CN1208914C

CN1208914C - Simulated gain control equipment and method for erbium-doped fiber amplifier

Info

Publication number: CN1208914C
Application number: CNB021124914A
Authority: CN
Inventors: 罗焱
Original assignee: Alcatel Lucent Shanghai Bell Co Ltd
Current assignee: Nokia Shanghai Bell Co Ltd
Priority date: 2002-07-12
Filing date: 2002-07-12
Publication date: 2005-06-29
Anticipated expiration: 2022-07-12
Also published as: CN1467928A

Abstract

The present invention relates to simulated gain control equipment and a method for an erbium-doped fiber amplifier. The method comprises the steps: the optical input coupling and the optical output coupling are respectively carried out on an optical input end and an optical output end; output optical signals are detected by optical input power and optical output power to carry out optoelectronic conversion; the converted electrical signals are respectively amplified to be compared in size to obtain an error control voltage; automatic power is locked, and a control signal is output; a pumping laser in the erbium-doped fiber amplifier is controlled by the laser drive to control the pumping current magnitude of the pumping laser, and thereby, the gain of the erbium-doped fiber amplifier is controlled. The present invention has the advantages that an automatic power locked circuit has high locking speed, the signal distrotion rate is low, locking the gain is an automatic course, and the circuit debugging work is simplified, the present invention has very high reliability, and simultaneously, the cost is saved.

Description

A kind of simulated gain control equipment and method thereof that is used for erbium-doped fiber amplifier

(1) technical field

The present invention relates to optical communication technique, relate in particular to a kind of gain of EDFA control in optical communication.

(2) background technology

Erbium-doped fiber amplifier is the important component part in the optical transmission system, is to be used for the parts that light signal amplifies in DWDM (dense wave division multipurpose) system.Increase owing to can cause remaining optical wavelength power during the optical wavelength signal decreased number of transmitting in the optical fiber, cause optical fiber non-linearity effect, influence system's optical power budget simultaneously, make dwdm system transmission performance deterioration.For fear of the generation of this situation, we need make the gain of light of erbium-doped fiber amplifier constant, make it to revert to an ordinary light yield value in very little a period of time when the optical wavelength signal decreased number.

Common gain of EDFA control method has two kinds, that is: digital gain control method and analog gain control method.

Digital gain control method decides the size of pump laser pumping current by the input and output light signal is sampled by DSP (Digital Signal Processing) or MCU (single-chip microcomputer) lock-in circuit.The shortcoming of this scheme is that precision is subjected to A/D (mould/number conversion), the influence of D/A (D/A switch) change-over circuit, response speed is slow, circuit is complicated, cost is high.As Chinese patent application number be 00102134.6, denomination of invention is " erbium-doped fiber amplifier that contains gain control circuit " disclosed a kind of technical scheme, referring to Fig. 1, between the output of light output end and erbium-doped fiber amplifier 18, second optical coupler is arranged, the output light of this second optical coupler has two-way, wherein one the tunnel be above-mentioned light output end, another road light is successively through exporting optical detection circuit 14, second mould/number conversion circuit 15, being connected to digital signal processor 13; The output of digital signal processor 13 is connected to drive circuit for laser 17 by D/A switch circuit 16, and erbium-doped fiber amplifier 18 is carried out gain controlling; Also comprise first optical coupler simultaneously, this coupler is connected between the input of light input end and erbium-doped fiber amplifier 18, its output light one road inserts the input of erbium-doped fiber amplifier 18, and another road is successively in input optical detection circuit 11, first mould/number conversion circuit 12 incoming digital signal processors 13.

