JPH0745888A - Collision pulse-mode synchronous ring laser device - Google Patents

Abstract

PURPOSE:To generate optical short pulses in a stable operation by a method wherein optical pulses are collided by an optical amplifier means which amplifies the optical pulses and by an optical saturable absorber whose loss is reduced as the intensity of incident light is increased. CONSTITUTION:The output of an oscillator 101 is superposed on the output of a DC bias power supply 103 by a bias T 102, it modulates a traveling-wave type semiconductor laser amplifier 104, and it is connected to an optically saturable absorber 16 and to an optical branching circuit 107 by a planar optical waveguide 105. A medium in which the loss of light is reduced as the intensity of incident light is increased is used as the optically saturable absorber 106. The peak value of optical pulses is made the same by the traveling-wave type semiconductor laser amplifier 104, the pulses propagate to mutually opposite directions, and collide with the optically saturable absorber 106. The optical pulses turned to both directions generate the standing waves of light only the moment they collide, the intensity of the standing waves increases, and the optical pulses become steep. Thereby, a collision pulse-mode synchronous operation can be realized, and an ultrashort optical pulse train can be generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for generating short optical pulses used for high-speed optical communication and various optical measurements, and more particularly to an optical modulator for modulating the loss or phase of light at a predetermined frequency. Optical amplifying means for amplifying the optical pulse, an optical saturable absorber whose loss decreases as the incident light intensity increases, and an optical branching means for extracting the optical pulse to the outside,
A collision pulse mode-locked ring laser device including an optical waveguide that optically couples each of the above means with each other to form a ring resonator, and an optical modulator that modulates a loss or phase of light at a predetermined frequency, and a modulator. Amplification means for amplifying the generated optical pulse, an optical saturable absorber whose loss decreases as the incident light intensity increases, an optical branching means for extracting the optical pulse to the outside, and an optical bandpass for changing the transmission wavelength. The present invention relates to a mode-locking ring laser device including a filter, an optical delay circuit, and an optical waveguide that optically couples the above-mentioned means with each other to form a ring resonator.

[0002]

2. Description of the Related Art Conventionally, a structure using an optical fiber has been mainly used as a means for forming a ring resonator of a mode-locked ring laser device. Examples of ring resonators using optical fibers are: Takara, Kawanishi, Saruwatari, "Ultrafast transform-limited optical pulse generation by mode-locked Er-doped fiber ring laser", 1
1992 IEICE Fall Conference No. B-732, etc.

The operation of the mode-locked laser in this conventional structure will be described below. First, in the mode-locking method, a large number of oscillation modes with the same frequency and the same phase interval as the longitudinal mode spacing of the laser resonator are generated, and an optical short circuit corresponding to the inverse Fourier transform of this oscillation spectrum is generated on the time axis. A pulse is generated.

FIG. 10 is a block diagram of a conventional mode-locking ring laser, in which (a) shows its basic configuration and (b).
Shows a typical spectrum characteristic obtained by mode locking, and (c) shows its time waveform characteristic. In FIG. 10, 701 is an oscillator, 702 is a power amplifier, 703 is an optical modulator, 704 is an optical fiber, 705 is an optical amplifier, and 7
Reference numeral 06 is an optical isolator, and 707 is an output optical fiber coupler.

In FIG. 10A, the output of an oscillator 701 having a predetermined frequency is amplified by a power amplifier 702 and applied to an optical modulator 703, and the loss or phase of light is modulated at that frequency by an electro-optical effect. To do. This optical modulator 703, an optical amplifier 705 that amplifies the modulated optical pulse, an optical isolator 706 that regulates the traveling direction of the optical pulse and blocks reflected return light, and an output for outputting the amplified optical pulse to the outside. The optical fiber coupler 707 is coupled in a ring shape via the optical fiber 704 to form a ring resonator.

As the optical amplifier, a rare earth-doped optical fiber amplifier doped with a rare earth such as erbium (Er) or neodymium (Nd) or a semiconductor laser amplifier is mainly used.

FIG. 11 is a diagram showing a configuration example of a rare earth-doped optical fiber amplifier, (a) is a backward pumping configuration,
(B) is a forward pumping configuration and (c) is a bidirectional pumping configuration.

