CN102200671B - Extinction ratio debugging device and method of optical module - Google Patents

Abstract

The invention discloses a method for realizing high precision debugging of an extinction ratio index of an optical module by using an algorithm. The optical module is arranged to work by using an APC (Automatic Program Control) loop; a modulation signal coupling mode between an LD (Laser Device) driving circuit and an LD of the optical module is set as an alternating current coupling mode; in the debugging method, the light emitting efficiency and a threshold current of a laser of the optical module are not needed to be tested in advance and the dependence on the incoming material data is also not needed; by using the debugging method, the extinction ratio of the optical module can be debugged to a target value and the debugging error is controlled within a range of +/- 1dB; the debugging method can be used for debugging the large extinction ratio of the OLT (Optical Line Terminal) optical module and assuring the precision within a commercial full temperature range; and the debugging method can be realized through full automatic control.

Description

A kind of extinction ratio debugging apparatus and adjustment method of optical module

Technical field

The present invention relates to a kind of extinction ratio debugging of optical module of the AC coupling of making a start, especially relate to debugging apparatus and the adjustment method of the extinction ratio that meets PON (EPON), OLT (optical fiber cable termination equipment) optical module.

Background technology

Along with developing rapidly of optical communication industry, optical module is widely used.The main task of optical module has been electricity/light (optical modulation), light/electricity (optical modulator) conversion.Main devices for the conversion of electricity/light has: laser instrument (LD) and laser diode (LED); Main devices for the conversion of light/electricity mainly contains: photodiode and avalanche photodide.

In Digital Optical Fibre Communication System, by " having light " and " unglazed ", carry out the binary code stream signal of corresponding transmission, this is also modal optical modulation transmission mode.This " having light " will directly affect the performance that receives optical module with the difference of " unglazed " light signal strength.In optical fiber telecommunications system, generally by delustring, recently weigh performance index of optical module.Extinction ratio refers to and is sending the ratio of " 1 " corresponding optical signal power with the corresponding optical signal power of transmission " 0 ".

Producing at present upper debugging extinction ratio method is in the situation that luminous power is debugged desired value, by laser driver, according to input binary signal output f, come drive laser to produce " 1 " and " 0 " light signal, again light signal is inputted to digital light oscillograph and measured the intensity of " 1 " and " 0 " optical signal power, and calculate " 1 " and obtain extinction ratio with the ratio of " 0 " optical signal power intensity.This delustring ratio can be increased and be reduced modulating current by laser driver to be debugged.But this kind of mode has two weak points, the one, when the intensity of each measurement " 1 " and " 0 " optical signal power ratio calculated, digital light oscillograph need to be aimed at phase place, spend the regular hour; The 2nd, digital light is oscillographic expensive, has significantly increased production cost.

Summary of the invention

Therefore the object of the invention is to solve and in prior art, debug the problem that extinction ratio debug time is long, cost is high, a kind of debugging apparatus and adjustment method of optical module extinction ratio are provided, and the method is the adjustment method of the extinction ratio of a kind of simple to operate, high precision, low cost, high efficiency PON optical module.

According to above-mentioned purpose, the invention provides a kind of adjustment method of optical module extinction ratio, described optical module comprises biasing circuit and modulation circuit, and described biasing circuit comprises first microprocessor, the first resistance, the first mirror current source, operational amplifier, NPN transistor, the second mirror current source, the second resistance, laser instrument and the first current source; Described modulation circuit comprises error analyzer, differential amplifier, the 3rd mirror current source, the second current source, the 3rd resistance, the second microprocessor and laser instrument; Wherein said first microprocessor comprises the first digital-to-analog conversion port and analog to digital conversion port, the digital-to-analog conversion port of described first microprocessor and analog to digital conversion port are N1 bit value, the conversion proportion of described the second mirror current source is 1: K, the resistance of described the second resistance is R, and the resistance of described the 3rd resistance is R _mODthe conversion proportion of described the 3rd mirror current source is 1: M, the digital-to-analog conversion port of described the second microprocessor and analog to digital conversion port are N2 bit value, and described adjustment method comprises the following steps: step 1: optical module to be debugged is inserted in an evaluation board; Step 2 a: light power meter is connected to a computing machine and described optical module to be debugged, wherein said light power meter comprises light mouth and GBIP interface, described light mouth is connected to described optical module to be debugged in order to measure luminous power, described GBIP interface is connected to described computing machine in order to measured optical power value is sent to described computing machine; Step 3: described evaluation board is placed in to a constant temperature oven; Step 4: constant temperature oven is set to normal temperature; Step 5: drive described laser instrument with a laser driver, the reference voltage of described laser driver is V _rEF; Step 6: the numerical value of setting described first microprocessor analog to digital conversion port is DAC_0, reads corresponding light power P from light power meter ₀, from first microprocessor, gather the value ADC_0 of its digital-to-analog conversion port, according to equation

