KR100796258B1 - Optical Fiter with Variable Bandwidth and Extinction Ratio using the Microring Resonator - Google Patents

Abstract

According to an embodiment of the present invention, one side of the first waveguide is formed to be parallel to the first waveguide and the first waveguide formed at a predetermined interval so as to transmit an optical signal. One end of the second waveguide and the first waveguide formed by an additional port through which an added optical signal other than an optical signal inputted into the input port of the first waveguide is input, and the other end of the first waveguide; A first ring resonator spaced apart from the first waveguide and the second waveguide at predetermined intervals between a vertical lower side adjacent to an input port and a vertical upper side adjacent to an additional port of the second waveguide by a closed loop, and the first ring resonator A ring resonator couples the optical signal incident from the first waveguide, and the coupled optical signal rotates along the first ring resonator to It operates as a passband filter for selectively passing only the optical signal of the corresponding resonant wavelength band according to the radius of the first ring resonator so as to be coupled to the second waveguide, and has a predetermined spacing on the vertical lower side adjacent to the inlet port of the second waveguide. The second ring resonator and the second ring resonator are spaced apart from each other and are coupled to the second waveguide so as to attenuate only an optical signal component of a corresponding resonant wavelength band by a ring radius of the second ring resonator. It operates as a filter, the bandwidth and the extinction ratio of the optical filter is controlled by the change in the ring radius and the refractive index of the second ring resonator, laminated on the upper layer of the second ring resonator is formed as an open loop and both ends of the open loop Bandwidth, characterized in that consisting of an electrode pattern for controlling the extinction ratio of the optical filter by the current change of the variable voltage formed in the It relates to an optical filter using the micro-ring resonator extinction ratio adjustment.

Accordingly, in the present invention, the bandpass filter and the bandstop filter are combined to electrically adjust the extinction ratio and the bandwidth of the bandpass filter, thereby adjusting the bandpass characteristics by the first ring resonator and the band by the second ring resonator. Adjusts the blocking characteristics, adjusts the bandwidth by changing the ring radius of the first and second ring resonators, and applies the current to the electrode pattern to adjust the extinction ratio by the change of the resonance wavelength according to the refractive index, as well as the current to the electrode pattern. There is an effect of adjusting the wavelength response by applying.

Ring Resonator, Bandwidth, Extinction Ratio, Coupling, Waveguide, Filter

Description

 Optical Filter with Variable Bandwidth and Extinction Ratio using the Microring Resonator

1 is a block diagram of an optical filter using a microring resonator in which a bandwidth and an extinction ratio are adjusted according to an embodiment of the present invention.

Figure 2 is a three-dimensional view of the second ring resonator and electrode pattern according to Figure 1 of the present invention

Figure 3a is a diagram showing the transmission characteristics when the extinction ratio according to Figure 1 of the present invention is controlled

Figure 3b is a view showing the output strength of the device according to the power applied to the electrode in the inlet port according to Figure 1 of the present invention

Figure 4a is a diagram showing the transmission characteristics when the bandwidth is adjusted according to Figure 1 of the present invention

Figure 4b is a view showing the output strength of the device according to the wavelength of the inlet port according to Figure 1 of the present invention

5 is a flowchart illustrating a method of manufacturing an optical filter using a microring resonator in which a bandwidth and an extinction ratio are adjusted according to the present invention.

* Description of the main drawing codes *

100: first waveguide 110: input port

120: through port 200: first ring resonator

300: second waveguide 330: additional port

340: inlet port 400: second ring resonator

500: electrode pattern 510: variable voltage

The present invention relates to an optical filter using a microring resonator in which a bandwidth and an extinction ratio are adjusted. More particularly, the first and second waveguides are formed to have a predetermined distance horizontally to each other, and the first ring resonator is a first waveguide. A second ring resonator is formed between the vertical lower side adjacent to the input port of the second waveguide and the vertical upper side adjacent to the additional port of the second waveguide, and a second ring resonator is formed on the vertical lower side adjacent to the inlet port of the second waveguide. The present invention relates to an optical filter laminated on an upper layer and having an electrode pattern formed thereon.

