KR102157629B1 - Optical signal generating apparatus and operating method thereof - Google Patents

Abstract

The optical signal generating apparatus according to an embodiment of the present invention modulates a first optical signal to generate a 2 ^N -level (where N is a positive integer) second optical signal in the form of a binary signal. Intensity modulator, a first optical amplifier configured to amplify the second optical signal to generate a third optical signal, and modulate the third optical signal to generate a ^2N+1 -level fourth optical signal in the form of a binary signal And a second light intensity modulator configured. The optical signal generation apparatus according to an embodiment of the present invention can generate a low-cost and high-quality optical signal by generating a multilevel optical signal using an optical element. In addition, the optical signal generation apparatus according to an embodiment of the present invention may generate a multilevel optical signal by sequentially performing optical modulation and optical amplification operations.

Description

Optical signal generating device and its operation method {OPTICAL SIGNAL GENERATING APPARATUS AND OPERATING METHOD THEREOF}

The present invention relates to an optical signal generation apparatus, and more particularly, to an optical signal generation apparatus for converting an electric signal into an optical signal in an optical transmission/reception module used in an optical network, and an operation method thereof.

Optical communication technology requires large-capacity and high-efficiency communication means as wired and wireless convergence services expand. In order to increase the speed and capacity of the optical network, a time division multiplexing (TDM) method that increases the speed of individual channels and an optical technology of a wavelength division multiplexing (WDM) method that widely utilizes optical frequency resources are utilized. do.

In addition, a multi-level optical signal modulation technology based on Ethernet is being studied to connect data centers. As one of the multilevel optical signal modulation techniques, pulse amplitude modulation (PAM) technique is used. The PAM optical signal modulator includes a digital to analog converter (DAC) for converting a binary electrical signal, which is a digital signal, into an analog signal.

Digital/analog electrical signal components required in next-generation communication technology based on large-capacity can incur large costs.

The present invention is to solve the above-described technical problem, an object of the present invention is to provide an optical signal generating device for generating a multi-level optical signal using an optical element instead of digital / analog electrical signal components and a method of operation thereof I have to.

The optical signal generating apparatus according to an embodiment of the present invention modulates a first optical signal to generate a 2 ^N -level (where N is a positive integer) second optical signal in the form of a binary signal. Intensity modulator, a first optical amplifier configured to amplify the second optical signal to generate a third optical signal, and modulate the third optical signal to generate a ^2N+1 -level fourth optical signal in the form of a binary signal And a second light intensity modulator configured.

The first light intensity modulator is configured to operate based on a first bias voltage and a first RF voltage, and the second light intensity modulator is configured to operate with a second bias voltage equal to the first bias voltage and the first RF voltage. It can be configured to operate based on a second RF voltage having an amplitude.

The optical intensity modulation width of the fourth optical signal may be the same as the optical intensity modulation width of the second optical signal.

The first optical amplifier may be configured to shape the second optical signal so that the optical intensity modulation width of the third optical signal is half of the optical intensity modulation width of the second optical signal.

The first optical amplifier operates based on an input current, and the magnitude of the input current may be a magnitude of a current that causes the first optical amplifier to operate in a nonlinear characteristic region.

The first light intensity modulator is configured to operate based on a first bias voltage and a first RF voltage, and the second light intensity modulator is a second bias voltage different from the first bias voltage and a second bias voltage different from the first RF voltage. It can be configured to operate based on a second RF voltage having an amplitude.

The amplitude of the second RF voltage may be half of the amplitude of the first RF voltage.

The first optical amplifier operates based on an input current, and the magnitude of the input current may be a magnitude of a current that causes the first optical amplifier to operate in a linear characteristic region.

The highest level of light intensity of the third optical signal may be the same as that of the first optical signal.

An optical signal generating apparatus according to an exemplary embodiment of the present invention includes a second optical amplifier configured to amplify the fourth optical signal to generate a fifth optical signal, and a second optical amplifier configured to modulate the fifth optical signal to form a binary signal of ^2N A third light intensity modulator configured to generate a ⁺² -level sixth optical signal may be further included.

The first light intensity modulator is configured to operate based on a first bias voltage and a first RF voltage, and the second light intensity modulator is configured to operate based on a second bias voltage and a second RF voltage, and the second light intensity modulator is configured to operate based on a second bias voltage and a second RF voltage. The three light intensity modulator is configured to operate based on a third bias voltage and a third RF voltage, and the first bias voltage, the second bias voltage, and the third bias voltage are the same, and the first RF voltage, the The second RF voltage and the third RF voltage may have the same amplitude.

The first optical amplifier is configured to shape the second optical signal so that the optical intensity modulation width of the third optical signal is half of the optical intensity modulation width of the second optical signal, and the second optical amplifier 5 It may be configured to shape the fourth optical signal so that the optical intensity modulation width of the optical signal is 1/4 of the optical intensity modulation width of the fourth optical signal.

The first light intensity modulator is configured to operate based on a first bias voltage and a first RF voltage, and the second light intensity modulator is configured to operate based on a second bias voltage and a second RF voltage, and the second light intensity modulator is configured to operate based on a second bias voltage and a second RF voltage. The three light intensity modulator is configured to operate based on a third bias voltage and a third RF voltage, and the first bias voltage, the second bias voltage, and the third bias voltage are different from each other, and the first RF voltage, the The second RF voltage and the third RF voltage may have different amplitudes.

The amplitude of the second RF voltage may be half the amplitude of the first RF voltage, and the amplitude of the third RF voltage may be half the amplitude of the second RF voltage.

The first light intensity modulator and the second light intensity modulator may be a Mach-Zehnder light intensity modulator or an electric field absorption modulator.

The method of operating an optical signal generating apparatus according to an embodiment of the present invention comprises the steps of generating a 2 ^N -level (where N is a positive integer) second optical signal in the form of a binary signal by modulating a first optical signal, Amplifying the second optical signal to generate a third optical signal, and modulating the third optical signal to generate a ^2N+1 -level fourth optical signal in the form of a binary signal.

Modulates the first optical signal based on a first bias voltage and a first RF voltage, and based on a second bias voltage equal to the first bias voltage and a second RF voltage having an amplitude equal to the first RF voltage The third optical signal may be modulated.

Modulates the first optical signal based on a first bias voltage and a first RF voltage, and based on a second bias voltage different from the first bias voltage and a second RF voltage having an amplitude different from the first RF voltage The third optical signal may be modulated.

The second optical signal is amplified based on an input current, and the magnitude of the input current may be a magnitude of a current such that the optical intensity modulation width of the third optical signal is different from the optical intensity modulation width of the second optical signal. have.

The second optical signal is amplified based on an input current, and the magnitude of the input current may be a magnitude of a current such that the optical intensity modulation width of the third optical signal is the same as the optical intensity modulation width of the second optical signal. have.

The optical signal generation apparatus according to an embodiment of the present invention can generate a low-cost and high-quality optical signal by generating a multilevel optical signal using an optical element.

