CN1278462C - Method for measuring semiconductor laser chip frequency response - Google Patents

Abstract

The present invention relates to a method for measuring frequency response of a semiconductor laser chip, which comprises the following steps: microstrip lines are manufactured; a metal base plate for testing and calibrating is manufactured; the microstrip lines are welded on the metal base plate, and a radio frequency coaxial connector and a match resistor matched with a vector network analyzer are welded on the base plate to form a test clamp and a calibration clamp; a chip welded on a heat sink is welded on a measurement clamp to manufacture a device to be measured; the vector network analyzer and an optical detector measure the frequency response of the device to be measured; the frequency response of the clamps is measured and calibrated; the parameters of the frequency response of the clamps are measured and calibrated; the transfer matrix of the test clamp is obtained by using the following formulas; the frequency response of the test clamp is obtained. A test system is utilized to measure the network parameters of the device to be measured namely the frequency response of the device to be measured, and the frequency response of the test clamp is subtracted to obtain the frequency response of the chip.

Description

The method of measurement of semiconductor laser chip frequency response

Technical field

The present invention relates to a kind of chip method of measurement, particularly utilize of the measurement of microwave radio technology the response of a kind of semiconductor laser (DFB-LD or FP-LD) chip frequency.

Background technology

For semiconductor laser chip, must be through ability practical application behind the subsequent technique (such as encapsulation, modularization).But before carrying out these technologies, must know the bandwidth of chip itself, could provide necessary foundation for encapsulation waits.

At present, the bandwidth measurement of chip mainly contains following two kinds of methods:

(1) chip is welded on special construction heat sink, relies on probe that the test signal that vector network analyzer produces is applied on the chip, calibrate at last.This method precision is very high, can carry out high-frequency test, can reach the test specification (as 22GHz) of network analysis in theory.Shortcoming is a complicated operation, and its middle probe costs an arm and a leg.

(2) chip is welded in heat sink on, carry out peripheral circuit; According to the manual testing of lightwave signal analyzer, utilize the lightwave signal analyzer to measure.Shortcoming is a low precision, can not carry out high frequency measurement.

Summary of the invention

The objective of the invention is to propose a kind of method of measurement of semiconductor laser chip frequency response, adopt this method bandwidth of measured chip quickly and accurately.

The method of measurement of a kind of semiconductor laser chip frequency response of the present invention is characterized in that, comprises the steps:

(1) makes microstrip line;

(2) make test and calibration metal base plate;

(3) microstrip line is welded on the metal base plate, and burn-on radio frequency (RF) coaxial connector and build-out resistor with vector network analyzer coupling, test fixture and calibration clamp made;

(4) be welded in and make measured device on the measured material being welded in chip on heat sink;

(5) add the frequency response that photo-detector is measured measured device with vector network analyzer;

(6) frequency response of measurement calibration clamp is $S_m=\left(\begin{array}{cc}{s}_{m11}& s_{m12}\\ s_{m21}& s_{m22}\end{array}\right)$ And use formula

$\left\{\begin{array}{c}{a}_m=(1+s_{m11}-s_{m22}+|s_m\left|\right)/2s_{m21}\\ b_m=(1+s_{m11}+s_{m22}+|s_m\left|\right)/2s_{m21}\\ c_m=(1-s_{m11}-s_{m22}+|s_m\left|\right)/2s_{m21}\\ d_m=(1-s_{m11}+s_{m22}-|s_m\left|\right)/2s_{m21}\end{array}\right.$ Be converted into calibration clamp (B) transfer matrix $A_m=\left(\begin{array}{cc}{a}_m& b_m\\ c_m& d_m\end{array}\right)$ ;

(7) s of the frequency response of measurement calibration clamp ₁₁Parameter;

