KR20070071451A - Wavelength conversion tunable device with optical waveguide and optical modulated electrode - Google Patents

Abstract

A wavelength converter integrated with an optical waveguide and an optical modulation electrode is provided to use a cheap laser diode as a pumping input light source and to perform optical modulation and wavelength conversion on the same chip by making a quasi phase matching period in nonlinear crystals where the optical waveguide is formed, and then forming the electrode. A wavelength converter is composed of wafer ferroelectric crystals(101) that are nonlinear media; an optical waveguide(102) through which the light source input to the ferroelectric crystals passes; an optical modulation electrode(103) for modulating phase by an electro-optics effect of the ferroelectric crystals; and at least one polarity conversion pattern(104,105) formed in the ferroelectric crystal and changed periodically. The optical waveguide is branched off. The optical waveguide has at least one Mach Zender structure for converting the phase by applying an electric field to the branched optical waveguides and thus modulating output power.

Description

Wavelength converters in which an optical waveguide and an optical modulation electrode are fused together {Wavelength conversion tunable device with optical waveguide and optical modulated electrode}

1 is a block diagram of a mid-IR wavelength tunable laser according to the prior art.

2 is a configuration diagram in which the optical waveguide and the electrode structure for optical modulation according to the present invention are fused.

3A to 3H are wavelength converters according to a first embodiment of the present invention.

4A and 4B illustrate a wavelength converter according to a second embodiment of the present invention.

5 is a wavelength variable according to a third embodiment of the present invention.

FIG. 6 is a wavelength converter in which polarized and inverted ferroelectric bulk crystals are inserted into DPSSL of Zone-A according to a fourth embodiment of the present invention.

FIG. 7 is a wavelength converter using flip chip bonding technology for a diode chip according to a fifth embodiment of the present invention.

8 is a wavelength converter using a pumping laser having a DPSSL structure according to a sixth embodiment of the present invention.

FIG. 9 is a wavelength converter using one or more Mach Gender optical waveguide structures according to a seventh embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

101 Ferroelectric Crystals

102 optical waveguide

103 Photomodulation Electrode

104, 105 polarization structure

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wavelength variabler and a method of manufacturing the same, and more particularly, to a wavelength variabler and a method of manufacturing the same, in which an optical waveguide and an electrode structure for optical modulation are fused.

Polarization-inverted nonlinear chips can be used to fabricate difference frequency mixers, sum frequency mixers, or optical parametric oscillators. In particular, in the case of an optical mediated resonator device, a device capable of converting a wavelength in a wide range can be manufactured by changing the polarization inversion period and the temperature and the wavelength of the input light. The wavelength tunable laser that can be implemented by applying the conventional laser technology includes argon (Ar) ion pumped titanium sapphire laser, but has a problem of low wavelength conversion efficiency. In the mid-infrared radiation (MID-Infrared) region, there are applications using birefringent phase matching technology using AgGaS ₂ , AgGaSe _2, and laser diode and applications using LiNbO ₃ Quasi Phase Matching technology. These techniques have the disadvantage of requiring a large-capacity laser pump light source having a W-class output or more to implement the wavelength variable. Most have features that require pumping power of more than 1.5W.

Another example of the prior art of wavelength tunables using pseudophase matching can be found in the application to the visible wavelength range. Second harmonic generation technology has been mainly used to fabricate a device having a wavelength in the visible light region. Second harmonic generation technology is one of the special cases of sum frequency generation technology.

LiNbO ₃ or LiTaO ₃ and the like are ferroelectrics with high electro-optics, piezoelectric and nonlinear coefficients. Recently, a technique for switching the polarization direction of nonlinear coefficients in crystals by developing a periodic polarization inversion structure using an external electric field and applying an external electric field has been developed. As a concrete example, researches have been made on optical storage using LiNbO ₃ polarization inversion technology (PPLN) and wavelength-variable laser fabrication using optical mediated resonator technology. In particular, the device using Periodic Poling technology has a characteristic that the wavelength is changed by pseudo-phase matching while the incident beam proceeds through the crystal. It is possible to switch to various wavelengths according to the lattice cycle of pseudo-phase matching, and the application and utilization of such a wavelength variable technology is very high. Most of the research and invention in this field still uses the nonlinear properties of bulk crystals. In this case, a laser with a large energy is required, and thus, it can be said that it is at the level of development of a wavelength variable commercialization technology that is relatively large in size and consumes high power.

