual dispersion amount of ±80 ps/nm, point A′ of FIG. 7 The slope from point B'is greater than the slope from point A to point B in Figure 5. In this way, in the case where the specific frequency band of each of the first and second band-pass filters 431, 432 is 1.5×FSR, the closer the error value of the error signal Es changes to zero, the more violent, so that the fiber dispersion The monitoring device 2 has high monitoring sensitivity.

It should be noted that, in FIGS. 5 and 7, considering the interaction between the fiber dispersion and the fiber nonlinear distortion or the chirp of the optical delay interferometer 3, when the error signal Es is equal to zero, The amount of residual dispersion of the compensated optical signal Cl is close to 0 ps/nm.

<Second Embodiment>

Referring to FIG. 8, the second embodiment of the optical fiber dispersion monitoring device 2 of the present invention is similar to the first embodiment. The difference between the two is that in the second embodiment: (1) The signal processing module 4 is based on these The first and second delayed interference signals Ld1, Ld2 generate two error signals E1, E2; (2) The control module 5 generates the control signal Cs according to the error signals E1, E2; and (3) Amplify with a signal Unit 42a, a band-pass filter unit 43a, a power detection unit 44a, and a comparison unit 45a respectively replace the signal amplification unit 42, the band-pass filter unit 43, the power detection unit 44 in the first embodiment, And the comparison unit 45 (see FIG. 1).

The signal amplifying unit 42a includes first and second signal amplifiers 423 and 424. The first and second signal amplifiers 423 and 424 are electrically connected to the first and second photoelectric converters 411 and 412, respectively, to receive the first and second conversion signals Et1 and Et2, respectively. The first signal amplifier 423 amplifies the first converted signal Et1 to generate two first amplified signals A1 (the first amplified signals A1 are combined into the first amplified signal output Ao1 of FIG. 1). The second signal amplifier 424 amplifies the second converted signal Et2 to generate two second amplified signals A2 (the second amplified signals A2 are combined into the second amplified signal output Ao2 of FIG. 1).

The band-pass filter unit 43a includes first to fourth band-pass filters 433, 434, 435, and 436. The first and second band-pass filters 433, 434 are electrically connected to the first signal amplifier 423 to receive the first amplified signals A1 respectively, and perform band-pass filtering on the first amplified signals A1, respectively, to Produce One and second filtered signals F11, F12 (the first and second filtered signals F11, F12 are combined into the first filtered signal output Fo1 of FIG. 1). The third and fourth band-pass filters 435 and 436 are electrically connected to the second signal amplifier 424 to receive the second amplified signals A2 respectively, and perform band-pass filtering on the second amplified signals A2 to The third and fourth filtered signals F21 and F22 are generated respectively (these third and fourth filtered signals F21 and F22 are combined into the second filtered signal output Fo2 of FIG. 1). In this embodiment, the first and third bandpass filters 433, 435 each allow a first specific frequency band to pass, and the second and fourth bandpass filters 434, 436 each allow a second Waves in a specific frequency band pass through. For example, the first specific frequency band is 0.5 times the free spectrum range (ie, 0.5×FSR), and the second specific frequency band is 1.5 times the free spectrum range (ie, 1.5×FSR), but is not limited to this .

The power detection unit 44a includes first to fourth power detectors 443, 444, 445, and 446. The first to fourth power detectors 443 to 446 are electrically connected to the first to fourth band pass filters 433 to 436 respectively to receive the first to fourth filtered signals F11, F12, F21, F22 , And detect the power of the first to fourth filtered signals F11, F12, F21, F22 respectively to generate first to fourth power detection signals P11, P12, P21, P22 (the first and second The two power detection signals P11, P12 are combined to form the first power detection signal output Po1 of FIG. 1, and the third and fourth power detection signals P21, P22 are combined to form the second power detection signal output of FIG. Po2).

