KR101104133B1 - Flexible fiber module, wavelength conversion device package using the same and fabrication method of the same - Google Patents

Abstract

A flexible fiber module is disclosed in which the optical connection power between the optical oscillation module and the polarization inverted waveguide chip module is kept constant regardless of external environment changes. The flexible fiber module is inserted into a welding sus jig equipped with a ceramic ferrule and a ceramic ferrule, and receives the light emitted from the optical oscillation module and transmits it to the polarization inversion waveguide chip module which is emitted as a modulated light. And a fiber for constant optical connection power between the oscillation module and the polarization inversion waveguide chip module.

Wavelength conversion device, periodically poling

Description

Flexible fiber module, wavelength converting device package using same and manufacturing method thereof {Flexible fiber module, wavelength conversion device package using the same and fabrication method of the same}

The present invention relates to a tunable device package, and more particularly, to a flexible fiber module, a tunable device package using the same, and a method of manufacturing the same.

Laser light source technology using polarized inverted nonlinear chips has been tried in various ways. For example, Difference Frequency Mixing, Sum Frequency Mixing, or Optical Parametric Oscillator can be fabricated.

Among them, a second harmonic generation technology, which is a special form of frequency, is applied to fabricate a wavelength light source in the visible light band. This refers to a technology in which a pumped light source having a low frequency is incident on a polarization inverted optical waveguide having a nonlinear characteristic and then converted to a light source having a frequency twice as high.

Theoretically, the power of the second harmonic wave source is determined in proportion to the square of the incident pumping light source power and the square of the length of the nonlinear chip, but the conversion efficiency is 100% due to the loss, absorption loss, and optical connection loss in the optical waveguide. You won't have it.

Representative of second harmonic wave generation technology using nonlinearity is a wavelength tunable laser device.

Important variables in the fabrication of nonlinear wavelength tunable lasers are as follows. Nonlinear coefficient value of the crystal, length of nonlinear sample, power of input pumping light source, line width of input pumping light source, alignment loss and temperature stabilization of pumping light source and optical waveguide, mode of optical waveguide, or waveguide loss of optical waveguide .

To package a waveguide with polarized inverted regions, two temperature stabilization modules must be applied to the laser diode and the polarized inverted waveguide, respectively. In this case, an alignment position shift phenomenon occurs according to each temperature optimization setting value, which causes the optical connection power to change.

A change in the optical connection power of 10% may be caused by a position change of about 1 micron, which causes a problem in that power of the wavelength-variable light source is also lost.

Conversion efficiency to the tunable light source has a characteristic proportional to the power of the input pumping light source. Thus, a 10% power loss causes a 10% conversion efficiency reduction.

1 is a block diagram of a nonlinear optical oscillator using a laser diode according to the prior art.

A laser diode 11 for outputting a laser and a light focusing lens 14 for focusing the output laser and irradiating the Ti diffusion waveguide 13 in which the polarizations 16 and 17 are periodically inverted on the ferroelectric crystal 12. And an optical collimation lens 15 for adjusting the focus of the laser light output from the optical waveguide 13.

While conventional Ti diffusion waveguides have advantages in terms of waveguide mode control and waveguide loss minimization, they have material problems due to photorefractive phenomena.

Optical refraction refers to a phenomenon in which the refractive index changes due to the intensity of the light source traveling through the optical waveguide. In general, in the case of a Ti diffusion waveguide, a photorefraction phenomenon occurs even for an input light source of 1 mW.

As a result, in the case of a tunable laser using a Ti diffusion waveguide, only a light source of less than 1 mW is possible. In general, when the optical connection method using the lenses 14 and 15 is applied, alignment is difficult and the connection loss is large.

In addition, after aligning the light focusing lens, the Ti diffusion waveguide and the light collimation lens in the path of the laser light output from the laser diode, there is a problem that the optical power is sensitively changed according to the external environment change and the set temperature.

2 is a block diagram of a nonlinear wave guide according to another conventional technique.

The optical waveguide 21 forms a thin film by depositing TiO ₂ -doped-Ta ₂ O ₅ on the LiNbO ₃ nonlinear crystal wafer 220, and then patterned to form periodic polarization inversions 16 and 17.

The period of the periodic polarization inversion grating is determined by the wavelength of the secondary harmonic wave to be generated.

By controlling the thickness and width of the TiO ₂ -doped-Ta ₂ O ₅ thin film and controlling the refractive index change (2.2 to 2.4) according to the doping amount, it is configured to optimize the waveguide mode of the pumping light source and the second harmonic wave light source.

When the optical waveguide having the polarization inversion region of the rib structure is formed by using thin film deposition, the refractive effect of the light of the diffusion waveguide can be alleviated somewhat, but the ratio of Ti / (Ti + Ta) is controlled to control the refractive index. As a result, there is a disadvantage in that the light refractive effect occurs.

In addition, when the optical connection method using the existing lens is applied, the optical connection loss occurs due to temperature control.

In particular, the optical waveguide and the wave guide according to the conventional technology described above have a disadvantage in that each component is difficult to align according to the laser light path due to external environmental factors. Due to this, aspects such as optimization of the loss between the input light source and the optical waveguide and the improvement of the structure for selecting and miniaturizing the packaging structure during device fabrication have not been realized yet.

The present invention has been made to solve the above-described problems, by combining the polarization inversion technology, precision processing technology, precision patterning technology, optical waveguide technology, conversion efficiency optimization technology according to the optical waveguide shape and temperature control technology, light weight, small size And a method for fabricating a variable wavelength device with low power consumption.