Figure 1 shows a configuration of the wavelength tunable laser fabrication in the mid-IR region of the prior art. This technology aims to fabricate broadband wavelength-variable devices using high power pumping light sources. As an input pumping light source, M-MOPA (monolithic master oscillator power amplifier, SDL Model Number 5760-A6) laser diode source is applied. The configuration consists of a pseudophase matched difference frequency generator (QPM DFM) or a pseudophase matched photoresonator resonator (QPM OPO) with at least one laser light source and a nonlinear frequency generator.

1 shows an example of a pseudophase matched difference frequency generator. A light source with two different frequencies is incident on the nonlinear frequency generator which, after passing through the generator, produces a light source with a new frequency that is different from the two incident frequencies. The right figure of FIG. 1 shows a structure in which the path through which an incident pumping light source passes is changed by fabricating the same generator with different pseudophase matching periods and changing the position of the nonlinear frequency generator using an electric stage. The newly created wavelength-variable range in one pseudophase matching period is limited by the temperature applied to the nonlinear frequency generator and the wavelength of the pumped light source. Therefore, in order to fabricate a wideband wavelength tunable laser, a pseudophase match generator having essentially several or several dozen different periods is required. 1 shows an example in which various periods are polarized inverted in one nonlinear frequency generator to solve this problem.

In the prior art, a pumping light source having a high power of several W should be applied to a bulk crystal in which a pseudo phase matching period is formed in order to change the nonlinear wavelength. In this case, the cost and size of the pumping light source are much larger than the manufacturing cost and the size of the nonlinear frequency generator. As a result, it was not possible to fabricate small, lightweight and inexpensive wavelength tunable lasers. This problem can be solved through the method of maximizing the nonlinear efficiency by applying the optical waveguide as in the present invention to limit the path of the light to a few micro region. In the case of applying an optical waveguide, an inexpensive laser diode can be applied as a pumping input light source. The application of optical waveguides can produce light with a new wavelength of several uW even with several mW of input light source.

In addition, in the prior art, in order to modulate the light source generated by the nonlinear wavelength tunable technology, an externally expensive modulator has to be used.

In particular, in order to implement a small display using a laser, a low cost red light source and a blue light source are required. No existing technology has produced a light source that is competitive in price. In particular, the green light source has a diode pumped solid state laser (Diode Pumped Solid State Laser), but in this case there is a problem in applying the light modulation technology. The laser light source for a display has a feature of applying a light modulation technology, but has a problem that it is difficult to implement with a conventional technology.

Accordingly, the present invention is to solve the above-mentioned disadvantages and problems of the prior art, an object of the present invention is to combine the optical waveguide technology and polarization reversal technology to provide a wavelength variable with an integrated optical waveguide and an optical modulator. . Pseudophase matching cycles were fabricated on non-linear crystals in which optical waveguides were formed, and an electrode of a special structure was formed to enable optical modulation and simultaneous wavelength modulation. It is another object of the present invention to provide a method for fabricating a wavelength converter having a novel structure incorporating optical waveguide fabrication by a wafer process, polarization inversion, and optical modulation technology.

The above object of the present invention is a wafer ferroelectric crystal which is a nonlinear medium; An optical waveguide through which a light source input to the ferroelectric crystal can pass-at least one Mach gender structure for branching and applying an electric field to the branched optical waveguide so that the phase can be converted so that the output power can be modulated Has-; An optical modulation electrode for phase modulation by the electro-optic effect of the ferroelectric crystal; And an optical waveguide including an optical waveguide and at least one polarization inversion pattern periodically changed inside the ferroelectric crystal.

Another object of the present invention is to produce an optical waveguide on the ferroelectric substrate; (b) forming periodic polarization inversion on the ferroelectric substrate; (c) forming a thin film for reducing the optical waveguide loss due to the electrode; And (d) fabricating an electrode in the ferroelectric substrate.

Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention is characterized in that the configuration of the optical waveguide and the electrode structure for the optical modulation is fused and shown in FIG. Referring to FIG. 2, by dividing an optical waveguide 102 and an optical waveguide through which a wafer ferroelectric crystal 101, an input pumping light source and a light source generated by a wavelength converter, can pass through, and apply an electric field to a branched optical waveguide. Mach Zender optical waveguide structure 102, the phase shifted to allow the output power to be modulated, the electrode 103 for phase modulation by the electro-optic effect of the ferroelectric crystal, the polarization structure periodically changed in the ferroelectric crystal It consists of (104, 105).