calculate bias current I now _{bIAS_}(0), and by result of calculation deposit a register in; Step 7: adjust the numerical value of described first microprocessor analog to digital conversion port, luminous power is debugged to target light performance number, the value that obtains described first microprocessor analog to digital conversion port is DAC_1, from light power meter, reading corresponding light power is P ₁, from first microprocessor device, gather the value ADC_1 of its digital-to-analog conversion port, according to equation

calculate bias current I now _{bIAS_}(1), and by result of calculation deposit described register in; Step 8: the luminous power P that step 5 and step 6 are read ₀, P ₁and the bias current I calculating _{bIAS_}and I (0) _{bIAS_}(1) substitution equation

calculate the luminescence efficiency SE of described optical module, and deposit result of calculation in described register; Step 9: according to equation

calculate average light power, and the luminescence efficiency SE substitution equation of the described optical module that result of calculation and step 7 are calculated

calculate debugging electric current I _mOD, and deposit result of calculation in described register; Step 10: provide respectively and grow " 0 " and grow " 1 " signal and send into optical module with error analyzer, until the luminous power ratio of the luminous power of optical module when growing " 1 " during divided by length " 0 " is target delustring ratio, obtain the target debugging electric current I of described optical module when target extinction ratio _mODT; Step 11: by the target debugging electric current I of step 9 debugging _mODTdebugging electric current I with step 8 calculating _mODsubstitution equation

calculate penalty coefficient; Step 12: the debugging electric current I that step 8 is calculated _mODpenalty coefficient C substitution equation with step 10 calculating

calculating when target extinction ratio described in the numerical value DAC of the second microprocessor analog to digital conversion port _{_ MOD}, and deposit result of calculation in register; Step 13: record the temperature of current first microprocessor, deposit register in.

According to above-mentioned purpose, the present invention also provides a kind of debugging apparatus of optical module extinction ratio, comprising: computing machine, described computing machine comprises I ²c parallel interface, GBIP interface and equipment control software; Optical module, described optical module comprises biasing circuit and modulation circuit, and described biasing circuit is in order to set the bias current of described optical module, and described modulation circuit is in order to set the modulating current of described optical module; Laser driver, in order to drive described optical module; Evaluation board, described optical module is inserted in described evaluation board, and described evaluation board comprises that one is connected to the power supply port of DC power supply; Constant temperature oven, for placing described evaluation board; Light power meter, described light power meter comprises GBIP interface and Guang Kou, described light mouth is connected to described optical module, in order to read the luminous power of described optical module; Described GBIP interface is connected to described computing machine, in order to the luminous power of described optical module is sent to described computing machine; Wherein said biasing circuit comprises first microprocessor, the first resistance, the first mirror current source, operational amplifier, NPN transistor, the second mirror current source, resistance, laser instrument and the first current source; Described modulation circuit comprises error analyzer, differential amplifier, the 3rd mirror current source, the second current source, the 3rd resistance, the second microprocessor and described laser instrument; Wherein said first microprocessor comprises analog to digital conversion port and digital-to-analog conversion port, and its digital-to-analog conversion port is exported the first electric current; Described the first resistance comprises first end and the second end, and its first end is connected to the digital-to-analog conversion port of described first microprocessor, to receive described the first electric current; Described the first mirror current source has first input end, the second input end and output terminal, described first input end is connected to the second end of described the first resistance, to receive described the first electric current, described the second input end is connected to described the first current source, the second current signal providing to receive described the first current source, described output terminal provides first mirror image current; Described operational amplifier receives the first mirror image current of described the first mirror current source output, and after being amplified, obtains an amplifying signal; Described NPN transistor comprises base stage, collector and emitter, described amplifying signal is transferred into described base stage, in order to drive described NPN transistor, described collector is connected to described laser instrument, described emitter is connected to described the second mirror current source, the described bias current of the driven rear generation of described NPN transistor, in order to set the average light power of described laser instrument; Described the second mirror current source comprises input end and output terminal, and its input end is connected to the emitter of described NPN transistor, in order to receive described bias current, and described bias current is changed into the second image current; Its output terminal is connected to one end of the second resistance; Described the second resistance comprises first end and the second end, and its first end is connected to the output terminal of described the second mirror current source, in order to receive described the second image current, and is translated into the analog to digital conversion port that voltage signal is delivered to described microprocessor; Its second end ground connection; Described the second microprocessor comprises digital-to-analog conversion port, and described digital-to-analog conversion port is exported the second electric current; Described the 3rd resistance comprises first end and the second end, and described first end is connected to the digital-to-analog conversion port of described the second microprocessor, and described the second end is connected to the reference voltage of described laser driver; Described the second current source comprises first end and the second end, and described first end is connected to the second end of described the 3rd resistance; Described the 3rd mirror current source comprises first end and the second end, and described first end is connected to the second end of described the second current source, and described the second end provides the 3rd image current; Described error analyzer comprises the first output terminal and the second output terminal, in order to the binary code stream of " 1 " and " 0 " to be provided respectively; Described differential amplifier comprises first input end, the second input end, the 3rd input end and output terminal, and its first input end and the second input end are connected to respectively described error analyzer, in order to receive described binary code stream; Described the 3rd input end is connected to the second end of described the 3rd mirror current source, and in order to receive described the 3rd image current, described output terminal provides described modulating current to described laser instrument.