(8) obtain the transfer matrix of test fixture with following formula $A=\left(\begin{array}{cc}a& b\\ c& d\end{array}\right)$ Wherein

a＝[b _m*(b _m-b _m*s ₁₁+c _m+c _m*s ₁₁-2*a _m+2*a _m*s ₁₁)/(-2*(b _m-b _m*S ₁₁+c _m+c _m*s ₁₁-2*a _m+2*a _m*s ₁₁)*c _m*(b _m*s ₁₁-b _m+c _m+c _m*s ₁₁))^(1/2)]

b＝[-(b _m*s ₁₁-b _m+c _m+c _m*s ₁₁)*(-b _m+2*a _m)/(-2*(b _m-b _m*s ₁₁+c _m+c _m*s ₁₁-2*a _m+2*a _m*s ₁₁)*c _m*(b _m*s ₁₁-b _m+c _m+c _m*s ₁₁)^(1/2)]

c＝[c _m*(b _m-b _m*s ₁₁+c _m+c _m*s ₁₁-2*a _m+2*a _m*s ₁₁)/(-2*(b _m-b _m*s ₁₁+c _m+c _m*S ₁₁-2*a _m+2*a _m*s ₁₁)*c _m*(b _m*s ₁₁-b _m+c _m+c _m*s ₁₁)^(1/2)]

d＝[1/2/(b _m-b _m*s ₁₁+c _m+c _m*s ₁₁-2*a _m+2*a _m*s ₁₁)*(-2*(b _m-b _m*s ₁₁+c _m+c _m*S ₁₁-2*a _m+2*a _m*s ₁₁)*c _m*(b _m*s ₁₁-b _m+c _m+c _m*s ₁₁)^(1/2)]

(9) further by transfer matrix A by formula $\left\{\begin{array}{c}{s}_{11}=\frac{a+b-c-d}{a+b+c+d}\\ s_{12}=\frac{2\left|a\right|}{a+b+c+d}\\ s_{21}=\frac{2}{a+b+c+d}\\ s_{22}=\frac{-a+b-c+d}{a+b+c+d}\end{array}\right.$ Be converted into the collision matrix of chip $S=\left(\begin{array}{cc}{s}_{11}& s_{12}\\ s_{21}& s_{22}\end{array}\right)$ , make s ₂₁The change curve of frequency is promptly obtained the frequency response of test fixture;

(10) utilize test macro to measure the network parameter s of measured device _D21Be the frequency response of measured device, the frequency response that deducts test fixture obtains the frequency response of chip at last.

The dielectric substrate of wherein said microstrip line is pottery or complex media or polytetrafluoroethylmaterial material, and substrate thickness 200-600um, microstrip line material must be gold, width＜1mm.

Wherein metal base plate can be with aluminium or copper, and upper surface must be gold-plated.

Wherein the radio frequency (RF) coaxial connector with the vector network analyzer coupling must be fixed by bolts on the metal base plate.

Description of drawings

For further specifying content of the present invention, the invention will be further described with concrete example below in conjunction with accompanying drawing, wherein:

Fig. 1 is the schematic diagram of measured material and measured material and chip;

Fig. 2 is the calibration clamp schematic diagram;

Specific embodiments

Consult Fig. 1, shown in Figure 2, the fast effective method of measurement of semiconductor chip of laser bandwidth of the present invention comprises that step is as follows:

(1) makes microstrip line 2, the dielectric substrate of microstrip line can be selected materials such as pottery, complex media or polytetrafluoroethylene, substrate thickness 200-600um, make that so little band height is suitable with heat sink height with chip, to reduce the lossy microwave that causes owing to difference in height, the microstrip line metal material must be a gold, because the superior electrical conductivity of gold can reduce lossy microwave, simultaneously equally be convenient to pressure welding with chips welding line (gold thread) material, little bandwidth＜1mm, make little bandwidth and chip size suitable, reduce lossy microwave like this;

(2) make test and calibration with metal base plate 3, metal base plate can be with aluminium or copper, and upper surface must be gold-plated, because the superior electrical conductivity of gold can reduce lossy microwave;

(3) microstrip line 2 is welded on the metal base plate, and burn-on radio frequency (RF) coaxial connector 1 and build-out resistor 3 with vector network analyzer coupling, (Fig. 1 a) and calibration clamp B to make test fixture A, C (Fig. 2 a, b), because cable needs closely to be connected (the certain strength of needs is tightened) with radio frequency (RF) coaxial connector 1 in test, for guarantee radio frequency (RF) coaxial connector 1 with little be with 2 and metallic plate 4 be connected firmly, need be with the radio frequency (RF) coaxial connector bolt, in addition build-out resistor 3 resistances according to chip characteristics between 46-48 ohm and will select the good Chip-R of high frequency characteristics for use;