The comparison unit 45a is electrically connected to the first to fourth power detectors 443 to 446 to receive the first to fourth power detection signals P11, P12, P21, P22, respectively, and connect the first and fourth power detectors The three power detection signals are compared P11, P21 (ie, the first power detection signal P11 is subtracted from the third power detection signal P21) to generate the error signal E1, and the second and fourth The power detection signals P12 and P22 are compared (ie, the second power detection signal P12 is subtracted from the fourth power detection signal P22) to generate the error signal E2. It should be noted that the waveform of the error signal E1 is the same as FIG. 5, and the waveform of the error signal E2 is the same as FIG. 7.

The operation mode and effect of the second embodiment are similar to those of the first embodiment. Compared with the first embodiment, in the second embodiment, the control module 5 can receive the error signals E1 at the same time E2 generates the control signal Cs accordingly. In this way, the optical fiber dispersion monitoring device 2 has the advantages of larger monitoring range and high monitoring sensitivity.

<Third Embodiment>

Referring to FIG. 9, the third embodiment of the optical fiber dispersion monitoring device 2 of the present invention is similar to the first embodiment. The difference between the two is that in the third embodiment: (1) a signal processing module 6 replaces the The signal processing module 4 (see FIG. 1) in the first embodiment; (2) The control module 5 is also used to generate and output a switching signal Sc to the signal processing module 6, each of the switching signal Sc A switching cycle has an alternating high logic level and a low logic level; and (3) At each switching cycle, the signal processing module 6 according to the The first and second delayed interference signals Ld1, Ld2, and the switching signal Sc generate two error signals E3, E4, so that the control module 5 generates the control signal Cs according to the error signals E3, E4. In this embodiment, the control module 5 adjusts the delay control signal Dc1 and the switching signal Sc according to an external setting signal (not shown), but it is not limited thereto.

The signal processing module 6 includes an optical switch 61, a photoelectric converter 62, a signal amplifier 63, first and second band-pass filters 64, 65, first and second power detectors 66, 67, and One comparator 68.

The optical switch 61 has a control terminal for receiving the switching signal Sc, a first input terminal coupled to the optical delay interferometer 3 to receive the first delayed interference signal Ld1, and a coupled to the optical delay interferometer 3 To receive the second input terminal of the second delayed interference signal Ld2, and an output terminal for outputting an output signal Os. The optical switch 61 operates according to the switching signal Sc, so that when the switching signal Sc has the high logic level, the optical switch 61 establishes a connection between the output terminal and the first input terminal, so that the output signal Os is the first delayed interference signal Ld1, and when the switching signal Sc has the low logic level, the optical switch 61 establishes the connection between the output terminal and the second input terminal, so that the output signal Os is the The second delayed interference signal Ld2.

The photoelectric converter 62 is coupled to the optical switch 61 to receive the output signal Os, and photoelectrically converts the output signal Os to generate a conversion signal Et3.

The signal amplifier 63 is electrically connected to the photoelectric converter 62 to receive the conversion signal Et3, and amplifies the conversion signal Et3 to generate two amplified signals A3.

The first and second band-pass filters 64 and 65 are electrically connected to the signal amplifier 63 to receive the amplified signals A3 respectively, and perform band-pass filtering on the amplified signals A3 to generate first and second Two filtered signals F1, F2. The first bandpass filter 64 allows a wave of a first specific frequency band to pass, and the second bandpass filter 65 allows a wave of a second specific frequency band to pass. For example, the first specific frequency band is 0.5 times the free spectrum range (ie, 0.5×FSR), and the second specific frequency band is 1.5 times the free spectrum range (ie, 1.5×FSR), but is not limited to this .

The first and second power detectors 66 and 67 are electrically connected to the first and second band-pass filters 64 and 65 respectively to receive the first and second filtered signals F1 and F2 respectively and detect The power of the first and second filtered signals F1, F2 is measured to generate first and second power detection signals P1, P2, respectively.

The comparator 68 is electrically connected to the first and second power detectors 66, 67 to receive the first and second power detection signals P1, P2, respectively. At each switching cycle, the comparator 68 generates the corresponding first and second power detection signals P1, P2 (each related to the first delay interference) when the switching signal Sc is the high logic level Signal Ld1), and the switching signal Sc is the corresponding ones of the first and second power detection signals P1, P2 (each related to the second delayed interference signal Ld2) generated when the low logic level is correspondingly generated Wait for the first power detection signal P1 to compare to generate the The error signal E3 and the second power detection signals are compared P2 to generate the error signal E4. It should be noted that the waveform of the error signal E3 is the same as FIG. 5, and the waveform of the error signal E4 is the same as FIG. 7.

