KR100475880B1 - An optical burst-mode receiver, and apparatus and method for automatically controlling optical input power of it - Google Patents

Abstract

An apparatus for automatically controlling input light intensity of a burst mode optical receiver according to the present invention includes: an optical power splitter for splitting an input optical signal into a first optical signal and a second optical signal which are the same signals; A signal processor for converting the first optical signal branched from the optical power splitter into an electrical signal proportional to an optical intensity to detect an intensity of an input optical signal; An optical fiber delay line configured to delay the second optical signal branched from the optical power distributor for a predetermined time; And a variable light attenuator for adjusting the attenuation size according to the input light intensity detected by the signal processor.

According to the present invention, since the size of the optical signal input to the burst mode optical receiver is made constant by the optical method, it is not necessary to the electrical circuit portion that should perform the automatic gain control function at a high speed, so that the electrical signal processing function Simplifications and speed improvements are expected.

Description

An optical burst-mode receiver, and apparatus and method for automatically controlling optical input power of it}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a burst mode type optical receiver used in an optical packet communication system, and more particularly to a burst mode having an input light intensity automatic control device capable of automatically and automatically adjusting a power level of an optical signal optically at an input terminal. It relates to a light receiver.

Asynchronous transfer mode (ATM) / wavelength division multiplexing (WDM) / passive optical network (Ethernet-PON), optical packet communication systems, and the like require a burst mode optical receiver to receive an optical packet in a burst mode.

As the Internet spreads to general households, the market demand for high speed burst mode optical signal transmission / reception technology is also increasing to speed up subscriber networks.

Research on the transmission and reception of burst mode optical signals has been steadily progressed for uplink signal transmission in passive optical subscriber systems, which began to appear in the early 1990s.

However, burst mode optical signal transmission / reception technology is far behind in transmission rate compared to continuous stream optical signal transmission / reception. This is because the strength of the burst mode optical signal and the transmission delay time vary depending on the transmission distance of the optical signal, so that high-speed restoration of the clock and high-speed determination of data are difficult.

Therefore, the direction of technology development for receiving a burst mode optical signal at high speed can be explained in two ways.

First, a method of using a specific frame transmission / reception technique for compensating for the variation of the intensity of the optical signal and the variation in the transmission delay time. This method can use a conventional continuous stream type optical receiver as it is, but there is a problem in that a repetitive bit pattern needs to be transmitted even when information is not transmitted.

Second, a high-speed clock / data recovery circuit technique that detects a change in signal strength and transmission delay time for each optical packet is used. This method finds information about the packet and the packet signal size within the first pulse width of the received optical signal and sets the level value of the data discrimination circuit to this value, and from the preamble included for clock extraction and recovery. This is a method of reproducing data by extracting a synchronized clock.

Recently, Gbps burst mode optical receiver products have appeared, but the performance is not good yet. In addition, some laboratories have announced success stories of receiving 10Gbps burst mode optical signals.

On the other hand, in order for the processing capacity of the intensive node of the passive optical network to be tens to hundreds of Gbps or more, the operation speed of the individual burst mode optical receiver must be 10 Gbps or more.

In such a high-speed environment, it is preferable to optically process the reception function of the burst mode optical signal rather than electrically.

However, the conventional burst mode optical receiver implements an automatic gain control function for compensating light intensity fluctuations according to the transmission distance as an electric circuit. As a result, the optical receiver requires an electric circuit capable of high-speed signal processing. There is a problem that the circuit implementation becomes complicated.

In order to solve the above problems, the present invention is a burst mode optical receiver and a burst mode optical receiver for overcoming the limitation of shortening the signal processing time of the electrical circuit and simplifying the circuit in the conventional burst mode optical receiver which was dependent on the electrical circuit. An object of the present invention is to provide an apparatus and a method for automatically controlling the input light intensity.

The input light intensity automatic control device of a burst mode optical receiver according to a feature of the present invention,

An apparatus for automatically controlling input light intensity for making a constant intensity of an optical signal input to a burst mode optical receiver, comprising: an optical power splitter for splitting an input optical signal into a first optical signal and a second optical signal which are the same signals; A signal processor for converting the first optical signal branched from the optical power splitter into an electrical signal proportional to an optical intensity to detect an intensity of an input optical signal; An optical fiber delay line configured to delay the second optical signal branched from the optical power distributor for a predetermined time; And a variable light attenuator for adjusting the attenuation size according to the input light intensity detected by the signal processor.

The signal processing unit may include: a photodiode converting the first optical signal into an electrical signal proportional to the optical signal; A transfer impedance amplifier for amplifying the electrical signal converted by the photodiode; And an analog-digital converter for converting the electrical signal amplified by the transfer impedance amplifier into a digital signal.

