A high-speed optical communication device and a chip mode jump test method

Abstract

The present application relates to chip testing technical field. Through scanning the PIV curve of the measured piece, the front light power kink value and the backlight current kink value of the curve are calculated again;According to the measured kink maximum value, whether the measured piece appears the mode jump phenomenon is judged. The present application uses the linear fitting algorithm when calculating the kink value, and determines three groups of test conditions covering all adjustment ranges of application, and can ensure that all possible mode jump failures can be displayed on the PIV curve. The method disclosed in the present application is more thorough in screening mode jump failures than the prior art, and there is no screening leakage phenomenon. The product processing and use effect can be guaranteed, no mode jump phenomenon occurs, and the product with mode jump hidden danger is better prevented from flowing out.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chip testing, and in particular to the stability testing field of light-emitting chips and light-emitting devices in the fields of optical communication and sensing. BACKGROUND

[0002] With the rapid rise of optoelectronic enterprises and other high-tech domestic enterprises in recent years, there are more and more domestic optical device and chip manufacturers, and the supply channels of chips are gradually becoming localized. However, the phenomenon of unstable spectrum commonly exists in the early research and development and trial production stages of chips.

[0003] The optical communication and sensing industries have very high requirements for wavelength and spectrum stability, especially for products related to DWDM applications, which are more demanding for wavelength stability. However, due to the immaturity of the chip manufacturing process technology, when certain DML or EML chips are subjected to changes in factors such as current, temperature difference, EA voltage, etc., stress deformation occurs, which leads to the disorder of the competition relationship of the wavelength output mode, and thus the phenomenon of spectrum double peaks or mode hopping occurs, as shown in the accompanying drawings Figure 1 、 2 This phenomenon is unacceptable for product application and needs to be eliminated. However, in practice, due to the many influencing factors of mode hopping, it is easy to miss screening. SUMMARY

[0004] The purpose of the present application is to solve the problem of easy screening of chip or device spectrum test mode hopping, and to provide a high-speed optical communication device and chip mode hopping test method to improve work efficiency.

[0005] The technical solution adopted by the present application to solve the above problems is:

[0006] A high-speed optical communication device and chip mode hopping test method, comprising the following steps:

[0007] S1, scan the PIV curve of the device to be tested; the die temperature is selected to be 25-55℃, and the EA is selected to be -1.1V-(-0.1)V;

[0008] S2, calculate the front light power kink value and the back light current kink value of the curve measured in step S1 by a linear fitting algorithm;

[0009] The linear fitting algorithm divides the current interval into N small intervals according to ΔI=0.5mA, then applies a linear fitting method to calculate the slope SE(i) in each small interval to obtain N SEs; then calculates the SE of the entire scanning current interval, and then calculates the SE of each interval current interval iThe ratio of SE is obtained, and the kink value kink(i) of each interval is obtained, that is, kink(1) to kink(N), then the maximum value kink(max) is found in the kink(i) value of each interval, and then the current Ikink corresponding to the maximum value kink(max) is obtained.

[0010] S3, according to the kink(max) value measured in the S2 step, whether the front light power and the backlight current kink value meets the standard is judged.

[0011] Preferably, a high-speed optical communication device and a chip jump mode test method, comprising the following steps:

[0012] S1, scanning the PIV curve of the to-be-tested device;

[0013] The test conditions are as follows, condition 1: die temperature = 25℃, EA =-1.1V; condition 2: die temperature = 45℃, EA =-0.8V; condition 3: die temperature = 55℃, EA =-0.1V;

[0014] S2, calculating the kink value of the front light power and the backlight current by a linear fitting algorithm;

[0015] The linear fitting algorithm divides the current interval into N small intervals according to the interval of ΔI=0.5mA, then the linear fitting method is applied to calculate the slope SE(i) in each small interval, and N SEs are obtained; then the SE of the whole scanning current interval is calculated by linear fitting, and then the SE of each interval current interval is calculated i The ratio of SE is obtained, and the kink value kink(i) of each interval is obtained, that is, kink(1) to kink(N), then the maximum value kink(max) is found in the kink(i) value of each interval, and then the current Ikink corresponding to the maximum value kink(max) is obtained.

[0016] S3, according to the kink(max) value measured in the S2 step, whether the front light power and the backlight current kink value meets the standard is judged.

[0017] Preferably, in the S3 step, the front light kink value standard is set to be within ±50%, and the backlight current kink value standard is set to be within ±30%.

[0018] Preferably, the to-be-tested device includes a high-speed optical communication EML device, an optical communication and sensing field optical device and an optical chip.