In FIG. 11, reference numeral 801 is rare earth (Er).
Doped optical fiber, 802 is a wavelength multiplex wave device, and 803 is an excitation light source. In FIG. 11, the optical pulse enters from one end of the rare earth-doped optical fiber 801 and exits from the other end. The excitation light is a rare-earth-doped optical fiber 801.
The optical pulse is incident on the rare earth-doped optical fiber 801 from the excitation light source through the emission end, the incidence end, or the wavelength multiplexing polymerization device 802 connected to both ends thereof. In the rare earth-doped optical fiber 801, the optical pulse is amplified by this pump light.

FIG. 12 is a diagram showing a configuration example of a semiconductor laser amplifier, in which 901 is a driving power source and 902 is a semiconductor laser amplifier. In FIG. 12, a semiconductor laser amplifier 902 is configured to amplify an input optical pulse according to a current injected from a current source.

Here, the operating principle of the conventional mode-locked optical ring laser will be described with reference to FIG.
The optical path length L of the ring resonator is a value obtained by multiplying each physical length h _i by each refractive index n _i , where h _i is the physical length of each component of the ring resonator and n _i is the refractive index. Optical path length).

[0011]

## EQU1 ## L = Σh _i n _{i In} the ring resonator, there are many longitudinal modes having a frequency interval given by fr = c / L (where c is the speed of light). Here, when optical modulation with a repetition frequency fm = Nfr (N is an integer of 1 or more) is applied in the optical modulator in the ring resonator, as shown in FIG. A mode-locked oscillation state in which the phases of all longitudinal modes are aligned is obtained, and as shown in FIG. 10C, an optical pulse train having a repetition frequency 1 / (N · fr) is obtained. The pulse width corresponds to the reciprocal of the oscillation spectrum width Δν determined by the envelopes of many longitudinal mode spectra, and the center of this spectrum envelope is the central wavelength (frequency ν ₀ ).

[0012]

The mode-locked ring laser described above has the following problems.

When a ring resonator is composed of a rare earth (Er) -doped optical fiber and an optical fiber, the resonator length is several tens of meters, so the size of the laser resonator is several tens.
cmφ, and the "unevenness" of the temperature distribution in the resonator and the side pressure received by the optical fiber differ depending on the part, so that the polarization of the optical pulse propagating through the optical fiber fluctuates and the laser oscillation operation becomes unstable. There was a problem.

The present invention has been made in view of such conventional problems, and an object thereof is to provide a technique capable of generating a short optical pulse with a stable operation.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[0016]

In order to achieve the above object, the means (1) of the present invention comprises an optical modulation means for modulating the loss or phase of light at a predetermined frequency, and a modulated optical pulse. An optical amplification means for amplifying, an optical saturable absorber whose loss decreases as the incident light intensity increases, an optical branching means for extracting the optical pulse to the outside, and a ring resonance by optically coupling the respective means with each other. A mode-locking ring laser device having an optical waveguide forming a container, wherein all of the optical modulation means, the optical amplification means, the optical branching means, and the optical waveguide have polarization dependence, and the optical main axis of each means. Are combined together, the optical modulator is a light intensity modulator, and the optical waveguide is a planar optical waveguide.

The means (2) of the present invention comprises: an optical modulating means for modulating the loss or phase of light at a predetermined frequency, an optical amplifying means for amplifying the modulated optical pulse, and an increasing incident light intensity. A mode-locking ring laser provided with an optical saturable absorber whose loss is reduced, an optical branching means for extracting the optical pulse to the outside, and an optical waveguide for optically coupling the respective means with each other to form a ring resonator. In the device, all of the optical modulator, the optical amplifier, the optical branching unit, and the optical waveguide have no polarization dependence, and the optical modulator is a light intensity modulator, and the optical waveguide. Is a planar type optical waveguide.

The means (3) of the present invention comprises: a light modulating means for modulating the loss or phase of light at a predetermined frequency; a light amplifying means for amplifying the modulated light pulse; and as the incident light intensity increases. An optical saturable absorber whose loss is reduced, an optical branching means for extracting the optical pulse to the outside, an optical bandpass filter for changing a transmission wavelength, an optical delay circuit, and the above means are optically coupled to each other. A mode-locking ring laser device including an optical waveguide forming a ring resonator, wherein all of the optical modulation means, the optical amplification means, the optical branching means, and the optical waveguide have polarization dependence, and It is characterized in that the optical principal axes are aligned and coupled together, and the optical waveguide is a planar optical waveguide.