Nonlinear linearity variable wavelength is mainly used a method using birefringence or a cyclic polarization inversion as in the present invention. The pseudophase matching period of the wavelength variable 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. The determination of the pseudophase matching period is briefly determined by the following equations (1) and (2).

Where n is the refractive index, λp is the wavelength of the pumping light source, λs is the wavelength of the signal light source, λi is the wavelength of the idler light source, ∧g is the polarization reversal period, m is the pseudophase matching order, and Δk is the phase difference.

It is important to increase the conversion efficiency when the pumped light source is generated at the new wavelength while passing through the wavelength converter. The conversion efficiency (Pω / P2ω) in generating the second harmonic wave using the wavelength variable is proportional to the square of the nonlinear coefficient, the square of the length of the wavelength converter, and the power of the input pumping light source, and inversely proportional to the square of the diameter of the light source passing through the wavelength converter. Has characteristics. Therefore, when fabricating a wavelength variable using a waveguide, it is possible to minimize the threshold power of the input pumping light source required for the wavelength change by adjusting the passage through the light source to several micro dimensions. Through this, it is possible to manufacture a small but low-cost wavelength variable laser for the purpose of the present invention.

Specific implementation method of the present invention is the same as FIG. The wavelength variable structure proposed in the present invention can be applied to various ferroelectric substrates. In the detailed fabrication method described below, LiNbO ₃ was selected as the ferroelectric substrate, and the fabrication method thereof was briefly described as follows.

(1) fabricating an optical waveguide on the ferroelectric substrate (FIG. 3A)

(2) forming periodic polarization inversion on the ferroelectric substrate (FIGS. 3B to 3C)

(3) forming a thin film for reducing the optical waveguide loss due to the electrode (Fig. 3d)

(4) manufacturing an electrode when the ferroelectric substrate is Z-cut (FIG. 3E)

(5) manufacturing an electrode when the ferroelectric substrate is X-cut (or Y-cut) (FIG. 3F)

(6) Details of the electrode structure when the ferroelectric substrate is Z-cut (FIG. 3G)

(7) Details of the electrode structure when the ferroelectric substrate is X-cut (or Y-cut) (FIG. 3H)

Detailed description of the manufacturing method is as follows.

(1) Referring to the step (FIG. 3a) of manufacturing the optical waveguide on the ferroelectric substrate, several methods can be used to fabricate the waveguide on the ferroelectric substrate. Such methods include annealed-proton exchange, titanium diffusion, ion implantation, and waveguides composed solely of ferroelectrics. In general, fabrication of an optical waveguide on a cyclic polarization inverted ferroelectric substrate is a two-step process. This depends on the optical waveguide formation technique. In the proton exchange method, periodic polarization inversion is first formed on a ferroelectric substrate, and then an optical waveguide is formed through proton exchange. On the other hand, the titanium diffusion method forms a periodic polarization reversal after waveguide formation through diffusion. Proton exchange waveguides are formed on ferroelectric substrates that are periodically polarized inverted at relatively low temperatures of 300-400 ° C. While proton exchange waveguides are highly resistant to photorefractive damage, only the abnormal mode (TE) can be used. In addition, the manufacture of waveguides by proton exchange reduces the nonlinear coefficients of the ferroelectric, thus requiring an extra heat treatment process.

The manufacturing method of the titanium diffusion waveguide in the ferroelectric substrate is as follows. First, a photoresist is uniformly spin-coated to a ferroelectric substrate at a predetermined thickness (201). That is, a mask in which the waveguide pattern is formed is mounted on the exposure machine so that the waveguide pattern is transferred to the photoresist (201). The photoresist developer is used to remove the waveguide-shaped photoresist, and titanium is deposited between the ferroelectric and the photoresist using equipment such as an E-beam (202). The remaining photoresist is removed and fabricated so that only the titanium waveguide shape remains on the ferroelectric substrate (203). Put the ferroelectric substrate produced at a temperature of about 1000 ~ 1060 ℃ to allow titanium to diffuse in the substrate to complete the optical waveguide fabrication. The waveguide fabricated in this way is characterized by high electro-optical characteristics, low waveguide light loss, and both normal and abnormal modes.