[0019] The application also discloses a simple jump mode test method, comprising the following steps:

[0020] S1, the spectral test conditions of the to-be-tested piece are as follows:

[0021] Condition 1: die temperature = 25 DEG C, EA = -1.1V, Bias = 40mA;

[0022] Condition 2: die temperature = 55 DEG C, EA = -0.1V, Bias = 100mA;

[0023] S2, the difference of the wavelengths measured under condition 1 and condition 2 is determined, and whether the mode jumping phenomenon occurs is further determined.

[0024] The application also discloses a test system, one end of the test clamp 9 is connected with a Keithy 2510 temperature control instrument 3, a Keithy 2400 source meter 1 4 and a Keithy 2400 source meter 2 5 through optical fibers, and finally connected to a test computer 2; the other end of the test clamp 9 is connected with a splitter 12 through optical fibers, the splitter 12 is connected with an optical power meter 6 through optical fibers, and the splitter 12 is also connected with a spectrometer 10 and a wavelength meter 11 through optical fibers.

[0025] Preferably, when the test is carried out, the to-be-tested piece 1 is clamped on the test clamp 9.

[0026] Compared with the prior art, the method disclosed by the application is more thorough in screening the mode jumping faults, and there is no screening omission phenomenon. The product processing in the subsequent process and the use effect can be ensured, and the mode jumping phenomenon does not occur. The product with hidden mode jumping risks is prevented from flowing out. Compared with the original single-condition test method, the accuracy is improved by at least 5 percentage points, and the proportion of defective products in the screened products fed back by the client is reduced by at least 10 percentage points. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a mode jumping phenomenon diagram;

[0028] Figure 2 is another mode jumping phenomenon diagram.

[0029] Figure 3 is a spectrum side mode suppression ratio (SMSR) and EA voltage change relationship diagram.

[0030] Figure 4 is a spectrum side mode suppression ratio (SMSR) and current change relationship diagram.

[0031] Figure 5 is a spectrum side mode suppression ratio (SMSR) and die temperature change relationship diagram.

[0032] Figure 6 is a spectrum wavelength and EA voltage change relationship diagram.

[0033] Figure 7 is a spectrum wavelength and current change relationship diagram.

[0034] Figure 8 is a plot of spectral wavelength versus change in die temperature.

[0035] Figure 9 is a plot of the kink current point of the PIV curve at EA = -0.1 V.

[0036] Figure 10 is a plot of the kink current point of the PIV curve at EA = -0.8 V.

[0037] Figure 11 is a plot of the kink current point of the PIV curve at TEC temperature 55 °C.

[0038] Figure 12 is a plot of the kink current point of the PIV curve at TEC temperature 45 °C.

[0039] Figure 13 is a plot of the kink value algorithm.

[0040] Figure 14 is a plot of the PIV test of condition 1 in Example 4.

[0041] Figure 15 is a plot of the PIV test of condition 2 in Example 4.

[0042] Figure 16 is a plot of the PIV test of condition 3 in Example 4.

[0043] Figure 17 is a plot of the PIV test of condition 1 in Example 5.

[0044] Figure 18 is a plot of the PIV test of condition 2 in Example 5.

[0045] Figure 19 is a plot of the PIV test of condition 2 in Example 5.

[0046] Figure 20 is a plot of the test system disclosed in Example 6.

[0047] The reference signs are as follows: 1 - the piece to be tested, 2 - the test computer, 3 - Keithy 2510 temperature control instrument, 4 - Keithy 2400 source meter 1, 5 - Keithy 2400 source meter 2, 6 - optical power meter, 7 - picoammeter, 8 - test optical fiber, 9 - test fixture, 10 - optical spectrometer.

[0048] The method disclosed in the present application is more thorough in screening for mode jumping faults, and there is no phenomenon of missing screening. The product can be guaranteed to be processed in the subsequent process and to have a use effect, and no mode jumping phenomenon occurs. Mode jumping products with hidden dangers are better prevented from flowing out. DETAILED DESCRIPTION

[0049] The method of the present application is further described below in connection with the accompanying drawings and examples.