An object of the present invention is to provide a flexible fiber module and a method of manufacturing the same to maintain a constant optical connection power regardless of external environment changes.

Still another object of the present invention is to provide a wavelength tunable device package and a method of manufacturing the same using the flexible fiber module.

The object of the present invention is not limited to the above-mentioned object, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

The flexible fiber module according to an aspect of the present invention for achieving the above object is a ceramic ferrule (ferrule), a welding sus jig (SUS) jig equipped with a ceramic ferrule, inserted into the ceramic ferrule and received from the optical oscillation module And a fiber which is transmitted to the polarization inversion waveguide chip module for modulating the wavelength of the light, and which has constant optical connection power between the optical oscillation module and the polarization inversion waveguide chip module.

According to another aspect of the present invention, there is provided a method of manufacturing a flexible fiber module, the method comprising: fastening a welding sus jig equipped with a ceramic ferrule with a fixing gripper; inserting a fiber into the ceramic ferrule; and And an alignment step, a fiber fixing step of fixing the fiber to the ceramic ferrule, a step of ending the fiber formed at one end of the welding jig connected to the polarization inversion waveguide chip, and a polishing step of the finished fiber.

According to another aspect of the present invention, a wavelength tunable device package includes an optical oscillation module that emits light from a light source, and a polarization inverted waveguide chip module and an optical oscillation module that receive light emitted from an optical oscillation module to generate a second harmonic wave. It includes a flexible fiber module for focusing the light emitted from the polarization inversion waveguide chip module.

According to another aspect of the present invention, there is provided a method of fabricating a tunable device package using a flexible fiber module, including manufacturing a flexible fiber module, arranging an optical oscillation module including a flexible fiber module and a laser diode chip, and a flexible fiber module and polarization reversal. Aligning the chip modules.

 According to the present invention, the path through which light passes may be limited to several micro ranges, thereby maximizing the wavelength variable conversion efficiency to maximize the characteristics of the wavelength variable element.

In addition, the packaging process using a flexible fiber module utilizes a fiber curvature radius tolerance characteristic that is independent of the loss of the flexible fiber module, thereby allowing the light of the laser diode chip to pass through the optical waveguide of the polarization inversion wavelength variable chip regardless of the tolerances between the packaging components. By focusing on and maintaining this, it is possible to maximize the power stability characteristics of the tunable device.

In addition, it is possible to reduce the loss due to the optical connection by using the radius of curvature of the flexible fiber module that does not cause loss even if misalignment occurs.

In addition, productivity and reliability can be improved in the fabrication of the tunable device using a packaging process using only laser welding.

In addition, the wavelength tunable device using the flexible fiber module according to the present invention is particularly applicable to the fabrication of a light source for a small display using a laser in the visible wavelength region, and laser spectroscopy and environmental monitoring in the IR and UV wavelength region. Application is possible for various purposes such as gas and chemical composition analysis and process control.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be embodied in various different forms, and only the present embodiments make the disclosure of the present invention complete, and those of ordinary skill in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims.

The present invention is the diode laser pumping light source and pumping light source submount design, optical connection technology using a flexible fiber module, polarization reversal technology, precision processing technology, precision patterning technology, optical waveguide technology, conversion efficiency optimization technology and temperature according to the optical waveguide shape By incorporating control technology, it is possible to fabricate small, light weight and low power consumption wavelength converting laser devices.

Hereinafter, a structure and a manufacturing process of a wavelength tunable device package using a flexible fiber module according to an embodiment of the present invention will be described with drawings. First, the structure of the wavelength tunable device package will be described with reference to FIGS. 3 to 5B, and the manufacturing process of the wavelength tunable device package will be described with reference to FIGS. 7A to 9D.

3 is a schematic block diagram of a wavelength tunable device package according to an embodiment of the present invention.

Referring to FIG. 3, the wavelength variable element package according to the exemplary embodiment of the present invention includes an optical oscillation module 100, a flexible fiber module 200, and a polarization inverting waveguide chip module 300.

The optical oscillation module 100 includes a light source, and emits light from the light source to the flexible fiber module 200, and the emitted light generates a second harmonic wave using the polarization inversion waveguide chip module 300. do. Preferably, the light source uses a laser diode. In addition, it is preferable to use a laser light source including a chip scale diode light source or a light source including a line width control of a wavelength or a tuning function of a wavelength. Hereinafter, the light source is called a laser diode.

The optical wave oscillation module 100 and the polarization reversal chip module 300 are optically connected to the flexible fiber module 200 so that the ultra-compact wavelength variable light source packaging can maintain the optical connection power regardless of external environmental changes and temperature optimization conditions. It is configured to be possible. The packaging configuration will be described in detail with reference to FIGS. 4A to 4C.

4A is a perspective view of a wavelength tunable device package according to an embodiment of the present invention, FIG. 4B is a side view of the tunable device package shown in FIG. 4A, and FIG. 4C is a plan view of the tunable device package shown in FIG. 4A. .

4A to 4C, the optical oscillation module 100 of the wavelength variable element package according to the exemplary embodiment of the present invention may include a laser diode temperature controller 110, a laser diode heat dissipation block 120, and a laser diode mount. Block 130, laser diode temperature sensor 140, laser diode chip 150, laser diode power monitoring photodiode 180.

