JPH0783797A - Modulation and spectral testing method and device for semiconductor laser - Google Patents

Abstract

PURPOSE:To provide a means accurately evaluating the longitudinal mode of laser inclusive of the disturbance of the longitudinal mode caused by the unstable state in the vicinity of a threshold current in a quasi-wafer state. CONSTITUTION:By supplying a sine wave signal, a rectangular wave signal or an alternating signal having a frequency lower than the relaxation oscillation frequency of laser by 1MGz or more to a laser chip or array in a quasi-wafer state not fixed to a radiator in a state superposed on a DC bias, the disturbance of a longitudinal mode caused by an unstable state in the vicinity of the threshold current of the laser is accurately evaluated in exactitude equal to that at the time of actual high speed modulation. By using a high frequency coaxial cable, a current having a high frequency as mentioned above can be supplied to the laser chip or array in a quasi-wafer state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser modulation spectroscopy test method and an apparatus therefor. In recent years, optical fiber communication using a semiconductor laser is carried out by NTT's backbone communication network or the communication network inside the intelligent building (optical LA
N), etc. show a wide variety of spreads.

In these cases, a single longitudinal mode oscillation laser is used in order to cope with the increase in the speed of optical communication, but in order to achieve the increase in the speed of the optical communication, the transmission speed is increased. However, the unity of the longitudinal mode of laser light is important. Therefore, a test method and an apparatus therefor capable of appropriately evaluating the unity of the longitudinal mode of laser light are required.

[0003]

2. Description of the Related Art In a conventional semiconductor laser modulation spectroscopy test method and apparatus therefor, a laser chip or a laser array not fixed to a heat sink is tested (Production Probe Test P
In the P test), a spectral test was performed by applying a continuous sine wave signal (CW) or a continuous rectangular wave signal of several kHz to a laser chip or a laser array.

[0004]

However, according to the conventional test method of applying a continuous sine wave signal or a continuous rectangular wave signal of several kHz as in the prior art, a vertical state caused by an unstable state near the threshold current of the laser is generated. It is impossible to evaluate the mode disturbance. The present invention provides a semiconductor laser modulation spectroscopy test method and a device therefor capable of accurately evaluating a longitudinal mode of a laser including a disturbance of the longitudinal mode due to an unstable state near a threshold current in a quasi-wafer state. The purpose is to provide.

[0005]

In the semiconductor laser modulation spectroscopy test method according to the present invention, a sine wave signal having a frequency of 1 MHz or more lower than the relaxation oscillation frequency of the laser is applied to a laser chip or a laser array not fixed to a radiator. The process of evaluating the disturbance of the longitudinal mode due to the unstable state near the threshold current of the laser is adopted by supplying a wave signal or an alternating signal corresponding thereto to the DC bias current in a superimposed manner.

Further, in the semiconductor laser modulation spectroscopy test apparatus according to the present invention, a sine wave signal, a rectangular wave signal or an alternation thereof which is 1 MHz or more lower than the relaxation oscillation frequency of the laser is applied to the laser chip or the laser array not fixed to the radiator. A configuration comprising means for superimposing and supplying signals and means for evaluating the disturbance of the longitudinal mode due to the unstable state near the threshold current of the laser is adopted.

Further, in the probing support device according to the present invention, a support base, a three-axis adjusting mechanism which is provided on the support base and can be moved in the three-axis directions manually or by a control signal, and the three-axis adjusting mechanism. A pillar vertically provided on the axis adjusting mechanism, an arm portion that can be rotated up and down about a fulcrum on the pillar, and an arm portion provided on the arm portion, and the coaxial structure or the surrounding area is shielded by an electric field. It is composed of a probe having a structure and a probe pressure adjustment detection unit that detects and adjusts the pressure applied to the object of this probe, and the Z axis position signal is fed back from this probe pressure adjustment detection unit to the triaxial adjustment mechanism. By controlling the position in the Z-axis direction, a configuration is adopted in which the pressure at the tip of the probe attached to this arm is adjusted and the position is adjusted high. It was.