(2) Looking at forming the periodic polarization inversion on the ferroelectric substrate (Figs. 3b to 3c), the method of forming the periodic polarization inversion on the ferroelectric is generally possible by the following two methods. The first method is to deposit an insulating dielectric thin film on a substrate, form an electrode pattern through a photolithography process, and then deposit a metal electrode thereon. The second method is to spin-coat a photoresist onto a substrate, form an electrode pattern through a photolithography process, and then form an electrode using an electrolyte solution in which LiCl is dissolved therein. 3-5 specifically illustrate a method of applying an electric field using an electrolyte solution. The photoresist is uniformly spin-coated to a certain thickness on the ferroelectric substrate on which the waveguide is manufactured (205). In order to form the periodic polarization inversion, an electrode pattern for polarization inversion is formed by a photolithography process using a mask having a pattern somewhat less than 50% of the period. The pattern is filled with an electrolyte and used as an electrode to apply an electric field to complete polarization inversion. In order to switch the polarization state inside the ferroelectric crystal, an external electric field must be applied. The electric field value is a material constant determined according to the ferroelectric substrate. For example, in the case of LiNbO ₃ , a polarization inversion pattern can be produced by applying an electric field of 21 [KV / mm] or more.

Here, the method of forming the electrode for polarization inversion may be applied differently depending on the axis of the ferroelectric substrate. For example, electrodes for Z direction polarization inversion on a Z-cut substrate are fabricated at the top and bottom of the substrate. On the other hand, electrodes for Z-direction polarization inversion on the X-cut substrate are manufactured parallel to the plane on which the waveguide of the substrate is formed.

(3) Looking at forming a thin film to reduce the optical waveguide loss due to the electrode (Fig. 3d), in order to apply the optical modulation technology using the electro-optic coefficient of the ferroelectric substrate, the optical waveguide polarization inverted dielectric prepared as described above An electrode for light modulation should be manufactured on the substrate. At this time, when the metal thin film is directly deposited on the ferroelectric substrate on which the waveguide is manufactured, a loss occurs in the optical waveguide. This can be solved by first fabricating an optically transparent dielectric thin film layer on the waveguide and then fabricating an electrode thereon. SiO ₂ may be used as the dielectric thin film. In FIG. 3D, an example of fabricating a dielectric thin film using a deposition apparatus such as a sputter on a ferroelectric substrate on which a periodic polarization inversion pattern and an optical waveguide are fabricated is described (step 208).

(4) Referring to the step of fabricating the electrode when the ferroelectric substrate is Z-cut (FIG. 3E), after forming a dielectric insulating film on the ferroelectric substrate, as shown in FIG. 3E, the photoresist 209 is uniformly spun to a predetermined thickness. Coating. A mask on which the light modulation electrode pattern is formed is mounted on the exposure machine so that the pattern is transferred to the photoresist. The photoresist developer is used to remove the waveguide-shaped photoresist, depositing a seed such as Ti, Cr, or Ni-Cr as an adhesion layer, and depositing or plating a metal such as Au on the light. Complete the fabrication of the modulation electrode. The principle of light modulation is explained as follows. The refractive index in the ferroelectric crystal is changed by applying voltages in different directions at both ends of the optical waveguide having the Mahzender structure. As a result, the phases of the light source traveling through the upper and lower waveguides of the Mach Gender structure are different from each other. As such, if the phase of the light source of the waveguide traveling through the upper part and the lower part is changed by π, it is possible to escape the Mach Gender structure and cause mutual interference, so that the light intensity disappears.

Equation 3 shows the amount of phase change according to the change of the refractive index. In addition, the refractive index change amount is expressed as a function of n (refractive index), r (electro-optic coefficient) and E (electric field). Equation 4 represents a voltage to be applied to the electrode in order to make the phase change amount of Equation 3 equal to π. It can be seen that this is expressed as d (waveguide size), L (electrode length), r (electro-optic coefficient) and n (refractive index) as shown in equation (4).

According to an embodiment of the present invention, the light modulation electrode may be designed such that a voltage is applied in an area of 50% of the polarized and inverted grating period. That is, light modulation can be made possible by applying a voltage to one of the regions of + or-polarization inversion to the ferroelectric substrate. By using the electrode structure of the present invention, the optical modulation technique can be implemented on the same chip in a wavelength variabler using pseudo phase matching. In this case, the problem of using an external optical modulator can be solved. Therefore, it is possible to manufacture a wavelength tunable laser that satisfies both low cost and high functionality at the same time.

(5) Looking at the steps of fabricating the electrode when the ferroelectric substrate is X-cut (or Y-cut), the polarization direction of the ferroelectric substrate can be manufactured to be parallel to the optical waveguide, unlike in the case of Z-cut. . In this case, as shown in FIG. 3H, the optical modulation electrode structure is positioned between the waveguides (214). Its manufacturing method is the same as described in step (4).