The laser diode temperature controller 110 controls the temperature measured by the laser diode temperature sensor 140. When the light emitted from the laser diode is transferred to the polarization inversion chip module, there is a problem that the power conversion efficiency is lowered due to the optical connection being distorted due to the change of the ambient temperature, so it is necessary to adjust the temperature of the laser diode.

The laser diode heat dissipation block 120 also performs a function similar to that of the laser diode temperature controller 110 and dissipates heat of the laser diode to the outside.

The laser diode mounting block 130 supports the laser diode chip 150, the temperature measuring sensor 140 measuring the temperature of the laser diode, and the photodiode 180 monitoring the power of the laser diode.

The flexible fiber module 200 receives the light emitted from the optical oscillation module 100 and emits the wavelength-modulated light. The flexible fiber module 200 will be described in detail later with reference to FIGS. 7A to 7F.

The polarization inversion waveguide chip module 300 is formed on the polarization inversion waveguide chip 310 including the optical waveguide, the polarization inversion waveguide chip mount block 320 supporting the polarization inversion waveguide chip, and the polarization inversion waveguide chip mount block. And a polarization reversal waveguide chip temperature control unit 330 for measuring the temperature of the polarization inversion waveguide chip, and a polarization inversion chip temperature control unit 350 formed under the polarization inversion waveguide chip mount block 320 to control the temperature of the optical waveguide.

The polarization inversion waveguide chip 310 includes an optical waveguide 314 through which light propagates, an optical waveguide support block 311, a cladding layer 312 for preventing light from being emitted, and an optical waveguide surface protection block for protecting an optical waveguide surface. ).

The optical waveguide 314 is configured with a polarization period of λ. In the polarization reversal period, the polarization direction of the crystal is made 50% + polarity and 50%-polarity. The optical effect of the periodic polarization inversion region causes the input pumping light source to be converted to another wavelength.

The nonlinear wavelength tunable device using the optical waveguide 314 is a method using birefringence or using periodic polarization inversion as in the present invention. The quasi phase matching period (QPM) of the tunable device is determined by applying the target wavelength to be generated, the temperature applied to the wavelength variable, and the wavelength of the input pumping light source. Determination of the QPM period can be briefly determined by the following equations (1) and (2).

Where n is the refractive index, p is the wavelength of the input pumping light source, λs is the wavelength of the signal light source, λi is the wavelength of the idler light source, λg is the polarization reversal period, m is the pseudo-phase matching (QPM) order and k is the phase difference. .

Here, the second harmonic wave has the same wavelength of lambda s and lambda i, and this wavelength can be used as an input pumping light source to generate a new lambda p. This is called a second harmonic generation.

As shown in Equation 2, it can be seen that the refractive index must be adjusted to fix the wavelength, fix the polarization inversion period, and make k equal to zero.

The method applied for adjusting the refractive index is to control the temperature of the device. It is desirable that the polarization period be precisely designed so that the refractive index control temperature at which k is zero has the most suitable temperature for use with the device. However, this suitable temperature may vary depending on the fabrication tolerances of the device.

Due to the temperature control requirement, the optical connection method using a single lens, which is one of the conventional laser diode packaging methods, has a problem of causing optical connection loss due to temperature control.

In order to solve such a problem, the present invention proposes an ultra-small wavelength variable element packaging method having an optical connection structure using the flexible fiber module illustrated in FIG. 4A.

Optical thin film layers 340 and 350 exist on both sides of the polarization inversion waveguide chip 310. The optical thin film layer connected to the laser diode light source forms an anti-reflection layer 340 with respect to the incident wave emitted from the laser diode, and the optical thin film layer on the side of the incident wave after the incident wave passes through the optical waveguide is the incident wave and the incident wave. The antireflection layer 340 is formed with respect to the second harmonic wave.

The polarization inversion waveguide chip mount block 320 supports the polarization inversion waveguide chip 310, and since one end of the flexible fiber module 200 is angle polished in consideration of the refractive index of the optical waveguide 314, the polarization inversion waveguide chip 310 is formed. It is preferable that the polarization inverting waveguide chip mount block 320 for mounting () is inclined at a predetermined angle.

The polarization inversion waveguide chip temperature measurement sensor 330 is located on the upper surface of the mount block 320 and is bonded to the mount block by solder and paste.

A fixing jig 340 is formed below the mounting block 320 to support the mounting block 320, and a temperature for controlling the temperature of the polarization reversing chip 310 is provided on the lower surface of the fixing jig 340. The adjusting unit 350 is attached. The fixing jig 340 and the temperature control unit 350 are bonded with a predetermined bonding material.

On the other hand, the optical oscillation module 100 and the polarization inverted waveguide chip module 300 is connected through the assembly jig 190 at the bottom. The laser diode temperature control unit 110 of the optical oscillation module 100 and the polarization inversion waveguide chip temperature control unit 350 of the polarization inversion waveguide chip module 300 are connected through the assembly jig 190.

FIG. 5A is a side view of a wavelength tunable device package according to another embodiment of the present invention, and FIG. 5B is a plan view of the wavelength tunable device package shown in FIG. 5A.

5A and 5B illustrate polarization reversal of a welding fiber for fixing a flexible fiber module in a package for fixing an alignment position between a flexible fiber module 200 for optical connection, a diode laser chip 150 and a polarization inversion waveguide chip 310. An embodiment applied to both ends of the waveguide chip 310 is represented.

