KR101880367B1 - Method and apparatus for generating complex format optical signal using direct modulation of optical injection-locked semiconductor laser - Google Patents

Abstract

A method and apparatus for generating a complex optical signal using amplitude and phase modulation phenomena of an optical signal generated by direct modulation of a light-injection locked semiconductor laser. The complex type optical signal generating apparatus according to an embodiment includes a light injection locked semiconductor laser that simultaneously adjusts a frequency difference and an output ratio under a light injection state by using a bias control of a slave light source.

Description

BACKGROUND OF THE INVENTION Field of the Invention [0001] The present invention relates to a method and an apparatus for generating a complex optical signal using direct modulation of a light-injection-locked semiconductor laser,

The following embodiments relate to a method and apparatus for generating a complex optical signal using the amplitude and phase modulation phenomenon of an optical signal generated by direct modulation of a light-injection-locked semiconductor laser.

A complex format optical signal is generated by modulating the phase and amplitude of the sinusoidal optical signal output from the laser light source, respectively. Phase and amplitude modulation is implemented using an external light modulator.

For example, an input signal applied to a light modulator from a laser light source, that is, a sinusoidal optical signal, is divided into upper and lower waveguides through an optical splitter. The signals transmitted to each waveguide are generally used for generating I (in-phase) or Q (quadrature) signals through a phase shifter. I-Q Each channel's signal passes through an external modulator, causing amplitude or phase modulation.

In order to generate 16-QAM (quadrature amplitude modulation) signals, it is a commonly used generation technique to implement a generator by allocating an external modulator to each I / Q channel. In general, I and Q channel signals are required for each channel in multiple stages such as a phase shifter, a high-speed phase modulator, and a high-speed amplitude modulator.

In the case of using an external optical modulator, problems such as a complicated structure due to an external optical modulator, a high cost, difficulty of phase control, and a demand for a high-speed modulator for high-speed data generation are encountered.

Embodiments can provide a technique for generating an ultrahigh speed low power complex type optical signal by using a direct modulation optical injection locking semiconductor laser.

Embodiments can provide a technique for generating an ultrafast complex modulated optical signal using amplitude and phase modulation phenomenon through control of light injection condition of a direct modulation optical injection locked semiconductor laser without an external light modulator.

Accordingly, embodiments can provide a method and apparatus for generating a complex optical signal capable of miniaturization, simplification, low power consumption, and high-speed signal generation.

The complex type optical signal generating apparatus according to an embodiment includes a light injection locked semiconductor laser that simultaneously adjusts a frequency difference and an output ratio under a light injection state by using a bias control of a slave light source.

The amplitude and phase of the optical signal can be modulated by using the optical injection lock state using the bias control of the slave light source.

A dual optical injection locking structure and technique capable of 180-degree phase modulation that overcomes the physical limitations of the optical injection locked semiconductor laser can be utilized.

The amplitude and the phase can be stabilized using the bias tuning of the slave light source under the light injection locked state.

A complex type optical signal generator according to an embodiment of the present invention includes a master light source for outputting an optical signal, an optical splitter for dividing the output optical signal, and a plurality of split optical signals output from the optical splitter, At least one of the plurality of slave light sources includes a slave light source unit for outputting a modulated optical signal generated in accordance with a light injection locking and a bias control which are physical phenomena based on input divided optical signals, And the optical signal modulated in the slave light source is multiplexed and locked by the other slave light source to achieve a 180 degree phase modulation.

At least one of the plurality of slave light sources may modulate and output at least one of the amplitude and phase of the input divided optical signal according to the bias control.

The slave light sources of the multiple light injection locking shapes may be continuously connected to achieve a 180 degree phase shift. At least one of the plurality of slave light sources may change into a light injection locked state upon input of the divided optical signal .

Wherein at least one of the plurality of slave light sources performs amplitude modulation and phase modulation on the input divided optical signal using an optical injection locking parameter adjusted in accordance with the bias control, And frequency detuning that is defined based on at least one oscillation frequency among the plurality of slave light sources and frequency detuning of the plurality of slaves in a size and free-running oscillation of a divided optical signal input to at least one of the plurality of slave light sources, And an injection ratio defined based on the size of the optical signal output by at least one of the light sources.

The optical coupling unit may combine a plurality of modulated optical signals output from the plurality of slave light sources to generate a complex type optical signal in which a carrier wave is unsuppressed.

Wherein the apparatus further comprises a phase shifter for shifting a phase of a split optical signal input from the optical splitter, wherein the optical coupler includes a plurality of modulated optical signals output from the plurality of slave light sources and a phase output from the phase shifter The divided optical signals are combined to generate a complex optical signal whose carrier is suppressed.