The probe device according to the present invention comprises a three-dimensional drive stage, a high frequency coaxial probe, and the probing support device, and the rigidity of the outer conductor of the high frequency coaxial probe is smaller than that of the center conductor of the high frequency coaxial probe. And a ground wire having, and when the three-dimensional drive stage is raised or the probing support device is lowered, the center conductor of the high-frequency coaxial probe contacts the object to be tested on the three-dimensional drive stage. The configuration is adopted in which the ground wire is brought into contact with the three-dimensional drive stage to adjust the load pressure of the center conductor of the high-frequency coaxial probe with respect to the object to be tested and to apply a high-frequency signal.

Further, the probing apparatus according to the present invention comprises the first and second probing supporting devices having the probe needles shielded from the electric field, the second probing supporting device, and the three-dimensional drive stage. When the original drive stage is raised or when the first probing support device and the second probing support device are lowered, the first probing support device and the first probing support device are attached to the same object to be tested on the three-dimensional drive stage. Arranged so that the probe needle of the second probing support device is in contact,
In addition, we adopted a configuration that enables Kelvin connection by taking the ground from the three-dimensional drive stage.

Further, in the optical semiconductor modulation spectroscopy test apparatus according to the present invention, an optical characteristic measuring apparatus, an optical spectrum measuring apparatus, a bias and high frequency signal applying apparatus, the probe apparatus, the probing apparatus, a three-dimensional driving stage, a plurality of A prober device having a test station, wherein the first station of the prober device measures the characteristic value of an object to be tested by using the optical characteristic measuring device and the probing device, and at the second station, This optical spectrum measuring device, the probe device, and the bias and high frequency signal applying device are used, and the optical characteristic of the test object is inspected by applying the signal calculated from this characteristic value to the test object. .

[0011]

1A and 1B are diagrams for explaining the principle of the semiconductor laser modulation spectroscopy test method of the present invention. FIG. 1A shows a DC biased continuous sine wave signal, and FIG. 1B shows a DC biased continuous rectangular wave signal. ing. In the present invention, as shown in this figure, the current supplied to the laser chip is a DC biased continuous sine wave signal (A) and a DC biased continuous rectangular wave signal (B). In both cases, by setting the modulation current amplitude so that it falls below the threshold current of laser oscillation, it is possible to create a condition that causes the disturbance of the longitudinal mode in the unstable state described above. The longitudinal mode of laser emission including turbulence can be evaluated.

The upper limit of the frequency of the continuous sine wave signal and the continuous rectangular wave signal is the upper limit frequency that the laser element can follow, and the lower limit is the rectangle per unit time determined by the characteristics required of the test object. It is the frequency that realizes the number of waves. An unstable state of the longitudinal mode of the laser occurs at the rising edge of the rectangular wave, and side modes occur at wavelengths other than the main wavelength.

SSR measured for side mode
(Side Mode Suppression Ra
tio) is a time-averaged waveform, and the more rectangular waves per unit time, the smaller the SSR value becomes, and the identification accuracy improves. The smaller the SSR, the worse the device characteristics.

FIG. 2 is an explanatory diagram of an evaluation example of SSR by the semiconductor laser modulation spectroscopy test method of the present invention. The horizontal axis of this figure shows the SSR when a continuous rectangular wave signal of 1 kHz is applied to the laser element using the conventional semiconductor laser modulation spectroscopy test method, and the vertical axis shows the semiconductor laser modulation spectroscopy test method of the present invention. , 200M with a power ratio of 16 dBm based on 1 mW from the modulation signal supply source to the laser element
The SSR is shown when a continuous sine wave signal of Hz is supplied and a bias current of +10 mA which is the threshold current of the laser is applied from the constant current source. In this case, the transfer of the modulation current amplitude below the threshold current was ˜5 mA.

The SSR, which is a parameter for evaluating the instability of the longitudinal mode of laser emission shown in this figure, was measured using the semiconductor laser modulation spectroscopy test method of the present invention and the conventional semiconductor laser modulation test method. As is clear from the correlation in the case, it is the effect of the present invention that deviates from the one-to-one correlation, and the SSR value is the same as that at the time of actual high-speed modulation. According to the semiconductor laser modulation spectroscopy test method of the present invention, it can be seen that the laser element which cannot evaluate SSR can be evaluated accurately.