The operation mode and effect of the third embodiment are similar to those of the first embodiment. Compared with the first embodiment, in the third embodiment, the comparator 68 is switched every time the switching signal Sc is switched. The error signals E3 and E4 are generated, so that the control module 5 can receive the error signals E3 and E4 and generate the control signal Cs accordingly. In this way, the optical fiber dispersion monitoring device 2 has the advantages of larger monitoring range and high monitoring sensitivity.

<Fourth embodiment>

Referring to FIG. 10, the fourth embodiment of the optical fiber dispersion monitoring device 2 of the present invention is similar to the first embodiment, the difference between the two is that, in the fourth embodiment, an optical fiber dispersion monitoring device 7 is used to replace the optical fiber dispersion monitoring device 2. The optical fiber dispersion monitoring device 7 includes an optical delay interferometer 71, a signal processing module 72, and a control module 73.

The optical delay interferometer 71 is adapted to receive the optical feedback signal Lf divided by the beam splitter 15 (see FIG. 1) and receive a delay control signal Dc2. The optical delay interferometer 71 operates at least for a first predetermined period and a second predetermined period following the first predetermined period. In this embodiment, the optical delay interferometer 71 is operated for a first predetermined period and a second predetermined period following the first predetermined period as an example, but it is not limited thereto. In other embodiments, the first predetermined period and the second The predetermined period is combined into an operation cycle, and the optical delay interferometer 71 can be repeatedly operated during the operation cycle. During the first predetermined period, the delay control signal Dc2 indicates a first delay time, so that the optical delay interferometer 71 has an amplitude response waveform of the kth orthogonal point among a plurality of orthogonal points The position corresponds to the center wavelength of the optical feedback signal Lf, and a first delayed interference signal Ld3 is generated according to the delay control signal Dc2 and the optical feedback signal Lf. During the second predetermined period, the delay control signal Dc2 indicates a second delay time to make the (k+1)th orthogonal of one of the orthogonal points of the amplitude response waveform of the optical delay interferometer 71 The position of the point corresponds to the center wavelength of the optical feedback signal Lf, and a second delayed interference signal Ld4 is generated according to the delay control signal Dc2 and the optical feedback signal Lf, the first and second delayed interference signals Ld3 , Ld4 has a phase difference of 180 degrees from each other, and k is any positive odd number. A free spectrum range of the optical delay interferometer 71 changes with the change of the delay control signal Dc2.

The signal processing module 72 is coupled to the optical delay interferometer 71 to sequentially receive the first and second delayed interference signals Ld3, Ld4, and when receiving the first and second delayed interference signals Ld3, Ld4 Accordingly, an error signal E5 is generated. In this embodiment, the signal processing module 72 includes a photoelectric converter 721, a signal amplifier 722, a band pass filter 723, a power detector 724, and a comparator 725.

The photoelectric converter 721 is coupled to the optical delay interferometer 71 to sequentially receive the first and second delayed interference signals Ld3 and Ld4, and extend the first and second delay signals The late interference signals Ld3 and Ld4 undergo photoelectric conversion to sequentially generate a first conversion signal Et4 and a second conversion signal Et5, respectively.

The signal amplifier 722 is electrically connected to the photoelectric converter 721 to receive the first and second conversion signals Et4, Et5 in sequence, and amplifies the first and second conversion signals Et4, Et5 to sequentially generate A first amplified signal A4 and a second amplified signal A5.

The band-pass filter 723 is electrically connected to the signal amplifier 722 to sequentially receive the first and second amplified signals A4, A5, and band-pass-filter the first and second amplified signals A4, A5 to The sequence generates a first filtered signal F3 and a second filtered signal F4, respectively. The band-pass filter 723 allows waves of a specific frequency band to pass through. The specific frequency band is n times the free spectrum range, n=N+0.5, N≧0, and N is an integer. In this embodiment, the specific frequency band is 0.5 times the free spectrum range.