The plurality of slave light sources may be allocated to each channel and connected in multiple stages.

A method of generating a complex optical signal according to an embodiment includes the steps of outputting an optical signal using a master light source, generating a plurality of divided optical signals by separating the optical signal, Outputting a plurality of modulated optical signals generated according to a physical development and a bias control based on the input of the plurality of divided optical signals; And generating a signal.

At least one of the plurality of slave light sources may modulate and output at least one of the amplitude and phase of the input divided optical signal according to the bias control.

At least one of the plurality of slave light sources may change into a light injection locked state upon input of the divided optical signal.

Wherein the step of outputting the plurality of modulated optical signals includes performing amplitude modulation and phase modulation on the input divided optical signal using an injection lock parameter adjusted according to the bias control, A frequency detuning defined based on an oscillation frequency of the master light source and at least one oscillation frequency among the plurality of slave light sources and a frequency detuning based on a frequency of a divided optical signal input to at least one of the plurality of slave light sources and a free- And an injection ratio defined based on the size of the optical signal output by at least one of the plurality of slave light sources.

The generating of the complex type optical signal may include generating a complex type optical signal in which a carrier wave is unsuppressed by combining a plurality of modulated optical signals output from the plurality of slave light sources.

The generating of the complex type optical signal may include generating a complex type optical signal in which a carrier is suppressed by combining a plurality of modulated optical signals output from the plurality of slave light sources and a divided optical signal having a phase shifted Step < / RTI >

The plurality of slave light sources may be allocated to each channel and connected in multiple stages.

1 is a view for explaining an injection lock oscillator.
2 is a view for explaining an output signal of the injection locked oscillator shown in FIG.
3 is a schematic block diagram of a light injection laser according to one embodiment.
4 is a diagram for explaining a light injection rate and a stable region according to frequency detuning between a master laser and a slave laser.
5 is a view for explaining a phase change according to a light injection ratio.
6 is a diagram for explaining a light injection laser which is directly modulated without an external light modulator according to an embodiment.
FIG. 7 shows a phase diagram of the master laser and light injection laser of FIG. 6;
8 is a view for explaining an example of a complex type optical signal generating apparatus according to an embodiment.
FIG. 9 is a view for explaining another example of a complex type optical signal generating apparatus according to an embodiment.
10 is a flowchart illustrating a method of generating a complex optical signal according to an embodiment of the present invention.

It is to be understood that the specific structural or functional descriptions of embodiments of the present invention disclosed herein are presented for the purpose of describing embodiments only in accordance with the concepts of the present invention, May be embodied in various forms and are not limited to the embodiments described herein.

Embodiments in accordance with the concepts of the present invention are capable of various modifications and may take various forms, so that the embodiments are illustrated in the drawings and described in detail herein. However, it is not intended to limit the embodiments according to the concepts of the present invention to the specific disclosure forms, but includes changes, equivalents, or alternatives falling within the spirit and scope of the present invention.

The terms first, second, or the like may be used to describe various elements, but the elements should not be limited by the terms. The terms may be named for the purpose of distinguishing one element from another, for example without departing from the scope of the right according to the concept of the present invention, the first element being referred to as the second element, Similarly, the second component may also be referred to as the first component.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between. Expressions that describe the relationship between components, such as "between" and "between" or "neighboring to" and "directly adjacent to" should be interpreted as well.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. It will be understood that, in this specification, the terms " comprises ", or " having ", and the like are to be construed as including the presence of stated features, integers, But do not preclude the presence or addition of steps, operations, elements, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning of the context in the relevant art and, unless explicitly defined herein, are to be interpreted as ideal or overly formal Do not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, the scope of the patent application is not limited or limited by these embodiments. Like reference symbols in the drawings denote like elements.

1 is a view for explaining an injection lock oscillator.

Referring to FIG. 1, an injection locked oscillator (or frequency locked oscillator) 100 includes a master oscillator 110 and a slave oscillator 130.

When the output signal of the master oscillator 110 is injected into the slave oscillator 130, the slave oscillator 130 does not have the oscillation characteristic (or free-running oscillation) originally possessed by the slave oscillator 130 And outputs a signal having other characteristics (e.g., frequency, output, phase, response characteristic, etc.).

For example, when the slave oscillator 130 oscillates in response to a signal output from the master oscillator 110, the slave oscillator 130 generates the frequency response characteristic (e.g., amplitude and phase response) It is possible to output a signal having a different frequency response characteristic. Also, the slave oscillator 130 can output a signal having a frequency different from that of its own frequency.

2 is a view for explaining an output signal of the injection locked oscillator shown in FIG.

2 is a view for explaining the phase of an output signal of the slave oscillator 130 shown in FIG. 1 and FIG. 2 (b) FIG. 5 is a diagram for explaining a phase change of an output signal according to frequency detuning.