The analog gain control method adopts analog circuit to realize the gain of EDFA locking, its key technical problem is how to produce control signal with analog circuit, reaches the automatic gain locking that realizes erbium-doped fiber amplifier by the control to pump laser size of current in the erbium-doped fiber amplifier.As shown in Figure 2, the simulated gain control equipment of present erbium-doped fiber amplifier, control method is: use amplifier as integrator 21, detect by 22,23 pairs of I/O luminous powers of I/O optical detection circuit, after output signal is amplified by

amplifier

24,25, by integrator 21 integrations, produce control signal and remove to control erbium-doped fiber amplifier 27 by drive circuit for laser 26.Because the gain controlling of erbium-doped fiber amplifier 27 is the integrating circuit generations by integrator 21, and integrating circuit is higher to the components and parts required precision, device has deviation slightly, will cause integrating circuit to produce bigger error, thereby make Amplifier Gain accurately to lock.So it is complicated that its shortcoming is a circuit debugging, precision is relatively poor, and is high to the device required precision.

Since existing digital gain control method exist precision be subjected to selected device influence big, response speed is slow, shortcomings such as circuit is complicated, cost height, can consider to adopt analog form to come the control amplifier gain, because it is fast that the common analog circuit that adopts has response speed, circuit is simple, low cost and other advantages.But the debugging of analog circuit is complicated, to device required precision height, production is brought inconvenience.

(3) summary of the invention

The object of the present invention is to provide a kind of simulated gain control equipment and device thereof that is used for erbium-doped fiber amplifier, it has overcome complicated, high to the device required precision shortcoming of analog control circuit debugging, have simultaneously the advantage of analog control circuit again, provide a good approach for adopting analog circuit to control erbium-doped fiber amplifier.

A kind of simulated gain control equipment that is used for erbium-doped fiber amplifier provided by the present invention, be characterized in: comprise light input, output, light input, output coupler, input, Output optical power testing circuit, two amplifiers, a comparator, an automated power lock, a drive circuit for laser and an erbium-doped fiber amplifier, wherein; Corresponding respectively light input, the output coupler of connecting of light input, output; This light input, corresponding respectively input, the Output optical power testing circuit of connecting of output coupler; This input, Output optical power testing circuit connect an amplifier respectively; Described comparator is connected with described automated power lock with this two amplifier respectively; This automated power lock is with after drive circuit for laser is connected, to erbium-doped fiber amplifier.

A kind of analog gain control method that is used for erbium-doped fiber amplifier that the present invention also provides, its process is; Light input, output carry out light input, output coupling respectively, the light signal of output detects, carries out light/electricity conversion through light input, Output optical power again, and the signal of telecommunication after will changing amplifies respectively, carry out size relatively, obtain an error control voltage, the locking automated power, and export a control signal, pass through Laser Drive, pump laser in the control erbium-doped fiber amplifier, to the control of pump laser pumping current size, thereby reach the control gain of EDFA.

Because adopt technique scheme, the present invention has: 1), make that automated power lock-in circuit lock speed is fast by the response time of control analog comparator; 2) owing to avoided A/D, the D/A that digital gain control method institute must employing, make the distorted signals greatly to reduce; 3) gain locking is an automatic process, can not be subject to the pump laser drive current---the discreteness of output power curve, simplified the debugging work of circuit; 4) has very high reliability; Circuit is realized simpler, has also saved cost simultaneously.

(4) description of drawings

Fig. 1 is the structural representation of the digital gain control device of existing erbium-doped fiber amplifier;

Fig. 2 is the structural representation of the simulated gain control equipment of existing erbium-doped fiber amplifier;

Fig. 3 for the simulated gain control equipment of erbium-doped fiber amplifier of the present invention structural representation;

Fig. 4 is the schematic diagram of luminous power testing circuit among Fig. 3;

Fig. 5 is the circuit theory diagrams of comparator among Fig. 3;

Fig. 6 is the circuit theory diagrams of automated power lock among Fig. 3;

Fig. 7 is the schematic diagram of drive circuit for laser among Fig. 3.