In the wavelength variable element package disclosed through FIGS. 4A to 4C, only one end of the flexible fiber module 200 connected to the light source direction is fixed through the welding saddle, but the welding saddle and the welding jig are illustrated in FIGS. 5A and 5B. Add both to fix both ends of the flexible fiber module 200.

Fixing both ends of the flexible fiber module 200 causes an increase in the material cost due to an increase in packaging parts, but has the advantage of maximizing the productivity and reliability of the alignment and bonding process by joining the entire process by laser welding. do.

Figure 6a shows an example of the periodic polarization inversion of the polarization inversion waveguide chip according to the present invention, Figure 6b is the power of the second harmonic wave generated as the input pumping light source proceeds inside the polarization inversion waveguide chip according to the present invention. Graph showing increase.

When the light emitted from the input pumping light source passes through the nonlinear chip to generate a new converted wavelength, it is important to increase the conversion efficiency.

When generating a second harmonic wave using a nonlinear chip, the conversion efficiency (P _{2 ω} / P _ω ) has characteristics that are proportional to the square of the nonlinear coefficient, the square of the nonlinear chip length, and the power of the input pumping light source. It is inversely proportional to the square of the diameter of the light source passing through it.

Therefore, when the wavelength variable element using the optical waveguide 314 is manufactured, the wavelength variable conversion efficiency (P _{2 ω} / P _ω ) can be maximized by adjusting the passage through which the light source passes to several micros (μm). Through such a configuration, it is possible to manufacture a compact, low-cost secondary harmonic wave light source laser.

6A to 6B, when Lc determining the periodic polarization inversion width is an odd multiple of lambda / 2, a second harmonic is generated, and an even multiple is not generated. In addition, it can be seen that the conversion efficiency is maximum when Lc is λ / 2 (that is, m = 1).

The Perfect PM (Phase Matching) curve is applied in a method using a birefringent optical axis rather than a QPM, but in this case, the nonlinear coefficient d33 has a significantly lower value than the method applied in QPM. Therefore, although the nonlinear conversion efficiency appears high in the graph shown in FIG. 6B, the conversion efficiency is smaller than that of the QPM method in actual application.

7A to 7F are views illustrating a manufacturing process of a flexible fiber module according to an embodiment of the present invention.

7A to 7F, the ultra-small wavelength variable device packaging structure using the nonlinear chip according to the present invention may be applied to a polarization inverted waveguide chip manufactured by applying various ferroelectric substrates (eg, Z-Cut MgO: LiNbO ₃ ). have. A diode laser may be used as the input pumping light source, and a ridge structure may be used as the optical waveguide.

The flexible fiber module manufacturing component is a ceramic ferrule 110 for inserting and fixing fibers as shown in FIG. 7, a welding SUS jig 120 equipped with a ceramic ferrule 110, a fixing gripper 140, and a fiber 130. It consists of).

First, the welding SUS jig 120 mounted with the ceramic ferrule 110 is fastened with the fixing gripper 140 (FIG. 7A).

Thereafter, the fiber 130 is inserted into the ceramic ferrule 110 (FIG. 7B). At this time, care must be taken not to damage the end of the fiber 130 to align with the laser diode 150.

The fiber 130 is aligned by holding the fiber opposite the fiber 130 that aligns with the laser diode 150 and performing rotational alignment as shown in FIG. 7C (FIG. 7C). Rotational alignment is essential for Wedge-type fibers, while rotational alignment is not required for spherical fibers because they are radially symmetrical. Set the exact fiber position by vision checking the tip protrusion at the same time as the rotation alignment.

Epoxy is injected to fix the fiber 130 and an epoxy curing process (generally, thermal curing) is performed to fix the fiber (FIG. 7D) while the position of the fiber 130 is fixed.

The end of the epoxy curing process is finished fiber as shown in Figure 7e, the gripper 140 is fixed to the fiber polishing jig is mounted in the state to perform an 8 degree angle polishing as shown in Figure 7f. The 8 degree angle polishing operation is to prevent the reflected light from being incident back to the laser diode 150 to prevent the laser diode from being broken or unstable.

8A to 8C are views illustrating a manufacturing process of the polarization inversion waveguide chip module according to the present invention.

The polarization inversion chip module 300 according to the present invention includes a polarization inversion waveguide chip mount block 320, a polarization inversion waveguide chip 310, a polarization half polarization temperature measuring sensor 330, a light waveguide 314, and an optical waveguide. The substrate 311 includes a support substrate 311, a cladding layer 312 for preventing light emission, an optical waveguide surface protection substrate 313, and optical thin film layers 340 and 350.

The temperature measuring sensor 330 is preferably soldered and paste bonded to the polarization inversion waveguide chip mount block 320.

The material of the polarization inverting waveguide chip mount block 320 is preferably W-Cu, but various materials such as silicone, AlN, or SiC may be applied as a thermal conductor.

The optical thin film layers 340 and 350 should be variously applied according to the wavelength variable center wavelength. For example, in the case of generating the second harmonic wave, when the 532 nm second harmonic wave is generated using a 1064 nm pumped light source, the optical thin film layer forms the antireflective thin film layer 340 for 1064 nm and the optical thin film layer 350 has two wavelengths of 1064 and 532 nm. It is preferable to form an antireflective thin film layer.

The manufacturing process of the polarization inversion waveguide chip 310 is as follows.