(210)는 슬레이브 발진기(130)로 주입되는 신호에 의해 발생하는 전기장을 나타내고,

(220)는 슬레이브 발진기의 free-running oscillation에 의해 발생하는 전기장(free-running electric field)을 나타내며,

(230)는 주입 잠금 상태의 슬레이브 발진기(130)의 출력 신호에 의해 발생하는 전기장을 나타낸다.Referring to Figures 1 and 2, in Figure 2 (a)

(210) represents an electric field generated by a signal injected into the slave oscillator (130)

(220) represents a free-running electric field generated by the free-running oscillation of the slave oscillator,

(230) represents an electric field generated by the output signal of the slave oscillator 130 in the injection locked state.

(230)는 슬레이브 발진기(130)의 주입 잠금 현상에 따른 전기장을 의미할 수 있다.When the output signal of the master oscillator 110 is injected into the slave oscillator 130, the slave oscillator 130 may be in the injection locked state. In other words,

(230) may refer to an electric field due to the injection locking phenomenon of the slave oscillator (130).

는 수학식 1과 같이 표현될 수 있다.
Maximum frequency range for maintaining injection lock phenomenon

Can be expressed as Equation (1).

는 슬레이브 발진기(130)의 free-running oscillation의 발진 주파수,

는 슬레이브 발진기(130)의 큐 팩터를 나타낸다.here,

The oscillation frequency of the free-running oscillation of the slave oscillator 130,

Represents the queue factor of the slave oscillator 130.

만큼 변한다.The phase of the output signal of the slave oscillator 130 is controlled by the output of the free-running oscillation when the slave oscillator 130 is locked by the output signal of the master oscillator 110, From the phase of the signal

.

이라 하면,

는 수학식 2로 표현될 수 있다.
The phase of the output signal of the slave oscillator 130 in the injection locking state

In other words,

Can be expressed by Equation (2).

)와

사이의 관계는 도 2의 (b)에 도시된 바와 같다. 마스터 발진기(110)로부터 주입되는 신호의 주파수 및 크기의 조절을 기초로

은 180도 범위에서 제어될 수 있다.
the frequency detuning of the master oscillator 110 and the slave oscillator 130 in a free-running oscillation

)Wow

Is as shown in Fig. 2 (b). Based on the adjustment of the frequency and magnitude of the signal injected from the master oscillator 110

Can be controlled in the range of 180 degrees.

3 is a schematic block diagram of a light injection laser according to one embodiment.

Referring to FIG. 3, the light injection laser 300 may include a master laser 310 and a slave laser 350. In addition, the light injection laser 300 may further include an optical isolator 330.

The master laser 310 and the slave laser 350 are physically separated and the optical isolator 330 can be located between the master laser 310 and the slave laser 350. [

The output characteristic of the light-injecting laser 300 can be adjusted based on the injection locking parameter. For example, the injection locking parameter may include frequency detuning and injection ratio.

)는

으로 정의될 수 있다.

는 마스터 레이저(310)의 발진 주파수를 나타내고,

는 슬레이브 레이저(350)의 발진 주파수를 나타낼 수 있다. 주입 비율(

)은

으로 정의될 수 있다.

는 슬레이브 레이저(350)로 주입되는 광 신호의 파워를 나타내고,

는 free-running oscillation에서 슬레이브 레이저(350)가 출력하는 광 신호의 파워를 나타낼 수 있다.For example, frequency detuning (

)

. ≪ / RTI >

Represents the oscillation frequency of the master laser 310,

Can represent the oscillation frequency of the slave laser (350). Injection rate (

)silver

. ≪ / RTI >

Represents the power of the optical signal injected into the slave laser 350,

May represent the power of the optical signal output by the slave laser 350 in a free-running oscillation.

)는 마스터 레이저(310)와 슬레이브 레이저(350)의 주파수 디튜닝을 의미하고, 주입 비율(

)은 마스터 레이저(310)와 슬레이브 레이저(350)의 광 출력 비율을 의미할 수 있다.That is, frequency detuning (

Means the frequency detuning of the master laser 310 and the slave laser 350, and the injection ratio (

) May mean a light output ratio of the master laser 310 and the slave laser 350. FIG.

The output characteristic of the light injection laser 300 shown in FIG. 3 can be expressed by a rate equation of Equations (3) to (5).

는 슬레이브 레이저(350)의 자유 전자(electron carrier)의 개수를 나타내고,

는 투명 전자 개수(transparency carrier number)를 나타내며,

는 순수 유도 방출 비율(Net stimulated emission rate)을 나타내고,

는 주입 커플링 계수(injection coupling coefficient)를 나타낸다. 또한,

는 광 주입 하에 있는 반도체 레이저, 즉 슬레이브 레이저(350)가 출력한 광 신호에 의해 발생하는 전기장을 나타낸다. 또한,

는 빛의 이중성에 의하여 광자의 개수를 나타낸다.