The power detector 724 is electrically connected to the band-pass filter 723 to sequentially receive the first and second filtered signals F3, F4, and detect the power of the first and second filtered signals F3, F4 to A first power detection signal P3 and a second power detection signal P4 are generated sequentially. It should be noted that the waveforms of the first and second power detection signals P3 and P4 are the same as the output of the first and second power detection signals Po1 and Po2 of FIG. 4, respectively.

The comparator 725 is electrically connected to the power detector 724 to sequentially receive the first and second power detection signals P3 and P4, and converts the first power detection signal P3 The second power detection signal P4 is subtracted to generate the error signal E5. It should be noted that the waveform of the error signal E5 is the same as the error signal Es of FIG. 5.

The control module 73 is electrically connected to the optical delay interferometer 71 and the signal processing module 72 for generating and outputting the delay control signal Dc2 to the optical delay interferometer 71 and receiving the signal from the signal processing module 72 An error signal E5, and generates and outputs the control signal Cs to the TDC device 14 (see FIG. 1) according to the error signal E5, so that the TDC device 14 adjusts its own tunable dispersion compensation value according to the control signal Cs, to Adjust the dispersion of the optical communication system 1.

The operation mode and effect of the fourth embodiment are similar to those of the first embodiment. When the specific frequency band is 0.5 times the free spectrum range, the optical fiber dispersion monitoring device 7 has the advantage of a larger monitoring range. When the specific frequency band At 1.5 times the free spectral range, the fiber dispersion monitoring device 7 has the advantage of high monitoring sensitivity. In addition, the fourth embodiment requires fewer circuit components than the first embodiment. Thus, the optical fiber dispersion monitoring device 7 has the characteristics of smaller circuit area and lower required cost.

<Fifth Embodiment>

Referring to FIG. 11, the fifth embodiment of the optical fiber dispersion monitoring device 2 of the present invention is similar to the first embodiment, the difference between the two is that, in the fifth embodiment, an optical fiber dispersion monitoring device 8 is used to replace the optical fiber dispersion monitoring device 8 2. The optical fiber dispersion monitoring device 8 includes an optical delay interferometer 81, a signal processing module 82, and a control module 83.

The optical delay interferometer 81 receives a delay control signal Dc3 indicating an adjustable delay time, and is suitable for receiving the optical feedback signal Lf divided by the beam splitter 15 (see FIG. 1). The optical delay interferometer 81 is controlled by the delay control signal Dc3 so that the position of one of the orthogonal points of an amplitude response waveform corresponds to the center wavelength of the optical feedback signal Lf, and according to The delay control signal Dc3 and the optical feedback signal Lf generate a delayed interference signal Ld5. A free spectrum range of the optical delay interferometer 81 changes with the change of the delay control signal Dc3.

The signal processing module 82 is coupled to the optical delay interferometer 81 to receive the delayed interference signal Ld5, and generates a first power detection signal P5 and a second power detection signal P6 according to the delayed interference signal Ld5. In this embodiment, the signal processing module 82 includes a photoelectric converter 821, a signal amplifier 822, first and second band pass filters 823, 824, and first and second power detectors 825, 826 .

The photoelectric converter 821 is coupled to the optical delay interferometer 81 to receive the delayed interference signal Ld5 and photoelectrically convert the delayed interference signal Ld5 to generate a conversion signal Et6.

The signal amplifier 822 is electrically connected to the photoelectric converter 821 to receive the conversion signal Et6, and amplifies the conversion signal Et6 to generate two amplified signals A6.

The first and second band-pass filters 823, 824 are each electrically connected to the signal amplifier 822 to receive the amplified signals A6, respectively, and respectively the amplified signals A6 performs band-pass filtering to generate first and second filtered signals F5 and F6, respectively. The first band pass filter 823 allows a wave of a first specific frequency band to pass, and the second band pass filter 824 allows a wave of a second specific frequency band to pass, the first specific frequency band is 0.5 times the free spectrum range, The second specific frequency band is 1.5 times the free spectrum range, but is not limited thereto.