The present invention has omitted oscillograph, only by the extinction ratio that light power meter detects, algorithm calculates to realize optical module, is a kind of high precision, high-level efficiency, produces and debug cheaply.

Accompanying drawing explanation:

Fig. 1 is the schematic diagram that is related between the luminous power of optical module and electric current.

Fig. 2 illustrates the biasing circuit theory diagram of optical module according to an embodiment of the invention.

Fig. 3 illustrates optical module modulation circuit theory diagram according to an embodiment of the invention.

Fig. 4 illustrates optical module extinction ratio debugging apparatus according to an embodiment of the invention.

Embodiment:

Below in conjunction with accompanying drawing, take that to drive the 1.25G EPON OLT optical module that chip is MAX3738 be example, modulating device of the present invention and adjustment method are elaborated and are demonstrated.

Fig. 1 is the schematic diagram that is related between the luminous power of optical module and electric current.As shown in Figure 1, bias current is set average light power, and modulation signal drives modulating current to be carried on bias current and to shake with positive negative direction, and obtains " 1 " and " 0 " light signal in conjunction with binary code stream.

Fig. 2 illustrates the biasing circuit theory diagram of optical module according to an embodiment of the invention.As shown in Figure 2, the biasing circuit theory diagram of optical module comprises power supply VCC, first microprocessor (MCU) 1, the first resistance 2, the first mirror current source 3, operational amplifier 4, NPN transistor 5, the second mirror current source 6; The second resistance 7, laser instrument 8 and the first current source 9; Wherein first microprocessor 1 comprises digital-to-analog conversion (A/D) port and analog to digital conversion (D/A) port, and first microprocessor 1 is exported the first electric current by digital-to-analog conversion port; The first resistance 2 is connected to the digital-to-analog conversion port of first microprocessor 1, receives the first electric current, and this first electric current is sent to the first mirror current source 3; The first mirror current source 3 comprises first input end, the second input end and output terminal, and its first input end receives described the first electric current, and its second input end receives the second current signal that the first current source 9 provides, its output terminal output first mirror image current; Operational amplifier 4 receives the first mirror image current of the first mirror current source 3 outputs, and after being amplified, obtains an amplifying signal, is delivered to the control utmost point (base stage) of NPN transistor 5, in order to driving N PN transistor 5; The collector of NPN transistor 5 is connected to laser instrument 8, and its emitter is connected to the second mirror current source 6; The driven rear generation of NPN transistor 5 is in order to control the bias current I of laser instrument 8 _bIAS; The second mirror current source 6 receives bias current I _bIAS, and bias current being changed into the second image current, this second image current is flowed through after the second resistance 7 and is converted into the analog to digital conversion port that voltage signal is transported to microprocessor 1; The first current source 9 and laser instrument 8 are all connected to power supply VCC.

In one embodiment, the conversion proportion of the first mirror current source 3 is 1: 2, and the conversion proportion of the second mirror current source 6 is 1: K.The voltage signal at the second resistance 7 two ends is

wherein R is the resistance value of the second resistance 7.

In the present embodiment, the full width voltage of the analog to digital conversion of first microprocessor 1 (A/D) port and digital-to-analog conversion (D/A) port is 2.5V, and analog to digital conversion is 12 bits,

$\frac{R\&times;\frac{I_{\mathrm{BIAS}}}{K}}{2.5}=\frac{\mathrm{<figure-callout\; id="2"\; label="ADC"\; filenames="HDA0000057267590000021.png,HDA0000057267590000031.png"\; state="\{\{state\}\}">ADC</figure-callout>}}{2^{12}}=\frac{\mathrm{ADC}}{4096}$

So we obtain bias current I _bIAScomputing formula be:

$I_{\mathrm{BIAS}}=\frac{\mathrm{ADC}\&times;2.5\&times;K}{4096\&times;R}---\left(1\right)$

Wherein ADC is the numerical value of first microprocessor 1 analog to digital conversion port.We just can, by setting the numerical value of first microprocessor 1 analog to digital conversion port, calculate the at this moment bias current I of optical module from equation (1) like this _bIAS.