In addition, the optical signal generation apparatus according to an embodiment of the present invention may generate a multilevel optical signal by sequentially performing optical modulation and optical amplification operations.

1 is a schematic diagram of an optical signal generating apparatus according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating an optical signal generating apparatus of FIG. 1.
3A and 3B are diagrams illustrating a modulation operation of an optical intensity modulator according to an embodiment of the present invention.
4A and 4B are views exemplarily showing an operation of an optical amplifier according to an embodiment of the present invention.
5 is a block diagram showing an optical signal generating apparatus according to an embodiment of the present invention.
6 is a diagram illustrating an optical signal output of the optical signal generating device of FIG. 5 by way of example.
7 is a flowchart illustrating a method of operating the optical signal generating device of FIG. 5.
8 is a block diagram illustrating an optical signal generating apparatus according to an embodiment of the present invention.
9 is a diagram illustrating an optical signal output of the optical signal generating device of FIG. 8 by way of example.
10 is a block diagram illustrating an optical signal generating apparatus according to an embodiment of the present invention.
11 is a diagram illustrating an optical signal output of the optical signal generating apparatus of FIG. 10 by way of example.
12 is a flow chart illustrating a method of operating the optical signal generating apparatus of FIG. 10.
13 is a block diagram showing an optical signal generating apparatus according to an embodiment of the present invention.
14 is a diagram illustrating an optical signal output from the optical signal generating apparatus of FIG. 13 by way of example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, detailed details such as detailed configurations and structures are provided simply to help overall understanding of embodiments of the present invention. Therefore, modifications of the embodiments described in the text may be performed by a person skilled in the art without departing from the spirit and scope of the present invention. Moreover, descriptions of well-known functions and structures are omitted for clarity and conciseness. Terms used in the present specification are terms defined in consideration of functions of the present invention, and are not limited to specific functions. The definition of terms may be determined based on the matters described in the detailed description.

Modules in the following drawings or detailed description may be shown in the drawings or may be connected to other things other than the components described in the detailed description. The connections between modules or components may be direct or non-direct, respectively. The connections between the modules or components may each be a communication connection or a physical connection.

Components described with reference to terms such as a unit or a unit, a module, and a layer used in the detailed description may be implemented in the form of software, hardware, or a combination thereof. Illustratively, the software may be machine code, firmware, embedded code, and application software. For example, the hardware may include an electrical circuit, an electronic circuit, a processor, a computer, an integrated circuit, integrated circuit cores, a pressure sensor, an inertial sensor, a Micro Electro Mechanical System (MEMS), a passive component, or a combination thereof. I can.

Unless otherwise defined, all terms including technical or scientific meanings used in the text have meanings that can be understood by those of ordinary skill in the art to which the present invention belongs. In general, terms defined in the dictionary are interpreted to have a meaning equivalent to a contextual meaning in a related technical field, and are not interpreted to have an ideal or excessively formal meaning unless clearly defined in the text.

1 is a schematic diagram of an optical signal generating apparatus according to an embodiment of the present invention. Referring to FIG. 1, the light source 10 may generate an optical signal from the current I_s. The light source 10 may output an optical signal of a certain intensity and transmit it to the optical signal generating apparatus 100.

The optical signal generating apparatus 100 may receive an optical signal from the light source 10 and modulate the received optical signal to generate a ^2N -level (N>1) (or multilevel) optical signal. That is, the optical signal generated from the optical signal generating apparatus 100 may represent one of 2 ^N -levels. Accordingly, the optical signal generating apparatus 100 may generate an optical signal capable of representing ^2N values.

The optical signal generation apparatus 100 may include a zeroth optical intensity modulator 101 and one or more binary signal generation units 110. The zeroth light intensity modulator 101 may modulate the light intensity by receiving an optical signal having a constant intensity from the light source 10. The zeroth optical intensity modulator 101 may generate an optical signal (hereinafter, referred to as a binary optical signal) in the form of a binary signal by modulating the optical intensity. That is, the zeroth optical intensity modulator 101 is a two-level optical signal having a high level (eg, "1") and a low level (eg, "0") values from an optical signal of one level. Can be created.

The binary signal generator 110 may receive and amplify the optical signal, and generate a binary optical signal by modulating the amplified optical signal. For example, the binary signal generator 110 may reshape the optical signal. When the optical signal is shaped, the optical intensity modulation width of the binary optical signal may vary.

The first binary signal generator 110-1 may receive a 2-level optical signal from the 0th optical intensity modulator 101. The first binary signal generator 110-1 may generate a binary optical signal representing a 4-level from an optical signal representing a 2-level.

The second binary signal generator 110-2 may receive a 4-level optical signal from the first binary signal generator 110. The second binary signal generator 110-2 may generate a binary optical signal representing an 8-level from an optical signal representing a 4-level.

The N-1th binary signal generator 110 -N-1 may receive a ^2N-1 -level optical signal from the ^N- 2th binary signal generator (not shown). The N-1th binary signal generator 110 -N-1 may generate a binary optical signal representing a ^2N -level from an optical signal representing the ^2N-1 -level.

As shown in FIG. 1, the zeroth light intensity modulator 101 and one or more binary signal generators 110 are connected in series to sequentially modulate the optical signal to generate a multilevel optical signal. Accordingly, the optical signal generation apparatus 100 may generate a ^2N -level optical signal through N-1 binary signal generation units, and generate a multilevel optical signal through one optical intensity modulator and one or more binary signal generation units. can do.

The optical signal generating apparatus according to an embodiment of the present invention may receive an optical signal generated from a separate light source 10 as shown in FIG. 1, but the present invention is not limited thereto. For example, the optical signal generating device according to an embodiment of the present invention may include a light source and generate an optical signal inside the optical signal generating device.

Hereinafter, for convenience of description, it is assumed that the optical signal generating apparatus receives an optical signal from a separate light source.

FIG. 2 is a block diagram illustrating an optical signal generating apparatus of FIG. 1. 1 and 2, the optical signal generating apparatus 100 may include a zeroth optical intensity modulator 101 and one or more binary signal generators 110. The binary signal generator 110 may include an optical amplifier 111 and an optical intensity modulator 112.

The light intensity modulators 101 and 112 may be implemented using an Electro-Absorption Modulator (EAM) or a Mach-Zehnder light intensity modulator.

The light intensity modulators 101 and 112 may modulate the received optical signal based on the bias voltage V _bias and the RF voltage V _RF . The bias voltage V _bias is a DC voltage and may be related to a reference operating point of the light intensity modulator. The RF voltage V _RF may be related to the optical intensity modulation width of the binary optical signal generated by modulating the optical signal. For example, the RF voltage V _RF may be an AC voltage or an electrical binary signal. For example, the light intensity reference value of the generated binary optical signal may be determined according to the bias voltage V _bias , and the light intensity modulation width of the binary optical signal may vary according to the RF voltage V _RF .

The optical amplifier 111 may amplify the intensity of the received optical signal based on the current I. The optical amplifier 111 may shape the optical signal by adjusting the optical intensity width of the binary optical signal based on the current I.