The first and second power detectors 825 and 826 are electrically connected to the first and second bandpass filters 823 and 824 respectively to receive the first and second filtered signals F5 and F6, respectively, and detect The power of the first and second filtered signals F5, F6 is measured to generate the first and second power detection signals P5, P6, respectively. Further refer to FIG. 12, which is a waveform diagram of the first and second power detection signals P5, P6.

The control module 83 is electrically connected to the optical delay interferometer 81 and the signal processing module 82 for generating and outputting the delay control signal Dc3 to the optical delay interferometer 81 and receiving the signal from the signal processing module 82 Wait for the first and second power detection signals P5, P6, and generate and output the control signal Cs to the TDC unit 14 according to one of the first and second power detection signals P5, P6 (see FIG. 1) to adjust the dispersion of the optical communication system 1. For example, the control module 83 first generates the control signal Cs according to the first power detection signal P5, so that the TDC device 14 coarsely adjusts its own tunable dispersion compensation value according to the control signal Cs, and then After a period of time, the control module 83 generates the control signal Cs according to the second power detection signal P6, so that The TDC device 14 finely adjusts its own tunable dispersion compensation value according to the control signal Cs.

It should be noted that in the first to fifth embodiments, each of the optical delay interferometers 3, 71, 81 is a Michelson Interferometer and a Mach-Zehnder interference (Mach-Zehnder Interferometer, MZI) One of the two, each of the photoelectric converters 411, 412, 62, 721, 821 is a conventional PIN photodiode, the signal amplifiers 421, 422, Each of 423, 424, 63, 722, and 822 is a transimpedance amplifier (TIA) but is not limited thereto.

In summary, each of the above embodiments has at least one of the following advantages. The control signal Cs generated by each of the control modules 5, 73, 83 can monitor and compensate for the dispersion of the optical communication system 1, so as to prevent the dispersion from seriously affecting the optical communication system 1. In addition, since each error signal Es, E1~E5 has a polarity, when each error signal Es, E1~E5 is greater than zero, it represents that the tunable dispersion compensation value of the TDC 14 is to be reduced; when each error signal When Es, E1~E5 is less than zero, it means that the adjustable dispersion value of the TDC device 14 needs to be increased, so that each control module 5, 73, 83 has high monitoring sensitivity (ie, has better monitoring accuracy) In addition, each control module 5, 73, 83 does not need to make the control signal Cs output from it jitter and offset, so as to avoid reducing the link transmission performance of the optical communication system 1. In addition, the optical delay interferometer 3 (71, 81) and the control module 5 (73, 83) can be used The optical fiber dispersion monitoring device of the embodiment has a larger monitoring range (that is, the monitoring range is less limited). In short, since the optical fiber dispersion monitoring device of this embodiment is applicable to all modulation formats with optical double-sideband spectrum, and has a larger monitoring range and better monitoring accuracy, it is better than conventional optical fiber dispersion The monitoring device is easier to use.

However, the above are only examples of the present invention, and should not be used to limit the scope of the present invention. Any simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the patent specification are still classified as This invention covers the patent.

Claims (15)