The means (4) of the present invention comprises: an optical modulating means for modulating the loss or phase of light at a predetermined frequency; an optical amplifying means for amplifying the modulated optical pulse; and an increasing intensity of incident light. An optical saturable absorber whose loss is reduced, an optical branching means for extracting the optical pulse to the outside, an optical bandpass filter for changing a transmission wavelength, an optical delay circuit, and the above means are optically coupled to each other. A mode-locking ring laser device having an optical waveguide forming a ring resonator, wherein the optical modulation means, the optical amplification means, the optical branching means and the optical waveguide are all configured not to have polarization dependence,
Further, the optical waveguide is a planar type optical waveguide.

[0020]

According to the above-mentioned means, the polarization of the optical pulse propagating in the ring resonator is stabilized by using the planar type optical waveguide instead of the optical fiber as the ring resonator, so that the mode lock operation is stabilized. can do.

Further, by using a traveling wave type semiconductor laser amplifier as the optical modulator, the driving power of the modulator can be reduced.

[0022]

Embodiments of the present invention will now be described in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a diagram showing the configuration of Embodiment 1 of a collision pulse mode-locked ring laser device of the present invention, in which 101 is an oscillator, 102 is a bias T, and 103.
Is a DC power supply, 104 is a traveling wave type semiconductor laser amplifier, 1
Reference numeral 05 is a planar optical waveguide, 106 is a light saturable absorber,
107 is an optical branch circuit, 108 and 109 are optical output ports,
110 is an optical branch circuit.

The traveling wave type semiconductor laser amplifier 104,
The light saturable absorber 106, the light branching circuit 107, and the light output ports 108 and 109 are integrally arranged on the planar optical waveguide 105, and the above-mentioned elements as a whole constitute a ring resonator having an optical length Lc. .

By making all the components in the resonator polarization-dependent and coupling their optical principal axes together, the polarization direction of the optical pulse in the resonator can be made constant. That is, since the optical pulse is held in the same polarization direction and guided through each component, it is possible to prevent the polarization state from fluctuating which causes unstable operation.

In FIG. 1, the output of the oscillator 101 having a predetermined frequency is superimposed on the output of the DC bias power source 103 by the bias T102 to modulate the traveling wave type semiconductor laser amplifier 104. As a means for optically coupling the traveling wave type semiconductor laser amplifier 104 and the planar optical waveguide 105, by using an optical fiber lens between them, the coupling efficiency at one end can be about 2 dB.

Regarding this coupling technique, Y. Hibino, H.
Terui, A. Sugita, and Y. Ohmori, “Silica-based opt
ical waveguide ring laser integrated with semicond
uctor laser amplifier on Si substrate, "Electroni
cs Letters ”, vol.28, pp.1932 to 1933, 1992.

The light saturable absorber 106 is a medium in which the loss of light decreases as the incident light intensity increases, and a dye or a semiconductor is usually used. In particular, for light of a wavelength of 1.55 μm, the operation of the optical saturable absorber has been confirmed by using a semiconductor waveguide having a multiple quantum well (MQW) structure with a reverse bias (for details, YK Chen, MCWu,
T. Tanbun-Ek, RA Logan, and JR Simpson, “Mo
nolithic colliding-pulse mode-locked quantum well
lasers, ”in Tech. Digest of Conference on Lasers
and Electro-optics (CLEO '91) No. CWK3, pp. 304-3
07, 1991).

The optical branching circuit 107 is for taking out a part of the power of the optical pulse circulating in the ring resonator to the outside of the resonator and outputting it from the optical output ports 108 and 109.

Here, the operating principle of the mode-locked optical ring laser device of the first embodiment will be described with reference to FIG.

The optical path length L of the ring resonator is, as shown in the above equation 1, given that the physical length h _i of each component of the ring resonator is n _i and the refractive index is n _i , the physical length h _i of each of the respective components is different. It is the sum of the values (respective optical path lengths) multiplied by the refractive index n _i .