The 0th optical intensity modulator 101 may receive a 0th bias voltage (V _bias 0), a 0th RF voltage (V _RF 0), and an optical signal. The 0th optical intensity modulator 101 may generate a binary optical signal by modulating the received optical signal based on the 0th bias voltage (V _bias 0) and the 0th RF voltage (V _RF 0). The binary optical signal generated by the zeroth optical intensity modulator 101 may be a 2-level optical signal.

The first optical amplifier 111-1 may receive the first current I_1 and the optical signal generated from the 0th optical intensity modulator 101. The first optical amplifier 111-1 may amplify the received optical signal based on the first current I_1. The first optical amplifier 111-1 may shape the received optical signal based on the first current I_1.

The first optical intensity modulator 112-1 may receive a first bias voltage V _bias 1, a first RF voltage V _RF 1, and an amplified optical signal from the first optical amplifier 111-1. . The first optical intensity modulator 112-1 may generate a binary optical signal by modulating the received optical signal based on the first bias voltage V _bias 1 and the first RF voltage V _RF 1. The binary optical signal generated by the first optical intensity modulator 112-1 may be a 4-level optical signal.

Like in the first optical amplifier 111-1, the second optical amplifier 111-2 may amplify the intensity of the optical signal based on the second current I_2 and shape the received optical signal. have. In addition, the N-1th optical amplifier 111-N-1 may amplify the intensity of the received optical signal based on the N-1th current I_N-1, and shape the received optical signal. .

Similar to the first light intensity modulator 112-1, the second light intensity modulator 112-2 is configured to receive light based on the second bias voltage V _bias 2 and the second RF voltage V _RF 2. The signal can be modulated to produce an 8-level optical signal. Also, the N-1th light intensity modulator 112-N-1 is configured to receive light based on the N- _1th bias voltage (V _bias N-1) and the N-1th RF voltage (V _RF N-1). The signal can be modulated to generate a 2 ^N -level optical signal.

Exemplarily, the magnitudes of the 0th bias voltage to the N- _1th bias voltage (V _bias 0 to V _bias N-1) may be the same, and the 0th RF voltage to the N-1th RF voltage (V _RF 0 The amplitude of ~V _RF N-1) may be the same, In this case, the light of the binary optical signal generated by the 0th optical intensity modulator to the N-1th optical intensity modulator 101 to 112-N-1 The intensity modulation width may be the same.

Exemplarily, the magnitudes of the 0th bias voltage to the N- _1th bias voltage (V _bias 0 to V _bias N-1) may be different, and the 0th RF voltage to the N-1th RF voltage (V _RF 0 to V The size of _RF N-1) may be different. In this case, the optical intensity modulation width of the binary optical signal generated by the 0th to N-1th optical intensity modulators 101 to 112-N-1 may be different.

1 and 2, the optical signal generation apparatus 100 may include N-1 binary signal generation units. However, the optical signal generation apparatus 100 is not limited to the number of binary signal generation units, and may generate a multilevel optical signal (eg, a 4-level optical signal) through, for example, one binary signal generation unit. have.

3A and 3B are diagrams illustrating a modulation operation of an optical intensity modulator according to an embodiment of the present invention. Specifically, FIG. 3A shows an example in which the 0th optical intensity modulator 101 modulates the received optical signal into a binary optical signal, and FIG. 3B shows that the 0th optical intensity modulator 101 has a bias voltage V _bias and It shows an example of modulating a received optical signal into a binary optical signal according to the voltage (V _RF ). For convenience of explanation, the light intensity modulator according to the embodiment of the present invention is described based on the 0th light intensity modulator 101, but other light intensity modulators 112-1 to 112-N-1 are similarly It can work.

Referring to FIG. 3A, the horizontal axis of FIG. 3A represents time and the vertical axis represents light intensity. The light intensity on the vertical axis represents a relative magnitude of the optical intensity of the output optical signal with respect to the optical intensity of the input optical signal, and may not mean an absolute optical intensity. Likewise, the light intensity shown in the drawings below may represent a relative light intensity level.

The 0th optical intensity modulator 101 may generate a second optical signal OS2 by modulating the received first optical signal OS1. For example, the generated second optical signal OS2 may be in the form of a binary signal. For example, among the second optical signals OS2, a second optical signal OS2 having a large light intensity p2 indicates a value of "1", and a second optical signal OS2 having a small light intensity p3 indicates " Can point to a value of 0".

As shown in FIG. 3A, the optical signal modulated through the 0th optical intensity modulator 101 may have a smaller optical intensity due to insertion loss. For example, the second light intensity p2 of the modulated second optical signal OS2 may be smaller than the first light intensity p1 of the first optical signal OS1 by an insertion loss.

Referring to FIG. 3B, the horizontal axis of FIG. 3B represents the applied voltage and the vertical axis represents the light intensity. 3B shows a light intensity response characteristic according to a voltage applied to the zeroth light intensity modulator 101. The zeroth light intensity modulator 101 may operate based on the light intensity modulator characteristic curve. For example, the response characteristic of the 0th light intensity modulator 101 (that is, the light intensity modulator characteristic curve) may vary depending on the structure and design of the 0th light intensity modulator 101, and the 0th light intensity modulator 101 ) May be determined in advance.

The applied voltage of FIG. 3B may be a bias voltage V _bias and an RF voltage V _RF . A bias voltage V _bias having a first voltage V1 and an RF voltage V _RF having a first amplitude a1 may be applied to the 0th light intensity modulator 101. In this case, the 0th light intensity modulator 101 is a second optical signal having a second light intensity p2 and a third light intensity p3 from the first optical signal OS1 having the first light intensity p1 (OS2) can be created.

The generated second optical signal OS2 may be determined based on an optical intensity modulator characteristic curve. As shown in FIG. 3B, the reference point of the modulated light intensity may vary according to the bias voltage V _bias . For example, when the bias voltage V _bias decreases, the modulated light intensity may increase, and when the bias voltage V _bias increases, the modulated light intensity may decrease.

In addition, according to the amplitude of the RF voltage (V _RF ), the optical intensity modulation width of the generated optical signal may vary. For example, when the amplitude of the RF voltage V _RF increases, the light intensity modulation width may increase, and when the amplitude of the RF voltage V _RF decreases, the light intensity modulation width may decrease.

For example, a bias voltage V _bias and an RF voltage V _RF may be applied so that the zeroth light intensity modulator 101 can operate in a linear characteristic region of the light intensity modulator characteristic curve. When the zeroth light intensity modulator 101 operates in the linear characteristic region, the light intensity modulation width may be easily controlled by adjusting the applied bias voltage V _bias and the RF voltage V _RF .

4A and 4B are views exemplarily showing an operation of an optical amplifier according to an embodiment of the present invention. Specifically, FIG. 4A shows an example in which the first optical amplifier 111-1 amplifies a received optical signal, and FIG. 4B shows a method of determining the optical amplification intensity output from the first optical amplifier 111-1. It shows an example for explanation. For convenience of explanation, the optical amplifier according to the embodiment of the present invention is described based on the first optical amplifier 111-1, but other optical amplifiers 111-2 to 111-N-1 operate similarly. can do.