[0016]

EXAMPLES Examples of the present invention will be described below. (First Embodiment) FIG. 3 is a schematic structural explanatory view of a semiconductor laser modulation spectroscopy test apparatus of the first embodiment. In this figure, 1 is a laser chip, 2 is a support base, 3 is a modulation signal generator, 4 is a capacitor, 5 is a constant current source, 6 is an inductor,
Reference numeral 7 is a laser contact probe, 8 is an optical fiber, and 9 is a spectroscope.

The configuration of the semiconductor laser modulation spectral test apparatus of the first embodiment will be described along with the test method using the semiconductor laser modulation spectral test apparatus with reference to this schematic configuration diagram.
In this semiconductor laser modulation test apparatus, a large number of laser chips 1 are placed on a grounded support 2 and a modulation signal output from a modulation signal generator 3 is passed through a capacitor 4 to
Further, the bias current output from the constant current source 5 is guided to the laser contact probe 7 through the inductor 6 and the support base 2
An operating current is sequentially supplied to the laser chip 1 mounted on the above.

The modulated light emitted from the laser chip 1 is
Coupled to the optical fiber 8 connected to the input of the spectroscope 9 and evaluated by the spectroscope 9. In this case, the above-mentioned laser chip may be replaced with a laser array including a plurality of laser emitting sections, and the emission characteristics thereof may be inspected.

According to the semiconductor laser modulation spectroscopy test method of this embodiment, it is possible to evaluate and select the disturbance of the laser in the same manner as in the actual high speed modulation by the test evaluation in the semiconductor laser chip or laser array state. It is possible to perform quality compensation of a semiconductor laser for a high speed optical communication system.

(Second Embodiment) In optical communication or the like, a modulation signal is applied to a semiconductor laser to generate an optical signal,
Although this modulated optical signal is propagated in the optical fiber, the wavelength of the optical signal propagating in the fiber often becomes a problem.
That is, since the optical fiber has the property that the propagation speed differs with respect to the wavelength of the optical signal, when considering the communication distance, the noise ratio of the transmission signal, etc., the semiconductor laser has a wide emission spectrum at the time of modulation. Alternatively, a semiconductor laser in which the wavelength range of high emission intensity is irregularly distributed is ineligible.

As a method for testing the suitability of the above-mentioned semiconductor laser, conventionally, a semiconductor laser is continuously cut in a quasi-wafer state in which a wafer after a wafer process is cleaved into laser element units or laser array units and separated into strips. Since it was difficult to realize a measurement probe that covers the characteristics of oscillation threshold current (1th), optical output conversion efficiency (η), optical spectrum waveform at specified optical output, etc. I was measuring it.

However, the test result may be different from the result when the optical spectrum waveform is measured by applying a modulation signal after assembling the semiconductor laser, and the internal state of the semiconductor laser depends on whether the applied signal is modulated or not. It is thought that the difference may be the cause. In such a case, as a matter of course, the pass / fail judgment needs to be made based on the result of retesting with the assembled modulation signal, that is, the modulation characteristic, so the optical spectrum measurement performed in the quasi-wafer state is wasted. There are cases.

This embodiment relates to a semiconductor laser modulation spectrum test method and a modulation spectrum test apparatus capable of testing the modulation spectrum characteristics of a semiconductor laser in a quasi-wafer state. According to the semiconductor laser modulation spectroscopy test method and the modulation spectroscopy test apparatus of this embodiment, the test in the quasi-wafer state allows
Since the laser element that may be determined to be defective after assembly can be excluded in advance, the manufacturing cost can be reduced.

FIG. 4 is an explanatory diagram of the overall configuration of the semiconductor laser modulation spectroscopy test apparatus of the second embodiment. In this figure,
11 is a prober, 12 is an optical characteristic measuring device, 12 ₁ is an application observation cable, 12 ₂ is a ground wire, 13 is an optical spectrum measuring device, 14 is a bias and high frequency signal applying device,
Reference numeral 15 is a controller, 16 is the first station of the prober, 17 is the second station of the prober, 17 ₁ is a high-frequency signal applying cable, 18 is a three-dimensional drive stage, 19
Is a control signal cable.