The variable optical attenuator may include: a processor configured to receive a digital optical signal converted from the analog-digital converter and determine an intensity of an input optical signal to calculate an attenuation amount; A driving circuit outputting a driving signal according to the attenuation amount calculated by the processor; And a variable optical attenuator for attenuating and outputting the second optical signal delayed for a predetermined time through the optical power distributor and the optical fiber delay line according to the driving signal of the driving circuit.

The predetermined time for delaying the second optical signal by the optical signal retarder may be a time required for the driving circuit to control the variable optical attenuator based on the first optical signal.

On the other hand, the automatic input light intensity control method of the burst mode optical receiver according to a feature of the present invention,

(a) dividing a first optical signal and a second optical signal, which are the same optical signal, from the input optical signal; (b) converting the branched first optical signal into an electrical signal proportional to signal strength and amplifying the converted optical signal; (c) delaying the branched second optical signal by a predetermined time; (d) determining the strength of the branched first optical signal using the converted digital signal and outputting a driving signal for attenuating the branched second optical signal based on the strength of the first optical signal step; And (e) attenuating the magnitude of the delayed second optical signal based on the driving signal.

The predetermined time period during which the second optical signal is delayed may be a time until the strength of the optical signal is determined using the first optical signal.

In addition, a burst mode optical receiver according to a feature of the present invention,

The input optical signal is divided into a first optical signal and a second optical signal which are the same optical signals, and the second optical signal is variably attenuated based on the light intensity of the first optical signal so that the second optical signal has a constant power. An automatic gain control device to have a level; An optical signal conversion device which receives a second optical signal having a predetermined size output from the automatic gain control device, converts the second optical signal into an electrical signal, and outputs the electrical signal; A clock restoring apparatus for extracting and restoring a clock of a burst mode signal from the electrical signal converted by the optical signal converter; And a signal discriminating device which receives a clock recovered from the clock recovering device and reproduces a data signal of an electrical signal converted by the optical signal converting device.

The automatic input light intensity control apparatus includes an optical power splitter for splitting an input optical signal into a first optical signal and a second optical signal that are the same signal; A signal processor for converting the first optical signal branched from the optical power splitter into an electrical signal proportional to an optical intensity to detect an intensity of an input optical signal; An optical fiber delay line configured to delay the second optical signal branched from the optical power distributor for a predetermined time; And a variable light attenuator for adjusting the attenuation size according to the input light intensity detected by the signal processor.

The signal processing unit may include: a photodiode converting the first optical signal into an electrical signal proportional to the optical signal; A transfer impedance amplifier for amplifying the electrical signal converted by the photodiode; And an analog-to-digital converter for converting the electrical signal amplified by the transfer impedance amplifier into a digital signal.

The variable optical attenuation unit may include: a processor configured to receive a digital optical signal converted from the analog-digital conversion unit, determine an intensity of an input optical signal, and calculate an attenuation amount; A driving circuit outputting a driving signal according to the attenuation amount calculated by the processor; And a variable optical attenuator for attenuating and outputting the second optical signal delayed for a predetermined time through the optical power distributor and the optical fiber delay line according to the driving signal of the driving circuit.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

1 is a block diagram showing the structure of a burst mode optical receiver according to an embodiment of the present invention.

As shown in FIG. 1, a burst mode optical receiver according to an embodiment of the present invention includes a burst mode optical receiver 100 and an automatic input light intensity control apparatus 200.

The burst mode optical receiver 100 includes a photo-diode / trans-impedance amplifier (PD / TIA) 110, a signal discrimination circuit 120, and a clock recovery circuit 130. Include.

The PD / TIA 110 converts the received optical signal into an electrical signal in a photodiode (PD) and amplifies it in a transimpedance amplifier (TIA).

The clock recovery circuit 130 extracts and restores the clock of the optical signal which is converted into an electrical signal in the PD / TIA 110 and amplified, and outputs the restored clock.

The signal discrimination circuit 120 reproduces the original data signal using the restored clock output from the clock recovery circuit 130 and the optical signal converted and amplified by the PD / TIA 110 into an electrical signal.

Brief description of the operation of the burst mode is as follows.

When the burst mode optical signal is input, the PD / TIA 110 converts the optical signal into an electrical signal and amplifies the optical signal. The PD / TIA 110 converts the optical signal into an electrical signal and inputs the signal to the signal discrimination circuit 120 and the clock restoration circuit 130. do.

The clock recovery circuit 130 receives an optical signal converted and converted into an electrical signal by the PD / TIA 110, extracts a clock, restores the clock, and provides the restored clock to the signal discrimination circuit 120.

The signal discrimination circuit 120 reproduces the optical signal amplified by converting the PD / TIA 110 into an electrical signal according to the restored clock signal provided by the clock recovery circuit 130 as a data signal.