Referring to FIG. 4A, the horizontal axis represents time and the vertical axis represents light intensity. The first optical signal OS1 is modulated from the 0th optical intensity modulator 101 to the second optical signal OS2, and the optical intensity of the second optical signal OS2 is amplified from the first optical amplifier 111-1. As a result, a third optical signal OS3 may be generated.

The second optical intensity p2 of the second optical signal OS2 by the first optical amplifier 111-1 may be amplified by the fourth optical intensity p4 of the third optical signal OS3, and the second The third light intensity p3 of the optical signal OS2 may be amplified by the fifth light intensity p5 of the third optical signal OS3.

The first optical amplifier 111-1 may not only amplify the light intensity, but also change the light intensity modulation width of the generated optical signal (ie, shape the optical signal). Accordingly, the light intensity modulation width before amplification and the light intensity modulation width after amplification may be different. For example, the first optical amplifier 111-1 may amplify the optical signal so that the light intensity modulation width before amplification and the light intensity modulation width after amplification are the same. Alternatively, the first optical amplifier 111-1 may amplify the optical signal so that the light intensity modulation width after amplification becomes smaller than the light intensity modulation width before amplification.

Referring to FIG. 4B, the horizontal axis represents the input light intensity, and the vertical axis represents the output light intensity. The first optical amplifier 111-1 may amplify the light intensity of the input optical signal based on the optical amplifier characteristic curve. According to the optical amplifier characteristic curve, the second light intensity p2 may be amplified to the fourth light intensity p4, and the third light intensity p3 may be amplified to the fifth light intensity p5.

The optical amplifier characteristic curve may have a linear characteristic region and a nonlinear characteristic region (or saturation region). When the light intensity is amplified according to the linear characteristic region, the output light intensity may be determined in proportion to the input light intensity. The light intensity modulation width before amplification may be the same as the light intensity modulation width after amplification. Therefore, when only amplifying the optical signal, the optical amplifier can operate according to the linear characteristic region.

When the light intensity is amplified according to the nonlinear characteristic region, the input light intensity and the output light intensity may not be proportional. The light intensity modulation width after amplification may be smaller than the light intensity modulation width before amplification. Therefore, when shaping an optical signal, the optical amplifier can operate according to the nonlinear characteristic region.

The first optical amplifier 111-1 may perform an amplification operation based on the input current. When the input current varies, the operating characteristics of the first optical amplifier 111-1 may be changed. That is, the optical amplifier characteristic curve shown in FIG. 4B may be different. For example, a linear characteristic region and a nonlinear characteristic region may vary according to the input current. Accordingly, the first optical amplifier 111-1 may amplify the optical signal according to the linear characteristic region or amplify the optical signal according to the nonlinear characteristic region according to the input current.

5 is a block diagram showing an optical signal generating apparatus according to an embodiment of the present invention. Referring to FIG. 5, the optical signal generating apparatus 200 may receive an optical signal and output a 4-level optical signal. The optical signal generation apparatus 200 may include a zeroth optical intensity modulator 201 and a binary signal generation unit 210. The binary signal generator 210 may include a first optical amplifier 211 and a first optical intensity modulator 212. The 0th optical intensity modulator 201, the first optical amplifier 211, and the first optical intensity modulator 212 perform operations similar to those of the optical intensity modulator and optical amplifier described in FIGS. 1 to 4B, and thus detailed descriptions are omitted. .

The 0th light intensity modulator 201 operates based on a 0th bias voltage (V _bias 0) and a 0th RF voltage (V _RF 0), and the first light intensity modulator 212 is configured with a first bias voltage (V _bias 0). 1) and the first RF voltage (V _RF 1) can be operated based on. The 0th bias voltage (V _bias 0) and the first bias voltage (V _bias 1) may be the same, and the amplitude of the 0th RF voltage (V _RF 0) and the amplitude of the first RF voltage (V _RF 1) may be the same. have. That is, the 0th light intensity modulator 201 and the first light intensity modulator 212 may operate by the same bias voltage V _bias and the RF voltage V _RF having the same amplitude.

As shown in FIG. 3B, when the amplitudes of the bias voltage V _bias and the RF voltage V _RF applied to the 0th and first light intensity modulators 201 and 212 are the same, the same light intensity modulation width is An optical signal having a can be generated. Accordingly, the optical intensity modulation width of the optical signal generated by the 0th optical intensity modulator 201 may be the same as the optical intensity modulation width of the optical signal generated by the first optical intensity modulator 212.

The first optical amplifier 211 may receive the first current I_1 to amplify and shape the optical signal received from the 0th optical intensity modulator 201. The first optical amplifier 211 may amplify and shape the received optical signal so that the interval between each signal level of the 4-level optical signal output from the optical signal generating apparatus 200 is the same. As shown in FIG. 4B, the first optical amplifier 211 may amplify and shape a received optical signal by operating in a nonlinear characteristic region. Accordingly, the first current I_1 may be a current that causes the first optical amplifier 211 to operate in a nonlinear characteristic region.

For example, when the optical signal input by the first optical amplifier 211 is shaped, the output light intensity modulation width may be half of the input light intensity modulation width.

The first optical intensity modulator 212 may generate a 4-level optical signal by modulating the amplified and shaped 2-level optical signal. Accordingly, the optical signal generating apparatus 200 may output a 4-level optical signal (ie, a multilevel optical signal).

6 is a diagram illustrating an optical signal output of the optical signal generating device of FIG. 5 by way of example. 6, the horizontal axis represents time, and the vertical axis represents light intensity. 5 and 6, the zeroth optical intensity modulator 201 may generate a second optical signal OS2 by modulating the first optical signal OS1. A two-level second optical signal OS2 having a second light intensity p2 and a third light intensity p3 may be generated from the first optical signal OS1 having the first light intensity p1. The 0th optical intensity modulator 201 generates a second optical signal OS2 having a first optical intensity modulation width w1 based on a 0th bias voltage (V _bias 0) and a 0th RF voltage (V _RF 0). Can be generated.

The first optical amplifier 211 may generate a third optical signal OS3 by amplifying the second optical signal OS2. The first optical amplifier 211 may generate a third optical signal OS3 based on the first current I_1. The third optical signal OS3 may be a 2-level optical signal having a fourth light intensity p4 and a fifth light intensity p5.

Compared to the second optical signal OS2, the third optical signal OS3 may have an increased light intensity and a light intensity modulation width may be decreased. For example, although illustrated differently in FIG. 6, in the first optical amplifier 211, the fourth optical intensity p4 of the third optical signal OS3 is equal to the first optical intensity p1 of the first optical signal OS1. ), the second optical signal OS2 may be amplified. The first optical amplifier 211 may shape the second optical signal OS2 so that the second optical intensity modulation width w2 of the third optical signal OS3 is half of the first optical intensity modulation width w1. have.