In this prober 11, the three-dimensional drive stage 18 on which the semiconductor laser elements separated into strips, which are the objects to be tested, are placed, is the first of the prober first.
After moving to the station 16, the optical characteristic measuring device 12 measures the threshold current (Ith), the applied current-optical output conversion efficiency (η), and the like.

Next, the three-dimensional drive stage 18 moves to the second station 17 of the prober, where a high frequency signal is applied to the object to be tested by the bias and high frequency signal applying device 14, and the optical output at this time is The wavelength intensity distribution is observed by the optical spectrum measuring device 13.

In this figure, the bias and high frequency signal application device 14 and the second station 17 of the prober are connected by a high frequency signal application cable 17 ₁ , and the optical characteristic measuring device 12 and the first station 16 of the prober are applied observation cable 12 _1. And ground line 12 ₂ .

The DC bias (If) for the object under test at the second station 17 of the prober is calculated from the threshold current (Ith) and the applied current-light output conversion efficiency (η) obtained by the first station 16 of the prober as follows. Is calculated as

If = Ith + Opt / η where If is a DC bias current (ampere), η is an applied current-optical output conversion efficiency (watt / ampere), Opt
Is the required optical output power (Watt) at DC bias current, which is determined in consideration of the mounting state of the test object.

Further, the high frequency signal applied at the second station 17 of the prober changes the impedance of the cable to X.
When superposed on the DC bias current (If),
Set to a value that does not apply reverse bias to the test object. For example, when a sine wave is applied, if the effective power of the sine wave is Pin (watt), the following formula is set.

(2 × Pin) ^1/2 / X <If Here, X is the impedance (ohm) of the cable. 2 in the parentheses of this equation is a coefficient that takes the peak value into consideration, and this coefficient can be calculated in the same manner for applied signals other than sinusoidal waves. All of the above processes are operation-controlled and data processed by the controller 15 via the control signal cable 19.

FIG. 5 is an explanatory view of the configuration of the first station of the prober of the second embodiment. (A) shows the overall configuration, (B) shows the front of the probing support device,
(C) shows the side surface. In this figure, 16
₁ is an application probe device, 16 ₂ is an observation probe device, 1
6 ₃ is a stereomicroscope, 21 is a support, 22 is a fulcrum, 23 is a support, 24 is an arm, 25 is a probe, 25 ₁ is an application observation cable, 26 is a triaxial adjustment mechanism, and 26 ₁ is a Z-axis control line. , 27 are pressure adjustment detection units, and 28 is a support leg.

The first station of the prober of this embodiment is, as shown in FIG. 2A, an application probe device 16 ₁ , an observation probe device 16 ₂ , and a stereoscopic microscope 16 ₃ for confirming alignment. It is composed by.

The probing support device, which is the substance of the application probe device 16 ₁ and the observation probe device 16 ₂ , is shown in FIG.
As shown in (B) and (C), a triaxial adjustment mechanism 26 is provided on the support base 23.
A column 21 is provided on the top in the vertical direction. An arm portion 24 made of an insulator is provided so as to be vertically rotatable around a fulcrum 22 of the support column 21, and a central portion of the arm portion 24 and a support leg 28 connected to the support column 28.
The pressure adjustment detection unit 27 is provided between the two.

The pressure adjustment detection unit 27 has a function of adjusting the contact pressure when the tip of the probe 25 comes into contact with the object to be tested. Therefore, the triaxial adjustment mechanism 26 is manually set to the basic position. Then, the signal sent by the Z-axis control lines 26 ₁ from a pressurized adjusting detector 27, Z
Under the control of the axial direction, the contact pressure of the probe 25 to the test object is adjusted.

The probe 25 is made of a material having high rigidity, and the displacement when the test object comes into contact is directly transmitted to the pressure adjustment detection section 27. Applied observation cable 25
₁ is built in and fixed to the arm portion 24 so that the vibration of itself does not cause the displacement of the tip of the probe 25 or the load.

The position of the tip of the probe 25 and the object to be tested is aligned by the triaxial adjustment mechanism 26, and the physical load applied to the object to be tested can also be detected by the pressurization adjustment detector 27. Since the application observation cable 25 ₁ is fixed and held by the arm portion 24, highly accurate positioning and load adjustment on the object to be tested are facilitated.