는 마스터 레이저(310)로부터 슬레이브 레이저(350)로 주입되는 광 신호의 크기를 나타내고,

는 전술한 주파수 디튜닝(frequency detuning)을 나타낸다.here,

Represents the number of electron carriers of the slave laser 350,

Represents a transparency carrier number,

Represents the net stimulated emission rate,

Represents the injection coupling coefficient. Also,

Represents an electric field generated by an optical signal output from a semiconductor laser under light injection, that is, a slave laser 350. [ Also,

Represents the number of photons by the duality of light.

Represents the magnitude of the optical signal injected from the master laser 310 into the slave laser 350,

Represents the above-described frequency detuning.

는 광 주입 하에 있는 반도체 레이저, 즉 슬레이브 레이저(350)의 출력(예를 들어, 전기장 또는 광자)의 위상을 나타낸다. 또한,

는 슬레이브 레이저(350)의 인가 전류이고, 1/

은 슬레이브 레이저(350) 내의 자유 전자에 대한 재결합 비율이며,

는 광자(또는 전기장)의 손실 비율이다.

(E.g., an electric field or a photon) of the semiconductor laser under light injection, i.e., the slave laser 350. Also,

Is the applied current of the slave laser 350,

Is the recombination ratio for the free electrons in the slave laser 350,

Is the loss ratio of the photons (or electric field).

는 마스터 레이저(310) 또는 슬레이브 레이저(350)와 같은 반도체 레이저의 물성 매개 변수 중 하나로, 증폭 물질로 이루어진 반도체 레이저가 발생하는 광 신호의 크기 및 위상 간의 커플링 정도를 나타낸다.

는 아래 수학식 6으로 정의될 수 있다.
In Equation (4), a linewidth enhancement factor

Is a property parameter of a semiconductor laser such as a master laser 310 or a slave laser 350 and represents the degree of coupling between the magnitude and phase of an optical signal generated by a semiconductor laser made of an amplifying material.

Can be defined by Equation (6) below.

는 반도체 레이저의 파장을 나타내고,

은 반도체 레이저의 자유 전자(electron carrier)의 개수(또는 밀도)와 굴절율의 미분값을 나타내며,

은 반도체 레이저의 자유 전자의 개수와 광 이득(optical gain)의 미분값이다.here,

Represents the wavelength of the semiconductor laser,

(Or density) of the electron carriers of the semiconductor laser and the refractive index,

Is the number of free electrons of the semiconductor laser and the differential value of the optical gain.

에 따라 변할 수 있다. 반도체 레이저의 광 주입 잠금 현상은 위상과 크기의 커플링 정도에 따라 변할 수 있다.Unlike electrical injection locking, which is independent of size and phase,

. ≪ / RTI > The optical injection locking phenomenon of a semiconductor laser can vary depending on the degree of phase and coupling coupling.

는 수학식 7로 표현될 수 있다.
(3) to (5) in the steady state of the optical signal output from the light injection laser 300, the locked state of the light injection locked state, i.e., the light injection locked state of the light injection laser 300, A locked phase of the optical signal output by the optical amplifier < RTI ID = 0.0 >

Can be expressed by Equation (7).

는 선폭 향상 계수

에 의해 0이 아니다. 즉,

는

로 인한 오프셋을 가진다.

는 180도 범위에 있으므로,

에 의해

내에 존재한다.In Equation (7)

The line width enhancement coefficient

Lt; / RTI > In other words,

The

Lt; / RTI >

Is in the range of 180 degrees,

By

Lt; / RTI >

에서 발생하고, 수학식 7에서 알 수 있듯이 광 주입 비율

및 주파수 디튜닝(frequency detuning)

을 기초로 제어될 수 있다.

는 마스터 레이저(310)로부터 슬레이브 레이저(350)로 주입되는 광 신호의 크기를 나타내고,

는 광 주입 잠금 상태에서 슬레이브 레이저(350)가 출력하는 광 신호의 전기장 크기를 나타낸다.The phase modulation of the optical signal output by the optical fiber 300

And as can be seen from the equation (7), the light injection ratio

And frequency detuning.

Lt; / RTI >

Represents the magnitude of the optical signal injected from the master laser 310 into the slave laser 350,

Represents the magnitude of the electric field of the optical signal output from the slave laser 350 in the light injection locked state.