Conventional optical filters have two pairs of waveguides formed horizontally at predetermined intervals, a ring resonator is formed between the two waveguides, and two pairs of electrodes on the left and right sides of the ring resonator between the two waveguides, That is, there was a technique of adjusting the characteristics of the optical filter according to the change of the waveguide by applying a voltage to the four electrodes consisting of four electrodes.

However, according to the conventional technology, the extinction ratio of the optical filter can be adjusted by mechanically moving the waveguide itself to change the propagation loss of the ring resonator, and the bandwidth of the optical filter is coupled between the optical waveguide and the ring resonator and the ring resonator. In this case, the loss ratio and the bandwidth characteristics of the optical filter are independently adjusted. In addition, the stability of the waveguide and the ring resonator due to the complicated structure and the mechanical movement is not only lowered but also driven. There was a problem that the current is high.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to provide a first ring resonator and a second ring resonator, in which an electrode pattern for varying current is deposited. Band pass characteristics are controlled by ring resonators, band stop characteristics are controlled by second ring resonators, extinction ratio is controlled by changes in resonant wavelength, and the ring radius of the first and second ring resonators is changed to increase bandwidth. In addition to the adjustment, an object thereof is to provide an optical filter that freely adjusts the wavelength response by applying a voltage to the electrode pattern.

In order to achieve the above object, an optical filter using a microring resonator having an adjustable bandwidth and an extinction ratio according to an embodiment of the present invention has an input port at which one end of an optical signal is input and an other end of an optical signal to transmit an optical signal. A first waveguide through which a passing port is formed is formed in parallel with the first waveguide at a predetermined interval, and one side end has an additional optical signal other than an optical signal input to an input port of the first waveguide. The first waveguide is formed between a second waveguide formed by an inlet port for outputting a signal and a vertical lower side adjacent to an input port of the first waveguide and a vertical upper side adjacent to an additional port of a second waveguide. And a first ring resonator spaced apart from the second waveguide at a predetermined interval and formed as a closed loop, and the first ring resonator includes: Coupling an optical signal incident from one waveguide, and the coupled optical signal rotates along the first ring resonator to be coupled to the second waveguide so as to couple the corresponding resonant wavelength band according to a radius of the first ring resonator; The second ring resonator and the second ring resonator may be operated as a passband filter for selectively passing only an optical signal, and are formed as closed loops spaced at predetermined intervals on a vertical lower side adjacent to the inlet port of the second waveguide. Coupled with the second waveguide and acting as a band stop filter for attenuating only the optical signal components of the corresponding resonant wavelength band by the ring radius of the second ring resonator, and the optical power due to the change in the ring radius and refractive index of the second ring resonator The bandwidth and the extinction ratio of the filter are adjusted, stacked on the upper layer of the second ring resonator to form an open loop, and formed at both ends of the open loop. Characterized in that by a current change of the substation transformer consisting of an electrode pattern for controlling the extinction ratio of the optical filter.

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According to an embodiment of the present invention, the extinction ratio of the optical filter is controlled by changing the current of the variable voltage generator formed at both ends of the open loop of the electrode pattern.

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According to an embodiment of the present invention, the side lobe of the band pass filter of the first ring resonator is removed by the band stop filter characteristic of the second ring resonator.

According to one embodiment of the present invention, the first and second ring resonators are characterized in that the material of any one of a polymer, silica, an electro-optic polymer, silicon and a compound semiconductor.