And as can see from Figure 1, the optical module of AC coupling is to set average light power by bias current, modulation signal drives modulating current to be carried on bias current and to shake with positive negative direction, thereby obtains " 1 " and " 0 " light signal.Because extinction ratio is the ratio of " 1 " and " 0 " optical signal power intensity, the average light power that defines optical module is P again _aVG, extinction ratio is ER, and the luminescence efficiency of laser instrument LD is SE, and " 1 " is respectively P with " 0 " optical signal power intensity ₁, P ₀, can obtain following equation:

$\mathrm{SE}=\frac{P_1-P_0}{I_{\mathrm{BIAS}\_}\left(1\right)-I_{\mathrm{BIAS}\_}\left(0\right)}---\left(2\right)$

$\mathrm{ER}=10\&times;\lg \frac{P_1}{P_0}---\left(3\right)$

$P_0=2\&times;\frac{P_{\mathrm{AVG}}}{\frac{P_1}{P_0}+1}---\left(4\right)$

${\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="HDA0000057267590000031.png"\; state="\{\{state\}\}">P</figure-callout>}}_1=\frac{2\&times;P_{\mathrm{AVG}}\&times;\frac{P_1}{P_0}}{\frac{P_1}{P_0}+1}---\left(5\right)$

$I_{\mathrm{MOD}}=\frac{P_1-P_0}{\mathrm{SE}}---\left(6\right)$

Arranging equation (3) obtains:

$\frac{P_1}{P_0}={10}^{\frac{\mathrm{ER}}{10}}---\left(7\right)$

Equation (4), (5) and (7) are brought into equation (6) and are obtained:

$I_{\mathrm{MOD}}=\frac{2\&times;P_{\mathrm{AVG}}\&times;({10}^{\frac{\mathrm{ER}}{10}}-1)}{\frac{\mathrm{<figure-callout\; id="1"\; label="SE"\; filenames="HDA0000057267590000031.png"\; state="\{\{state\}\}">SE</figure-callout>}}{1+{10}^{\frac{\mathrm{ER}}{10}}}}---\left(8\right)$

With 10 optical modules that printed circuit board (PCB) field engineering (PCBA) is identical, under lab test the debugging electric current I while debugging out target extinction ratio by oscillograph _mODwith by above formula, calculate I _mODthe value penalty coefficient C while obtaining this PCBA with adjustment method of the present invention debugging that is divided by.

Fig. 3 illustrates optical module modulation circuit theory diagram according to an embodiment of the invention.As shown in Figure 3, optical module modulation circuit theory diagram comprises: power supply VCC, error analyzer 1, differential amplifier 2, the 3rd mirror current source 3, the second current source 4, the 3rd resistance 5, the second microprocessor (MCU) 6, laser instrument (LD) 7.Wherein the second microprocessor 6 comprises analog to digital conversion port and digital-to-analog conversion port, and its analog to digital conversion port receives setting value (not shown), and its digital-to-analog conversion port is exported the second electric current; The 3rd resistance 5 comprises first end and the second end, and its first end is connected to the digital-to-analog conversion port of the second microprocessor 6, and its second end is connected to the reference voltage V of laser driver MAX3738 _{rEF_MAX3738}; The second current source 4 comprises first end and the second end, and its first end is connected to the second end of the 3rd resistance 5; The 3rd mirror current source 3 comprises first end and the second end, and its first end is connected to the second end of the second current source 4, and its second end provides the 3rd image current; Error analyzer 1 comprises the first output terminal and the second output terminal, in order to the binary code stream of " 1 " and " 0 " to be provided respectively; Described differential amplifier comprises first input end, the second input end, the 3rd input end and output terminal, and its first input end and the second input end are connected to respectively error analyzer 1, in order to receive described binary code stream; Its 3rd input end is connected to the second end of the 3rd mirror current source 3, and in order to receive described the 3rd image current, its output terminal provides modulating current I _mODto laser instrument 7; Differential amplifier 2 and laser instrument 7 are all connected to power supply VCC.

The conversion proportion of the 3rd mirror current source is 1 in the present embodiment: M.The digital-to-analog conversion port of the second microprocessor and analog to digital conversion port are 12 bit values.

In one embodiment, first microprocessor and the second microprocessor are same microprocessor.

By setting the numerical value DAC of the second correct microprocessor 6 analog to digital conversion ports _{_ MOD}, the modulating current I in the time of can obtaining target extinction ratio _mODT; Therefore by the numerical value DAC of the analog to digital conversion port of the second correct microprocessor 6 is set _{_ MOD}just can obtain target extinction ratio.And can obtain from Fig. 3

$\frac{{\mathrm{DAC}\_}_{\mathrm{MOD}}}{4096}=\frac{V_{\mathrm{REF}\_\mathrm{MAX}3738}-\frac{R_{\mathrm{MOD}}\&times;I_{\mathrm{MOD}}\&times;C\&times;1000}{M}}{2.5},$ ?

${\mathrm{DAC}\_}_{\mathrm{MOD}}=\frac{(V_{\mathrm{REF}\_\mathrm{MAX}3738}-\frac{R_{\mathrm{MOD}}\&times;I_{\mathrm{MOD}}\&times;C\&times;1000}{M})\&times;4096}{2.5}---\left(9\right)$

Therefore by biasing circuit shown in Fig. 2, obtain bias current I _mODin conjunction with modulation circuit shown in Fig. 3, can obtain the second microprocessor 6 analog to digital conversion port numerical value under target extinction ratio afterwards.