The stability of the light injection phenomenon can be considered in the analysis of the light injection locking phenomenon. Stability can be confirmed from the response characteristics obtained based on the linearization of the output value of the optical signal when the equations (3) to (5) are analyzed in the small signal state of the optical signal output from the light injection laser 300. Hereinafter, this will be described with reference to FIG. 4 and FIG. 5. FIG.

4 is a diagram for explaining a light injection rate and a stable region according to frequency detuning between a master laser and a slave laser.

가 3인 경우를 나타내고, 도 4의 (b)는

가 0인 경우를 나타낸다. 수학식 6의

의 정의와 같이 슬레이브 레이저(350)로 광 신호가 주입되고, 슬레이브 레이저(350)에서 광 신호의 주입으로 인해 광자가 증가하여 자유 전자의 개수가 변화한다. 따라서,

가 0이 아닌 경우, 슬레이브 레이저(350)와 같은 반도체 레이저는 비대칭적인 안정 영역을 갖는다. 일반적인 반도체 레이저의

는 약 3 내지 5이므로, 안정적인 위상 변조 효과를 얻을 수 있는 stable locking range 및 위상 변조 정도를 예측하거나 구현하기 위해

가 고려되어야 한다.
4 (a)

Is 3, and Fig. 4 (b)

Is zero. Equation 6

The optical signal is injected into the slave laser 350 and the number of free electrons is changed due to the injection of the optical signal by the slave laser 350. As a result, therefore,

Is not zero, the semiconductor laser such as the slave laser 350 has an asymmetric stable region. A typical semiconductor laser

Is about 3 to 5, so that a stable locking range and a phase modulation degree capable of obtaining a stable phase modulation effect can be predicted or implemented

Should be considered.

5 is a view for explaining a phase change according to a light injection ratio.

가 3인 경우를 나타내고, 도 5의 (b)는

가 0인 경우를 나타낸다. 약한 광 주입 비율에서 안정한 광 주입 현상이 발생할 수 있고, 주파수 디튜닝(frequency detuning)를 제어하여 180도의 위상 변화를 얻을 수 있다.
5 (a)

Is 3, and Fig. 5 (b)

Is zero. Stable light injection phenomenon may occur at a weak light injection rate, and a phase change of 180 degrees can be obtained by controlling frequency detuning.

6 is a diagram for explaining a light injection laser which is directly modulated without an external light modulator according to an embodiment.

Referring to FIG. 6, the light injection laser 600 may include a master laser 610 and a slave laser 630.

The configuration and operation of the light injection laser 600 of FIG. 6 may be substantially the same as the configuration and operation of the light injection laser 300 described with reference to FIGS. 3 to 5, The operation of the light-injection laser 300 can be applied to the light-injection laser 600 of FIG. 6 as it is, and thus its detailed description is omitted.

When the output signal of the master laser 610 is incident on the slave laser 630, the frequency of the slave laser 630 is locked to the frequency of the master laser 610 and the slave laser 630 is in the injection locked state .

The injection locking parameter of the light-injecting laser 600 can be adjusted through the bias control of the slave laser 630. For example, the injection locking parameter may include frequency detuning and injection ratio. The frequency detuning may mean the detuning frequency of the light-injecting laser 600. [ The injection rate and the detuning frequency of the light injection laser 600 can be adjusted independently.

Also, an external cavity tunable laser may be used as the master laser 610 to adjust the detuning frequency, and an attenuator may be installed in front of the slave laser 630 to adjust the injection rate.

When the bias current of the injected locked slave laser 630 is adjusted in the locked state, the injection ratio and the detuning frequency are changed in a fixed state at the frequency of the master laser 610, The optical signal may have a phase change due to a change in the bias current. In addition, the amplitude of the optical signal output by the light-injection laser 600 can be modulated by controlling the output power of the slave laser 630 through encoding of bias current.

FIG. 7 shows a phase diagram of the master laser and light injection laser of FIG. 6;

7 (a) shows the phase diagram of the master laser 610, and Fig. 7 (b) shows the phase diagram of the light injection laser 600. Fig. Since the output frequency of the light injection laser 600 and the output frequency of the master laser 610 are the same, they can be expressed in the same phase diagram.

In Fig. 7 (a), the arrow indicates the light output of the master laser 610, and the angle of the arrow indicates the initial phase.

In Fig. 7 (b), the arrows indicate the light output and the initial phase of the light injection laser 600, respectively. The dashed-line fan-shaped region represents the phase modulation region of the light-injecting laser 600 according to the detuning frequency and the injection ratio corresponding to the change of the bias applied to the slave laser 630.

The phase of the light-injecting laser 600 may be changed by adjusting the bias current applied to the slave laser 630, for example, a direct current.

8 is a view for explaining an example of a complex type optical signal generating apparatus according to an embodiment.