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

1 is a block diagram of an optical filter using a microring resonator in which a bandwidth and an extinction ratio are adjusted according to an embodiment of the present invention. In order to transmit an optical signal, one end of an input port 110 and an other side of an optical signal are input. A stage is formed parallel to the first waveguide 100 and the first waveguide 100 in which a pass port 120 through which an optical signal passes is formed at a predetermined interval, and is formed in parallel with one end of the first waveguide 100. The second waveguide 300 and the second port 300 formed by the additional port 330 to which the added optical signal other than the optical signal input to the input port 110 is input and the inlet port 340 for outputting a signal The first waveguide 100 and the second waveguide 300 between the vertical lower side adjacent to the input port 110 of the first waveguide 100 and the vertical upper side adjacent to the additional port 330 of the second waveguide 300. And spaced apart at predetermined intervals to form a closed loop The first ring resonator 200 and the first ring resonator 200 couple an optical signal incident from the first waveguide 100, and the coupled optical signal is the first ring resonator 200. And a second passband filter for selectively passing only an optical signal of a corresponding resonant wavelength band according to a radius of the first ring resonator 200 so as to couple along the second waveguide 300 by rotating along the second waveguide. The second ring resonator 400 and the second ring resonator 400 that are spaced apart at predetermined intervals on the vertical lower side adjacent to the inlet port 340 of the 300 and the second ring resonator 400 are the second waveguide 300. And a band stop filter for attenuating only an optical signal component of a corresponding resonant wavelength band by a ring radius of the second ring resonator 400, and a ring radius and refractive index of the second ring resonator 400. The bandwidth and the extinction ratio of the optical filter are controlled by the change. Stacked on the upper layer of the second ring resonator 400 is formed as an open loop, the electrode pattern 500 for controlling the extinction ratio of the optical filter by the current change of the variable voltage generator 510 formed at both ends of the open loop Is done.

More specifically, the first waveguide is coupled between the vertical lower side adjacent to the input port 110 of the first waveguide 100 and the vertical upper side adjacent to the additional port 330 of the second waveguide 300. The first ring resonator 200 formed to be spaced apart from the 100 and the second waveguide 300 at a predetermined interval by the interval between the first ring resonator 200 and the first waveguide 100 is controlled by the extinction ratio The resonant wavelength is controlled by the length of the first ring resonator 100 and the resonant characteristics are periodically displayed for each free spectral range (FSR).

In addition, FSR = c (beam) / 2 n (refractive index) can be represented by L (ring resonator length).

The first ring resonator 200 is coupled with an optical signal incident from the first waveguide 100 to be rotated and guided along a closed curve of the first ring resonator 200.

In particular, an optical signal coupled to the first ring resonator 200 and the first waveguide 200 and coupled to the second waveguide 300 is given by a ring radius of the first ring resonator 200. By selectively passing only the optical signal component of the resonant wavelength band, the first ring resonator 200 exhibits periodic bandpass filter characteristics.

The second waveguide 300 has an additional port 330 formed on one side and an inlet port 340 formed on the other side so as to be spaced apart from the first ring resonator 200 by a predetermined interval and the first ring resonator ( 200 is coupled to receive an optical signal.

The additional port 330 may input an optical signal other than the optical signal incident from the input port 110, and the optical signal is output from the inlet port 340.

The second ring resonator 400 is formed on the vertical lower side adjacent to the inlet port 340 of the second waveguide 300 at a predetermined interval so that the optical signal transmitted from the second waveguide 300 is closed loop. It rotates along the closed curve of the formed second ring resonator 400 and is guided to the inlet port 340.

In particular, the optical signal output to the inlet port 340 along the second ring resonator 400 attenuates only the optical signal component of the resonance wavelength band given by the ring radius of the second ring resonator 400, The second ring resonator 400 obtains periodic bandstop filter characteristics.

Accordingly, the output characteristic of the inlet port 340 is determined by appropriately canceling the bandpass characteristic of the first ring resonator 200 and the band blocking characteristic of the second ring resonator 400.

In addition, since the first and second ring resonators 200 and 400 detect specific wavelengths, the first and second ring resonators 200 and 400 receive an optical signal from the input port 110 formed in the first waveguide 100. In the case of coupling occurs at the coupling), the coupling is coupled to the first ring resonator 200 and rotated along the closed curve to be waveguided, and the optical signal transmitted from the second waveguide 300 is applied to the second ring resonator 400. Only the optical signal component of the resonance wavelength band is attenuated and guided to the inlet port 340.

The electrode pattern 500 is formed as an open loop, and includes a variable voltage generator 510 at both ends, and changes the electrical output power in the variable voltage generator 510 to heat the second ring resonator 400. The resonance condition of the second ring resonator may be adjusted by changing the refractive index and changing the length of the second waveguide 300.