In the ring resonator, fr = c / L
There are a number of longitudinal modes with a frequency spacing given by (where c is the speed of light). Here, the traveling wave type semiconductor laser amplifier 104 in the ring resonator is repeatedly fed with the repetition frequency f.
When modulated with m = N · fr (N is an integer of 1 or more), FIG.
As shown in (a), a mode-locked oscillation state in which the phases of all longitudinal modes at the frequency interval N · fr are aligned becomes as shown in FIG.
As shown in (b), repetition frequency 1 / (N · fr)
The optical pulse train of is obtained.

The pulse width corresponds to the reciprocal of the oscillation spectrum width δν determined by the envelopes of many longitudinal mode spectra, and the center of this spectrum envelope is the central wavelength (frequency ν ₀ ).

Next, the operation of the optical saturable absorber 106 provided in the ring laser resonator of the first embodiment will be described. In the ring laser resonator of the first embodiment, optical pulses propagating in mutually opposite directions exist in the ring resonator, and the traveling wave type semiconductor laser amplifier 104 is present in the ring resonator as shown in FIG. And light saturable absorber 106
, The clockwise and counterclockwise pulses propagating in the ring resonator are
06 at the same time in the opposite direction.

The positional relationship between the mode locker and the optical saturable absorber 106 in the ring resonator will be described below with reference to FIG.

FIG. 3 is a diagram showing the positional relationship between the mode rocker, the optically saturable absorber 106 and the light pulses in both directions in the ring resonator. The ring resonator is cut at the position of the mode rocker and expanded. , The positions of the two ends separated are set to 0 and 2π, and the position in the resonator is displayed in phase.

The conditions under which the mode-locking operation of the ring resonator of the first embodiment is stable are as follows. 1. Collision of light pulses in both directions at the light saturable absorber, That is, the two conditions that the optical pulses of both directions pass through the traveling wave type semiconductor laser amplifier 104 alternately at equal intervals are satisfied. This principle is described in Yoichi Fujii and Koichi Nishizawa, “Advanced Optical Technology” pp. 110-129 (Agne Seofusha)
Explained in.

This operation is settled in such a manner that the light pulses in both directions collide in the light saturable absorber 106. In such a state, a standing wave of light is generated only at the moment when the pulses of both directions collide in the light saturable absorber 106, and the intensity of this standing wave of light becomes high. The shutter action of 106 becomes steep and the light pulse becomes steep. In this case, the driving frequency condition is 2N · fr instead of the above-mentioned N · fr.

Now, one peak of the optical pulse train propagating in both directions through the ring resonator (herein called clockwise) is 0.
And the phase of the pulse at the position closest to 0 in the other one-sided (here, called counterclockwise) pulse train is x (0
<X <2π). When there are n number of light pulses for each rotation in the ring resonator, the driving frequency is 2nf ₀ (f ₀
= 1 / L ₀ ; L ₀ is the resonator length), and the optical pulse interval around each is 2π / n. According to the condition 2, the counterclockwise light pulse at the position of phase x is at the center of the clockwise pulse interval,

[0040]

## EQU00002 ## X = .pi. / N.

From the condition 1, the light saturable absorber 106
The phase of is a clockwise pulse of phase 0 and the phase (π / n + 2π
i / n) (i is an integer of 0 or more and n-1 or less) in the middle of the counterclockwise pulse. Therefore, the phase θ of the light saturable absorber 106 can be represented by the following formula.

[0042]

## EQU3 ## Optical saturable absorber 1 in each case of θ = π / 2n + πi / n n = 1, 2, 3, 4
The phase of 06 is as follows.

[0043]

N = 1 π / 2 n = 2 1 / 4π, 3 / 4π n = 3 1 / 6π, π / 2, 5 / 6π n = 4 1 / 8π, 3 / 8π, 5 / 8π, 7 The / 8π traveling wave type semiconductor laser amplifier 104 is driven by a forward bias current.

FIG. 4 is a diagram showing an example of applied current-gain characteristics of the traveling wave type semiconductor laser amplifier 104. Looking at this characteristic, when the bias current is 50 mA and the amplitude of the modulation signal is 50 mA _0-p , the extinction ratio is 30 d.
It is possible to perform modulation with an average optical gain of 10 dB including coupling efficiency of B or higher. The power of the modulation signal required at this time is 62.5 mW (18 dBm) in the 50Ω system. This value is 1/10 of the power for driving the LiNbO ₃ optical modulator, and it is possible to directly drive the traveling wave type semiconductor laser amplifier without amplifying the output of the oscillator by the power amplifier.