As described above, in order for the burst mode optical receiver 100 according to the present invention to operate, it is important to input an optical signal maintained at a constant size to the PD / TIA 110. The 200 receives the input optical signal to make an optical signal of a predetermined size, and transmits it to the burst mode optical receiver 100.

This is because, as described above, in the transmission of the burst mode optical signal, since the intensity and the transmission delay time of the optical signal change according to the transmission distance, accurate restoration of the optical signal received at high speed without controlling the signal intensity to a certain size Because this is difficult.

2 is a block diagram showing the structure of the automatic input light intensity control apparatus 200 of FIG. 1 according to an embodiment of the present invention.

Referring to FIG. 2, the automatic input light intensity control apparatus 200 includes an optical power distributor 210, an optical fiber delay line (FDL) 220, a variable optical attenuator 230, and a driving circuit ( 250, a processor 250, an analog to digital converter (ADC) 260, a trans-impedance amplifier (TIA) 270, and a photo-diode; PD) 280.

The optical power distributor 210 splits the input burst mode optical signal into two identical signals and inputs them to the FDL 220 and the PD 280, respectively.

The PD 280, the TIA 270, and the ADC 260 constitute a signal processing unit a for performing a signal processing operation for converting an optical signal branched by the optical power divider 210 into an electrical signal.

In addition, the processor 250, the driving circuit 230, and the variable optical attenuator 230 are optical signals having a constant size when another optical signal branched by the optical power distributor is delayed through the FDL 220. The variable optical attenuator b is attenuated and output.

In the signal processing unit (a), the PD 280 converts the input burst mode optical signal into a current proportional to the light intensity, and the TIA 270 converts the current signal converted by the PD 280 into a voltage signal and amplifies it. .

The ADC 260 converts the voltage signal amplified and converted into a voltage signal by the TIA 270 into a digital signal.

In the variable light attenuator b, the processor 250 determines the intensity of the input optical signal by reading the output value of the digital signal converted by the ADC 260, and calculates the amount of light attenuation based on the determined intensity of the optical signal. do.

The driving circuit 240 outputs a driving signal corresponding to the attenuation amount calculated by the processor 250.

The variable optical attenuator 230 attenuates and outputs the intensity of the optical signal to a predetermined size according to the driving signal of the driving circuit 240.

In this case, the optical signal that is variable attenuated by the variable optical attenuator 230 is delayed for a time taken from the burst mode optical signal branched by the optical power divider 210 to the output of the drive signal for attenuation via the FDL (220) do.

An automatic gain control method of a burst mode optical receiver using the input light intensity automatic control device 200 according to an embodiment of the present invention is as follows.

3 is an operation flowchart of a method for automatically controlling input light intensity of a burst mode optical receiver according to an exemplary embodiment of the present invention.

Referring to FIG. 3, when an optical signal is input to the automatic input light intensity control apparatus 200 (S301), the same optical signal is divided by splitting another optical signal, such as the optical signal input from the optical power distributor 210. One to the PD (280) and the other to the FDL (220) (S302).

The optical signal input to the PD 280 is converted into a current signal proportional to the light intensity, and amplified by converting the current signal converted by the TIA 270 into a voltage signal (S303).

In step S303, the ADC 260 converts the optical signal converted into a voltage signal and amplified into a digital signal (S304).

The processor 250 extracts the intensity value of the optical signal using the digital signal converted into the burst mode optical signal (S305), and determines the amount of attenuation using the digital signal (S306).

The driving circuit 240 outputs a driving signal corresponding to the attenuation amount determined by the processor 250, and drives the variable optical attenuator 230 to output a constant optical signal (S307).

In addition, the FDL 220 inputs another burst mode signal input by the FDL 220 in step S302 while outputting a signal for driving the variable optical attenuator 230 using the burst mode optical signal input to the PD 280. The time delay is caused by keeping in the line.

When the driving signal for driving the variable optical attenuator 230 is output from the driving circuit 240 and the variable optical attenuator 230 starts to operate, the burst mode optical signal in the FDL 220 is changed into the variable optical attenuator 230. As it is input to the optical signal is adjusted to a certain size (S308).

The optical signal adjusted to a predetermined size as described above is received by the burst mode optical receiver 100 and restored to the data signal.

As described above, according to the present invention, since the burst mode optical signal received by the burst mode optical receiver is controlled to a predetermined size in advance, the signal processing time can be shortened as compared with the conventional technology which solved this by an electric circuit. .

In addition, since the burst mode optical receiver can receive an optical signal having a constant size, only an apparatus for restoring a clock and converting the signal into a data signal can simplify the electrical circuit of the burst mode optical receiver itself, thereby improving performance.

1 is a block diagram showing the structure of a burst mode optical receiver according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a structure of an input light intensity automatic control device of FIG. 1 according to an exemplary embodiment of the present invention.