[0050] Example 1

[0051] First, through experiments, the characteristics of the change of the spectral mode are determined, and the experimental method of the DOE is used. First, it is determined that there are three influencing factors: TEC (built-in semiconductor cooler) temperature, BIAS (chip LD current), and EA (electro-absorption modulator) reverse bias. It is determined that two of the factors remain unchanged, and the other variable is adjusted. The characteristics of the mode hopping phenomenon are summarized as follows: a) all three factors can individually affect the output of the light-emitting chip mode, as shown in the accompanying Figures 3-8 b) the main peak and the secondary peak are exchanged during mode hopping, and the wavelength mutates, as shown in the accompanying Figures 1-2 c) the output optical power and the back light current mutate due to the change in mode during mode hopping, so the method of scanning the PIV curve can be used for testing. See Table 1; d) during the scanning of the PIV curve (the curve of the light power and the back light current with the LD current), it is found that increasing the chip temperature increases the current point at which mode hopping occurs, and decreasing the chip temperature decreases the current point at which mode hopping occurs; deepening the EA reverse voltage decreases the current point at which mode hopping occurs, as shown in the accompanying Figures 9-12 Figure 9 The test conditions are a chip (TEC) temperature of 55°C, and an EA voltage of -0.1V; Figure 10 The test conditions are a chip temperature of 55°C, and an EA voltage of -0.8V; Figure 11 The test conditions are a chip temperature of 55°C, and an EA voltage of -0.8V; Figure 12 The test conditions are a chip temperature of 45°C, and an EA voltage of -0.8V;

[0052] Table 1: Record of the change in the amount of the sudden change in the front light power and the back light current

[0053]

[0054] Example 2

[0055] According to the conclusion of Example 1, the test selection range of the chip temperature and the EA voltage can be summarized. The chip temperature is selected to be 25-55°C, and the EA is selected to be -1.1V-(-0.1)V.

[0056] Meanwhile, the embodiment discloses a high-speed optical communication device and a chip mode hopping test method, which comprises the following steps:

[0057] S1, scan the PIV curve of the device to be tested; the chip temperature is 25°C, the EA is -1.0V, and the scanning range is 0-100mA.

[0058] ​S2. Calculate the front optical power kink (the tortuosity of the laser output power as a function of the LD current) and back light current kink (the tortuosity of the back light current detected by the back light detector as a function of the LD current) values ​​of the curves measured in step S1 using a linear fitting algorithm.

[0059] like Figure 12 As shown, the linear fitting algorithm subdivides the current interval into N smaller intervals with an interval of ΔI = 0.5mA. Then, it applies the linear fitting method to calculate the slope SE(i) within each smaller interval, obtaining N SE values. Next, it calculates the SE of the entire scanning current interval using linear fitting, and then calculates the SE within each interval of the current range. i The ratio of SE is used to obtain the kink (torsion ratio) value between each cell, kink(i) = SE(i) / SE, that is, from kink(1) to kink(N). Then, the maximum value kink(max) is found among the kink(i) values ​​between each cell, and the current Ikink = I[kink(max)] under the maximum value of kink(max) is obtained.

[0060] S3. Based on the maximum value of kink measured in step S2, determine whether the front light power and back light current kink values ​​meet the standards. The standard for front light power kink is set within ±50%, and the standard for back light current kink is set within ±30%.

[0061] The linear fitting algorithm subdivides the current interval into N smaller intervals with an interval of ΔI = 0.5mA. Then, it applies the linear fitting method to calculate the slope SE(i) within each smaller interval, obtaining N SE values. Finally, it calculates the SE for the entire scanning current interval using linear fitting, and then calculates the SE within each interval. i The ratio of SE is used to obtain the kink value between each cell, kink(i) = SE(i) / SE, that is, from kink(1) to kink(N). Then, the maximum value kink(max) is found among the kink(i) values ​​between each cell, and the current Ikink = I[kink(max)] under the maximum value of kink(max) is obtained.

[0062] Example 3

[0063] Three test conditions were initially determined through Examples 1 and 2 (Condition 1: die temperature 25℃, EA = -1.1V; Condition 2: die temperature 45℃, EA = -0.8V; Condition 3: die temperature 55℃, EA = -0.1V) for testing. These three conditions cover all adjustment ranges of the application and can ensure that all possible mode skipping faults can be displayed on the PIV curve.

[0064] The embodiment discloses a high-speed optical communication device and a chip jump mode testing method, and comprises the following steps:

[0065] S1, scanning the PIV curve of the to-be-tested device;

[0066] The testing conditions are as follows: condition 1: die temperature = 25 DEG C, EA = -1.1 V, and scanning range 0-100 mA; condition 2: die temperature = 45 DEG C, EA = -0.8 V, and scanning range 0-100 mA; and condition 3: die temperature = 55 DEG C, EA = -0.1 V, and scanning range 0-100 mA.

[0067] S2, calculating the kink values of the front optical power and the back optical current by using a linear fitting algorithm;

[0068] The linear fitting algorithm is the same as that in embodiment 2.