8, a complex optical signal generator 800 includes a master light source 810, an optical splitter 830, a slave light source 850, a phase shifter 870, and a combiner 890.

The master light source unit 810 outputs an optical signal. The optical signal output from the master light source unit 810 is applied to the optical splitter 830.

The optical distributor 830 separates the optical signal output from the master light source unit 810.

The slave light source unit 850 receives a plurality of divided optical signals output from the optical distributor 830. The slave light source unit 850 may include a plurality of slave light sources 850-1 and 850-3. For example, the slave light source 850-1 may be assigned to an in-phase channel, and the slave light source 850-3 may be assigned to a quadrature channel.

That is, each of the plurality of slave light sources 850-1 and 850-3 can receive each of the plurality of divided optical signals output from the optical distributor 830. [

Each of the plurality of slave light sources 850-1 and 850-3 outputs a modulated optical signal by using a physical phenomenon generated based on the input divided optical signal. For example, each of the plurality of slave light sources 850-1 and 850-3 may be in the light injection locking state based on the input divided optical signal.

At this time, each of the plurality of slave light sources 850-1 and 850-3 may output a modulated optical signal having the characteristic of optical injection locking. For example, each of the plurality of slave light sources 850-1 and 850-3 may perform amplitude modulation and / or phase modulation according to a bias control (DC). The light injection condition, i. E. The injection lock parameter, can be adjusted according to the bias control (DC). The injection lock parameters may include frequency detuning and injection ratio. The frequency detuning is defined based on the oscillation frequency of the master light source 810 and the oscillation frequency in the free-running oscillation of the slave light source 850-1 or 850-3, and the injection ratio is defined as the slave light source 850-1 or 850 -3) and the magnitude of the optical signal output from the slave light source 850-1 or 850-3 in the free-running oscillation.

For example, the slave light source 850-1 amplitude-modulates and / or phase modulates the split optical signal output from the optical splitter 830 based on the injection lock parameter adjusted according to the bias control (DC) -phase channel signal. The slave light source 850-3 amplitude-modulates and / or phase-modulates the divided optical signal output from the optical distributor 830 based on the injection locking parameter adjusted according to the bias control DC to generate a quadrature channel signal Can be generated. An in-phase (I) channel signal and a quadrature (Q) channel signal may be amplitude modulated and / or phase modulated optical signals.

The phase shifter 870 transitions the phase of the divided optical signal output from the optical splitter 830. The phase shifter 870 can output the phase-shifted divided optical signal to the combining unit 890.

The combining unit 890 generates a complex format optical signal based on the modulated optical signal output from the plurality of slave light sources 850-1 and 850-3. For example, a complex optical signal may be a 16QAM signal. At this time, the coupling unit 890 may suppress or suppress the carrier wave according to a desired light output type.

For example, the coupling unit 890 couples the modulated optical signals output from the plurality of slave light sources 850-1 and 850-3 via the plurality of couplers 890-1 and 890-3, A complex optical signal can be generated.

As another example, the coupling portion 890 couples the modulated optical signal output from each of the plurality of slave light sources 850-1 and 850-3 to the phase shifter 870 through the plurality of couplers 890-1 and 890-3, The phase-shifted divided optical signals output from the phase-shifted optical amplifiers can be combined to generate a complex optical signal whose carrier is unrestrained.

1 through 7 can be applied to the matters described with reference to FIG. 8, detailed description will be omitted.

FIG. 9 is a view for explaining another example of a complex type optical signal generating apparatus according to an embodiment.

9, the complex optical signal generator 900 includes a master light source unit 910, an optical splitter 930, a slave light source unit 950, and a coupling unit 970.

The configuration and operation of the master light source unit 910, the optical splitter 930, the slave light source unit 950 and the coupling unit 970 of FIG. 9 are the same as those of the master light source unit 810, the optical distributor 830, the slave light source unit 850 ) And the coupling portion 890, as shown in Fig.

In the case where the phase modulation range of the optical injection laser, for example, the slave light source section 950 is insufficient, or when the complex type optical signal generating apparatus 900 desires to generate a complex optical signal of 64QAM in a challenging manner, As described above, the plurality of slave light sources 950-1 through 950-7 may be connected in multiple stages for each channel. For example, a plurality of slave light sources 950-1 and 950-3 may be assigned to an I channel to be cascade-connected, and a plurality of slave light sources 950-5 and 950-7 are allocated to Q channels, Can be connected.

By continuously connecting the plurality of slave light sources 950-1 and 950-3 and / or the plurality of slave light sources 950-5 and 950-7, the complex-type optical signal generator 900 can generate 180- Transition can be achieved.

1 through 8 can be applied to the matters described with reference to FIG. 9, detailed description will be omitted.