Therefore, the traveling wave type semiconductor laser amplifier 104 functions as both an optical amplification medium and a mode locker in the mode-locked ring laser. Further, as described above, the traveling wave type semiconductor laser amplifier 104
Since the light pulses passing through the right and left are alternated at equal intervals and at equal intervals, it is possible to obtain uniform amplification characteristics without gain variations for each light pulse due to gain saturation and transient characteristics of the traveling-wave semiconductor laser amplifier 104. it can.

Further, if the branching ratios of the optical branching circuits 107 and 110 inserted in the ring resonator are the same, the light pulses in both directions amplified by the traveling wave type semiconductor laser amplifier 104 are optically saturable. The same attenuation occurs until the collision with the absorber 106, and the peak values of the two optical pulses become the same when colliding with the optical saturable absorber 106, so stable collision pulse mode-locking operation can be expected. . Although the optical branch circuit 110 is inserted so that the attenuation of the optical pulses in both directions is the same, the optical output can also be taken out from here.

As can be seen from the above description, the first embodiment
According to the method, an optical pulse propagates with stable polarization in a ring resonator formed on a planar optical waveguide, and a collision pulse mode-locking operation is realized by an optical saturable absorber provided in the resonator. Therefore, the ultrashort optical pulse train can be stably generated.

As shown in FIGS. 5 and 6, a LiNbO ₃ modulator 201 may be used instead of the traveling wave type semiconductor laser amplifier 104 as an optical modulator. In this case, the semiconductor laser amplifiers 201A and 201B are placed on one side or both sides of the LiNbO ₃ modulator 201.

(Embodiment 2) FIG. 7 is a diagram showing the structure of Embodiment 2 of the collision pulse mode-locked ring laser device of the present invention, in which 401 is an oscillator, 402 is a bias T, and 403.
Is a DC power supply, 404 is a traveling wave type semiconductor laser amplifier, 4
Reference numeral 05 is a planar optical waveguide, 406 is a light saturable absorber,
407 and 410 are optical branch circuits, and 408 and 409 are optical output ports.

As shown in FIG. 7, the collision pulse mode-locked ring laser device of the second embodiment includes the oscillator 401,
The bias T402, the DC power supply 403, the traveling wave type semiconductor laser amplifier 404, the planar optical waveguide 405, the optical saturable absorber 406, the optical branch circuits 407 and 410, and the optical output ports 408 and 409 are ring resonators each having an optical length Lc. Are configured. This is a polarization-independent traveling-wave type semiconductor laser amplifier (Kamijo et al., "Polarization-independent semiconductor optical amplifier", IEICE Technical Report OQE 91-93, p19,
31, 1991), all the constituent elements in the resonator are polarization independent, and even if the polarization direction of the optical pulse in the resonator changes due to external fluctuation, The component can avoid that effect. That is, even if the polarization state changes due to external fluctuation, the effect can be removed and stable operation can be maintained.

(Third Embodiment) FIG. 8 is a diagram showing the structure of a collision pulse mode-locked ring laser device according to a third embodiment of the present invention, in which 501 is an oscillator, 502 is a bias T, and 503.
Is a DC power supply, 504 is an optical modulator, 505 is a planar optical waveguide, 506 is an optical saturable absorber, 507 is an optical branch circuit, 508 and 509 are optical output ports, 510 is an optical branch circuit, and 511 is a wavelength tunable optical band. Pass filter 512
Is an optical delay circuit. The optical modulator 504, the optical saturable absorber 506, the optical branch circuit 507, and the optical output port 50.
The reference numerals 8 and 509 are integrally arranged on the planar optical waveguide 505.

The basic operation principle of the collision pulse mode-locked ring laser device of the third embodiment is the same as that of the first embodiment, but in the third embodiment, the wavelength tunable optical bandpass filter is included in the resonator. 511 is inserted, and the mode-locked operation can be realized at any wavelength within the gain band of the optical amplification medium by changing the transmission wavelength of the wavelength tunable optical bandpass filter 511.