[0069] S3, judging whether the kink values of the front optical power and the back optical current meet the standard according to the maximum kink value measured in the step S2.

[0070] Embodiment 4

[0071] The embodiment tests the product by using the testing method disclosed in embodiment 3, and the product that passes the test has good PIV curves under the three conditions, and the result is determined to be qualified, and the PIV curve diagram is as shown in Figure 14 .

[0072] Embodiment 5

[0073] The embodiment tests the product by using the testing method disclosed in embodiment 3, and the product that passes the test has good PIV curves under the three conditions, and the result is determined to be qualified, and the PIV curve diagram is as shown in Figure 15 .

[0074] Embodiment 6

[0075] As Figure 16 , the application also discloses a testing system. During testing, the to-be-tested device (1) is clamped to the testing clamp (9), one end of the testing clamp (9) is connected to the Keithy 2510 temperature control instrument (3), the Keithy 2400 source table one (4) and the Keithy 2400 source table two (5) through an optical fiber, and finally connected to the testing computer (2); the other end of the testing clamp (9) is connected to the splitter (12) through an optical fiber; the splitter (12) is connected to the optical power meter (6) through an optical fiber; and the splitter (12) is also connected to the optical spectrum analyzer (10) and the wavelength meter (11) through an optical fiber.

[0076] Embodiment 7

[0077] The present embodiment discloses a simple test method which uses the test system described in embodiment 6.

[0078] First step: insert the test fiber (8) into the device on one side and the optical power meter (6) on the other side, then clamp the product on the test fixture.

[0079] Second step: test and determine the spectrum and wavelength of the first condition (die temperature 25℃, EA=-1.1V, Bias=40mA).

[0080] Third step: then test the spectrum and wavelength of the second condition (die temperature 55℃, EA=-0.1V, Bias=100mA)

[0081] Fourth step: determine the relationship between the two wavelengths under the condition of no mode hopping as λ2=λ1+ΔT*0.09+ΔBias*η (ΔT is the temperature difference of the two conditions, ΔBias is the current difference of the two test conditions, and η is the coefficient of the wavelength drift of the chip with current, which is determined by the chip itself) according to the two test conditions, and obtain the difference Δλ between the wavelengths of the two conditions under the condition of no mode hopping as Δλ=ΔT*0.09+ΔBias*η.

[0082] Fourth step: difference value determination of the wavelengths of the two conditions, the difference value is Δλ±0.3nm, which is determined as defective.

[0083] The present embodiment mainly determines whether the mode hops by determining the difference value of the wavelengths under the two conditions. Because the main influencing factors of the wavelength of the chip are the current and the die temperature, and the change rates of the current and the die temperature are basically stable, the difference value of the wavelengths of the two conditions is also basically stable, and if the mode hops, the wavelength difference value will be abnormal.

[0084] The above only describes the preferred embodiments of the present application, but the protection scope of the present application is not limited to this. Any skilled person in the art can make equivalent replacements or changes to the technical solutions and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for testing mode hopping in high-speed optical communication devices and chips, characterized in that, Includes the following steps: S1. Scan the PIV curve of the device under test; select die temperature of 25-55℃, and select reverse bias voltage EA of electroabsorption modulator from -1.1V to -0.1V; S2. Calculate the front light power kink value and back light current kink value of the curve measured in step S1 using a linear fitting algorithm; The linear fitting algorithm subdivides the current interval into N small intervals with an interval of ΔI=0.5mA. Then, the linear fitting method is used to calculate the slope SE(i) in each small interval to obtain N SE(i). Then, the SE of the entire scanning current interval is calculated by linear fitting. Then, the ratio of SE(i) to SE in each interval current interval is calculated to obtain the kink value between each cell: kink(i)=SE(i) / SE, that is, kink(1) to kink(N). Then, the maximum value kink(max) is found in the kink(i) value between each cell, and the current Ikink=I[kink(max)] corresponding to kink(max) is obtained. S3. Based on the kink(max) measured in step S2, the standard setting for the front light kink value is within ±50%, and the standard setting for the back light current kink value is within ±30%. Determine whether the front light power and back light current kink values ​​meet the standards.

2. The high-speed optical communication device and chip mode hopping test method according to claim 1, characterized in that, The test conditions for step S1 are as follows: Condition 1: die temperature = 25℃, EA = -1.1 V; Condition 2: die temperature = 45℃, EA = -0.8V; Condition 3: die temperature = 55℃, EA = -0.1V.

3. The method for testing mode hopping of high-speed optical communication devices and chips according to claim 1 or 2, characterized in that, The device under test includes a high-speed optical communication EML device.

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