In addition, the first and second ring resonators 200 and 400 may be used as any one material of a polymer, silica, an electro-optic polymer, silicon, and a compound semiconductor.

FIG. 2 is a three-dimensional view of a second ring resonator and an electrode pattern according to FIG. 1, wherein the electrode pattern is formed by being stacked on an upper layer of the second resonator, and the variable voltage formed on the electrode pattern 500. When the electrical output power is increased through the device 510, heat is generated in the electrode pattern 500, and the refractive index of the optical material is changed by the generated heat. When the refractive index is changed, the effective refractive index of the optical material is changed. This indicates that the characteristics of the resonance wavelength of the second ring resonator 400 are shifted.

3A is a diagram illustrating a transmission characteristic when the extinction ratio according to FIG. 1 of the present invention is adjusted, in which case the resonance wavelengths of the first ring resonator 200 and the second ring resonator 400 coincide with each other. When the intensity of the output signal at the center wavelength is minimum, when the output power applied to the electrode pattern 500 is increased, the resonance wavelength of the second ring resonator 400 is shortened by the thermo-optic effect of the polymer. As it is moved toward the wavelength and gradually changes from the resonance wavelength of the first ring resonator 200, the output signal from the inlet port 340 is gradually increased.

As shown in FIG. 3A, the filter characteristic when no electric signal is applied is # 1, and when the electric output power is increased, # 2 is increased, and when the electric output power is increased more than # 2, the filter moves to short wavelength band # 3. do.

Therefore, when the band blocking wavelength characteristic is equal to # 3, the band pass filter characteristic is output to the inlet port 340 without attenuation, and consequently an optical signal having a specific resonance wavelength by applying a current to the electrode pattern 500. The output strength for is electrically controlled.

3B is a view showing the output strength of the device according to the power applied to the electrode in the inlet port according to FIG. 1 of the present invention, in the initial wavelength state is not applied to the electrode pattern 500 at the center wavelength There is no signal output to the inlet port 340, and as the intensity of the current increases by applying a current to the electrode pattern 500, the band stop characteristic is moved to increase in proportion to the electrical signal applied by the output signal. It can be seen that.

4A is a diagram illustrating a transmission characteristic when the bandwidth according to FIG. 1 of the present invention is adjusted, assuming that a radius of the first ring resonator 200 is smaller than a radius of the second ring resonator 400. Since the FSR is larger than the FSR of the second ring resonator 400, the FSR of the first ring resonator 200 may be inversely proportional to the ring radius.

4B is a view showing the output strength of the device according to the wavelength of the inlet port according to FIG. 1 of the present invention, when the band blocking characteristic is present symmetrically on both sides of the bandpass characteristic, in the inlet port 340 The resulting total output characteristic shows a reduced bandwidth.

On the other hand, when there is no second ring resonator 400, the pass bandwidth is determined by the first ring resonator 200, although the bandwidth is relatively wide, by introducing the second ring resonator 400, the second By the radius of the ring resonator 400 can accurately obtain the pass bandwidth according to the change of the FSR.

Therefore, the relative wavelength position of the band blocking characteristic of the second ring resonator 400 is easily adjusted by using the power applied from the electrode pattern 500, and the band blocking characteristic is symmetrically on both sides of the bandpass characteristic. If present, the overall output characteristic obtained from the inlet port is reduced in bandwidth as shown in FIG. 4B.

In addition, the sidelobe characteristic has an ideal bandpass filter characteristic by improving the bandpass filter by the bandstop filter, and by changing the electrical output power of the variable regulator 510 formed on the electrode pattern 500 The output bandwidth can be adjusted.