(6) A detailed view (Fig. 3G) of the light modulating electrode structure when the ferroelectric substrate is Z-cut.

(7) Fig. 3H is a detailed view of the structure of an optical path electrode in the case where the ferroelectric substrate is X-cut (or Y-cut).

Second Embodiment

4A and 4B show an embodiment in which the structure of FIG. 2 is separated into two components. That is, it is composed of a wavelength variable portion in which the waveguide and the polarization inversion period are fused and an optical modulator manufactured using the Mach-Zehnder structure. The advantage of this structure is that the electrode structure is simple, so it is easy to implement the light modulation characteristics. In addition, the waveguide loss can be minimized by optimizing the optical waveguide having the Mahzender structure to the newly generated wavelength. On the other hand, this structure, unlike FIG. 2, increases the length of the device relatively, which reduces the number of products that can be manufactured per wafer by approximately half. In other words, the cost of production increases. In FIG. 4A, a ferroelectric substrate 301, an optical waveguide 302, a mahgender structure 303, an optical modulation electrode 304, and a pseudo phase match polarization inversion 305 are shown, respectively. In the case of FIG. 4B, the optical modulation electrode 306 is positioned between the optical waveguides. This shows an example in which the direction of the light modulation electrode is applied differently according to the crystal direction of the ferroelectric substrate as described above.

Another embodiment of the invention is shown in FIG. 5. In order to miniaturize and reduce the price of the wavelength tunable laser, it is important to select an input pumping light source. For example, the wavelength of the pumping light source required for manufacturing a green or blue light source using Second Harmonic Generation requires a light source around 1064 nm or 970 nm in each case. Currently, laser diodes have been inexpensive through mass production in the 600-800nm region and the 1310nm or 1550nm region. On the other hand, in the 1064nm or 970nm region, it is possible to manufacture high-power laser diodes, but the production price is still hundreds of times higher. In order to solve the price problem of the pumping light source, the most widely used method is to generate a gain wavelength by injecting a solid laser material using a low-cost high-power laser diode in the 600-800nm region as a pumping light source. diode pumped solid state laser). The portion labeled Zone-A in FIG. 5 shows an example of such a structure. For example, for 1064nm DPSSL, Zone-A is a 808nm diode 401, a focus lens 402, an input reflector 403, a solid state laser generation medium (404, Nd: YVO _4, etc.) and an output reflector 405. Consists of. By applying Zone-A (DPSSL) as the pumping light source as shown in FIG. 5 and using Zone-B (Focus lens 406), alignment with Zone-C, the wavelength variable proposed in the present invention, has a minimum light loss. A wavelength tunable laser can be manufactured.

FIG. 6 illustrates a pumping light source in which the wavelength variation is generated inside the DPSSL by inserting a polarized and inverted ferroelectric bulk crystal 501 into the DPSSL of Zone-A. The device to which the toilet is applied can be manufactured. In this case, the pumping light source output from Zone-A and the light source whose wavelength is changed by the bulk crystal can be used simultaneously.

FIG. 7 illustrates an embodiment of a wavelength converter having a simple structure in which a diode chip 601 is bonded to a wavelength variable proposed by the present invention by applying a flip chip bonding technique.

FIG. 8 illustrates another embodiment in which a pumping laser having a DPSSL structure is applied as described with reference to FIG. 5. One or more Mach Gender optical waveguide structures are formed, and each of them has a feature in which a polarization reversal pattern having a different period from the optical modulation electrode is formed (701). In such a structure, one or more diode chips may be formed on an optical waveguide chip to manufacture a product that implements various wavelengths simultaneously on one chip (702). The diode chip may be integrated by a flip chip bonding technique, but an optical connection method of aligning an external device using a lens or a fiber array may be used. Such a structure can be applied to an application that simultaneously generates various wavelengths and photomodulates them. In particular, when applied to a laser display, the structure can be applied to a technology of manufacturing a single device that simultaneously realizes three primary colors of red, green, and blue.