FIG. 6 is an explanatory view of the structure of the pressure adjustment detection unit of the second embodiment. In this figure, 24 is an arm portion, 2
6 ₁ is a Z-axis control line, 28 is a support leg, 29 is a capacitance sensor,
30 tension spring 31 is ejecting spring, 32 ejecting spring holder, the tension spring holder 33, 34 contacts, 34 ₁ contact switching detection coaxial cable, 35 capacitance detection converting display circuit 35 ₁ is capacitance change detection Is a coaxial cable, 36 is an indicator, 37 is a probe with a spring, and 38 is an insulator.

In the pressurization adjustment detecting section of this embodiment, the contact 34 is separated to detect the contact of the probe 25 (see FIG. 5) with the object to be tested. The capacitance detection conversion display circuit 35 starts to operate by the detection signal transmitted by the contact opening / closing detection coaxial cable 34 ₁ ,
The probe 25 (see FIG.
The amount of pushing up (see FIG. 3) is detected, the detected amount is converted and displayed on the display 36, and an audible sound is generated, and the amount is indicated by its pitch, sounding interval, and the like.

The capacitance sensor 29 has, for example, a cylindrical shape, and is electrically insulated from the arm portion 24 and the support leg 28 by an insulator 38. The capacitance change detection coaxial cable 35 ₁ is connected to _{one side} of the capacitance sensor 29. Spring-loaded probe 3 fixed so that it passes through the inside of the
The arm portion 2 is configured to be brought into contact with the other by 7
A small change in capacitance due to the vertical movement of 4 is detected. The tension spring 30 and the pushing spring 31 are provided in the arm portion 2.
Considering the load such as 4, etc., either one or both are used to adjust the load applied to the test object.

In addition to mechanical springs, air suspensions or the like may be used for the tension spring 30 and the pushing spring 31. Further, the capacity detection conversion display circuit 35 is set with an allowable amount of load on the object to be tested, and the capacity sensor 29 is set so as to be less than or equal to this allowable amount.
It has a function of sending a control signal for feeding back the height in the Z-axis direction to the Z-axis control line 26 ₁ in accordance with the value from. Note that the correlation between the capacitance value and the tip load of the probe 25 (see FIG. 5) is calibrated using a tension gauge or the like to determine the allowable amount of pressure load on the test object.

FIG. 7 is an explanatory diagram of the configuration of the first station of the prober of the second embodiment. In this figure, 18 is a three-dimensional drive stage, 25 ₂ is an application probe, 25 ₃ is an observation probe, 39 is an object to be tested, 40 is a light emitting element array, 41 is light emission, and 42 is a ground wire.

In this figure, the stereoscopic microscope 16 ₃ is attached to the first station 16 (see FIG. 4) of the prober of the second embodiment from above.
(See FIG. 5). As shown in this figure, the application probe 25 ₂ provided in the application probe device 16 ₁ (see FIG. 5) and the observation probe 25 ₃ provided in the observation probe device 16 ₂ (see FIG. 5). Is a Kelvin connection to the light emitting element array 40 of the test object 39, and the ground lines 42 for both probes are connected to the three-dimensional drive stage 18.

The connection in which the current is supplied by the first probing device and the voltage is observed by the second probing device is referred to as Kelvin connection. With this configuration, a current can be supplied from the application probe 25 ₂ to the light emitting element array 40 to obtain light emission 41, and the voltage can be observed by the observation probe 25 ₃ .

FIG. 8 is a structural explanatory view of the tip of the high frequency applying probe of the second station of the prober of the second embodiment. In this figure, 18 is a three-dimensional drive stage, 39
Is an object to be tested, 41 is light emission, 43 is a ground wire, 44 is a coaxial probe, 45 is the vertical movement width of the ground wire, Δy ₂ is the height of the object to be tested, and Δy ₁ is the outer conductor of the coaxial probe. The height, θ is the inclination of the coaxial probe, and L is the length of the ground wire.

This figure shows the second station 1 of the prober.
7 shows the structure of the tip of the high frequency applying probe used in FIG. 7 (see FIG. 4). The ground wire 43 is soldered to the outer conductor of the coaxial probe 44 for applying a high frequency signal and connected by brazing or the like so that the tip of the ground wire 43 contacts the three-dimensional drive stage 18. The width 45 of the vertical movement of the ground wire 43 is considered to be several times the height Δy ₂ of the test object 39, and the material, shape, and coating used for the ground wire 43 are determined.