Fig. 4 illustrates optical module extinction ratio debugging apparatus according to an embodiment of the invention.As shown in Figure 4, described debugging apparatus comprises computing machine, and described computing machine comprises I ²c parallel interface, GBIP interface and equipment control software; Optical module, described optical module comprises biasing circuit and modulation circuit, and described biasing circuit is in order to set the bias current of described optical module, and described modulation circuit is in order to set the modulating current of described optical module; Evaluation board, described optical module is inserted in described evaluation board, and described evaluation board comprises that one is connected to the power supply port (not shown) of DC power supply, in order to guarantee each chip normal operation in optical module; Light power meter, comprises light mouth and GBIP interface, and its light mouth is connected to optical module by optical fiber, and in order to read the luminous power of optical module, its GBIP interface is connected to the GBIP interface of computing machine, so that the luminous power of described optical module is sent to computing machine; Error analyzer, is connected to evaluation board by coaxial cable.Wherein optical module comprises biasing circuit and modulation circuit.

In one embodiment, debugging apparatus also comprises constant temperature oven, for placing evaluation board; Laser driver, in order to drive optical module.

The present invention also provides a kind of adjustment method of optical module extinction ratio, described optical module comprises biasing circuit and modulation circuit, and described biasing circuit comprises first microprocessor, the first resistance, the first mirror current source, operational amplifier, NPN transistor, the second mirror current source, the second resistance, laser instrument and the first current source; Described modulation circuit comprises error analyzer, differential amplifier, the 3rd mirror current source, the second current source, the 3rd resistance, the second microprocessor and laser instrument; Wherein said first microprocessor comprises the first digital-to-analog conversion port and analog to digital conversion port, the digital-to-analog conversion port of described first microprocessor and analog to digital conversion port are N1 bit value, the conversion proportion of described the second mirror current source is 1: K, the resistance of described the second resistance is R, and the resistance of described the 3rd resistance is R _mOD, the conversion proportion of described the 3rd mirror current source is 1: M, and the digital-to-analog conversion port of described the second microprocessor and analog to digital conversion port are N2 bit value, described adjustment method comprises the following steps:

Step 1: optical module to be debugged is inserted in evaluation board, and described debugging optical module is connected with the golden finger that is connected to of described evaluation board;

Step 2: light power meter is connected to computing machine and described optical module to be debugged, wherein said light power meter comprises light mouth and GBIP interface, described light mouth is connected to described optical module to be debugged in order to measure luminous power, described GBIP interface is connected to a computing machine in order to measured optical power value is sent to described computing machine;

Step 3: described evaluation board is placed in to a constant temperature oven;

Step 4: constant temperature oven is set to normal temperature;

Step 5: drive described laser instrument with a laser driver, the reference voltage of described laser driver is V _rEF;

Step 6: the numerical value of setting described first microprocessor analog to digital conversion port is DAC_0, reads corresponding light power P from light power meter ₀, from first microprocessor, gather the value ADC_0 of its digital-to-analog conversion port, according to equation calculate bias current I now _{bIAS_}(0), and by result of calculation deposit a register in;

Step 7: adjust the numerical value of described first microprocessor analog to digital conversion port, luminous power is debugged to target light performance number, the value that obtains described first microprocessor analog to digital conversion port is DAC_1, from light power meter, reading corresponding light power is P ₁, from first microprocessor device, gather the value ADC_1 of its digital-to-analog conversion port, according to equation calculate bias current I now _{bIAS_}(1), and by result of calculation deposit described register in;

Step 8: the luminous power P that step 5 and step 6 are read ₀, P ₁and the bias current I calculating _{bIAS_}and I (0) _{bIAS_}(1) substitution equation

calculate the luminescence efficiency SE of described optical module, and deposit result of calculation in described register;

Step 9: according to equation

calculate average light power, and by result of calculation and step 7

The luminescence efficiency SE substitution equation of the described optical module calculating

calculate debugging electric current I _mOD, and deposit result of calculation in described register;

Step 10: debug out the target debugging electric current I of described optical module when the target extinction ratio with oscillograph _mODT;

Step 11: by the target debugging electric current I of step 9 debugging _mODTdebugging electric current I with step 8 calculating _mODsubstitution equation

calculate penalty coefficient;

Step 12: the debugging electric current I that step 8 is calculated _mODpenalty coefficient C substitution equation with step 10 calculating

calculating when target extinction ratio described in the numerical value DAC of the second microprocessor analog to digital conversion port _{_ MOD}, and deposit result of calculation in register;

Step 13: record the temperature of current first microprocessor, deposit register in;

Step 14: constant temperature oven is set to low temperature, repeating step 6～step 13.

In the present embodiment, the digital-to-analog conversion port that first microprocessor and the second microprocessor go and analog to digital conversion port are 12 bit values; The driving chip that laser driver is MAX3738 for model.