The complex type optical signal generator 800 or 900 is capable of downsizing, integrating, speeding up, and lowering power by using a stable injection locking region and a size / phase modulation phenomenon that can be obtained from a light-injected semiconductor laser, For example, a complex optical signal) can be realized within a simple generator structure. More specifically, the complex-type optical signal generator 800 or 900 may not require an external optical modulator, thereby reducing the size of the complex-type optical signal generator 800 or 900. In addition, since the optical system does not include a lens, a mirror or the like used in free space optics, the size of the complex optical signal generator 800 or 900 can be reduced.

The complex-form optical signal generator 800 or 900 can realize a high-speed modulated signal (for example, a complex-form optical signal) by using the improved chirp characteristic and the frequency response characteristic of the semiconductor laser.

Further, since the complex-type optical signal generator 800 or 900 does not include unnecessary amplifiers by using the optical gain, the deterioration of the noise of the signal can be minimized without causing signal interference between different frequencies. The complex-type optical signal generator 800 or 900 uses an array of optical injection locking lasers, and since the operating current of each laser is about 2 to 15 mA, the power consumed by each array is less than about 1 mW. Therefore, low power consumption is possible.

10 is a flowchart illustrating a method of generating a complex optical signal according to an embodiment of the present invention. The arbitrary waveform signal generating method according to one embodiment can be performed by the complex type optical signal generating apparatus.

Referring to FIG. 10, the master light source of the complex type optical signal generator outputs an optical signal (1010).

The optical distributor of the complex type optical signal generator generates a plurality of divided optical signals by separating the optical signals, and transmits the plurality of divided optical signals to a plurality of slave light sources (1030).

A plurality of slave light sources of the complex type optical signal generating apparatus outputs 1050 a plurality of modulated optical signals generated in accordance with physical development and bias control based on input of a plurality of divided optical signals.

The coupling unit of the complex type optical signal generating apparatus combines a plurality of modulated optical signals to generate a complex optical signal (1070).

The method and apparatus for generating a complex optical signal using a light-injection direct-modulation semiconductor laser described with reference to FIGS. 1 to 10 is applicable to the generation of ultra high-speed and low-power signals for data centers, a broadband long- haul optical transmission system, It can be the next generation core technology in optical signal information processing, bio application, and optical instrument development. The method and apparatus for generating a complex optical signal according to an embodiment can realize this by using the phase and amplitude modulation effect generated in the optical injection laser without using an external phase / amplitude modulator.

The apparatus described above may be implemented as a hardware component, a software component, and / or a combination of hardware components and software components. For example, the apparatus and components described in the embodiments may be implemented within a computer system, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA) , A programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to execution of the software. For ease of understanding, the processing apparatus may be described as being used singly, but those skilled in the art will recognize that the processing apparatus may have a plurality of processing elements and / As shown in FIG. For example, the processing unit may comprise a plurality of processors or one processor and one controller. Other processing configurations are also possible, such as a parallel processor.

The software may include a computer program, code, instructions, or a combination of one or more of the foregoing, and may be configured to configure the processing device to operate as desired or to process it collectively or collectively Device can be commanded. The software and / or data may be in the form of any type of machine, component, physical device, virtual equipment, computer storage media, or device , Or may be permanently or temporarily embodied in a transmitted signal wave. The software may be distributed over a networked computer system and stored or executed in a distributed manner. The software and data may be stored on one or more computer readable recording media.

The method according to an embodiment may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions to be recorded on the medium may be those specially designed and configured for the embodiments or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI > or equivalents, even if it is replaced or replaced.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (20)