For example, the ground wire 43 has a rigidity that is about 1/5 to 1/10 of the rigidity of the center conductor. In practice, a 100 μm diameter gold wire coated with Ti (titanium) and the like can be mentioned as the optimum material. The ground wire 43 is arcuate or coil-shaped, and its length L is about L = Δy ₁ / sin θ, where Δy _{1 is} the height of the outer conductor of the coaxial probe and θ is the tilt of the coaxial probe. Can be used as a guide.

FIG. 9 shows the optical characteristic measuring apparatus and the device of the second embodiment.
It is a structure explanatory view of the 1st station of a rover. This figure
At 12₃Is an optical device tester, 12_FourIs photo de
Detector, 16 ₁Is an application probe device, 16₂Is the observation
Lobe device, 18 is a three-dimensional drive stage, 19 is a control signal
No. cable, 41 light emission, 42 ground wire, 46₁Is applied
Signal line, 46₂Is an observation signal line.

This drawing shows the optical characteristic measuring apparatus 1 of this embodiment.
2 (see FIG. 4) and the first station 16 of the prober 16 (see FIG. 4). The optical device testing apparatus 12 _{3 in} this figure supplies a current to an object to be tested of the three-dimensional drive stage 18 through an application probe device 16 ₁ connected by an application signal line 46 ₁ , and an observation signal line 46 ₂ The quantity of electricity is measured through the connected observation probe device 16 ₂ . Along with this, the light emission 41
Is photoelectrically converted and detected by the photodetector 12 ₄ having sensitivity to the light emission 41, and the light emission efficiency with respect to the supply current is calculated.

FIG. 10 is an explanatory view of the configuration of the optical spectrum measuring apparatus of the second embodiment and the second station of the prober. In this figure, 13 ₁ is an optical spectrum measuring device, 13 ₂ is an optical fiber with a lens and a connector, 1
Reference numeral 4 is a bias and high frequency signal application device, 14 ₁ is a high frequency signal application cable, 17 ₂ is a high frequency application probe device, 18 is a three-dimensional drive stage, 19 is a control signal cable, and 41 is light emission.

This drawing shows the structure of the optical spectrum measuring device 13 (see FIG. 4) and the second station 17 (see FIG. 4) of the prober of this embodiment. In the optical spectrum measuring device 13 (see FIG. 1) and the second station 17 of the prober (see FIG. 4), the signals from the bias and high frequency signal applying device 14 are supplied to the three-dimensional drive stage via the high frequency applying probe device 17 _2. By applying to the object under test placed on 18,
A high frequency modulated wave component is generated in the light emission 41. The optical spectrum measuring device 13 ₁ observes the spectrum of the light emission 41 via the lens and the optical fiber 13 ₂ with a connector.

FIG. 11 shows bias and high frequency signal application.
It is a structure explanatory view of a device. 14 in this figure₁Is high frequency
Wave signal application cable, 14₂Is a DC power supply, 14₃Is high frequency
Wave signal generator, 14_FourIs bias tee, 14_FiveIs sir
Curator, 14 ₆Is a terminating resistor, 14₇Is a coil, 14
₈Is a capacitor, and 19 is a control signal cable.

In this bias and high frequency signal applying device, a direct current is applied to the object to be tested by the direct current power source 1.
4 _{2 and} a sine wave signal of hundreds of megahertz and tens of milliwatts is generated by the high frequency signal generator 14 ₃ .
The bias tee 14 ₄ is used for coupling the DC signal and the high frequency signal, and the high frequency signal applying cable 14 ₁
A DC signal and a high-frequency signal flow through this.

Since a part of the high-frequency signal applied to the object to be tested becomes a reflection component as a result of impedance mismatch and tries to return to the high-frequency signal generator 14 ₃ , a 3-port circulator 14 ₅ is arranged. The return component is consumed by the terminating resistor 14 ₆ and the high frequency signal generator 14 ₃
Protect the internal circuit of.