3 is an operation flowchart of a method for automatically controlling input light intensity of a burst mode optical receiver according to an exemplary embodiment of the present invention.

<Brief description of the main parts of the drawings>

100: burst mode optical receiver 110: PD / TIA

120: signal discrimination circuit 130: clock recovery circuit

200: automatic control of input light intensity 210: optical power distributor

220: FDL 230: variable optical attenuator

240: driving circuit 250: processor

260: ADC 270: TIA

280: PD

Claims (10)

In the input light intensity automatic control device for making the intensity of the optical signal input to the burst mode optical receiver constant, An optical power splitter for splitting the input optical signal into a first optical signal and a second optical signal which are the same signals; A signal processor for converting the first optical signal branched from the optical power splitter into an electrical signal proportional to an optical intensity to detect an intensity of an input optical signal; An optical fiber delay line configured to delay the second optical signal branched from the optical power distributor for a predetermined time; And Variable light attenuator for adjusting the attenuation size according to the input light intensity detected by the signal processor Automatic input light intensity control device of the burst mode optical receiver comprising a. The method of claim 1, The signal processing unit, A photodiode for converting the first optical signal into an electrical signal proportional to the optical signal; A transfer impedance amplifier for amplifying the electrical signal converted by the photodiode; And Analog-to-digital converter for converting the electrical signal amplified by the transfer impedance amplifier into a digital signal Automatic input light intensity control device of the burst mode optical receiver comprising a. The method of claim 2, The variable light attenuation unit, A processor configured to receive the digital optical signal converted from the analog-digital converter, determine the strength of the input optical signal, and calculate an attenuation amount; A driving circuit outputting a driving signal according to the attenuation amount calculated by the processor; And A variable optical attenuator for attenuating and outputting the second optical signal delayed for a predetermined time through the optical power distributor and the optical fiber delay line according to the driving signal of the driving circuit. Automatic input light intensity control device of the burst mode optical receiver comprising a. The method of claim 3, wherein The predetermined time for delaying the second optical signal in the optical signal delay unit, And the time required for the driving circuit to control the variable optical attenuator based on the first optical signal. (a) dividing a first optical signal and a second optical signal, which are the same optical signal, from the input optical signal; (b) converting the branched first optical signal into an electrical signal proportional to signal strength and amplifying the converted optical signal; (c) delaying the branched second optical signal by a predetermined time; (d) determining the strength of the branched first optical signal using the converted digital signal and outputting a driving signal for attenuating the branched second optical signal based on the strength of the first optical signal step; And (e) attenuating the magnitude of the delayed second optical signal based on the driving signal; Automatic input light intensity control method of the burst mode optical receiver comprising a. The method of claim 5, The predetermined time delay of the second optical signal is the time until the determination of the intensity of the optical signal using the first optical signal, characterized in that the automatic control method of the input light intensity of the burst mode optical receiver. The input optical signal is divided into a first optical signal and a second optical signal which are the same optical signals, and the second optical signal is variably attenuated based on the light intensity of the first optical signal so that the second optical signal has a constant power. An automatic gain control device to have a level; An optical signal conversion device which receives a second optical signal having a predetermined size output from the automatic gain control device, converts the second optical signal into an electrical signal, and outputs the electrical signal; A clock restoring apparatus for extracting and restoring a clock of a burst mode signal from the electrical signal converted by the optical signal converter; And A signal discrimination apparatus for receiving a clock recovered from the clock recovery apparatus and reproducing a data signal of an electrical signal converted by the optical signal conversion apparatus Burst mode optical receiver comprising a. The method of claim 7, wherein The input light intensity automatic control device, An optical power splitter for splitting the input optical signal into a first optical signal and a second optical signal which are the same signals; A signal processor for converting the first optical signal branched from the optical power splitter into an electrical signal proportional to an optical intensity to detect an intensity of an input optical signal; An optical fiber delay line configured to delay the second optical signal branched from the optical power distributor for a predetermined time; And Variable light attenuator for adjusting the attenuation size according to the input light intensity detected by the signal processor Burst mode optical receiver comprising a. The method of claim 8, The signal processing unit, A photodiode for converting the first optical signal into an electrical signal proportional to the optical signal; A transfer impedance amplifier for amplifying the electrical signal converted by the photodiode; And Analog-to-digital converter for converting the electrical signal amplified by the transfer impedance amplifier into a digital signal Burst mode optical receiver comprising a. The method of claim 9, The variable light attenuation unit, A processor configured to receive the digital optical signal converted from the analog-digital converter, determine the strength of the input optical signal, and calculate an attenuation amount; A driving circuit outputting a driving signal according to the attenuation amount calculated by the processor; And A variable optical attenuator for attenuating and outputting the second optical signal delayed for a predetermined time through the optical power distributor and the optical fiber delay line according to the driving signal of the driving circuit. Burst mode optical receiver comprising a.