(4) be welded in and make measured device D (Fig. 1 b) on the measured material being welded in chip 5 on heat sink;

(5) frequency response of measuring measured device D with vector network analyzer and photo-detector;

(6) frequency response of measurement calibration clamp is $S_m=\left(\begin{array}{cc}{s}_{m11}& s_{m12}\\ s_{m21}& s_{m22}\end{array}\right)$ And use formula

$\left\{\begin{array}{c}{a}_m=(1+s_{m11}-s_{m22}+|s_m\left|\right)/2s_{m21}\\ b_m=(1+s_{m11}+s_{m22}+|s_m\left|\right)/2s_{m21}\\ c_m=(1-s_{m11}-s_{m22}+|s_m\left|\right)/2s_{m21}\\ d_m=(1-s_{m11}+s_{m22}-|s_m\left|\right)/2s_{m21}\end{array}\right.$ Be converted into calibration clamp B transfer matrix $A_m=\left(\begin{array}{cc}{a}_m& b_m\\ c_m& d_m\end{array}\right)$ ;

(7) s of the frequency sound of measurement calibration clamp ₁₁Parameter;

(8) obtain the transfer matrix of test fixture $A=\left(\begin{array}{cc}a& b\\ c& d\end{array}\right)$ , concrete computational methods are as follows: survey the collision matrix S that leads calibration clamp B _mFor:

$S_m=\left(\begin{array}{cc}{s}_{m11}& s_{m12}\\ s_{m21}& s_{m22}\end{array}\right)...\left(1\right)$

Calculate transfer matrix Am thus:

$A_m=\left(\begin{array}{cc}{a}_m& b_m\\ c_m& d_m\end{array}\right)...\left(2\right)$

Wherein:

a _m＝(1+s _m11-s _m22+|s _m|)/2s _m21

b _m＝(1+s _m11+s _m22+|s _m|)/2s _m21 (3)

c _m＝(1-s _m11-s _m22+|s _m|)/2s _m21

d _m＝(1-s _m11+s _m22-|s _m|)/2s _m21

This transfer matrix equals two duplicate network distiches, promptly

A _m＝A ₁A ₂ (4)

Wherein, second network A 2 is equivalent to the input and output exchange of first network A 1, by defining of A matrix:

$\left(\begin{array}{c}{u}_1\\ i_1\end{array}\right)=\left(\begin{array}{cc}{a}_1& b_1\\ c_1& d_1\end{array}\right)\left(\begin{array}{c}{u}_2\\ -i_2\end{array}\right)=\left(A_1\right)\left(\begin{array}{cc}& u_2\\ & {-i}_2\end{array}\right)...\left(5\right)$

$\left(\begin{array}{c}{u}_2\\ i_2\end{array}\right)=\left(\begin{array}{cc}{a}_2& b_2\\ c_2& d_2\end{array}\right)\left(\begin{array}{c}{u}_1\\ -i_1\end{array}\right)=\left(A_2\right)\left(\begin{array}{c}{u}_1\\ -i_1\end{array}\right)...\left(6\right)$

With u2 and I2 is that the variable group (6) of solving an equation obtains following relation:

a ₂＝-d ₁/(-a ₁×d ₁+b ₁×c ₁)

b ₂＝-b ₁/(-a ₁×d ₁+b ₁×c ₁) (7)

c ₂＝-c ₁/(-a ₁×d ₁+b ₁×c ₁)

d ₂＝-a ₁/(-a ₁×d ₁+b ₁×c ₁)

(4) formula launched:

$\left(\begin{array}{cc}{a}_m& b_m\\ c_m& d_m\end{array}\right)=\left(\begin{array}{cc}{a}_1& b_1\\ c_1& d_1\end{array}\right)\left(\begin{array}{cc}{a}_2& b_2\\ c_2& d_2\end{array}\right)\left(\begin{array}{cc}\frac{-a_1{d}_1-b_1{c}_1}{-a_1{d}_1+b_1{c}_1}& \frac{-2a_1{b}_1}{-a_1{d}_1+b_1{c}_1}\\ \frac{-2c_1{d}_1}{-a_1{d}_1+b_1{c}_1}& \frac{-a_1{d}_1-b_1{c}_1}{-a_1{d}_1+b_1{c}_1}\end{array}\right)...\left(8\right)$