First, a seed layer and a photoresist layer are sequentially formed on the ferroelectric substrate. Thereafter, a photoresist pattern is formed by a photolithography process. A Ni film is formed in the space between the photosensitive film patterns, and the photosensitive film pattern is removed. Only the Ni thin film remaining on the ferroelectric substrate to serve as a mask for etching the substrate is left.

The ferroelectric substrate on which the metal mask is manufactured is etched to a depth of about 1-10 μm by a dry or wet etching method. After forming a metal electrode on the non-etched surface of the ferroelectric, a periodic polarization inversion is performed by applying an external electric field to the electrode.

Alternatively, the organic material such as a photoresist may be patterned on the etching surface of the substrate, and then an external electric field may be applied and polarized inverted using a conductive solution such as LiCl.

Since the optical waveguide 314 is formed on the surface of the substrate, if there are irregularities etched on the surface, the optical waveguide 314 is damaged and cannot be used as an element. Therefore, the uneven part of the substrate should be removed.

In more detail, the substrate is attached onto the circular jig surface made of ceramic using thermal wax. At this time, the attached substrate and the ceramic circular jig should have a flatness of less than 1 ~ 3㎛ for uniform polishing, polishing the attached substrate using a lapping machine and a chemical mechanical polishing machine.

The completed periodic polarization inversion substrate can be obtained by performing a washing process on the prepared substrate.

Ridge-type optical waveguide fabrication process in the z-axis ferroelectric crystal is as follows.

A z-axis substrate on which a waveguide is formed by a dry etching process is manufactured using the substrate having the above-described polishing.

Ni, Ti, Cr, photosensitizer, etc. may be used as a material of the mask required for the etching process.

When a mask for etching is formed on a periodic polarization inversion ferroelectric substrate, the etching process is performed to a depth of about 3 to 15 micro. The etched ferroelectric has an angle of about 65 ° to 85 ° and a trapezoidal optical waveguide having a wide bottom and a narrow top is formed.

The waveguide and the dummy substrate thus formed may be bonded using the same material as the ferroelectric substrate or a glass-based substrate having a low refractive index. On the dummy substrate, a curable epoxy or wax that is cured by UV or heat treatment is applied using spin coating or direct bonding.

When epoxy or wax is applied on the dummy substrate, the surface etched on the ferroelectric substrate is bonded to the dummy substrate, and then the bonding surfaces of the two substrates are cured using ultraviolet rays or heat.

In the case of direct bonding, the bonding strength is increased after attaching the substrate. In this case, the distance between the two substrates should be uniform, and defects such as foreign matter or vacancy between the substrates should be removed in advance.

9A to 9D are views illustrating a wavelength tunable device package assembly process using the flexible fiber module illustrated in FIG. 5.

In order to manufacture the wavelength tunable device package according to an embodiment of the present invention, a laser diode module (optical oscillation module) 100 is prepared, a flexible fiber module 200 and a laser diode module 100 are aligned, a flexible fiber module 200 and the polarization reversal chip module 300 alignment step, and final outer housing assembly step.

1) Laser Diode Module Preparation Step

In the preparation step of the laser diode module 100, the laser diode module 100 includes a temperature control unit 110, a heat dissipation block 120, a mount block 130, a temperature measuring sensor 140, and a laser diode of the laser diode. A chip 150, a power monitoring photodiode 180, a polarization inversion chip temperature controller 350, an assembly jig 190, and welding birds 210 for fixing the flexible fiber module are included.

The diode laser chip 150, which is an input pumping light source, is the windy diode light source, and a diode light source including a line width adjusting function or a tuning function of a wavelength may be applied.

The laser diode mount block 130 may be applied with various materials such as Silicon, AlN, W-Cu, or SiC.

First, the laser diode heat dissipation block 120 and the laser diode mount block 130 are solder bonded.

Solder bonding requires an Au metal plating or thin film deposition layer, which is completed prior to the bonding process.

When soldering, the die bonder is used for precise position control.

After AuSn solder is deposited on the submount and patterned to have a desired shape, the blocks to be bonded are aligned with the solder bump patterns, and then a pressing force is controlled and bonded using various heat sources such as an ultrasonic wave, a laser, or a metal resistance plate heater.

In the same way, the temperature measurement sensor 140, the diode laser chip 150, the laser diode temperature controller 110, the polarization inverted waveguide chip temperature controller 350 and the assembly jig through the precise position control using the die bonder equipment. Solder bonding (190) to prepare a laser diode module.

Among the solder types, various solders such as Au-Sn, Sn-Ag, Sn-Ag-Cu, and Sn-Bi can be selectively applied. Solder temperature varies by solder type, allowing you to select a solder with the appropriate temperature for the multistage joining sequence.

In addition, in the case of the laser diode temperature control unit 110 and the polarization inversion waveguide chip temperature control unit 350 that require a low temperature bonding process, it is preferable to bond using a bonding material such as silver paste.

2) Flexible Fiber Module and Laser Diode Module Alignment Step

Loss of optical connection between the flexible fiber module 200 and the laser diode chip 150 is achieved by mounting and fixing the jig of the equipment for aligning the flexible fiber module 200 for optical connection and using a precision control stage or automated alignment equipment. Align it to the minimum.

 When the alignment is completed, mounting the flexible fiber module fixing welding saddle 210 as shown in Figure 4b and using a laser welder laser diode heat dissipation block 120 and the flexible fiber module 200 is the welding saddle ( The laser is irradiated and bonded so as to be fixed by 210.