FIG. 5 is a flowchart illustrating a method of fabricating an optical filter using a microring resonator in which a bandwidth and an extinction ratio are controlled according to the present invention, and a first step S10 of forming a lower cladding by spin coating a polymer having a low refractive index on a silicon substrate. And a second step (S20) of applying a photoresist to an upper surface of the lower cladding and performing a lithography process using a photomask and a left external light source, and etching the reactive ions into the lower cladding after performing the lithography process. A third step (S30) of forming a device pattern as a core pattern by performing a process; a fourth step (S40) of forming an optical filter pattern by spin coating a polymer having a high refractive index on the upper surface of the formed device pattern; A fifth step (S50) of forming an upper cladding by spin-coating a polymer on an upper surface of the optical filter pattern and the optical filter panel on an upper surface of the upper cladding A sixth step S60 of forming a gold thin film electrode pattern 500 at a position covering the second ring resonator 400 in a turn is performed.

More specifically, spin-coating a polymer on a silicon substrate and curing it appropriately to form a bottom cladding, apply a photoresist to the formed bottom cladding to perform a lithography process using a photomask and an ultraviolet light source, the lithography process Subsequently, a reactive ion etching process is performed to form an element pattern, which is a core pattern, on the lower cladding, followed by spin coating a polymer having a high refractive index to form the first and second waveguides 100 and 300, and the first and second ring resonators ( 200 and 400, and thereafter, an upper cladding is formed in the same manner as the lower cladding, and the upper cladding upper surface is positioned to cover the second ring resonator in the optical filter pattern. The gold thin film electrode pattern 500 is formed to complete the optical filter.

The present invention has been described in detail so far, but the embodiments mentioned in the process are only illustrative and are not intended to be limiting, and the present invention is provided by the following claims and the technical spirit and field of the present invention. Within the scope not departing from the scope of the present invention, changes in the components to the extent that they can be dealt with evenly will fall within the scope of the present invention.

 As described above, in the present invention, the band pass filter and the band stop filter are combined to electrically adjust the extinction ratio and the bandwidth of the band pass filter, thereby controlling the band pass characteristic by the first ring resonator and the second ring resonator. By adjusting the band stop characteristics by adjusting the ring radius of the first and second ring resonators, and controlling the bandwidth, by applying a voltage to the electrode pattern to adjust the extinction ratio by the change of the resonance wavelength according to the refractive index, Applying a voltage to the pattern has the effect of adjusting the wavelength response.

Claims (6)

delete delete delete A first waveguide formed by an input port through which an optical signal is input and the other end by a passage port through which the optical signal is passed to transmit the optical signal; The first waveguide is spaced apart from the first waveguide at a predetermined interval and formed in parallel, and one end of the first waveguide inputs an additional port to which an additional optical signal other than an optical signal is input, and the other end of the first waveguide outputs a signal. A second waveguide formed by the port; A first ring resonator spaced apart from the first waveguide and the second waveguide at a predetermined interval between the vertical lower side adjacent to the input port of the first waveguide and the vertical upper side adjacent to the additional port of the second waveguide by a closed loop; Wow; The first ring resonator couples the optical signal incident from the first waveguide, and the coupled optical signal rotates along the first ring resonator to couple the second ring waveguide to the second ring waveguide. Operating as a passband filter for selectively passing only the optical signal of the corresponding resonant wavelength band according to the radius; A second ring resonator spaced apart at a predetermined interval from a vertical lower side adjacent to the inlet port of the second waveguide by a closed loop; The second ring resonator is coupled to the second waveguide and operates as a band stop filter for attenuating only optical signal components of a corresponding resonant wavelength band by a ring radius of the second ring resonator, and a ring radius of the second ring resonator. And the bandwidth and the extinction ratio of the optical filter are adjusted by changing the refractive index; The second ring is laminated on the upper layer of the resonator is formed from an open-loop bandwidth and extinction, characterized in that formed as an electrode pattern for controlling the extinction ratio of the optical filter by a current change of the variable potentiometer formed on both ends an end of the open-loop ratio Optical filter using a controlled microring resonator. The method of claim 4, wherein An optical filter using a microring resonator, in which a bandwidth and an extinction ratio are controlled, in which a side lobe of a bandpass filter of the first resonator is removed by a band stop filter characteristic of the second ring resonator. The method of claim 4, wherein the first and second ring resonator, An optical filter using a microring resonator, in which a bandwidth and an extinction ratio are controlled, wherein the material is one of a polymer, silica, an electro-optic polymer, silicon, and a compound semiconductor.

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