That is:

$\frac{-a_1{d}_1-b_1{c}_1}{-a_1{d}_1+b_1{c}_1}=a$

$\frac{-2a_1{b}_1}{-a_1{d}_1+b_1{c}_1}=b$ (9)

$\frac{-2c_1{d}_1}{-a_1{d}_1+b_1{c}_1}=c$

$\frac{-a_1{d}_1-b_1{c}_1}{-a_1{d}_1+b_1{c}_1}=d$

By structure as can be known this network be symmetrical network.Character according to symmetrical network | a|=1, a=d.Consistent with the a=d as a result that equation obtains.Because what fill in the network all is isotropic medium, S1 and S2 are reciprocal networks.Get by reciprocal network character | a|=1.The result has only three independent equations, four unknown numbers.

Record the s of calibration clamp C ₁₁Parameter promptly obtains first network A ₁Pairing s ₁₁Parameter.Obtain the 4th equation thus, thereby form the equation group of four equations of four unknown numbers:

$\frac{a_1+b_1-c_1-d_1}{a_1+b_1+c_1+d_1}$

a ₁d ₁+b ₁c ₁＝a _m (10)

2a ₁b ₁＝b _m

2c ₁d ₁＝c _m

Can solve transfer matrix A1 by this equation group, promptly obtain the network parameter of test fixture.The omission subscript gets $A=\left(\begin{array}{cc}a& b\\ c& d\end{array}\right)$ , wherein

a＝[b _m*(b _m-b _m*s ₁₁+c _m+c _m*s ₁₁-2*a _m+2*a _m*s ₁₁)/(-2*(b _m-b _m*S ₁₁+c _m+c _m*s ₁₁-2*a _m+2*a _m*s ₁₁)*c _m*(b _m*s ₁₁-b _m+c _m+c _m*s ₁₁))^(1/2)]

b＝[-(b _m*s ₁₁-b _m+c _m+c _m*s ₁₁)*(-b _m+2*a _m)/(-2*(b _m-b _m*s ₁₁+c _m+c _m*s ₁₁-2*a _m+2*a _m*s ₁₁)*c _m*(b _m*s ₁₁-b _m+c _m+c _m*s ₁₁)^(1/2)]

c＝[c _m*(b _m-b _m*s ₁₁+c _m+c _m*s ₁₁-2*a _m+2*a _m*s ₁₁)/(-2*(b _m-b _m*s ₁₁+c _m+c _m*S ₁₁-2*a _m+2*a _m*s ₁₁)*c _m*(b _m*s ₁₁-b _m+c _m+c _m*s ₁₁)^(1/2)]

d＝[1/2/(b _m-b _m*s ₁₁+c _m+c _m*s ₁₁-2*a _m+2*a _m*s ₁₁)*(-2*(b _m-b _m*s ₁₁+c _m+c _m*S ₁₁-2*a _m+2*a _m*s ₁₁)*c _m*(b _m*s ₁₁-b _m+c _m+c _m*s ₁₁)^(1/2)]

(9) further by transfer matrix A ₁By formula $\left\{\begin{array}{c}{s}_{11}=\frac{a+b-c-d}{a+b+c+d}\\ s_{12}=\frac{2\left|a\right|}{a+b+c+d}\\ s_{21}=\frac{2}{a+b+c+d}\\ s_{22}=\frac{-a+b-c+d}{a+b+c+d}\end{array}\right.$ Be converted into the collision matrix of chip $S=\left(\begin{array}{cc}{s}_{11}& s_{12}\\ s_{21}& s_{22}\end{array}\right)$ , make s ₂₁The change curve of frequency is promptly obtained the frequency response of test fixture;

(10) utilize test macro to measure the network parameter s of measured device D _D21Be the frequency response of measured device, the frequency response that deducts test fixture obtains the frequency response of chip at last.