This circulator 14_FiveIs a high frequency signal
Raw vessel 14₃From bias tee 14 _FourReduction of signal component to
Bias tee 14_Fourof
Coil 14₇Is an inductor of a size that does not let high-frequency components pass
Having a chest and a condenser 14₈DC power supply 14₂Etc.
Use one that can withstand the resulting voltage.

According to the semiconductor laser modulation spectroscopy test apparatus of this embodiment, when measuring the optical spectrum by the test of the light emitting element in the quasi-wafer state, the high frequency signal in consideration of the threshold current and the light emitting efficiency of the light emitting element is accurately applied. Since it is possible to perform the test result close to the actual operation test after assembly in the upstream of the manufacturing process, it is possible to reduce the manufacturing cost of the product and perform highly accurate quality compensation.

[0057]

As described above, according to the present invention,
Disturbance in the longitudinal mode of laser emission can be evaluated with the same accuracy as in actual high-speed modulation by test evaluation in the semiconductor laser chip or laser array state, and in the quasi-wafer state test of the light emitting element, the light emitting element Since it is possible to apply a high-frequency signal considering the threshold current, light emission efficiency, etc., it is possible to perform a test with accuracy close to the operation test after assembly upstream of the manufacturing process, thus reducing the manufacturing cost, It becomes possible to perform reliable quality compensation, and it has a great contribution to the technical field of optical communication and the like.

[Brief description of drawings]

FIG. 1 is an explanatory view of the principle of a semiconductor laser modulation spectroscopy test method of the present invention, where (A) shows a DC biased continuous sine wave signal and (B) shows a DC biased continuous rectangular wave signal.

FIG. 2 is an explanatory diagram of an evaluation example of SSR according to the semiconductor laser modulation spectroscopy test method of the present invention.

FIG. 3 is a schematic configuration explanatory diagram of a semiconductor laser modulation spectroscopy test apparatus of a first embodiment.

FIG. 4 is an explanatory diagram of the overall configuration of a semiconductor laser modulation spectroscopy test apparatus of a second embodiment.

5A and 5B are configuration explanatory diagrams of a first station of a prober of a second embodiment, FIG. 5A shows the overall configuration, and FIG.
Shows a front surface of the probing support device, and (C) shows a side surface thereof.

FIG. 6 is an explanatory diagram of a configuration of a pressure adjustment detection unit of a second embodiment.

FIG. 7 is an explanatory diagram of a configuration of a first station of the prober of the second embodiment.

FIG. 8 is a structural explanatory view of the tip of the high frequency applying probe of the second station of the prober of the second embodiment.

FIG. 9 is a first view of the optical characteristic measuring device and the prober of the second embodiment.
It is a structure explanatory view of a station.

FIG. 10 is an explanatory diagram of a configuration of an optical spectrum measuring apparatus of a second embodiment and a second station of the prober.

FIG. 11 is an explanatory diagram of a configuration of a bias and high frequency signal applying device.

[Explanation of symbols]

1 Laser Chip 2 Support 3 Modulation Signal Generator 4 Capacitor 5 Constant Current Source 6 Inductor 7 Laser Contact Probe 8 Optical Fiber 9 Spectrometer 11 Prober 12 Optical Property Measuring Device 12 ₁ Applied Observation Cable 12 ₂ Ground Wire 12 ₃ Optical Element Test equipment 12 ₄ Photodetector 13 Optical spectrum measurement device 13 ₁ Optical spectrum measurement device 13 ₂ Optical fiber with lens and connector 14 Bias and high frequency signal application device 14 ₁ High frequency signal application cable 14 ₂ DC power supply 14 ₃ High frequency signal generator 14 ₄ bias Tee 14 ₅ Circulator 14 ₆ Termination resistor 14 ₇ Coil 14 ₈ Capacitor 15 Controller 16 Prober's first station 16 ₁ Applied probe device 16 ₂ Observation probe device 16 ₃ Stereomicroscope 17 Prober's second station 17 ₁ High frequency signal Signal application cable 17 ₂ High frequency application probe device 18 Three-dimensional drive stage 19 Control signal cable 21 Strut 22 Support point 23 Support stand 24 Arm part 25 Probe 25 ₁ Applied observation cable 25 ₂ Applied probe 25 ₃ Observation probe 26 Triaxial adjustment mechanism 26 ₁ Z-axis control line 27 Pressurization adjustment detection unit 28 Support leg 29 Capacity sensor 30 Extension spring 31 Extrusion spring 32 Extrusion spring holder 33 Extension spring holder 34 Contact 34 ₁ Contact open / close detection coaxial cable 35 Capacity detection conversion display circuit 35 ₁ capacity Coaxial cable for change detection 36 Indicator 37 Spring probe 38 Insulator 39 Object under test 40 Light emitting element array 41 Light emission 42 Ground wire 43 Ground wire 44 Coaxial probe 45 Vertical movement width of ground wire 46 ₁ Applied signal wire 46 ₂ observation signal line Δy ₁ coaxial probe The length of the height θ coaxial probe of the outer conductor height [Delta] y ₂ under test of inclination L ground line