An optical fiber dispersion monitoring device is suitable for monitoring the dispersion of an optical communication system. The optical fiber dispersion monitoring device includes: an optical delay interferometer, receiving a delay control signal indicating an adjustable delay time, and suitable for receiving the optical communication system An optical feedback signal divided by an optical splitter, the optical delay interferometer is controlled by the delay control signal so that the position of one of the orthogonal points of an amplitude response waveform corresponds to the A center wavelength of the optical feedback signal, and generating a first delayed interference signal and a second delayed interference signal according to the delay control signal and the optical feedback signal, the first and second delayed interference signals having 180 degrees to each other A phase difference; a signal processing module coupled to the optical delay interferometer to receive the first and second delayed interference signals and generate at least one error signal based at least on the first and second delayed interference signals; and A control module, electrically connected to the optical delay interferometer and the signal processing module, for generating and outputting the delay control signal to the optical delay interferometer, and receiving the at least one error signal from the signal processing module, The control module generates and outputs a control signal to the optical communication system according to the at least one error signal to adjust the dispersion of the optical communication system. The optical fiber dispersion monitoring device according to claim 1, wherein a free spectrum range of the optical delay interferometer changes with the change of the adjustable delay time, the optical delay interferometer is a Michelson interferometer and a One of the two Mach-Zehnder interferometers. The optical fiber dispersion monitoring device according to claim 1, wherein the signal processing module includes a photoelectric conversion unit coupled to the optical delay interferometer to receive the first and second delayed interference signals, and One and second delayed interference signals are photoelectrically converted to generate a first conversion signal and a second conversion signal, respectively, a signal amplification unit electrically connected to the photoelectric conversion unit to receive the first and second conversion signals, and Amplify the first and second conversion signals to generate a first amplified signal output and a second amplified signal output, respectively, a band-pass filter unit, electrically connected to the signal amplification unit to receive the first and second signals Amplified signal output, and band-pass filtering the first and second amplified signal outputs to generate a first filtered signal output and a second filtered signal output, respectively, a power detection unit, electrically connected to the band-pass filter The unit receives the first and second filtered signal outputs and detects the respective powers of the first and second filtered signals to generate a first power detection signal output and a second power detection signal, respectively An output, and a comparison unit, electrically connected to the power detection unit to receive the first and second power detection signal outputs, and compare the first and second power detection signal outputs to generate the at least An error signal. The optical fiber dispersion monitoring device according to claim 3, wherein the band-pass filtering unit allows waves of a specific frequency band to pass through, the specific frequency band being n times the free spectral range of the optical delay interferometer, n=N +0.5, N≧0, N is an integer. The optical fiber dispersion monitoring device according to claim 3, wherein the photoelectric conversion unit includes first and second photoelectric converters, and the first and second photoelectric converters are each coupled to the optical delay interferometer to respectively receive the Waiting for the first and second delayed interference signals, and photoelectrically converting the first and second delayed interference signals, respectively, to generate the first and second conversion signals, respectively, the signal amplification unit includes first and second A signal amplifier, the first and second signal amplifiers are electrically connected to the first and second photoelectric converters respectively to receive the first and second conversion signals, and the first and second conversion signals respectively Performing amplification to generate the first and second amplified signal outputs, respectively, the band-pass filtering unit includes first and second band-pass filters, and the first and second band-pass filters are electrically connected to the first A and second signal amplifiers respectively receive the first and second amplified signal outputs, and perform band-pass filtering on the first and second amplified signal outputs, respectively, to generate the first and second filtered signals, respectively Output, and the power detection unit includes first and second power detectors, the first and second power detectors are electrically connected to the first and second band pass filters to receive the first The first and second filtered signals are output, and the powers of the first and second filtered signals are detected to generate the first and second power detection signal outputs, respectively. The fiber dispersion monitoring device according to claim 3, wherein the signal processing module generates two error signals based on the first and second delayed interference signals, and the control module generates the control signal based on the error signals, The photoelectric conversion unit includes first and second photoelectric converters. The first and second photoelectric converters are respectively coupled to the optical delay interferometer to receive the first and second delayed interference signals, respectively, and respectively The first and second delayed interference signals undergo photoelectric conversion to generate the first and second converted signals, respectively. The signal amplification unit includes first and second signal amplifiers. The first and second signal amplifiers respectively The first and second photoelectric converters are connected to receive the first and second conversion signals, respectively, and the first signal amplifier amplifies the first conversion signal to generate two first amplified signals, and