Claims (4)

1, a kind of method of measurement of semiconductor laser chip frequency response is characterized in that, comprises the steps:

(1) makes microstrip line;

(2) make test and calibration metal base plate;

(3) microstrip line is welded on the metal base plate, and burn-on radio frequency (RF) coaxial connector and build-out resistor with vector network analyzer coupling, test fixture and calibration clamp made;

(4) be welded in and make measured device on the measured material being welded in chip on heat sink;

(5) add the frequency response that photo-detector is measured measured device with vector network analyzer;

(6) frequency response of measurement calibration clamp is $S_m=\left(\begin{array}{cc}{s}_{m11}& s_{m12}\\ s_{m21}& s_{m22}\end{array}\right);$ And use formula $\left\{\begin{array}{c}{a}_m=(1+s_{m11}-s_{m22}+|s_m\left|\right)/2s_{m21}\\ b_m=(1+s_{m11}+s_{m22}+|s_m\left|\right)/2s_{m21}\\ c_m=(1-s_{m11}-s_{m22}+|s_m\left|\right)/2s_{m21}\\ d_m=(1-s_{m11}+s_{m22}-|s_m\left|\right)/2s_{m21}\end{array}\right.$ Be converted into calibration clamp (B) transfer matrix $A_m=\left(\begin{array}{cc}{a}_m& b_m\\ c_m& d_m\end{array}\right);$

(7) s of the frequency response of measurement calibration clamp ₁₁Parameter;

(8) obtain the transfer matrix of test fixture with following formula $A=\left(\begin{array}{cc}a& b\\ c& d\end{array}\right);$ Wherein

a＝[b _m*(b _m-b _m*s _m+c _m+c _m*s ₁₁-2*a _m+2*a _m*s ₁₁)/(-2*(b _m-b _m*S ₁₁+c _m+c _m*s ₁₁-2*a _m+2*a _m*s ₁₁)*c _m*(b _m*s ₁₁-b _m+c _m+c _m*s ₁₁))^(1/2)]

b＝[-(b _m*s ₁₁-b _m+c _m+c _m*s ₁₁)*(-b _m+2*a _m)/(-2*(b _m-b _m*s ₁₁+c _m+c _m*s ₁₁-2*a _m+2*a _m*s ₁₁)*c _m*(b _m*s ₁₁-b _m+c _m+c _m*s ₁₁)^(1/2)]

c＝[c _m*(b _m-b _m*s ₁₁+c _m+c _m*s ₁₁-2*a _m+2*a _m*s ₁₁)/(-2*(b _m-b _m*s ₁₁+c _m+c _m*S ₁₁-2*a _m+2*a _m*s ₁₁)*c _m*(b _m*s ₁₁-b _m+c _m+c _m*s ₁₁)^(1/2)]

d＝[1/2/(b _m-b _m*s ₁₁+c _m+c _m*s ₁₁-2*a _m+2*a _m*s ₁₁)*(-2*(b _m-b _m*s ₁₁+c _m+c _m*S ₁₁-2*a _m+2*a _m*s ₁₁)*c _m*(b _m*s ₁₁-b _m+c _m+c _m*s ₁₁)^(1/2)]

(9) further by transfer matrix A by formula $\left\{\begin{array}{c}{s}_{11}=\frac{a+b-c-d}{a+b+c+d}\\ s_{12}=\frac{2\left|a\right|}{a+b+c+d}\\ s_{21}=\frac{2}{a+b+c+d}\\ s_{22}=\frac{-a+b-c+d}{a+b+c+d}\end{array}\right.$ Be converted into the collision matrix of chip $S=\left(\begin{array}{cc}{s}_{11}& s_{12}\\ s_{21}& s_{22}\end{array}\right),$ Make s ₂₁The change curve of frequency is promptly obtained the frequency response of test fixture;

(10) utilize test macro to measure the network parameter s of measured device _D21Be the frequency response of measured device, the frequency response that deducts test fixture obtains the frequency response of chip at last.

2, the method for measurement of semiconductor laser chip frequency response according to claim 1, it is characterized in that the dielectric substrate of wherein said microstrip line is pottery or complex media or polytetrafluoroethylmaterial material, substrate thickness 200-600um, the microstrip line material must be a gold, width＜1mm.

3, the method for measurement of semiconductor laser chip frequency response according to claim 1 is characterized in that, wherein metal base plate is with aluminium or copper, and upper surface must be gold-plated.

4, the method for measurement of semiconductor laser chip frequency response according to claim 1 is characterized in that, wherein the radio frequency (RF) coaxial connector with the vector network analyzer coupling must be fixed by bolts on the metal base plate.

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