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyotsugu 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor, Yoji Hosaka, 1000, Kami-Koma, Showa-cho, Yamanashi Prefecture. Within the corporation

Claims (6)

[Claims] 1. A laser chip or a laser array that is not fixed to a radiator has a relaxation oscillation frequency of 1 M from the laser.
Evaluate the disturbance of the longitudinal mode caused by the unstable state near the threshold current of the laser by supplying the sine wave signal, the rectangular wave signal or the alternating signal corresponding to the low frequency of Hz or more superposed on the DC bias current. A semiconductor laser modulation spectroscopy test method, comprising: 2. A laser chip or a laser array that is not fixed to a radiator has a relaxation oscillation frequency of 1 M
And a means for superimposing and supplying a sine wave signal lower than Hz, a rectangular wave signal, or an alternating signal equivalent thereto, and means for evaluating the disturbance of the longitudinal mode due to the unstable state near the threshold current of the laser. A semiconductor laser modulation spectroscopic test device characterized by: 3. A support base, a three-axis adjustment mechanism provided on the support base and movable in three-axis directions manually or by a control signal, and a vertical direction provided on the three-axis adjustment mechanism. And a probe having a coaxial structure or a structure in which the surroundings are shielded by an electric field, and an object of the probe. A probe pressure adjustment detection unit that detects and adjusts the pressure applied to an object, and controls the Z-axis position by feeding back the Z-axis position signal from the probe pressure adjustment detection unit to the triaxial adjustment mechanism. A probing support device for adjusting the pressure of a tip of a probe attached to the arm part to an object and performing high position adjustment. 4. A ground comprising a three-dimensional drive stage, a high frequency coaxial probe, and the probing support device according to claim 3, wherein the outer conductor of the high frequency coaxial probe has a rigidity lower than that of the center conductor of the high frequency coaxial probe. A line is provided, and when the three-dimensional drive stage is raised or when the probing support device according to claim 3 is lowered, the center conductor of the high-frequency coaxial probe is applied to an object to be tested on the three-dimensional drive stage. Along with the contact, the ground wire comes into contact with the three-dimensional drive stage to adjust the load pressure of the center conductor of the high-frequency coaxial probe with respect to the object to be tested and to enable the application of a high-frequency signal. Probe device. 5. The first probing support device of claim 3, comprising an electric field shielded probe needle.
A second probing support device and a three-dimensional drive stage, which is used when the three-dimensional drive stage is raised or the first
When the probing support device and the second probing support device are lowered, the first probing support device and the second probing support device are attached to the same object to be tested on the three-dimensional drive stage.
The probing device is arranged so that the probe needle of the probing support device of 1 is brought into contact with the probe needle, and grounding is performed from the three-dimensional drive stage to enable Kelvin connection. 6. An optical characteristic measuring device, an optical spectrum measuring device, a bias and high frequency signal applying device, a probe device according to claim 4, a probing device according to claim 5, a three-dimensional drive stage, and a plurality of tests. A prober device having a station, wherein the first station of the prober device measures the characteristic value of the object to be tested by using the optical characteristic measuring device and the probing device according to claim 5; In the second station, the optical spectrum measuring apparatus, the probe apparatus according to claim 4, and the bias and high frequency signal applying apparatus are used to apply a signal calculated from the characteristic value to the object to be tested. An optical semiconductor modulation spectroscopic test device characterized by inspecting optical characteristics of an object.