The first optical intensity modulator 212 modulates the third optical signal OS3 based on the first bias voltage V _bias 1 and the first RF voltage V _RF 1 to generate the fourth optical signal OS4. can do. The first bias voltage (V _bias 1) is equal to the 0th bias voltage (V _bias 0), and the amplitude of the first RF voltage (V _RF 1) is equal to the amplitude of the 0th RF voltage (V _RF 0). I can.

The fourth optical signal OS4 may be a 4-level optical signal having a sixth light intensity p6, a seventh light intensity p7, an eighth light intensity p8, and a ninth light intensity p9. The first optical intensity modulator 212 includes a fourth optical signal OS4 having a sixth optical intensity p6 and an eighth optical intensity p8 from the third optical signal OS3 having a fourth optical intensity p4. Can be created. The first light intensity modulator 212 includes a fourth optical signal OS4 having a seventh light intensity p7 and a ninth light intensity p9 from the third optical signal OS3 having the fifth light intensity p5. Can be created. That is, the first optical intensity modulator 212 may generate a 4-level fourth optical signal OS4 from the 2-level third optical signal OS3.

The first light intensity modulator 212 may generate a fourth optical signal OS4 having a third light intensity modulation width w3 from the third optical signal OS3 having a fourth light intensity p4. The first optical intensity modulator 212 may generate a fourth optical signal OS4 having a fourth optical intensity modulation width w4 from the third optical signal OS3 having a fifth optical intensity p5. The third light intensity modulation width (w3) and the fourth light intensity modulation width (w4) may be the same, and the third light intensity modulation width (w3) and the fourth light intensity modulation width (w4) are the first light intensity modulation width. It may be the same as the width w1. Also, the intervals between the light intensities p6, p7, p8, and p9 of the fourth optical signal OS4 may be the same.

In this specification, the light intensity modulation width may mean the light intensity width of a binary optical signal generated from an optical signal of a predetermined level through the light intensity modulator. That is, the third light intensity modulation width w3 or the fourth light intensity modulation width w4 of the fourth optical signal OS4 is the light intensities p6, p7, p8, and p9 of the fourth optical signal OS4. It may have a different meaning than the spacing of.

7 is a flowchart illustrating a method of operating the optical signal generating device of FIG. 5. 5 and 7, in step S101, the optical signal generation apparatus 200 modulates the optical signal according to the 0th bias voltage (V _bias 0) and the 0th RF voltage (V _RF 0) to generate a binary optical signal. Can be created. In step S102, the optical signal generating apparatus 200 may amplify and shape the generated binary optical signal. In step S103, the optical signal generation apparatus 200 may generate a multilevel optical signal by modulating the shaped binary optical signal according to the first bias voltage V _bias 1 and the first RF voltage V _RF 1. . The first bias voltage (V _bias 1) is equal to the 0th bias voltage (V _bias 0), and the amplitude of the first RF voltage (V _RF 1) is equal to the amplitude of the 0th RF voltage (V _RF 0). I can.

The optical signal generating apparatus according to an exemplary embodiment of the present invention is not limited to that shown in FIG. 7, and by repeatedly performing steps S102 and S103, an optical signal having more levels may be generated. For example, if steps S102 and S103 are performed N-1 times, the optical signal generating apparatus may generate a ^2N -level optical signal.

8 is a block diagram illustrating an optical signal generating apparatus according to an embodiment of the present invention. The optical signal generation apparatus 300 may include a zeroth optical intensity modulator 301, a first binary signal generation unit 310 and a second binary signal generation unit 320. The first binary signal generation unit 310 includes a first optical amplifier 311 and a first optical intensity modulator 312, and the second binary signal generation unit 320 includes a second optical amplifier 321 and a second optical amplifier. A light intensity modulator 322 may be included. Since the operation of the 0th light intensity modulator 301 and the first binary signal generation unit 310 is similar to the operation of the 0th light intensity modulator 201 and the binary signal generation unit 210 of FIG. 5, detailed description Is omitted.

The optical signal generation apparatus 300 may generate an 8-level optical signal through the 0th optical intensity modulator 301 and the first and second binary signal generation units 310 and 320. The zeroth light intensity modulator 301, the first light intensity modulator 312, and the second light intensity modulator 322 have the same bias voltage (V _bias 0 = V _bias 1 = V _bias 2) and an RF voltage having the same amplitude. (V _RF 0=V _RF 1=V _RF 2) can be applied. The first optical amplifier 311 and the second optical amplifier 321 may each receive a first current I_1 and a second current I_2.

9 is a diagram illustrating an optical signal output of the optical signal generating device of FIG. 8 by way of example. In FIG. 9, the horizontal axis represents time and the vertical axis represents light intensity. 8 and 9, the 0th optical intensity modulator 301 modulates the first optical signal OS1 based on the 0th bias voltage (V _bias 0) and the 0th RF voltage (V _RF 0). A second optical signal OS2 having a first optical intensity modulation width w1 may be generated.

The first optical amplifier 311 may amplify and shape the second optical signal OS2 based on the first current I_1 to generate the third optical signal OS3. The second light intensity modulation width w2 of the shaped third optical signal OS3 may be different from the first light intensity modulation width w1. For example, the second light intensity modulation width w2 may be half of the first light intensity modulation width w1. The highest level of light intensity of the third optical signal OS3 may be the same as that of the first optical signal OS1.

The first optical intensity modulator 312 modulates the third optical signal OS3 based on the first bias voltage V _bias 1 and the first RF voltage V _RF 1 to obtain a third optical intensity modulation width w3. A fourth optical signal OS4 having a may be generated. The first bias voltage (V _bias 1) is equal to the 0th bias voltage (V _bias 0), and the amplitude of the first RF voltage (V _RF 1) is equal to the amplitude of the 0th RF voltage (V _RF 0). I can. For example, the third light intensity modulation width w3 may be the same as the first light intensity modulation width w1, and the interval between each signal level of the fourth optical signal OS4 may be the same.

The second optical amplifier 321 may generate a fifth optical signal OS5 by amplifying and shaping the fourth optical signal OS4 based on the second current I_2. The fifth optical signal OS5 may have a fourth optical intensity modulation width w4 different from the third optical intensity modulation width w3. For example, the fourth light intensity modulation width w4 may be 1/4 of the third light intensity modulation width w3. That is, the optical signal generating apparatus 100 according to an embodiment of the present invention may shape the optical signal so that the optical intensity modulation width is further reduced as the optical signal amplification step increases. For example, the optical signal generation apparatus 100 shapes the optical signal modulation width to be 1/2 in the first optical amplifier, the optical signal modulation width to 1/4 in the second optical amplifier, and the third optical amplifier The optical signal modulation width can be set to 1/8. The highest level of light intensity of the fifth optical signal OS5 may be equal to the highest level of light intensity of the third optical signal OS3.