3) Fiber and polarization reverse waveguide chip alignment step

The optical connection process between the polarization inversion waveguide chip module 300 and the flexible fiber module 200 includes a flexible fiber module 200 for optical connection, a polarization inversion waveguide chip mount block 320, a polarization inversion waveguide chip 310, The temperature measuring sensor 330, the polarization inversion waveguide chip mount block fixing jig 340, the bonding material 360 of the polarization inversion waveguide chip mount block fixing jig 340 and the polarization inversion waveguide chip temperature control unit 350 and the optical thin film layer ( 210 is a step of combining.

The light emitted from the laser diode chip 150 has a constant polarization direction (TE mode), and the polarization inversion direction inside the optical waveguide 314 of the polarization inversion waveguide chip 310 coincides with the polarization direction of the laser diode chip.

As shown in FIG. 8C, the polarization inversion chip is mounted on the mount so that the polarization inversion direction matches the polarization direction of the light emitted from the laser diode chip.

When the polarization inversion waveguide chip 310 is fabricated using Z-Cut LiNbO ₃ nonlinear crystals, the nonlinear photonic crystals may be X, Y, Z-cut or arbitrary axes depending on the wafer cutting axis.

Accordingly, the axis forming the periodic polarization direction may be applied differently from the direction of the optical waveguide 310 shown in FIG. 8C, and in this case, the mount direction of the polarization inversion waveguide chip 310 may be changed. Thus, the present invention does not exclude the variety of the mount directions.

In order to align the polarization inversion waveguide chip module 300, the positions of the polarization inversion waveguide chip 310, the mounting block 320, the temperature measuring sensor 330, and the fixing jig 340 constituting the polarization inversion chip module 300 are described. Should be set.

The polarization inversion waveguide chip 310, the mounting block 320, and the temperature measuring sensor 330 are transported while being fixed to the jig of the equipment for alignment.

The fiber 314 is optically aligned using a precision control stage (not shown) mounted to the polarization inversion waveguide chip module 300 in a fixed state, and is aligned so that the optical connection loss is minimized.

At this time, a bonding material such as a silver paste is previously applied to a gap between the polarization inversion waveguide chip mount block 320, the polarization inversion waveguide chip mount block fixing jig 340, and the polarization inversion waveguide chip temperature control unit 350, and the fiber ( 314) and the polarization inversion waveguide chip 310 after the alignment and alignment position fixing so that the whole part can be bonded fixed on the room temperature or hot plate.

When the optical alignment using the precision control stage (not shown) is completed, the alignment position of the two components is epoxy fixed by applying UV epoxy to the gap between the fiber 314 and the polarization inversion waveguide chip 310 and irradiating UV.

When the alignment position fixing is completed, the assembly is detached from the alignment equipment, and as described above, the curing process of the pre-coated silver paste is completed to complete all the packaging processes.

 4) Final outer housing assembly process

The completed assembly described above is mounted on the final outer housing to complete electrical wiring such as wire bonding and soldering, and to perform airtightening to evaluate the final product characteristics.

The assembly jig 190 and the outer housing are preferably a low temperature solder joint or a silver paste joint.

In general, the outer housing bottom is composed of W-Cu, the outer wall is made of Kovar, and the airtightness between the metal pin and the outer housing for electrical wiring is preferably glass sealing.

10A to 10C are diagrams illustrating a process for photoaligning a polarization inversion chip module according to the present invention with a laser diode module.

As shown in FIG. 10A, two cases may occur depending on manufacturing tolerances of a component used for packaging.

Case 2 is preferable for bonding after moving the polarization inversion waveguide chip module 300 to optical alignment.

In order to perform this process smoothly, the case of Case 2 should always occur by applying a (-) tolerance to the dimension of F.

This is possible by applying a packaging process using a fiber 314 block having a flexible fiber module 200 according to the present invention.

By using the fiber bending allowance characteristic independent of the loss of the flexible fiber module 200, the light of the laser diode chip 150 is directed to the optical waveguide 314 of the polarization inverting waveguide chip 300 regardless of the tolerances between the packaging components. Packaging technologies that focus and maintain optical connection power are possible.

After the alignment, the bonded laser diode module 100 and the polarization inversion waveguide chip module 300 should be maintained at a constant temperature by the respective temperature controllers 110 and 350.

The optimum holding temperature is set differently according to the wavelength characteristics of the laser diode and the fabrication characteristics of the polarization inversion waveguide chip 310.

The temperature control characteristic varies according to the change of the external environment, and the final alignment junction heights G and H of the laser diode module 100 and the polarization inversion waveguide chip module 300 change according to the temperature setting.

If G and H fixed by the optical alignment are changed due to the new temperature setting, losses due to the optical connection additionally occur.

FIG. 11 is a graph showing a theoretical optical connection loss change due to misalignment of light due to temperature change.

In the present invention, when such misalignment occurs, the loss can be minimized by using the radius of curvature of the flexible fiber module 200.

Although the fiber blocks in the aligned state as shown in FIG. 10C are straight lines, the case of Case3 or Case4 may occur depending on the heights G and H.

In general, in an optical system using a lens, even if the position difference is only sub-micron, a loss in which the amount of light connected to the polarization inversion waveguide chip 310 is reduced from the laser diode light source is generated. This is a major disadvantage to the final properties of the device.

The present invention can manufacture a wavelength tunable device having stabilized optical characteristics by eliminating the shortcomings of the optical loss change according to the respective temperature optimization condition settings in the laser diode module 100 and the polarization inversion waveguide chip module 300.