the second signal The amplifier amplifies the second converted signal to generate two second amplified signals. The first amplified signals are combined to form the first amplified signal output, and the second amplified signals are combined to form the second amplified signal output. The pass filter unit includes first to fourth band pass filters, the first and second band pass filters are each electrically connected to the first signal amplifier to receive the first amplified signals, respectively, and the first The amplified signal is band-pass filtered to generate first and second filtered signals, respectively, the third and fourth band-pass filters are each electrically connected to the second signal amplifier to respectively receive the second amplified signals, and respectively The second amplified signals are band-pass filtered to generate third and fourth filtered signals, respectively, the first and second filtered signals are combined into the first filtered signal output, and the third and fourth filtered signals are combined Into the second filtered signal output, the first and third bandpass filters each allow a wave of a first specific frequency band to pass, and the second and fourth bandpass filters each allow a wave of a second specific frequency band Through, the power detection unit includes first to fourth power detectors, the first to fourth power detectors are electrically connected to the first to fourth band pass filters respectively to receive the first To the fourth filtered signal, and respectively detect the power of the first to fourth filtered signals to generate first to fourth power detection signals, respectively, the first and second power detection signals are combined into the first A power detection signal output, the third and fourth power detection signals are combined into the second power detection signal output, and the comparison unit is electrically connected to the first to fourth power detectors to receive the Wait for the first to fourth power detection signals, and compare the first and third power detection signals to generate one of the error signals, and detect the second and fourth power detection signals The signals are compared to produce the other of the error signals. The fiber dispersion monitoring device according to claim 1, wherein the control module is further used to generate and output a switching signal to the signal processing module, and each switching cycle of the switching signal has an alternating high logic level And a low logic level, at each switching cycle, the signal processing module generates two error signals according to the first and second delayed interference signals, and the switching signal, and the control module generates according to the error signals The control signal. The optical fiber dispersion monitoring device according to claim 7, wherein the signal processing module includes an optical switch having a control terminal for receiving the switching signal, and an optical delay interferometer coupled to receive the first delay A first input terminal of the interference signal, a second input terminal coupled to the optical delay interferometer to receive the second delayed interference signal, and an output terminal for outputting an output signal, the optical switch is based on the switching signal Operating such that when the switching signal has the high logic level, the output signal is the first delayed interference signal, and when the switching signal has the low logic level, the output signal is the second delayed interference signal , A photoelectric converter, coupled to the optical switch to receive the output signal, and photoelectric conversion of the output signal to generate a conversion signal, a signal amplifier, electrically connected to the photoelectric converter to receive the conversion signal, and The converted signal is amplified to generate two amplified signals, a first and a second band-pass filter, each electrically connected to the signal amplifier to receive the amplified signals separately, and band-pass-filtering the amplified signals to separate Generate first and second filtered signals, the first band-pass filter allows a first specific frequency band to pass, the second band-pass filter allows a second specific frequency band to pass, the first and second power detection The detector is electrically connected to the first and second band-pass filters to receive the first and second filtered signals, respectively, and detects the power of the first and second filtered signals, respectively, to generate the first One and second power detection signals, and a comparator, electrically connected to the first and second power detectors to receive the first and second power detection signals, respectively, at each switching cycle, the comparison The switch generates the corresponding first and second power detection signals corresponding to the first delayed interference signal when the switching signal is the high logic level, and when the switching signal is the low logic level Comparing the first power detection signals among the first and second power detection signals correspondingly generated and related to the second delayed interference signal, and comparing the second power detection signals, To generate the error signals separately. The fiber dispersion monitoring device according to claim 6 or 8, wherein the first specific frequency band is 0.5 times a free spectral range of the optical delay interferometer, and the second specific frequency band is 1.5 of the free spectral range Times. An optical fiber dispersion monitoring device is suitable for monitoring the dispersion of an optical communication system. The optical fiber dispersion monitoring device includes: an optical delay interferometer, suitable for receiving an optical feedback signal divided by an optical splitter of the optical communication system, And receiving a delay control signal, the optical delay interferometer is operated at least for a first predetermined period and a second predetermined period following the first predetermined period. During the first predetermined period, the delay control signal indicates a first A delay time so that the position of the kth orthogonal point among the orthogonal points of an amplitude response waveform of the optical delay interferometer corresponds to a central wavelength of the optical feedback signal, and according to the The delay control signal and the optical feedback signal generate a first delayed interference signal. During the second predetermined period, the