The second optical intensity modulator 322 modulates the fifth optical signal OS5 based on the second bias voltage V _bias 2 and the second RF voltage V _RF 2 to obtain a fifth optical intensity modulation width w5. A sixth optical signal OS6 having a may be generated. The second bias voltage (V _bias 2) is equal to the 0th bias voltage (V _bias 0), and the amplitude of the second RF voltage (V _RF 2) is equal to the amplitude of the 0th RF voltage (V _RF 0). I can. For example, the fifth light intensity modulation width w5 may be the same as the first and third light intensity modulation widths w1 and w3, and the interval between each signal level of the sixth optical signal OS6 may be the same. I can.

The optical signal generation apparatus 300 may output a sixth optical signal OS6 generated from the second optical intensity modulator 322. From this, the optical signal generating apparatus 300 may output an 8-level optical signal. The 8-level optical signal output from the optical signal generating apparatus 300 may indicate a value corresponding to allocated bits as shown in FIG. 9 and Table 1 below.

8-level optical signal The magnitude of the zeroth RF voltage of the zeroth light intensity modulator The magnitude of the first RF voltage of the first light intensity modulator The magnitude of the second RF voltage of the second light intensity modulator 000 0 0 0 001 One 0 0 010 0 One 0 011 One One 0 100 0 0 One 101 One 0 One 110 0 One One 111 One One One

As shown in Table 1, when receiving an 8-level optical signal from the optical signal generating apparatus 300, the receiving end may recognize a value indicated by the optical signal as one of "000" to "111" according to the optical signal level. For example, a zeroth RF voltage (V _RF 0) corresponding to "1" is input to the 0th light intensity modulator 301, and a first RF voltage corresponding to "0" is input to the first light intensity modulator 312 When a voltage (V _RF 1) is input and a second RF voltage (V _RF 2) corresponding to “0” is input to the second light intensity modulator 322, the receiving end receives an optical signal indicating “001” can do.

The 0 is the zero RF voltage (V _RF 0) corresponding to "0", the optical intensity modulator 301 is input, first the first RF voltage corresponding to "1" in the light intensity modulator (312) (V _RF When 1) is input and a second RF voltage V _RF 2 corresponding to “1” is input to the second light intensity modulator 322, the receiving end may receive an optical signal indicating “110”.

Bit values may be allocated to the 8-level optical signal as shown in Table 1, but the present invention is not limited thereto, and bit values corresponding to each level may vary.

As described above, the optical signal generation apparatus according to embodiments of the present invention sequentially generates an optical signal through a plurality of optical intensity modulators operating based on the same bias voltage (V _bias ) and the same amplitude of the RF voltage (V _RF ). It is possible to generate a multilevel optical signal by modulating with

10 is a block diagram illustrating an optical signal generating apparatus according to an embodiment of the present invention. Referring to FIG. 10, the optical signal generating apparatus 400 may receive an optical signal and output a 4-level optical signal. The optical signal generation apparatus 400 may include a zeroth optical intensity modulator 401 and a binary signal generation unit 410. The binary signal generator 410 may include a first optical amplifier 411 and a first optical intensity modulator 412. Since the 0th optical intensity modulator 401, the first optical amplifier 411, and the first optical intensity modulator 412 perform operations similar to those of the optical intensity modulator and optical amplifier described in FIGS. 1 to 4B, detailed descriptions are omitted. .

The 0th light intensity modulator 401 may modulate an optical signal by inputting a 0th bias voltage (V _bias 0) and a 0th RF voltage (V _RF 0), and the first light intensity modulator 412 may An optical signal may be modulated by inputting 1 bias voltage (V _bias 1) and first RF voltage (V _RF 1). As shown in FIG. 3B, when the amplitudes of the bias voltage V _bias and the RF voltage V _RF applied to the 0th and first light intensity modulators 401 and 412 are different, the light intensity modulation width is different. An optical signal can be generated.

The first optical amplifier 411 may receive the first current I_1 and amplify the optical signal received from the 0th optical intensity modulator 401. The first optical amplifier 411 may amplify an optical signal while maintaining the same optical intensity modulation width. As shown in FIG. 4B, the first optical amplifier 411 may amplify an optical signal by operating in a linear characteristic region. Accordingly, the first current I_1 may be a current that causes the first optical amplifier 411 to operate in the linear characteristic region.

The first optical intensity modulator 412 may generate a 4-level optical signal by modulating the amplified 2-level optical signal. Accordingly, the optical signal generating apparatus 400 may output a 4-level optical signal (ie, a multilevel optical signal).

11 is a diagram illustrating an optical signal output of the optical signal generating apparatus of FIG. 10 by way of example. In FIG. 11, the horizontal axis represents time and the vertical axis represents light intensity. 10 and 11, the zeroth optical intensity modulator 401 may generate a second optical signal OS2 by modulating the first optical signal OS1. 2-level second light having a second light intensity p2 and a third light intensity p3 from the first light signal OS1 having the first light intensity p1 by the 0th light intensity modulator 401 A signal OS2 may be generated. The 0th optical intensity modulator 401 generates a second optical signal OS2 having a first optical intensity modulation width w1 based on a 0th bias voltage (V _bias 0) and a 0th RF voltage (V _RF 0). Can be generated.

The first optical amplifier 411 may generate a third optical signal OS3 by amplifying the second optical signal OS2 based on the first current I_1. The third optical signal OS3 may be a 2-level optical signal having a fourth light intensity p4 and a fifth light intensity p5. The first optical amplifier 411 provides the second optical signal OS2 so that the fourth optical intensity p4 of the third optical signal OS3 is equal to the first optical intensity p1 of the first optical signal OS1. Can amplify. The second light intensity modulation width w2 of the third optical signal OS3 may be the same as the first light intensity modulation width w1.

The first optical intensity modulator 412 modulates the third optical signal OS3 based on the first bias voltage V _bias 1 and the first RF voltage V _RF 1 to generate the fourth optical signal OS4. can do. The fourth optical signal OS4 may be a 4-level optical signal having a sixth light intensity p6, a seventh light intensity p7, an eighth light intensity p8, and a ninth light intensity p9. The first light intensity modulator 412 includes a fourth optical signal OS4 having a sixth light intensity p6 and a seventh light intensity p7 from the third optical signal OS3 having the fourth light intensity p4. Can be created. The first light intensity modulator 412 includes a fourth optical signal OS4 having an eighth light intensity p8 and a ninth light intensity p9 from the third optical signal OS3 having the fifth light intensity p5 Can be created. Accordingly, the first optical intensity modulator 412 may generate a 4-level fourth optical signal OS4 from the 2-level third optical signal OS3.

The first optical intensity modulator 412 may generate a fourth optical signal OS4 having a third optical intensity modulation width w3 and a fourth optical intensity modulation width w4 from the third optical signal OS3. . The first light intensity modulator 412 makes the interval between each signal level of the fourth optical signal OS4 equal (that is, the third light intensity modulation width w3, the fourth light intensity modulation width w4), and 5 The light intensity modulation width w5 is the same) The third optical signal OS3 may be modulated. For example, by applying the first RF voltage V _RF 1, which is half the amplitude of the 0th RF voltage V _RF 0, the interval between each signal level of the fourth optical signal OS4 may be the same.