Next, the tunable optical bandpass filter 5
11 will be described. By inserting a wavelength tunable optical bandpass filter 511 in the ring resonator, it is possible to make the oscillation wavelength of the mode-locked ring laser of the present invention variable. Tunable optical bandpass filter 5
As the element 11, a dielectric multilayer filter can be used in the simplest configuration. Typical bandwidth is 0.
A wavelength variable range of several nm is realized at 1 to 3 nm.

When the wavelength tunable optical bandpass filter 511 using this dielectric multilayer filter is used, when the center wavelength is changed, the optical path length of the resonator also changes at the same time. Therefore, for example, when the collision pulse mode-locking ring laser device of the third embodiment is used in a system that requires constant repetition of optical pulses, the optical delay circuit 51 is provided in the ring resonator.
It is necessary to insert 2 to adjust the resonance frequency. With this optical delay circuit, it is possible to compensate for a change in the optical wavelength that occurs when the oscillation wavelength changes and to oscillate at a constant repetition frequency.

(Embodiment 4) FIG. 9 is a diagram showing the structure of Embodiment 4 of the collision pulse mode-locked ring laser device of the present invention, in which 601 is an oscillator, 602 is a bias T, and 603.
Is a DC power supply, 604 is an optical modulator, 605 is a planar optical waveguide, 606 is an optical saturable absorber, 607 is an optical branch circuit, 608 and 609 are optical output ports, 610 is an optical branch circuit, and 611 is a wavelength tunable optical band. Pass filter, 612
Is an optical delay circuit.

The optical modulator 604, the optical saturable absorber 60
6, optical branch circuit 607, and optical output ports 608, 60
9 is integrated and arranged on the planar optical waveguide 605.

The collision pulse mode-locked ring laser device of the fourth embodiment is different from that of the third embodiment only in that all the elements constituting the resonator have a polarization independent structure.
The principle of operation is the same, and the polarization-independent configuration makes it possible to realize mode-locked operation that is not affected by polarization fluctuations.

As described above, the invention made by the present inventor is
Although the specific description has been given based on the above-described embodiments, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the scope of the invention.

[0059]

As described above, according to the present invention, an optical pulse propagates with stable polarization in a ring resonator formed on a planar optical waveguide and is provided in the resonator. Since the collision pulse mode-locking operation is realized by the optically saturable absorber, it is possible to stably generate an ultrashort optical pulse train.

By using a traveling wave type semiconductor laser amplifier as the mode locker, the power of the drive signal can be greatly reduced.

Further, since the semiconductor has a better drift characteristic than the ferroelectric substance, a stable operation of the mode-lock ring laser can be achieved.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a first embodiment of a collision pulse mode-locked ring laser device of the present invention,

FIG. 2 is a diagram for explaining the operation of the collision pulse mode-locked ring laser device of the first embodiment,

FIG. 3 is a diagram showing a positional relationship between a mode locker and an optical saturable absorber in the ring resonator of the first embodiment,

FIG. 4 is a diagram showing an example of applied current-gain characteristics of the traveling wave type semiconductor laser amplifier of the first embodiment,

FIG. 5 is a diagram for explaining a modified example of the first embodiment,

FIG. 6 is a diagram for explaining a modified example of the first embodiment,

FIG. 7 is a diagram showing a configuration of a collision pulse mode-locked ring laser device according to a second embodiment of the present invention;

FIG. 8 is a diagram showing the configuration of Example 3 of the collision pulse mode-locked ring laser device of the present invention,

FIG. 9 is a diagram showing a configuration of a collision pulse mode-locked ring laser device according to a fourth embodiment of the present invention;

FIG. 10 is a diagram for explaining problems of a mode-locking ring laser device using a conventional optical fiber,

FIG. 11 is a diagram showing a configuration example of a rare earth-doped optical fiber amplifier,

FIG. 12 is a diagram showing a configuration example of a semiconductor laser amplifier.