12 is a system configuration diagram for evaluating the characteristics of the tunable device fabricated using the above-described process.

The light source controller 410 controls the characteristics of the current, the temperature, the power of the emitted light and the modulation and evaluates the characteristics thereof, and the QPM controller 420 controls the voltage and the temperature and evaluates the characteristics thereof.

Finally, the light emitted from the nonlinear chip is measured and monitored, and the result is fed back to the light source controller 410 and the nonlinear QPM chip controller 420 for real-time control. Finally, the characteristics of the tunable device are evaluated.

Those skilled in the art will appreciate that the present invention can be embodied in other specific forms without changing the technical spirit or essential features of the present invention.

It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the scope of the claims, which will be described later rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and the equivalent concept are included in the scope of the present invention. Should be interpreted.

1 is a cross-sectional view showing a wavelength conversion device according to the prior art.

Figure 2 is a perspective view showing a wavelength conversion device according to the prior art.

3 is a schematic block diagram of a wavelength tunable device package according to an embodiment of the present invention;

4A is a perspective view of a wavelength tunable device package according to an embodiment of the present invention, FIG. 4B is a side view of the tunable device package shown in FIG. 4A, and FIG. 4C is a plan view of the tunable device package shown in FIG. 4A.

FIG. 5A is a side view of a wavelength tunable device package according to another embodiment of the present invention, and FIG. 5B is a plan view of the wavelength tunable device package shown in FIG. 5A.

Figure 6a shows an example of the periodic polarization inversion of the polarization inversion waveguide chip according to the present invention, Figure 6b is the power of the second harmonic wave generated as the input pumping light source proceeds inside the polarization inversion waveguide chip according to the present invention. Graph indicating increase.

7A to 7F are views illustrating a manufacturing process of a flexible fiber module according to an embodiment of the present invention.

8A to 8B are views showing a manufacturing process of the polarization inversion waveguide chip module according to the present invention, and FIG. 8C is a top view and a side view of the polarization inversion waveguide chip according to the present invention.

9A to 9D are views illustrating a wavelength tunable device package assembly process using the flexible fiber module illustrated in FIG. 5.

10A to 10C are views showing a process for photoaligning a polarization inversion chip module according to the present invention with a laser diode module.

11 is a graph showing the theoretical optical connection loss change due to optical alignment misalignment with temperature change.

12 is a system block diagram for evaluating characteristics of a tunable element using a flexible fiber module according to an embodiment of the present invention.

`` Explanation of symbols for main parts of drawings ''

100: optical oscillation module 110: laser diode temperature control unit

120: laser diode heat dissipation block 130: laser diode mount block

140: laser diode temperature measurement sensor 150: diode laser chip

180: diode laser power monitoring photodiode

200: flexible fiber module

210: welding saddle for flexible fiber module fixing

300: polarized reverse waveguide chip module 310: polarized reverse waveguide chip

311: optical waveguide support block 312: cladding layer

313: optical waveguide surface protection block 314: optical waveguide

320: polarized reverse waveguide chip mount block

320: polarized reverse waveguide chip temperature measurement sensor

340: polarization reverse waveguide chip fixing jig

350: polarized reverse waveguide chip temperature control unit

Claims (31)