delay control signal indicates a second delay time to delay the optical response of the amplitude response waveform of the interferometer The position of the (k+1)th orthogonal point among the orthogonal points corresponds to the center wavelength of the optical feedback signal, and generates a second delayed interference signal according to the delay control signal and the optical feedback signal, The first and second delayed interference signals have a phase difference of 180 degrees from each other, and k is any positive odd number; a signal processing module coupled to the optical delay interferometer to sequentially receive the first and second delays Interference signal, and an error signal is generated when receiving the first and second delayed interference signals; and a control module, electrically connected to the optical delay interferometer and the signal processing module, for generating and outputting The delay control signal is sent to the optical delay interferometer, and receives the error signal from the signal processing module, and generates and outputs a control signal to the optical communication system according to the error signal to adjust the dispersion of the optical communication system. The fiber dispersion monitoring device according to claim 10, wherein the signal processing module includes an optical-to-electrical converter, coupled to the optical delay interferometer to sequentially receive the first and second delayed interference signals, and convert the Waiting for the first and second delayed interference signals to perform photoelectric conversion to sequentially generate a first conversion signal and a second conversion signal, respectively, and a signal amplifier electrically connected to the photoelectric converter to sequentially receive the first and second conversion signals Two converted signals, and amplifying the first and second converted signals to sequentially generate a first amplified signal and a second amplified signal, a band-pass filter electrically connected to the signal amplifier to sequentially receive the signal Waiting for the first and second amplified signals, and band-pass filtering the first and second amplified signals to sequentially generate a first filtered signal and a second filtered signal, a power detector, and an electrical connection The band-pass filter receives the first and second filtered signals in sequence and detects the respective powers of the first and second filtered signals to sequentially generate a first power detection signal and a first Two power detection signals, and a comparator, electrically connected to the power detector to sequentially receive the first and second power detection signals, and subtracting the first power detection signal from the second power detection signal Signal to generate the error signal. The optical fiber dispersion monitoring device according to claim 11, wherein the delay interferometer has a free spectrum range that changes with the change of the delay control signal. The optical delay interferometer is a Michelson interferometer and a Mach- One of the two Zendl interferometers, and the band-pass filter allows waves of a specific frequency band to pass through. The specific frequency band is n times the free spectral range, n=N+0.5, N≧0, and N is an integer. An optical fiber dispersion monitoring device is suitable for monitoring the dispersion of an optical communication system. The optical fiber dispersion monitoring device includes: an optical delay interferometer, receiving a delay control signal indicating an adjustable delay time, and suitable for receiving the optical communication system An optical feedback signal divided by an optical splitter, the optical delay interferometer is controlled by the delay control signal to make the position of one of the orthogonal points of an amplitude response waveform corresponding to the A center wavelength of the optical feedback signal, and generating a delayed interference signal according to the delay control signal and the optical feedback signal; a signal processing module, coupled to the optical delay interferometer to receive the delayed interference signal, and according to the The delayed interference signal generates a first power detection signal and a second power detection signal; and a control module, electrically connected to the optical delay interferometer and the signal processing module, for generating and outputting the delayed control signal to The optical delay interferometer receives the first and second power detection signals from the signal processing module, and generates and outputs a control according to one of the first and second power detection signals Signal to the optical communication system to adjust the dispersion of the optical communication system. The optical fiber dispersion monitoring device according to claim 13, wherein the signal processing module includes a photoelectric converter, coupled to the optical delay interferometer to receive the delayed interference signal, and photoelectrically converts the delayed interference signal to Generate a conversion signal, a signal amplifier, electrically connected to the photoelectric converter to receive the conversion signal, and amplify the conversion signal to generate two amplified signals, the first and second band-pass filters, each electrically connected to the signal The amplifier receives the amplified signals separately, and performs band-pass filtering on the amplified signals respectively to generate first and second filtered signals. The first band-pass filter allows waves of a first specific frequency band to pass through. The second bandpass filter allows a second specific frequency band to pass, and the first and second power detectors are electrically connected to the first and second bandpass filters to receive the first and second bandpass filters, respectively Two filtered signals, and respectively detect the power of the first and second filtered signals to generate the first and second power detection signals, respectively. The optical fiber dispersion monitoring device according to claim 14, wherein the optical delay interferometer has a free spectrum range that changes with the change of the delay control signal, the optical delay interferometer is a Michelson interferometer and a Mach -One of the two Zender interferometers, and the first specific frequency band is 0.5 times the free spectral range, and the second specific frequency band is 1.5 times the free spectral range.

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