[Explanation of symbols]

101 ... Oscillator, 102 ... Bias T, 103 ... DC power supply, 104 ... Traveling wave type semiconductor laser amplifier, 105 ... Planar optical waveguide, 106 ... Optical saturable absorber, 107 ...
Optical branch circuit, 108, 109 ... Optical output port, 110 ...
Optical branch circuit, 201 ... LiNbO ₃ modulator, 201A,
201B ... Semiconductor laser amplifier, 401 ... Oscillator, 40
2 ... Bias T, 403 ... DC power supply, 404 ... Traveling wave type semiconductor laser amplifier, 405 ... Planar optical waveguide, 4
06 ... Optical saturable absorber, 407, 410 ... Optical branch circuit,
408, 409 ... Optical output port, 501 ... Oscillator, 50
2 ... Bias T, 503 ... DC power supply, 504 ... Optical modulator, 505 ... Planar optical waveguide, 506 ... Optical saturable absorber, 507 ... Optical branch circuit, 508, 509 ... Optical output port, 510 ... Optical branch circuit, 511 ... Wavelength variable optical bandpass filter, 512 ... Optical delay circuit, 601 ... Oscillator, 602 ... Bias T, 603 ... DC power supply, 604 ...
Optical modulator, 605 ... Planar optical waveguide, 606 ... Optical saturable absorber, 607 ... Optical branch circuit, 608, 609 ... Optical output port, 610 ... Optical branch circuit, 611 ... Tunable optical bandpass filter, 612 ... Optical Delay circuit, 701 ...
Oscillator, 702 ... Power amplifier, 703 ... Optical modulator, 7
04 ... Optical fiber, 705 ... Optical amplifier, 706 ... Optical isolator, 707 ... Output optical fiber coupler, 801
... Rare earth (Er) -doped optical fiber, 802 ... Wavelength multiple polymerization wave device, 803 ... Excitation light source, 901 ... Driving power supply, 902
… Semiconductor laser amplifier.

Claims (4)

[Claims] 1. A light modulating means for modulating the loss or phase of light at a predetermined frequency, an optical amplifying means for amplifying a modulated light pulse, and an optical saturable absorption whose loss decreases as the incident light intensity increases. A mode-locking ring laser device comprising a body, an optical branching means for extracting the optical pulse to the outside, and an optical waveguide for optically coupling the respective means with each other to form a ring resonator, wherein the optical modulation All of the means, the optical amplification means, the optical branching means and the optical waveguide have a polarization dependency, the optical principal axes of the respective means are aligned and coupled, the optical modulation means is a light intensity modulator, A collision pulse mode-locked ring laser device, wherein the optical waveguide is a planar optical waveguide. 2. An optical modulator that modulates the loss or phase of light at a predetermined frequency, an optical amplifier that amplifies the modulated optical pulse, and an optical saturable absorber whose loss decreases as the incident light intensity increases. A mode-locking ring laser device comprising a body, an optical branching means for extracting the optical pulse to the outside, and an optical waveguide for optically coupling the respective means with each other to form a ring resonator, wherein the optical modulation Means, an optical amplifying means, an optical branching means, and an optical waveguide, all of which have no polarization dependence, the optical modulating means is an optical intensity modulator, and the optical waveguide is a planar optical waveguide. Collision pulse mode-locked ring laser device characterized by: 3. An optical modulator that modulates the loss or phase of light at a predetermined frequency, an optical amplifier that amplifies the modulated optical pulse, and an optical saturable absorber whose loss decreases as the incident light intensity increases. A body, an optical branching means for extracting the optical pulse to the outside, an optical bandpass filter for changing a transmission wavelength, an optical delay circuit, and an optical waveguide for optically coupling the respective means with each other to form a ring resonator. A mode-locking ring laser device comprising: a light-modulating means, a light-amplifying means, a light-splitting means, and an optical waveguide, all of which have polarization dependence, and the optical principal axes of the respective means are combined together And the optical waveguide is a planar type optical waveguide. 4. An optical modulation means for modulating the loss or phase of light at a predetermined frequency, an optical amplification means for amplifying the modulated optical pulse, and an optical saturable absorption whose loss decreases as the incident light intensity increases. A body, an optical branching means for extracting the optical pulse to the outside, an optical bandpass filter for changing a transmission wavelength, an optical delay circuit, and an optical waveguide for optically coupling the respective means with each other to form a ring resonator. A mode-locking ring laser device comprising: an optical modulator, an optical amplifier, an optical splitter, and an optical waveguide, all of which have no polarization dependence, and the optical waveguide is a planar optical waveguide. A mode-locking ring laser device characterized by: