JP3290888B2 - Laser length measuring device and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser measuring device used for a positioning sensor, a displacement sensor, a micromachine, and the like utilizing coherency of a semiconductor laser, and a method of manufacturing the same.

[0002]

2. Description of the Related Art FIG. 17 shows a conventional laser measuring device (Journal of Modern Optics).
Optics, Vol. 35, No. 6 (1988) 993-1005, "Silicon-b
ased Integrated Optics Technology for Optical Sens
or Applications (Silicon-based optical sensor integration technology))). As shown in the figure, a lens 23, a beam splitter 24, a phase shifter 25, and a mirror 26 are provided on a Si substrate 21 having a quartz optical waveguide, and a semiconductor laser 22 and a photodiode 28 are externally bonded and mounted on the Si substrate 21. , The distance L to the measurement object 7 is measured.

[0003]

However, in such a laser length measuring device, since the semiconductor laser 22 and the photodiode 28 are externally bonded and mounted on the Si substrate 21, the semiconductor laser 22 and the photodiode 28 are tertiary. Since it is necessary to originally perform alignment, it is difficult to connect the optical waveguide to the semiconductor laser 22 and the photodiode 28, so that manufacturing is not easy and the device becomes large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a laser length measuring device which is easy to manufacture and small in size, and a method of manufacturing the same.

[0005]

In order to achieve this object, according to the present invention, an object to be measured is irradiated with light emitted from a semiconductor laser, reflected and scattered light from the object is detected, and interference light is detected. In the laser-side elongate measuring the moving amount of the object to be measured based on the, disposed on the same substrate,
A semiconductor laser emitting from the first and second end faces, at least two photodiodes, and first to third film-shaped optical waveguides including a lower cladding layer, a core layer, and an upper cladding layer; One end of the film-shaped optical waveguide is optically coupled to the first end face of the semiconductor laser, the other end is disposed to face the object to be measured, and one end of the second film-shaped optical waveguide is connected to the semiconductor laser. Optically coupled to the second end face, a first gap is provided in the middle, and the second film-shaped optical waveguide is formed such that one part of the first gap bordering the center is the other of the first gap. The third film-shaped optical waveguide is formed so as to have an optical path length difference of (１ ／ + integer) times the used wavelength as compared with the portion, and the first film-shaped optical waveguide and the second film-shaped The semiconductor laser of the second film-shaped optical waveguide is formed so as to intersect with the optical waveguide. Two optically coupled to at least one of the end opposite to the coupled end or the end of the third film-shaped optical waveguide that intersects with the second film-shaped optical waveguide A first groove having a function of a half mirror is provided at an intersection of the first film-shaped optical waveguide and the third film-shaped optical waveguide, and the second film-shaped optical waveguide is A second groove having a function of a half mirror is provided at the intersection with the third film-shaped optical waveguide.

In this case, a second gap is provided in the middle of the first film optical waveguide, and the semiconductor laser side of the second gap is formed in a convex arc shape, and the second film optical waveguide is formed. Is provided, and the semiconductor laser side of the third gap is formed in a convex arc shape.

Further, the first and second grooves are filled with a material having a different refractive index from the surroundings.

Further, a cylindrical lens is provided at the other end of the first film-shaped optical waveguide.

The material of the first to third film-shaped optical waveguides is fluorinated polyimide or quartz glass.

In the method of manufacturing a laser length measuring device, the first to third film-shaped optical waveguides are formed on a Si substrate, a SiC substrate or an AlN substrate, and then the semiconductor laser chip and the photodiode chip are activated. The semiconductor laser chip and the photodiode chip are bonded such that the height of the layer substantially coincides with the height of the center of the core layer of the first to third film-shaped optical waveguides.

In the method for manufacturing a laser length measuring device, the photodiode is formed on a Si substrate, a SiC substrate or an AlN substrate, and the first to third film-shaped optical waveguides are formed. The semiconductor laser chip is bonded such that the height of the active layer of the chip is substantially equal to the height of the center of the core layer of the first to third film-shaped optical waveguides.

In the method of manufacturing a laser length measuring device, the semiconductor laser and the photodiode are formed on the same substrate, and then the first to third film-shaped optical waveguides are connected to the semiconductor laser. First, the second end face is formed so as to cover the light receiving end face of the photodiode.

[0013]

FIG. 1 is a schematic plan view showing a laser length measuring device according to the present invention, FIG. 2 is an enlarged sectional view taken along line AA of FIG. 1, and FIG. 3 is an enlarged sectional view taken along line BB of FIG. is there. As shown in the figure,
The semiconductor laser 1 is monolithically mounted on a substrate 5555 made of GaAs, and the photodiodes 2111, 2112, 2211, 2212, and 2 have the same sectional structure as the semiconductor laser 1.
221, 2222, first to fluorinated polyimide
Third film optical waveguides 31 to 33 are provided. One end of the film optical waveguide 31 is optically coupled to the first end face (etched mirror) 11 of the semiconductor laser 1, and the other end of the film optical waveguide 31 is One end of the film optical waveguide 32 is optically coupled to the second end face (etched mirror) 12 of the semiconductor laser, and the film optical waveguide 33 is formed of the film optical waveguide 31 and the film optical waveguide 31. The photodiodes 2221 and 2222 are optically coupled to the end of the film-shaped optical waveguide 32 opposite to the end optically coupled to the semiconductor laser 1, and are formed so as to intersect with the optical waveguide 32. Photodiodes 2211 and 2212 are optically coupled to the end on the side intersecting with the optical waveguide 31, and the photodiodes 2111 and 2112 are provided on the end of the film optical waveguide 33 on the side intersecting with the film optical waveguide 32.
Are optically coupled. Each of the film-shaped optical waveguides 31 to 33 includes a lower clad layer 3131, a core layer 3132, and an upper clad layer 3133.
A cylindrical lens 4 is disposed at the other end of the lens, and the cylindrical lens 4 converts a light beam spread in a vertical direction, that is, a direction perpendicular to the substrate 5555, into a substantially parallel light beam. Also,
Total reflection mirrors 1031 and 1031 are provided on the film-shaped optical waveguides 31 and 32.
32, a gap 322 is provided in the middle of the film-shaped optical waveguide 32, and one end of the gap 322 with respect to the center of the film-shaped optical waveguide 32 has a wavelength of the used wavelength as compared with the other part of the gap 322. It is formed so as to have an optical path length difference of (1/4 + integer) times. That is, the wavelength in the atmosphere is λ, and the integer is m
Then, the optical path length difference d of the gap 322 is expressed by the following equation.

[0014]

## EQU1 ## d (n-1) = {(1/4) + m} .λ In this embodiment, m = 1 is selected and the optical path length difference d = 1.94.
μm (n: 1.54). Also, the film-shaped optical waveguide 31
Cladding layer 313 at the intersection of the optical waveguide 33 and the optical waveguide 33
A first groove 313 having an angle with respect to the light traveling direction is formed in a part of the groove 3 by etching, and the groove 313 has a function of the half mirror 51, and is formed between the film-shaped optical waveguide 32 and the film-shaped optical waveguide 33. A second groove 323 having an angle with respect to the traveling direction of light is formed in a part of the upper cladding layer 3133 at the intersection by etching, and the groove 323 is formed by the half mirror 52.
With the function of. The grooves 313 and 323 are filled with a material having a different refractive index from the surroundings. Note that the characteristics of the half mirrors 51 and 52, that is, the ratio between the amount of transmitted light and the amount of reflected light can be controlled by the width of the grooves 313 and 323, and the reflectance can be increased by increasing the width of the grooves 313 and 323. it can. Further, a second gap 311 is provided in the middle of the film-shaped optical waveguide 31 by etching, and the semiconductor laser 1 side of the gap 311 is formed in a convex arc shape. A gap 321 is provided, the semiconductor laser 1 side of the gap 321 is formed in a convex arc shape, and the gaps 311 and 321 have a lens function of converting a light beam spread in a lateral direction, that is, a direction parallel to the substrate 5555, into a substantially parallel light beam. Then, as shown in FIG. 1, when the coordinates are represented by the X axis and the Y axis with the origin of the lens shape as the origin, and the parameters representing the lens shape of the gap 311 (321) are C and m, the shape of the gap 311 (321) Has a quadratic curve pattern shape expressed by the following equation.

[0015]

Y = CX ² / {1 + √ (1−C ² mX ² )} Note that the first gap and the third gap may be provided at different positions. The semiconductor laser 1 has an active layer 4444. The semiconductor laser 1 is provided with a front ohmic electrode 82 and a back ohmic electrode 83.
2 is connected to an electrode pad 81.

Next, the operation of the laser measuring device shown in FIGS. 1 to 3 will be described. When a current flows from the electrode pad 81 of the semiconductor laser 1 and a current is injected from the front ohmic electrode 82 to the back ohmic electrode 83, the semiconductor laser 1 oscillates and a light beam is emitted from the vicinity of the active layer 4444 on the end faces 11 and 12 of the semiconductor laser 1. 61 and 62 are emitted, and the light beams 61 and 62 are transmitted while spreading in the horizontal direction while being constrained in the film-shaped optical waveguides 31 and 32 in the vertical direction.
The light beams 61 and 62 become substantially parallel light beams in the gaps 311 and 321, and the left and right sides of the light beam 62 passing through the film-shaped optical waveguide 32 are 90 degrees from the center of the film-shaped optical waveguide 32 by the gap 322. And transmitted as a light beam having a phase difference of Thereafter, the light beam 62 is split into the light beams 621 and 622 by the half mirror 52, and the light beam 61 is split into the light beams 611 and 61 by the half mirror 51.
2, the light beam 611 is emitted to the outside of the film-shaped optical waveguide 31, and hits the measurement object 7 having high external reflectance. Then, the light beam 611 is again incident on the film-shaped optical waveguide 31. A part of the light beam 611 is reflected by the half mirror 51, and the reflected light beam 6111 is split into light beams 61111 and 61112 by the half mirror 52,
The light beam 61111 transmitted through the photodiode 21
11 and 2112, the light beam 622 is also received by the photodiodes 2111 and 2112, and the light beam 612 is received.
Are received by the photodiodes 2211 and 2212. The light beam 61112 reflected by the half mirror 52 is received by the photodiodes 2221 and 2222, and the light beam 621 is also received by the photodiodes 2221 and 2222. Then, the sinusoidal curve I _A displacement in the photodiode 2111, 2112 with the (moving) a phase as shown in FIG. 4 different 90-degree measurement object 7, although I _B obtained, gap 322 strictly speaking It is difficult to form an optical path length difference d having a phase that differs by exactly 90 degrees due to the error δ
Occurs. However, by comparing the difference and the sum of the signals of the photodiodes 2111 and 2112, a signal having a phase difference of 90 degrees can always be obtained, so that the displacement measurement accuracy can be made 0.1 μm or less.

Next, a method of manufacturing the laser measuring device shown in FIGS. 1 to 3 will be described. First, 6FDA obtained by copolymerization of acid dianhydride 6FDA and organic diamine TFDB
/ TFDB and PMDA / TFDB obtained in the same manner
(The refractive indices of both are 1.533 and 1.541, and the refractive index difference Δn
= 0.008). Next, the semiconductor laser 1 and the six photodiodes 2111 and 211
2, 22, 211, 2212, 2221, 2222 are produced. In this case, as shown in FIGS. 5 and 6, the semiconductor laser 1 and the photodiodes 2111, 2112, 221 are used.
A surface ohmic electrode 82 is provided on the upper surface of the ridge of each of 1, 2, 212, 2221, 2222, and an insulating film 333 and a pad electrode film 81 are formed. In this case, the end faces 11 and 12 of the semiconductor laser 1 are formed by etching a total depth of 8 μm of 5.5 μm below and 2.5 μm above the active layer 4444 using a reactive gas of pure chlorine. Next, as shown in FIG. 7, after applying a fluorinated polyimide having a refractive index of 1.533, the film-shaped optical waveguide 3 was baked to cause a dehydration reaction.
The lower cladding layers 3131 of 1 to 33 are formed. The thickness T of the lower cladding layer 3131 is the end face 1 of the semiconductor laser 1.
Except for the vicinity of 1 and 12, it was 3.9 μm against the target of 4 μm. Next, as shown in FIG. 8, a refractive index 1.541 different from the lower cladding layer 3131 and having a different refractive index.
Of the fluorinated polyimide material, and sintering the core layer 31
32 are formed. In this case, the refractive index difference Δn is 0.008
Since the thickness of the core layer 3132 at which a single mode can be obtained is 3.5 μm, the target thickness of the core layer 3132 at this time is 3 μm. Actually, it was 3.0 μm, which was almost the target. After this, FIG.
As shown in FIG. 5, the portion exposed to the oxygen plasma is SiO 2
A photosensitive resist changes ₂ SPP (Silicone-ba
After photolithography of a propagation path for guiding light using a sed positive resist (resist 91), a slope portion 101 (FIG. 8) generated near the end faces 11 and 12 of the semiconductor laser 1 in an oxygen gas atmosphere is removed. Remove with reactive etching. The etching depth at that time was 4 μm, which was slightly oversized. The width L ₁ is 10 between the end face of the core layer 3132 and the end faces 11 and 12 of the semiconductor laser 1.
A gap 102 of μm is formed. In this reactive etching, the lower cladding layer 3131 includes the semiconductor laser 1, the photodiodes 2111, 2112, and 221.
1, 2222, 2221, 2222. Therefore, even if the core layer 3132 is over-etched, the end faces 11 and 12 of the semiconductor laser 1 may be subjected to ion bombardment during etching because the end faces 11 and 12 of the semiconductor laser 1 are covered with the fluorinated polyimide. Therefore, the characteristics of the semiconductor laser 1 do not deteriorate. The center of the core layer 3132 is 5.4 μm from the bottom of the etching and the height of the active layer 4444 is 5.5.
there is only 0.1μm deviation L ₂ is the [mu] m, moreover for the core layer 3132 is 3μm and thick, well semiconductor laser 1
The light beam emitted from is transmitted into the core layer 3132. Next, as shown in FIG. 10, the clad layer material is applied again and sintered in the same procedure as the formation of the lower clad layer 3131 to produce the upper clad layer 3133.
The gap 10 between the semiconductor laser 1 and the core layer 3132
Fill 2 as well. In this case, since the viscosity of the fluorinated polyimide was high, it was effective for flattening. After coating and baking, the steps near the end faces 11 and 12 of the semiconductor laser 1 were greatly reduced.
Next, the upper cladding layer 3133 has a width of 10 to 30 μm.
And grooves 313 and 32 inclined at 75 ° with respect to the optical axis.
3 are provided, and half mirrors 51 and 52 are formed. Next, as shown in FIG. 11, fluorinated polyimide having a three-layer structure is processed by a photolithographic technique using an SPP resist 91 and reactive ion etching using oxygen plasma to form film optical waveguides 31 to 33. In processing the film-shaped optical waveguides 31 to 33, total reflection mirrors 1031 and 1031 are used.
32, gaps 311, 321 (322)
Are performed simultaneously. Further, the three fluorinated polyimide layers are etched and, at the same time, the fluorinated polyimide layers on the electrode pads 81 are opened. When etching is performed using oxygen plasma, Au or the like functions as a stopper because the etching rate is small, and the electrode pad 81 having a window is easily formed. Next, as shown in FIG. 12, the back surface is thinned and polished to a thickness of about 100 μm, and the back surface ohmic electrode 83 is formed. Next, the chip of the laser length measuring device is heat-bonded to the Si heat sink (not shown) bonded to the copper header with AuSn solder.

In the present embodiment, the chip of the laser length measuring device of 1.5 mm or less is formed only by the Braina technology for manufacturing the semiconductor laser 1 and the fluorinated polyimide optical waveguide manufacturing technology.
Approximately 250 pieces were easily formed simultaneously on a 2-inch substrate at a yield of 60%, which was one digit smaller than the conventional size of several cm. In addition, since the gaps 311 and 321 have a lens function of converting the light beam spread in the horizontal direction into substantially parallel rays, the measurement can be performed with high accuracy. Further, since the grooves 313 and 323 are filled with a material having a refractive index different from that of the surroundings, dust and the like do not enter the grooves 313 and 323, so that the measurement can be reliably performed. Further, since the cylindrical lens 4 converts the light beam spread in the vertical direction into a substantially parallel light beam, measurement can be performed even when the distance to the measurement object 7 is large. Further, since the film-shaped optical waveguides 31 to 33 made of fluorinated polyimide are used,
Since the light beam can be reliably transmitted, the measurement can be reliably performed.

In the above embodiment, the substrate 5555 made of GaAs is used.
The same can be said for a substrate for high wavelengths such as P.
The present invention does not limit the type of the substrate. Further, in the above-described embodiment, the film-shaped optical waveguides 31 to 33 made of fluorinated polyimide are used. However, first to third film-shaped optical waveguides made of quartz glass may be used. Can reliably transmit the light beam, so that the measurement can be reliably performed.

FIG. 13 is a diagram showing another laser length measuring device according to the present invention. As shown in the figure, six photodiodes 333 are provided on a Si substrate 100 which also functions as a heat sink.
1 to 3336 are formed, the semiconductor laser chip 301 is bonded to the electrode pattern 3337 provided on the Si substrate 100, and total reflection mirrors 1030, 1031, 1032, and 1033 are provided in the middle of the film-shaped optical waveguides 31 and 32. .

Next, a method of manufacturing the laser length measuring device shown in FIG. 13 will be described. First, as shown in FIG. 14, six photodiodes 3331 to 3336 are formed on a Si substrate 100, and an electrode pattern 3337 for bonding the semiconductor laser chip 301 is formed. In this case, as the electrode pattern 3337, in order to increase the adhesion to the base, tens to hundreds of Cr is applied, and then Au is deposited. Next, as shown in FIG. 15, a lower clad layer, a core layer, and an upper clad layer made of fluorinated polyimide are formed in the same manner as described with reference to FIG. The film-shaped optical waveguides 31 to 33 are manufactured by dry etching. In this case, the height of the center of the core layer is
The thickness of the lower cladding layer and the thickness of the core layer are determined so that the heights of the lower cladding layer and the center of the active layer of the photodiodes 3331 to 3336 substantially coincide with each other. In particular,
The thickness of the lower cladding layer is 5 μm and the thickness of the core layer is 4 μm
I made it. The depth of the active layer of the semiconductor laser chip 301 is set to 4.5 μm from the surface, and the electrode pattern 3337 is formed.
Is set to 0.5 μm, and a 2 μm thick AuSn solder film is deposited on the semiconductor laser chip 301 by EB evaporation. Further, at the same time when the film-shaped optical waveguides 31 to 33 are formed, lens-shaped gaps 311 and 321 for forming parallel rays are formed in the film-shaped optical waveguides 31 and 32. A gap 322 for forming a 90-degree phase difference is provided, and total reflection mirrors 1030, 1031, 1032, 1 are provided in the middle of the film-shaped optical waveguides 31, 32.
033 is provided. Next, as shown in FIG. 16, the semiconductor laser chip 301 is bonded with a precision of several μm.
Further, the half mirrors 51 and 55 are manufactured by forming the grooves 313 and 323 in the upper clad layer. In addition,
Since the cleavage accuracy for determining the size accuracy of the semiconductor laser chip 301 is only 10 μm, the gap 37 between the film-shaped optical waveguides 31 and 32 is manufactured with a margin of about 20 to 30 μm. The height accuracy of the active layer depends on the depth of the active layer, which is determined by the thickness accuracy of the crystal growth of the semiconductor laser chip 301, and the thickness of the electrode pattern 3337 and the solder film. Can be controlled by simply placing and heating with the junction down (surface down).
You can bond 01 without any problem. Also, the Si substrate 1
There is no problem since bonding in the direction parallel to 00 may be performed with a precision of several μm.

In the manufacturing method described with reference to the laser length measuring device shown in FIG.
Since the semiconductor laser chip 301 is attached to the surface of the Si substrate 100 by bonding, the semiconductor laser chip 301 may be aligned two-dimensionally, so that the work of connecting the film-shaped optical waveguides 31 and 32 and the semiconductor laser is easy. It is easy to manufacture and the device is small. Also, although the number of bonding steps of the semiconductor laser chip 301 is increased as compared with the laser length measuring device shown in FIG. 1 and the like, since the heat sink is already used for the base, the laser length measuring device chip is further pumped to the heat sink. There is no need to load. In addition, since it is not necessary to form the exposed surface of the active layer of the semiconductor laser by etching and it is sufficient to perform normal cleavage, a highly reliable and long-life laser-side elongate device can be realized even without etching technology. . The semiconductor laser chip 30
When a wavelength of 1 μm or less is used as 1, Si has high sensitivity and can increase the light receiving area.
A high S / N ratio is obtained.

In the above-described embodiment, the photodiodes 3331 to 3336 and the film-shaped optical waveguides 31 to 33 are formed on the Si substrate 100.
A photodiode and first to third film-shaped optical waveguides may be formed on the N substrate. Further, in the above embodiment, S
After the photodiodes 3331 to 3336 were formed on the i-substrate 100 and the film-shaped optical waveguides 31 to 33 were formed, the semiconductor laser chip 301 was bonded.
After forming the first to third film-shaped optical waveguides on the SiC substrate or the AlN substrate, the height of the active layer of the semiconductor laser chip or the photodiode chip and the height of the center of the core layer of the first to third film-shaped optical waveguides. And the semiconductor laser chip and the photodiode chip may be bonded to each other so that the semiconductor laser chip and the photodiode chip are attached to the surface of the Si substrate, the SiC substrate or the AlN substrate by bonding. Since the chip and the photodiode chip need only be aligned two-dimensionally, the connection work between the first to third film-shaped optical waveguides, the semiconductor laser, and the photodiode is easy, so that the manufacturing is easy, and the device is easy to use. It becomes small.

[0024]

As described above, in the laser measuring device according to the present invention, the connection between the first to third film-shaped optical waveguides, the semiconductor laser, and the photodiode is easy, and therefore, the manufacturing is easy. And the device becomes smaller.

Further, a second gap is provided in the middle of the first film-shaped optical waveguide, and the semiconductor laser side of the second gap is formed in a convex arc shape, and the third gap in the middle of the second film-shaped optical waveguide is formed. When the third gap is formed and the semiconductor laser side of the third gap is formed in a convex arc shape, it has a lens function of converting a light beam spread in the lateral direction into a substantially parallel light beam, so that measurement can be performed with high accuracy.

Further, when the first and second grooves are filled with a material having a different refractive index from the surroundings, dust and the like do not enter the first and second grooves, so that the measurement can be performed reliably. .

When a cylindrical lens is provided at the other end of the first film-shaped optical waveguide, the light beam spread in the vertical direction can be made substantially parallel, so that the distance to the object to be measured can be increased. Can be measured even when is large.

Further, when the material of the first to third film-shaped optical waveguides is made of fluorinated polyimide or quartz glass, the light beam can be transmitted reliably, so that the measurement can be performed reliably.

Also, a Si substrate, a SiC substrate or an AlN
After forming the first to third film-shaped optical waveguides on the substrate, the height of the active layer of the semiconductor laser chip or the photodiode chip substantially matches the height of the center of the core layer of the first to third film-shaped optical waveguides. When the semiconductor laser chip and the photodiode chip are bonded to each other, the semiconductor laser chip and the photodiode chip may be aligned two-dimensionally. Therefore, the connection between the first to third film-shaped optical waveguides and the semiconductor laser and the photodiode is performed. Since the work is easy, the manufacture is easy and the device is small.

Further, a Si substrate, a SiC substrate or an AlN
After forming a photodiode on the substrate and forming the first to third film optical waveguides, the height of the active layer of the semiconductor laser chip and the height of the center of the core layer of the first to third film optical waveguides are determined. When the semiconductor laser chips are bonded almost in alignment with each other, the semiconductor laser chips may be aligned two-dimensionally, so that the connection work between the first and second film-shaped optical waveguides and the semiconductor laser is easy. It is easy to manufacture and the device is small.

After the semiconductor laser and the photodiode are formed on the same substrate, the first to third film-shaped optical waveguides are formed so as to cover the first and second end faces of the semiconductor laser and the light receiving end face of the photodiode. Since the work of connecting the first to third film-shaped optical waveguides to the semiconductor laser and the photodiode is easy, it can be easily manufactured and the device can be downsized.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a laser length measuring device according to the present invention.

FIG. 2 is an enlarged sectional view taken along line AA of FIG.

FIG. 3 is an enlarged sectional view taken along line BB of FIG. 1;

FIG. 4 is a graph for explaining the operation of the laser measuring device shown in FIGS. 1 to 3;

FIG. 5 is an explanatory diagram of a method of manufacturing the laser length measuring device shown in FIGS.

FIG. 6 is a partial detailed view of FIG. 5;

FIG. 7 is an explanatory diagram of a method of manufacturing the laser length measuring device shown in FIGS.

FIG. 8 is an explanatory diagram of a method of manufacturing the laser length measuring device shown in FIGS.

FIG. 9 is an explanatory diagram of a method for manufacturing the laser length measuring device shown in FIGS.

FIG. 10 is an explanatory diagram of a method of manufacturing the laser length measuring device shown in FIGS.

FIG. 11 is an explanatory diagram of a method of manufacturing the laser length measuring device shown in FIGS.

FIG. 12 is an explanatory diagram of a method of manufacturing the laser length measuring device shown in FIGS.

FIG. 13 is a diagram showing another laser length measuring device according to the present invention.

FIG. 14 is an explanatory diagram of a method of manufacturing the laser length measuring device shown in FIG.

15 is an explanatory diagram of a method of manufacturing the laser length measuring device shown in FIG.

FIG. 16 is an explanatory diagram of a method of manufacturing the laser length measuring device shown in FIG.

FIG. 17 is a view showing a conventional laser length measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Semiconductor laser 11, 12 ... 1st, 2nd end face 100 ... Si substrate 2111, 2112 ... Photodiode 2211, 2212 ... Photodiode 2221, 2222 ... Photodiode 301 ... Semiconductor laser chip 31-33 ... 1st-3rd film -Shaped optical waveguides 311, 321: second and third gaps 313, 323-first and second grooves 322-first gaps 3331 to 336-photodiodes 4-cylindrical lenses 51, 52-half mirrors 5555-substrate 7 … Measurement target

Continuation of front page (72) Inventor Mieko Tsubamoto 1-3-1 Gotenyama, Musashino-shi, Tokyo NTT Advanced Technology Co., Ltd. (56) References JP-A-62-5106 (JP, A JP-A-63-262504 (JP, A) JP-A-4-30341 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01B 11/00-11/30 G01B 9 / 02 G02B 6/12-6/14

Claims (8)

(57) [Claims] 1. A laser-side length for irradiating a measurement object with light emitted from a semiconductor laser, detecting reflection and scattered light from the measurement object, and measuring a movement amount of the measurement object based on interference light. A semiconductor laser emitting from the first and second end faces, at least two photodiodes, a lower cladding layer, a core layer, and an upper cladding layer disposed on the same substrate. A film-shaped optical waveguide, one end of the first film-shaped optical waveguide is optically coupled to the first end face of the semiconductor laser, and the other end is arranged to face the object to be measured; One end of the optical waveguide is optically coupled to the second end face of the semiconductor laser, a first gap is provided in the middle,
And the first film-shaped optical waveguide at the center of the second film-shaped optical waveguide.
One of the gaps is formed so as to have an optical path length difference of (１ ／ + integer) times the used wavelength as compared to the other of the first gap, and the third film-shaped optical waveguide is The second film-shaped optical waveguide is formed so as to intersect with the first film-shaped optical waveguide and the second film-shaped optical waveguide. Two photodiodes optically coupled to at least one of the ends of the third film-shaped optical waveguide that intersect with the second film-shaped optical waveguide are provided, and the first film-shaped optical waveguide is provided. A first groove having a function of a half mirror is provided at an intersection of the second film-shaped optical waveguide and the third film-shaped optical waveguide. Is a laser measuring device provided with a second groove having a function of a half mirror. 2. A second gap is provided in the middle of said first film optical waveguide, and said semiconductor laser side of said second gap is formed in a convex arc shape. 2. The laser side elongator according to claim 1, wherein an intermediate third gap is provided, and the semiconductor laser side of the third gap is formed in a convex arc shape. 3. The laser-side elongate device according to claim 1, wherein the first and second grooves are filled with a material having a different refractive index from the surroundings. 4. A laser length measuring device according to claim 1, wherein a cylindrical lens is provided at the other end of said first film-shaped optical waveguide. 5. The laser length measuring device according to claim 1, wherein the first to third film optical waveguides are made of fluorinated polyimide or quartz glass. 6. A method for manufacturing a laser length measuring device according to claim 1, wherein the Si substrate, the SiC substrate, or the AlN
After forming the first to third film-shaped optical waveguides on the substrate,
Bonding the semiconductor laser chip and the photodiode chip such that the height of the active layer of the semiconductor laser chip and the photodiode chip substantially coincides with the height of the center of the core layer of the first to third film-shaped optical waveguides; A method for manufacturing a laser length measuring device, comprising: 7. The method for manufacturing a laser length measuring device according to claim 1, wherein the Si substrate, the SiC substrate, or the AlN
After forming the photodiode on the substrate and forming the first to third film optical waveguides, the height of the active layer of the semiconductor laser chip and the center of the core layer of the first to third film optical waveguides are determined. And bonding the semiconductor laser chip so that the height of the semiconductor laser chip is substantially equal to the height of the semiconductor laser chip. 8. A method for manufacturing a laser length measuring device according to claim 1, wherein said semiconductor laser and said photodiode are formed on the same substrate, and then said first to third film-shaped optical waveguides are formed. A method for manufacturing a laser length measuring device, wherein the semiconductor laser is formed so as to cover the first and second end faces and the light receiving end face of the photodiode.