Use above-mentioned adjustment method to carry out low temperature, normal temperature and high temperature test to the extinction ratio of optical module, obtain as the experimental results of following table 1, table 2 and table 3.Wherein table 1 is low temperature test test data table, and table 2 is normal temperature test data of experiment table; Table 3 high temperature test data of experiment table.Wherein BOSA is optical transceiver module interface module, and the dB that AOP is average light power represents value, and Pavg is average light power, and target_ER is that the dB of target extinction ratio represents value, I _mODfor debugging electric current, IMOD_DAC is the binary form indicating value of debugging electric current, and test_ER represents value for debugging the dB of extinction ratio, and Δ (test_ER-target_ER) is the difference of target extinction ratio and debugging extinction ratio.

Table 1

Table 2

Table 3

From the data of above table 1, table 2 and table 3, can find out, adopt optical module extinction ratio debugging apparatus of the present invention and method, its debugging error, in +/-1dB, has greatly guaranteed adjustment accuracy.And this debugging apparatus and adjustment method, without using oscillograph, greatly reduce cost.

Need statement, foregoing invention content and embodiment are intended to prove the practical application of technical scheme provided by the present invention, should not be construed as limiting the scope of the present invention.Those skilled in the art are in spirit of the present invention and principle, when doing various modifications, be equal to and replace or improve.Protection scope of the present invention is as the criterion with appended claims.

Claims (21)

1. the adjustment method of an optical module extinction ratio, laser driver is in order to drive described optical module, described optical module comprises biasing circuit and modulation circuit, described biasing circuit is in order to set the bias current of described optical module, described modulation circuit is in order to set the modulating current of described optical module, it is characterized in that, described adjustment method comprises the following steps:

Step 1: optical module to be debugged is inserted in an evaluation board; The biasing circuit of described optical module comprises first microprocessor, the first resistance, the first mirror current source, operational amplifier, NPN transistor, the second mirror current source, the second resistance, the first laser instrument and the first current source, described modulation circuit comprises error analyzer, differential amplifier, the 3rd mirror current source, the second current source, the 3rd resistance, the second microprocessor and second laser, the conversion proportion of described the second mirror current source is 1:K, and the conversion proportion of described the 3rd mirror current source is 1:M; Described first microprocessor comprises analog to digital conversion port and digital-to-analog conversion port, and its digital-to-analog conversion port is exported the first electric current; Described the first resistance comprises first end and the second end, and its first end is connected to the digital-to-analog conversion port of described first microprocessor, to receive described the first electric current; Described the first mirror current source has first input end, the second input end and output terminal, its first input end is connected to the second end of described the first resistance, to receive described the first electric current, its second input end is connected to described the first current source, the second current signal providing to receive described the first current source, its output terminal provides first mirror image current; Described operational amplifier receives the first mirror image current of described the first mirror current source output, and after being amplified, obtains an amplifying signal; Described NPN transistor comprises base stage, collector and emitter, described amplifying signal is transferred into described base stage, in order to drive described NPN transistor, described collector is connected to described the first laser instrument, described emitter is connected to described the second mirror current source, the described bias current of the driven rear generation of described NPN transistor, in order to set the average light power of described the first laser instrument; Described the second mirror current source comprises input end and output terminal, its input end is connected to the emitter of described NPN transistor, in order to receive described bias current, and described bias current is changed into the second image current, its output terminal is connected to the first end of the second resistance; Described the second resistance comprises first end and the second end, its first end is connected to the output terminal of described the second mirror current source, in order to receive described the second image current, and be translated into the analog to digital conversion port that voltage signal is delivered to described microprocessor, its second end ground connection; Described the second microprocessor comprises digital-to-analog conversion port, and its digital-to-analog conversion port is exported the second electric current; Described the 3rd resistance comprises first end and the second end, and its first end is connected to the digital-to-analog conversion port of described the second microprocessor, and its second end is connected to the reference voltage of described laser driver; Described the second current source comprises first end and the second end, and its first end is connected to the second end of described the 3rd resistance; Described the 3rd mirror current source comprises first end and the second end, and its first end is connected to the second end of described the second current source, and its second end provides the 3rd image current; Described error analyzer comprises the first output terminal and the second output terminal, in order to the binary code stream of " 1 " and " 0 " to be provided respectively; Described differential amplifier comprises first input end, the second input end, the 3rd input end and output terminal, its first input end and the second input end are connected to respectively described error analyzer, in order to receive described binary code stream, its the 3rd input end is connected to the second end of described the 3rd mirror current source, in order to receive described the 3rd image current, its output terminal provides described modulating current to described second laser;

Step 2 a: light power meter is connected to a computing machine and described optical module to be debugged, wherein said light power meter comprises light mouth and GBIP interface, described light mouth is connected to described optical module to be debugged in order to measure luminous power, described GBIP interface is connected to described computing machine in order to measured optical power value is sent to described computing machine;