As shown in FIG. 11, the optical signal generating apparatus 400 may generate a multilevel optical signal similar to the optical signal generating apparatus 200 of FIG. 5, but may generate other types of multilevel optical signals. .

12 is a flow chart illustrating a method of operating the optical signal generating apparatus of FIG. 10. 10 and 12, in step S201, the optical signal generating apparatus 400 modulates the optical signal according to the 0th bias voltage (V _bias 0) and the 0th RF voltage (V _RF 0) to obtain a binary optical signal. Can be created. In step S202, the optical signal generating apparatus 400 may amplify the generated binary optical signal. In step S203, the optical signal generating apparatus 400 may generate a multilevel optical signal by modulating the amplified binary optical signal according to the first bias voltage V _bias 1 and the first RF voltage V _RF 1. . The first bias voltage V _bias 1 is different from the 0th bias voltage V _bias 0, and the amplitude of the first RF voltage V _RF 1 may be different from the amplitude of the 0th RF voltage V _RF 0. .

The method of operating the optical signal generating apparatus according to an exemplary embodiment of the present invention is not limited to that shown in FIG. 12, and steps S202 and S203 are repeated to generate an optical signal having a higher level. For example, if steps S202 and S203 are performed N-1 times, the optical signal generating apparatus may generate a ^2N -level optical signal.

13 is a block diagram showing an optical signal generating apparatus according to an embodiment of the present invention. The optical signal generation apparatus 500 may include a zeroth optical intensity modulator 501, a first binary signal generation unit 510, and a second binary signal generation unit 520. The first binary signal generator 510 includes a first optical amplifier 511 and a first optical intensity modulator 512, and the second binary signal generator 520 includes a second optical amplifier 521 and a second optical amplifier. A light intensity modulator 522 may be included. Since the operation of the 0th light intensity modulator 501 and the first binary signal generation unit 510 is similar to the operation of the 0th light intensity modulator 401 and the binary signal generation unit 410 of FIG. 10, detailed description Is omitted.

The optical signal generating apparatus 500 may generate an 8-level optical signal through the 0th optical intensity modulator 501 and the first and second binary signal generators 510 and 520. The 0th light intensity modulator 501, the first light intensity modulator 512, and the second light intensity modulator 522 have different bias voltages (V _bias 0, V _bias 1, V _bias 2) and RF voltages ( V _RF 0, V _RF 1, V _RF 2) can be applied. For example, the amplitude of the first RF voltage (V _RF 1) input to the first light intensity modulator 512 may be half the amplitude of the 0th RF voltage (V _RF 0), and the second light intensity modulator 522 The amplitude of the second RF voltage V _RF 2 input to) may be half the amplitude of the first RF voltage V _RF 1. That is, the size of the amplitude of the RF voltage (V _RF) input to the optical intensity modulator can be reduced at a certain rate as compared with the RF voltage (V _RF) input to the optical intensity modulator from the previous step.

A first current I_1 may be input to the first optical amplifier 511, and a second current I_2 may be input to the second optical amplifier 521. The first optical amplifier 511 and the second optical amplifier 521 may receive a first current I_1 and a second current I_2, respectively, to amplify an optical signal.

14 is a diagram illustrating an optical signal output from the optical signal generating apparatus of FIG. 13 by way of example. 14, the horizontal axis represents time and the vertical axis represents light intensity. 13 and 14, the 0th optical intensity modulator 501 modulates the first optical signal OS1 based on the 0th bias voltage (V _bias 0) and the 0th RF voltage (V _RF 0). A second optical signal OS2 having a first optical intensity modulation width w1 may be generated.

The first optical amplifier 511 may amplify the second optical signal OS2 based on the first current I_1 to generate the third optical signal OS3. The third optical signal OS3 may have a second light intensity modulation width w2 equal to the first light intensity modulation width w1. For example, the highest level of light intensity of the third optical signal OS3 may be the same as the light intensity of the first optical signal OS1.

The first optical intensity modulator 512 modulates the third optical signal OS3 based on the first bias voltage V _bias 1 and the first RF voltage V _RF 1 to obtain a third optical intensity modulation width w3. A fourth optical signal OS4 having a may be generated. The interval between each signal level of the fourth optical signal OS4 may be the same as the third optical intensity modulation width w3. For example, the first RF voltage (V _RF 1), which is half the amplitude of the 0th RF voltage (V _RF 0), is the first light intensity modulator so that the interval between each signal level of the fourth optical signal OS4 is the same. Can be applied as 512.

The second optical amplifier 521 may generate a fifth optical signal OS5 by amplifying the fourth optical signal OS4 based on the second current I_2. The amplified fourth optical signal OS4 may have a fourth light intensity modulation width w4 equal to the third light intensity modulation width w3. For example, the light intensity of the highest level of the fifth optical signal OS5 may be the same as the light intensity of the highest level of the third optical signal OS3.

The second optical intensity modulator 522 modulates the fifth optical signal OS5 based on the second bias voltage V _bias 2 and the second RF voltage V _RF 2 to obtain a fifth optical intensity modulation width w5. A sixth optical signal OS6 having a may be generated. The interval between each signal level of the sixth optical signal OS6 may be the same as the fifth optical intensity modulation width w5. For example, the sixth optical signal (OS6) becomes equal to the distance between each of the signal level, the first half the second RF voltage of amplitude of the RF voltage _{(V RF 1) (V RF} 2) a second optical intensity modulator of Can be licensed as (522).

The optical signal generating apparatus 500 may output a sixth optical signal OS6 generated from the second optical intensity modulator 522. From this, the optical signal generating apparatus 500 may output an 8-level optical signal. The 8-level optical signal output from the optical signal generating apparatus 500 may indicate a value corresponding to allocated bits, as shown in FIG. 14 and Table 2 below.

8-level optical signal The magnitude of the zeroth RF voltage of the zeroth light intensity modulator The magnitude of the first RF voltage of the first light intensity modulator The magnitude of the second RF voltage of the second light intensity modulator 000 0 0 0 001 0 0 One 010 0 One 0 011 0 One One 100 One 0 0 101 One 0 One 110 One One 0 111 One One One

As shown in Table 2, when receiving an 8-level optical signal from the optical signal generating apparatus 500, the receiving end may recognize a value indicated by the optical signal as one of "000" to "111" according to the optical signal level. For example, a zeroth RF voltage (V _RF 0) corresponding to "0" is input to the 0th light intensity modulator 501, and a first RF voltage corresponding to "0" is input to the first light intensity modulator 512 When a voltage (V _RF 1) is input and a second RF voltage (V _RF 2) corresponding to “1” is input to the second light intensity modulator 522, the receiving end receives an optical signal indicating “001” can do.

The 0 is the zero RF voltage (V _RF 0) corresponding to "1", the optical intensity modulator 501 is input, first the first RF voltage corresponding to "1" in the light intensity modulator (512) (V _RF When 1) is input and the second RF voltage V _RF 2 corresponding to “0” is input to the second light intensity modulator 522, the receiving end may receive an optical signal indicating “110”.

Bit values may be assigned to the 8-level optical signal as shown in Table 2, but the present invention is not limited thereto, and bit values corresponding to each level may vary.