Ceramic ferrules; A welding sus jig equipped with the ceramic ferrule; And It is inserted into the ceramic ferrule and receives the light emitted from the optical oscillation module and transmits it to the polarization inverted waveguide chip module that is emitted as the wavelength-modulated light, the optical connection power between the optical oscillation module and the polarization inverted waveguide chip module Constant fiber Flexible fiber module comprising a. The method of claim 1, The light source of the optical oscillation module is a flexible fiber module is a laser diode. The method of claim 1, wherein the fiber Flexible fiber module is fixed by the ceramic ferrule mounted on both ends of the welding sus jig. The method of claim 3, wherein the fiber Fiber module that is flexible to be fixed to both ends of the welding jig for the use of epoxy. The method of claim 1, One end of the fiber is connected to the optical oscillation module, and the other end is connected to the polarization inversion waveguide chip module such that the optical oscillation module, the fiber and the polarization inversion waveguide chip module form an optical alignment. And the other end of the fiber connected to the polarization inversion waveguide chip module is angle polished. The method of claim 5, Wherein said angle polishing is 8 degree angle polished. The method of claim 1, One end of the flexible fiber module is coupled to and fixed by the optical oscillation module and the welding saddle. The method of claim 1, And both ends of the flexible fiber module are coupled and fixed by the optical oscillation module and the polarization inverting waveguide chip module and the welding saddle, respectively. Fastening a welding sus jig equipped with a ceramic ferrule with a fixing gripper; Inserting a fiber into the ceramic ferrule; The fiber alignment step; A fiber fixing step of fixing the fiber to the ceramic ferrule; Ending a fiber formed at one end of the welding jig connected to the polarization inversion waveguide chip; And Polishing the finished fibers Flexible fiber module manufacturing method comprising a. The method of claim 9, wherein the fiber alignment step If the fiber is a wedge type, flexible fiber module manufacturing method for the alignment of the fiber. The method of claim 9, wherein the fiber fixing step A method for manufacturing a flexible fiber module mounted on both ends of the welding jig to perform epoxy curing by injecting epoxy into the ceramic ferrule into which the fiber is inserted. 10. The method of claim 9, wherein the finished fiber polishing step is Flexible fiber module manufacturing method for polishing the end-treated fiber 8 degrees. An optical oscillation module for emitting light from a light source; A polarization inverted waveguide chip module receiving the light emitted from the optical oscillation module to generate a second harmonic wave; And Flexible fiber module for focusing the light emitted from the optical oscillation module to the polarization inverted waveguide chip module Wavelength variable device package using a flexible fiber module comprising a. The method of claim 13, wherein the optical oscillation module Laser diode as a light source; A temperature measuring sensor measuring a temperature of the laser diode; A laser diode mount block for supporting the laser diode and the temperature measuring sensor; A temperature control unit formed under the laser diode mount block to adjust the temperature of the laser diode to maintain the optical oscillation module and the polarization inverting waveguide chip module so as to maintain a constant temperature after optical alignment; And Laser diode heat dissipation block for dissipating heat generated from the laser diode to the outside Wavelength variable device package using a flexible fiber module comprising a. The method of claim 14, wherein the laser diode Wavelength-tunable device package with flexible fiber modules, including line width adjustment or wavelength tuning The method of claim 14, wherein the laser diode mount block Wavelength-tunable device package using a flexible fiber module consisting of W-Cu, AlN, or SiC. The method of claim 14, And the laser diode heat dissipation block and the laser diode mount block are solder bonded to each other. 15. The method of claim 13, wherein the polarization inverted waveguide chip module A polarization inversion waveguide chip including an optical waveguide; And A polarization inversion waveguide chip mount block for supporting the polarization inversion waveguide chip; A temperature sensor formed on the polarization inversion waveguide chip mount block to measure a temperature of the polarization inversion waveguide chip; And A polarization inversion chip temperature control unit formed under the polarization inversion waveguide chip mount block to control the temperature of the optical waveguide Wavelength variable device package using a flexible fiber module comprising a. 19. The method of claim 18, wherein the polarization inversion waveguide chip And a polarization inversion waveguide chip mount block mounted in the polarization inversion waveguide chip mount block such that a polarization inversion direction coincides with a polarization direction of light emitted from the optical oscillation module. 19. The method of claim 18, wherein the polarization inversion waveguide chip Optical waveguide support blocks; A cladding layer for preventing the light from diverging; Optical waveguide surface protection blocks; And Optical thin film layer formed on both sides Wavelength variable device package using a flexible fiber module comprising a. The method of claim 20, wherein the optical thin film layer A first antireflection thin film layer for incident waves from the laser diode of the optical oscillation module; And A second antireflection thin film layer for the incident wave and the second harmonic wave of the incident wave Wavelength variable device package using a flexible fiber module comprising a. 19. The method of claim 18, wherein the polarization inversion waveguide chip mount block Wavelength variable device package using flexible fiber modules consisting of W-Cu, Silicone, AlN, or SiC. The method of claim 18, The temperature sensor is a variable wavelength device package using a flexible fiber module is bonded to the polarization inverted waveguide chip mount block and solder and paste. 19. The method of claim 18, wherein the polarization inverted waveguide chip module And a fixing jig formed in the lower portion to support the polarization inverting waveguide chip mount block. 19. The method of claim 18, wherein the polarization inverted waveguide chip module And a wedding jig supporting the welding saddle for fixing one end of the flexible fiber module. The method of claim 13, wherein the flexible fiber module The variable wavelength device package using a flexible module that is coupled to the heat dissipation block of the optical oscillation module through a welding saddle. Fastening a welding sus jig equipped with a ceramic ferrule with a fixing gripper, inserting a fiber into the ceramic ferrule, aligning the fiber, and fixing the fiber to the ceramic ferrule A flexible fiber module manufacturing step including a fiber fixing step, ending processing of a fiber formed at one end of the welding jig connected to the polarization inversion waveguide chip, and polishing the finished fiber; Aligning an optical oscillation module comprising the flexible fiber module and a laser diode chip; And Aligning the flexible fiber module with the polarization inverted waveguide chip module Wavelength variable device package manufacturing method using a flexible fiber module comprising a. The method of claim 27, Solder bonding the laser diode thermal diffusion block and the laser diode mount block; And Wavelength variable device package using a flexible fiber module further comprising a step of preparing an optical oscillation module including solder bonding a temperature measuring sensor, a laser diode chip, a temperature controller for a laser diode, a polarization inversion chip temperature controller and an assembly jig Manufacturing method. 28. The method of claim 27, wherein aligning the flexible fiber module and the polarization inverted waveguide chip module Mounting welding saddles to the flexible fiber module to secure the flexible fiber module; And Laser bonding to allow a laser diode heat dissipation block and the flexible fiber module to be secured by the welding saddle Wavelength variable device package manufacturing method using a flexible fiber module comprising a. 28. The method of claim 27, wherein aligning the flexible fiber module and the polarization inverted waveguide chip module Mounting the polarization inversion waveguide chip on the polarization inversion waveguide chip mount block such that the polarization inversion direction of the optical waveguide coincides with the polarization direction of the light emitted from the laser diode chip; An optical alignment step between an angle polishing surface formed on one side of the flexible fiber module and an optical waveguide of the polarization inverting waveguide chip; And Fixing the optical alignment position Wavelength variable device package manufacturing method using a flexible fiber module comprising a. 31. The method of claim 30, wherein fixing the light alignment position Method for manufacturing a wavelength tunable device package using a flexible fiber module comprising an epoxy immobilization step.

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