Specifically, 1064 nm is generated by the 808nm pumping light source in DPSSL of Zone-A, and some 808nm and newly generated 1064nm light sources are output in front of Zone-B. The two light sources pass through Zone-B again to split the 1064nm light source, some go straight and focus on the second Mach Gender waveguide, and the others are reflected and focused on the first Mach Gender waveguide. This can be implemented by a power split optical filter or the like. The 1064nm light source focused on the first Mach Gender waveguide is wavelength converted into a 532nm green light source as it passes through the ferroelectric waveguide that has been polarized and inverted to generate the second harmonic wave. In addition, the 1064 nm light source focused on the second Mach Gender optical waveguide is wavelength converted into a 460 nm blue light source while passing through the sum frequency generating wavelength variable together with the 808 nm light source of the diode laser 702 connected by the optical waveguide. In this case, 808nm used as a DPSSL pumping light source output from Zone-A without using a 808nm light source may be implemented by focusing the optical waveguide coupler by adding a wavelength division filter to Zone-B. In this case, there is no need to use a separate 808nm diode laser. The third Mach Gender optical waveguide can be directly applied with a red diode laser. As a result, it is possible to integrate a red, green, and blue laser light source into one device, and at the same time, it is possible to configure a laser display product by applying light modulation technology. Such a wavelength variable structure is a ferroelectric polarization inverting substrate that changes the pumping wavelength of Zone-A as well as the application of display device fabrication and integrates one or more diode lasers and optical modulators and optical waveguides of Zone-B and Zone-C. By designing and applying differently according to the required application wavelength, it has the merit to manufacture devices necessary for various fields.

FIG. 9 illustrates a pumping light source in which wavelength variation is generated inside the DPSSL by inserting a polarized and inverted ferroelectric bulk crystal 501 into the DPSSL of Zone-A. The embodiment of a wavelength variable unit to which the above-mentioned Mach Gender optical waveguide structure is applied is shown. This device structure can be the same application as described in FIG. On the other hand, the difference from FIG. 9 is that the wavelength generated in Zone-A is output by the pumping wavelength of DPSSL and the sum or difference frequency generated in the bulk crystal, and is applied to the technique proposed in the present invention. An application embodiment for a technique of simultaneously implementing various wavelengths and photomodulating them is shown.

Although the present invention has been shown and described with reference to the preferred embodiments as described above, it is not limited to the above embodiments and those skilled in the art without departing from the spirit of the present invention. Various changes and modifications will be possible.

The wavelength variableer in which the optical waveguide and the optical modulation electrode of the present invention are fused is used to fabricate the wavelength variable using the nonlinear characteristics of the ferroelectric crystal, thereby maximizing the nonlinear efficiency by limiting the path through which the light passes to several micro ranges. Threshold pumping power of the wavelength converter can be reduced to a few mW. In the case of applying an optical waveguide, it is possible to apply a low-cost laser diode as a pumping input light source. By fabricating a pseudophase matching cycle on a nonlinear crystal in which an optical waveguide is formed and forming an electrode of a special structure, the optical modulation and the wavelength variability can be realized on the same chip. In addition, by adopting a structure that directly aligns and bonds the diode chip as a pumping light source, it is possible to mass-produce and manufacture a micro-tunable laser.

Claims (8)

Wafer ferroelectric crystals that are nonlinear media; An optical waveguide through which a light source input to the ferroelectric crystal can pass-at least one Mach gender structure for branching and applying an electric field to the branched optical waveguide so that the phase can be converted so that the output power can be modulated Has-; An optical modulation electrode for phase modulation by the electro-optic effect of the ferroelectric crystal; And At least one polarization inversion pattern that periodically changes within the ferroelectric crystal Wavelength variable comprising a. The method of claim 1, The polarization inversion pattern is for pseudo phase matching (QPM), and includes a at least one period according to the wavelength of the input pumping light source and the output light source. The method of claim 1, And the optical modulation electrode is capable of optical modulation by applying a voltage to only one of + or-polarized inverted regions, which are 50% of the polarization-inverted lattice period, to the ferroelectric substrate. The method of claim 1, Wherein the optical modulation electrode is located in the front end or the rear end of the polarization-inverted grating period polarized on the ferroelectric substrate, characterized in that the wavelength conversion and light modulation occurs. The method according to any one of claims 1 to 4, The ferroelectric substrate is a wavelength variable, characterized in that the single crystal substrate of LiNbO ₃ , LiTaO ₃ , Mg: LiNbO ₃ , Zn: LiNbO ₃ or KTP. The method of claim 1, wherein the pumping light source is diode; Focus lens; Input reflector; Laser generating medium in solid state; And a wavelength reflector comprising an output reflector. The method of claim 6, wherein the pumping light source And a ferroelectric bulk crystal between the solid state laser generation medium and the output reflector. The method of claim 6, wherein the pumping light source And a wavelength division filter between the output reflector and the optical waveguide.

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