As described above, the optical signal generating apparatus according to embodiments of the present invention provides an optical signal through a plurality of light intensity modulators operating based on different bias voltages (V _bias ) and RF voltages (V _RF ) of different amplitudes. It is possible to generate a multilevel optical signal by sequentially modulating the.

The optical signal generating apparatus according to embodiments of the present invention may generate a multilevel optical signal by sequentially performing an optical modulation operation and an optical amplification operation. That is, the optical signal generating apparatus according to embodiments of the present invention may generate a multilevel optical signal by arranging a plurality of optical intensity modulators in series. In the case of generating a multilevel optical signal by arranging a plurality of light intensity modulators in parallel, a separate device for combining the optical signals output from the respective light intensity modulators may be required. Accordingly, the optical signal generating apparatus according to embodiments of the present invention may generate a multilevel optical signal with only an optical intensity modulator and an optical amplifier without a separate device for combining optical signals.

In addition, in generating a multilevel optical signal, the optical signal generating apparatus according to the embodiments of the present invention may generate a multilevel optical signal using an optical element without using a multilevel electric signal. Accordingly, the optical signal generating apparatus according to the embodiments of the present invention can generate an optical signal of low cost and high quality.

The above-described contents are specific examples for carrying out the present invention. The present invention will include not only the above-described embodiments, but also embodiments that can be simply changed or easily changed. In addition, the present invention will also include techniques that can be easily modified and implemented using the embodiments. Therefore, the scope of the present invention is limited to the above-described embodiments and should not be defined, and should be determined by the claims and equivalents of the present invention as well as the claims to be described later.

10: light source
100, 200, 300, 400, 500: optical signal generator
101, 201, 301, 401, 501: 0th light intensity modulator
110, 210, 310, 410, 510: binary signal generator

Claims (20)

A first optical intensity modulator configured to modulate the first optical signal to generate a 2 ^N -level (wherein N is a positive integer) second optical signal in the form of a binary signal;
A first optical amplifier configured to amplify the second optical signal to generate a third optical signal; And
A second optical intensity modulator configured to modulate the third optical signal to generate a 2 ^N+1 -level fourth optical signal in the form of a binary signal,
The first light intensity modulator is based on a first bias voltage A modulation reference operating point of the first optical signal is set, the modulation width of the first light intensity is adjusted based on the first RF voltage, and the second light intensity modulator is a second bias equal to the first bias voltage. An optical signal generation device configured to set a modulation reference operating point of the second optical signal based on a voltage and adjust a modulation width of the intensity of the second light based on a second RF voltage having the same amplitude as the first RF voltage . delete The method of claim 1,
An optical signal generating apparatus in which the optical intensity modulation width of the fourth optical signal is the same as the optical intensity modulation width of the second optical signal. The method of claim 1,
The first optical amplifier is configured to shape the second optical signal so that the optical intensity modulation width of the third optical signal is half of the optical intensity modulation width of the second optical signal. The method of claim 1,
The first optical amplifier operates based on an input current,
The size of the input current is the size of the current that causes the first optical amplifier to operate in a nonlinear characteristic region. The method of claim 1,
The first light intensity modulator is configured to operate based on a first bias voltage and a first RF voltage,
The second light intensity modulator is configured to operate based on a second bias voltage different from the first bias voltage and a second RF voltage having an amplitude different from the first RF voltage. The method of claim 6,
The amplitude of the second RF voltage is half of the amplitude of the first RF voltage. The method of claim 1,
The first optical amplifier operates based on an input current,
The size of the input current is the size of the current that causes the first optical amplifier to operate in a linear characteristic region. The method of claim 1,
An optical signal generating device in which the highest level of light intensity of the third optical signal is the same as that of the first optical signal. The method of claim 1,
A second optical amplifier configured to amplify the fourth optical signal to generate a fifth optical signal; And
Further comprising a third optical intensity modulator configured to modulate the fifth optical signal to generate a ^2N+2 -level sixth optical signal in the form of a binary signal,
The third light intensity modulator sets a modulation reference operating point of the third optical signal based on a third bias voltage, and adjusts a modulation width of the third light intensity based on a third RF voltage. . The method of claim 10,
The first light intensity modulator is configured to operate based on a first bias voltage and a first RF voltage,
The second light intensity modulator is configured to operate based on a second bias voltage and a second RF voltage,
The first bias voltage, the second bias voltage, and the third bias voltage are the same, and the first RF voltage, the second RF voltage, and the third RF voltage have the same amplitude. The method of claim 10,
The first optical amplifier is configured to shape the second optical signal so that the optical intensity modulation width of the third optical signal is half of the optical intensity modulation width of the second optical signal,
The second optical amplifier is configured to shape the fourth optical signal so that the optical intensity modulation width of the fifth optical signal is 1/4 of the optical intensity modulation width of the fourth optical signal. The method of claim 10,
The first light intensity modulator is configured to operate based on a first bias voltage and a first RF voltage,
The second light intensity modulator is configured to operate based on a second bias voltage and a second RF voltage,
The third light intensity modulator is configured to operate based on a third bias voltage and a third RF voltage,
The first bias voltage, the second bias voltage, and the third bias voltage are different from each other, and the first RF voltage, the second RF voltage, and the third RF voltage have different amplitudes. The method of claim 13,
The amplitude of the second RF voltage is half the amplitude of the first RF voltage,
An optical signal generating device in which the amplitude of the third RF voltage is half the amplitude of the second RF voltage. The method of claim 1,
The first light intensity modulator and the second light intensity modulator are Mach-Zehnder light intensity modulators or electric field absorption modulators. In the operating method of the optical signal generating device,
Modulating the first optical signal to generate a 2 ^N -level (wherein N is a positive integer) second optical signal in the form of a binary signal;
Amplifying the second optical signal to generate a third optical signal; And
Modulating the third optical signal to generate a 2 ^N+1 -level fourth optical signal in the form of a binary signal,
The first light intensity modulator sets a modulation reference operating point of the first optical signal based on a first bias voltage, adjusts a modulation width of the first light intensity based on a first RF voltage, and a second light intensity The modulator sets a modulation reference operating point of the second optical signal based on a second bias voltage equal to the first bias voltage, and the second RF voltage based on a second RF voltage having the same amplitude as the first RF voltage. An operation method of adjusting the modulation width of the light intensity. delete The method of claim 16,
Modulate the first optical signal based on a first bias voltage and a first RF voltage,
An operating method of modulating the third optical signal based on a second bias voltage different from the first bias voltage and a second RF voltage having an amplitude different from the first RF voltage. The method of claim 16,
Amplifying the second optical signal based on the input current,
The magnitude of the input current is the magnitude of the current such that the optical intensity modulation width of the third optical signal is different from the optical intensity modulation width of the second optical signal. The method of claim 16,
Amplifying the second optical signal based on the input current,
The magnitude of the input current is the magnitude of the current such that the optical intensity modulation width of the third optical signal is the same as the optical intensity modulation width of the second optical signal.

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