Step 3: described evaluation board is placed in to a constant temperature oven;

Step 4: constant temperature oven is set to normal temperature;

Step 5: drive described second laser with described laser driver, described laser driver is that model is the driving chip of MAX3738, and the reference voltage of described laser driver is V _{rEF_max3738};

Step 6: the numerical value of setting first microprocessor analog to digital conversion port is DAC_0, reads corresponding light power P from light power meter ₀, from first microprocessor, gather the value ADC_0 of its digital-to-analog conversion port, according to equation

calculate bias current I now _{bIAS_}(0), and deposit result of calculation in a register, wherein, the ADC in equation is the numerical value of the digital-to-analog conversion port that gathers on first microprocessor, R is the resistance of the second resistance in biasing circuit, and N1 refers to that the digital-to-analog conversion port of first microprocessor and analog to digital conversion port are N1 bit value;

Step 7: adjust the numerical value of described first microprocessor analog to digital conversion port, luminous power is debugged to target light performance number, the value that obtains described first microprocessor analog to digital conversion port is DAC_1, from light power meter, reading corresponding light power is P ₁, the value ADC_1 of its digital-to-analog conversion port of Bian collection from first microprocessor device, according to equation calculate bias current I now _{bIAS_}(1), and by result of calculation deposit described register in;

Step 8: the luminous power P that step 6 and step 7 are read ₀, P ₁and the bias current I calculating _{bIAS_}and I (0) _{bIAS_}(1) substitution equation

calculate the luminescence efficiency SE of described optical module, and deposit result of calculation in described register;

Step 9: according to equation

calculate average light power, and the luminescence efficiency SE substitution equation of the described optical module that result of calculation and step 8 are calculated

calculate debugging electric current I _mOD, and deposit result of calculation in described register, wherein, the ER in equation is extinction ratio;

Step 10: provide respectively and grow " 0 " and grow " 1 " signal and send into optical module with error analyzer, until the luminous power ratio of the luminous power of optical module when growing " 1 " during divided by length " 0 " is target delustring ratio, obtain the target debugging electric current I of described optical module when target extinction ratio _mODT; Step 11: by the target debugging electric current I of step 10 debugging _mODTdebugging electric current I with step 9 calculating _mODsubstitution equation

calculate penalty coefficient;

Step 12: the debugging electric current I that step 9 is calculated _mODpenalty coefficient C substitution equation with step 11 calculating ${\mathrm{DAC}}_{\_\mathrm{MOD}}=\frac{(V_{\mathrm{REF}\_\mathrm{MAX}3738}-\frac{R_{\mathrm{MOD}}\&times;I_{\mathrm{MOD}}\&times;C\&times;1000}{M})\&times;2^{N2}}{2.5}$ Calculating when target extinction ratio, the numerical value DAC of described the second microprocessor analog to digital conversion port _{_ MOD}, and deposit result of calculation in register, and wherein, the V in equation _{rEF_max3738}for described laser driver is that model is the reference voltage of the driving chip of MAX3738, R _mODfor the resistance of the 3rd resistance of modulation circuit, N2 refers to that the digital-to-analog conversion port of the second microprocessor and analog to digital conversion port are N2 bit value;

Step 13: record the temperature of current first microprocessor, deposit register in.

2. adjustment method as claimed in claim 1, is characterized in that, further comprises:

Step 14: constant temperature oven is set to low temperature, repeating step 6～step 13.

3. adjustment method as claimed in claim 1, is characterized in that, further comprises:

Step 15: constant temperature oven is set as to high temperature, repeating step 6～step 13.

4. adjustment method as claimed in claim 1, is characterized in that, wherein the digital-to-analog conversion port of first microprocessor and analog to digital conversion port are 12 bit values.

5. adjustment method as claimed in claim 1, is characterized in that, wherein the digital-to-analog conversion port of the second microprocessor and analog to digital conversion port are 12 bit values.

6. adjustment method as claimed in claim 5, is characterized in that, the full width voltage of the analog to digital conversion port of wherein said microprocessor and digital-to-analog conversion port is 2.5V.

7. the adjustment method as described in one of claim 1 to 6, its spy is being, wherein said optical module is connected with the golden finger that is connected to of described evaluation board.

8. the adjustment method as described in one of claim 1 to 6, its spy is being, the conversion proportion of wherein said the first mirror current source is 1:2.

9. the adjustment method as described in one of claim 1 to 6, its spy is being, wherein said computing machine comprises I2C parallel interface, GBIP interface and equipment control software.

10. the adjustment method as described in one of claim 1 to 6, its spy is being, wherein said evaluation board comprises that one is connected to the power supply port of DC power supply.

11. adjustment methods as described in one of claim 1 to 6, its spy is being, the light mouth of wherein said light power meter is connected to described optical module by optical fiber.