(5) embodiment

The analog gain control method of the erbium-doped fiber amplifier of being invented, its process is: the light input, output carries out the light input respectively, the output coupling, the light signal of output is again through the light input, Output optical power detects, carry out light/electricity conversion, and the signal of telecommunication after will changing amplifies respectively, carry out size relatively, obtain an error control voltage, the locking automated power, and export a control signal, pass through Laser Drive, pump laser in the control erbium-doped fiber amplifier to the control of pump laser pumping current size, thereby reaches the control gain of EDFA.

As shown in Figure 3, the present invention, it is the simulated gain control equipment of erbium-doped fiber amplifier, comprise light input, output 31,32, light input, output coupler 33,34, input, Output optical power testing circuit 35,36, two amplifiers 37,38, a comparator 39, an automated power lock 40, a drive circuit for laser 30 and an erbium-doped fiber amplifier 300, wherein; Light input, corresponding respectively light input, the output coupler 33,34 of connecting of output 31,32; This light input, corresponding respectively input, the Output optical power testing circuit 35,36 of connecting of output coupler 33,34; This input, Output optical power testing circuit 35,36 connect amplifier 37,38 respectively; Described comparator 39 is connected with described automated power lock 40 with this two amplifier 37,38 respectively; This automated power lock 40 is with after drive circuit for laser 30 is connected, to erbium-doped fiber amplifier 300.

As shown in Figure 4, input optical power testing circuit 35 and Output optical power testing circuit 36 all adopt this circuit.This circuit is the current/voltage-converted circuit, and wherein diode D1 is the PIN pipe of erbium-doped fiber amplifier inside, selects different resistance R 1 value, the adjustable output voltage size.Adopting model is the high-speed low-noise amplifier of MAX4164, and the luminous power of its output detects voltage and sends in the comparator 39.

As shown in Figure 5, the circuit of comparator 39, its effect is that input optical power detection voltage and error control voltage of Output optical power detection voltage generation are removed to control automated power lock-in circuit 40.Adopting model is the LM339 operational amplifier.

As shown in Figure 6, automated power lock-in circuit 40 adopts the X9C104 digital regulation resistance of Xicor company.This digital regulation resistance precision is 100 grades, and resistance is 100K (maximum), by the adjusting that high voltage VH is gone up resistance R1 and R2 resistance, produces a constant maximum controlling voltage at high voltage VH end.In the trailing edge Acquisition Error control signal of clock, the slide plate of control figure potentiometer inside slides to high voltage (VH) or to low-voltage (VL), thereby removes to control drive circuit for laser 30 at the slip output output laser control voltage of digital regulation resistance.

As shown in Figure 7, drive circuit for laser 30 adopts power operational amplifier, and model is that its output maximum current of OPA547 can reach 500mA, and can limit its maximum output current by current-limiting resistance.By regulating the resistance of resistance R 1 and R3, can realize controlling the pump laser that voltage goes to drive erbium-doped fiber amplifier inside with laser.

Claims

1. simulated gain control equipment that is used for erbium-doped fiber amplifier, it is characterized in that: comprise light input, output, light input, output coupler, input, Output optical power testing circuit, two amplifiers, a comparator, an automated power lock, a drive circuit for laser and an erbium-doped fiber amplifier, wherein;

Corresponding respectively light input, the output coupler of connecting of light input, output; This light input, corresponding respectively input, the Output optical power testing circuit of connecting of output coupler; This input, Output optical power testing circuit connect an amplifier respectively; Described comparator is connected with described automated power lock with this two amplifier respectively; This automated power lock is with after drive circuit for laser is connected, to erbium-doped fiber amplifier.

2. an analog gain control method that is used for erbium-doped fiber amplifier is characterized in that; Light input, output carry out light input, output coupling respectively, the light signal of output detects, carries out light/electricity conversion through light input, Output optical power again, and the signal of telecommunication after will changing amplifies respectively, carry out size relatively, obtain an error control voltage, the locking automated power, and export a control signal, pass through Laser Drive, pump laser in the control erbium-doped fiber amplifier, to the control of pump laser pumping current size, thereby reach the control gain of EDFA.