Optical injection locking semiconductor laser that adjusts the frequency difference and output ratio under light injection state by using bias control of slave light source
Lt; / RTI >
The slave light source includes a first slave light source for generating an in-phase channel signal from the optical signal and a second slave light source for generating a quadrature channel signal from the optical signal
Complex type optical signal generator.
The method according to claim 1,
The amplitude and the phase of the optical signal are modulated using the optical injection locking state using the bias control of the slave light source
Complex type optical signal generator.
The method according to claim 1,
A dual optical injection lock structure and technique capable of 180-degree phase modulation that overcomes the physical limitations of the optical injection locked semiconductor laser, and
Complex type optical signal generator.
The method according to claim 1,
The amplitude and phase stabilization using the bias tuning of the slave light source under the light injection locked state
Complex type optical signal generator.
A master light source for outputting an optical signal;
An optical splitter for separating the output optical signal;
At least one of the plurality of slave light sources includes a plurality of slave light sources for receiving a plurality of divided optical signals output from the optical splitter, A slave light source unit for outputting a modulated optical signal generated according to the modulated optical signal; And
An optical coupler for generating a complex optical signal based on the modulated optical signal,
Lt; / RTI >
The optical signal modulated by the slave light source is multiplexed and locked by the other slave light source to achieve a 180 degree phase modulation,
Wherein the plurality of slave light sources include a first slave light source for generating an in-phase channel signal from the split optical signal and a second slave light source for generating a quadrature channel signal from the split optical signal
Complex type optical signal generator.
6. The method of claim 5,
The physical phenomenon,
Said light injection lock comprising:
Wherein at least one of the plurality of slave light sources comprises:
And modulates and outputs at least one of an amplitude and a phase of the input divided optical signal according to the bias control,
Complex type optical signal generator.
The method of claim 5, wherein
The slave light sources of the multiple light injection locking phenomenon are continuously connected to achieve a 180 degree phase shift
Complex type optical signal generator.
6. The method of claim 5,
Wherein at least one of the plurality of slave light sources comprises:
And a light-injection locked state according to input of the divided optical signal,
Complex type optical signal generator.
6. The method of claim 5,
Wherein at least one of the plurality of slave light sources comprises:
And performs amplitude modulation and phase modulation on the input split optical signal using an injection lock parameter adjusted according to the bias control,
Wherein the injection locking parameter includes a frequency detuning defined based on an oscillation frequency of the master light source and at least one oscillation frequency among the plurality of slave light sources and a frequency detuning based on a magnitude of a divided optical signal input to at least one of the plurality of slave light sources, And an injection ratio defined on the basis of a size of an optical signal output by at least one of the plurality of slave light sources in a free-running oscillation.
Complex type optical signal generator.
6. The method of claim 5,
The optical coupling unit includes:
And a plurality of modulated optical signals output from the plurality of slave light sources are combined to generate a complex type optical signal in which a carrier wave is unsuppressed,
Complex type signal generator.
6. The method of claim 5,
A phase shifter for shifting a phase of a divided optical signal input from the optical splitter;
Further comprising:
The optical coupling unit includes:
A plurality of modulated optical signals output from the plurality of slave light sources and a divided optical signal having a phase shifted by the phase shifter are combined to generate a complex optical signal suppressed in a carrier wave,
Complex type signal generator.
6. The method of claim 5,
Wherein the plurality of slave light sources are connected to each other in a multi-
Complex type signal generator.
Outputting an optical signal using a master light source;
Separating the optical signal to generate a plurality of divided optical signals, and transmitting the plurality of divided optical signals to a plurality of slave light sources;
Outputting a plurality of modulated optical signals generated according to physical development and bias control based on input of the plurality of divided optical signals; And
And combining the plurality of modulated optical signals to generate a complex optical signal
Lt; / RTI >
The plurality of slave light sources include a first slave light source for generating an in-phase channel signal from the plurality of divided optical signals, and a second slave light source for generating a quadrature channel signal from the plurality of divided optical signals Included
A method for generating a complex type optical signal.
14. The method of claim 13,
The physical phenomenon,
Including a light injection lock,
Wherein at least one of the plurality of slave light sources comprises:
And modulates and outputs at least one of an amplitude and a phase of the input divided optical signal according to the bias control,
A method for generating a complex type optical signal.
14. The method of claim 13,
Wherein at least one of the plurality of slave light sources comprises:
And a light-injection locked state according to input of the divided optical signal,
A method for generating a complex type optical signal.
14. The method of claim 13,
Wherein the step of outputting the plurality of modulated optical signals comprises:
Performing amplitude modulation and phase modulation on the input split optical signal using an injection lock parameter adjusted according to the bias control
Lt; / RTI >
Wherein the injection locking parameter includes a frequency detuning defined based on an oscillation frequency of the master light source and at least one oscillation frequency among the plurality of slave light sources and a frequency detuning defined by at least one of the plurality of slave light sources, And an injection ratio defined based on the size of an optical signal output by at least one of the plurality of slave light sources in a free-running oscillation.
A method for generating a complex type optical signal.
14. The method of claim 13,
Wherein the step of generating the complex-
A step of generating a complex type optical signal in which a carrier wave is unsuppressed by combining a plurality of modulated optical signals output from the plurality of slave light sources
/ RTI >
A method for generating a complex type optical signal.
14. The method of claim 13,
Wherein the step of generating the complex-
Generating a complex optical signal in which a carrier is suppressed by combining a plurality of modulated optical signals output from the plurality of slave light sources and a divided optical signal whose phase is shifted,
/ RTI >
A method for generating a complex type optical signal.
14. The method of claim 13,
Wherein the plurality of slave light sources are connected to each other in a multi-
A method for generating a complex type optical signal.
A computer-readable recording medium on which a program for executing the method according to any one of claims 13 to 19 is recorded.

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