12. adjustment methods as described in one of claim 1 to 6, its spy is being, wherein said error analyzer is connected to described evaluation board by coaxial cable.

The debugging apparatus of 13. 1 kinds of optical module extinction ratios, is characterized in that, described debugging apparatus comprises:

Computing machine, described computing machine comprises I ²c parallel interface, GBIP interface and equipment control software;

Optical module, described optical module comprises biasing circuit and modulation circuit, and described biasing circuit is in order to set the bias current of described optical module, and described modulation circuit is in order to set the modulating current of described optical module;

Laser driver, in order to drive described optical module;

Evaluation board, described optical module is inserted in described evaluation board, and described evaluation board comprises that one is connected to the power supply port of DC power supply;

Constant temperature oven, for placing described evaluation board;

Light power meter, described light power meter comprises GBIP interface and Guang Kou, described light mouth is connected to described optical module, in order to read the luminous power of described optical module; Described GBIP interface is connected to described computing machine, in order to the luminous power of described optical module is sent to described computing machine;

Described biasing circuit comprises first microprocessor, the first resistance, the first mirror current source, operational amplifier, NPN transistor, the second mirror current source, the second resistance, the first laser instrument and the first current source; Described modulation circuit comprises error analyzer, differential amplifier, the 3rd mirror current source, the second current source, the 3rd resistance, the second microprocessor and second laser; Described first microprocessor comprises analog to digital conversion port and digital-to-analog conversion port, and its digital-to-analog conversion port is exported the first electric current; Described the first resistance comprises first end and the second end, and its first end is connected to the digital-to-analog conversion port of described first microprocessor, to receive described the first electric current; Described the first mirror current source has first input end, the second input end and output terminal, its first input end is connected to the second end of described the first resistance, to receive described the first electric current, its second input end is connected to described the first current source, the second current signal providing to receive described the first current source, its output terminal provides first mirror image current; Described operational amplifier receives the first mirror image current of described the first mirror current source output, and after being amplified, obtains an amplifying signal; Described NPN transistor comprises base stage, collector and emitter, described amplifying signal is transferred into described base stage, in order to drive described NPN transistor, described collector is connected to described the first laser instrument, described emitter is connected to described the second mirror current source, the described bias current of the driven rear generation of described NPN transistor, in order to set the average light power of described the first laser instrument; Described the second mirror current source comprises input end and output terminal, its input end is connected to the emitter of described NPN transistor, in order to receive described bias current, and described bias current is changed into the second image current, its output terminal is connected to the first end of the second resistance; Described the second resistance comprises first end and the second end, its first end is connected to the output terminal of described the second mirror current source, in order to receive described the second image current, and be translated into the analog to digital conversion port that voltage signal is delivered to described microprocessor, its second end ground connection; Described the second microprocessor comprises digital-to-analog conversion port, and its digital-to-analog conversion port is exported the second electric current; Described the 3rd resistance comprises first end and the second end, and its first end is connected to the digital-to-analog conversion port of described the second microprocessor, and its second end is connected to the reference voltage of described laser driver; Described the second current source comprises first end and the second end, and its first end is connected to the second end of described the 3rd resistance; Described the 3rd mirror current source comprises first end and the second end, and its first end is connected to the second end of described the second current source, and its second end provides the 3rd image current; Described error analyzer comprises the first output terminal and the second output terminal, in order to the binary code stream of " 1 " and " 0 " to be provided respectively; Described differential amplifier comprises first input end, the second input end, the 3rd input end and output terminal, its first input end and the second input end are connected to respectively described error analyzer, in order to receive described binary code stream, its the 3rd input end is connected to the second end of described the 3rd mirror current source, in order to receive described the 3rd image current, its output terminal provides described modulating current to described second laser.

14. debugging apparatus as claimed in claim 13, is characterized in that, the digital-to-analog conversion port of wherein said first microprocessor and analog to digital conversion port are 12 bit values.

15. debugging apparatus as claimed in claim 14, is characterized in that, the digital-to-analog conversion port of wherein said the second microprocessor and analog to digital conversion port are 12 bit values.

16. debugging apparatus as claimed in claim 15, is characterized in that, the full width voltage of the digital-to-analog conversion port of wherein said microprocessor and analog to digital conversion port is 2.5V.

17. debugging apparatus as claimed in claim 13, is characterized in that, wherein said laser driver is that model is the driving chip of MAX3738.

18. debugging apparatus as claimed in claim 13, is characterized in that, wherein said optical module is connected with the golden finger that is connected to of described evaluation board.

19. debugging apparatus as claimed in claim 13, is characterized in that, wherein said error analyzer is connected to described evaluation board by coaxial cable, to provide binary code stream to described optical module.

20. debugging apparatus as claimed in claim 13, is characterized in that, the light mouth of wherein said light power meter is connected to described optical module by optical fiber.

21. debugging apparatus as claimed in claim 13, is characterized in that, the conversion proportion of wherein said the first mirror current source is 1:2.

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