JP2003517625A - Resonant type light energy control apparatus and method - Google Patents

Abstract

(57) Abstract: Lightwave energy control devices and methods allow signal control, such as modulation and switching, within a propagation element without discontinuities, such as optical fibers or planar optical waveguides. The propagating element is configured such that a portion of the energy guided by the waveguide penetrates the outer surface of the element and intersects the periphery of the adjacent high-Q three-dimensional resonator. Energy at the selected resonant wavelength is coupled into the resonator according to the principles of a whispering gallery mode device, where it circulates with very low loss and returns the energy to the propagating element. By introducing losses in the resonator, the propagation energy can be varied between a substantially perfect wavelength and a substantially zero wavelength. The loss factor is set such that the resonator is over-coupled, i.e., there is a critical coupling state in which the parasitic loss is smaller than the coupling loss and a small change in the control effect causes a disproportionately large change in the output optical signal. Can be maintained.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION

The present invention relates to a lightwave energy control apparatus and method, and more particularly to a modulation and switching system, device and method for signals propagated by an optical waveguide.

[0002]

BACKGROUND OF THE INVENTION

In the fast-growing fiber optic technology, numerous individual devices and subsystems have been developed to modulate or otherwise control a light beam of a particular wavelength. However, conventional approaches do not completely solve the problems inherent in the various conditions imposed on modern systems. In modern communication systems, optical waveguides are used to propagate dense wavelength-multiplexed light beams and to modulate these beams at very high digital data rates, or with wideband analog data, or both. Usage is increasing.

For example, a method of modulating the energy of a single frequency laser light source, typically a semiconductor laser, is known. When using such a light source, the laser has a limited on / off switching speed, which limits the acceptable modulation bandwidth. In addition, this type of modulation causes chirping or expansion of the signal bandwidth of a single-frequency laser, resulting in wavelength-dependent dispersion of the signal propagated through the optical fiber over a substantial distance. Distance is subject to unique constraints. This approach has the advantage of being able to modulate at the light source, compared to some other systems, and allows the continuity of the fiber optic structure to be maintained. However, the semiconductor laser to be modulated must be coupled to the optical waveguide by means of yield, reliability and cost issues. Therefore, due to the constraints mentioned above, there is a tendency to use external modulators in long-haul propagation systems.

Currently, there are two types of external modulators in use, but they are monolithic waveguide devices. This popular type of lithium niobate modulator utilizes a Mach-Zehnder interferometer, but it produces clean waveforms at the highest data rates and has the least amount of chirping, which results in long-range propagation systems and other Is used for. Since the monolithic waveguide device must be coupled to the optical fiber at the input and the output, the mounting and assembling costs are high, and there is a substantial mismatch between the chip waveguide device and the optical fiber waveguide. Loss in the range of In addition, this modulator is polarization sensitive and requires active temperature stabilization to compensate for the temperature drift characteristics of the interferometer.

The recently introduced second waveguide device is a monolithic device that uses the electroabsorption effect.
It is an on-chip device. Since this modulator is manufactured integrally with the semiconductor laser, it requires an elaborate and high-cost manufacturing process, and as a result, the yield of the entire laser device is reduced. In addition, this device is susceptible to chirping and is constrained at high modulation rates (10 Gbit / s and above).
Also, the integrated laser / modulator chip must be coupled to the optical fiber, which increases manufacturing costs.

There are numerous interesting patents showing various examples of monolithic devices, but all require matching techniques to work with optical fibers. At least two of these patents refer to signal modulation using dielectric microcavities that recycle electromagnetic energy at light wavelengths. Generally spherical, ring-shaped or disk-shaped microresonators
"Whispering gallery mode" -WG
The M) structure is formed of a dielectric material such as glass or silica. Although they are essentially total internal reflection and support internal modes at frequencies determined by size and other factors with very low losses and thus high Q, research is currently underway for use in many different optical waveguides. Has been. For example, US Pat. No. 5,343,
No. 390 (inventor: McCall) discloses a closed loop WGM system configured as a thin film device which is characteristically described as an active material with a maximum half-wave thickness (
See column 1, lines 62-63). The disk thickness is in the range of 1000-1500 angstroms with at least one optically active layer interposed between the thick barrier layers. As an example, the optically active substance is InGaAs and the barrier layer is InGaAsP. This microcavity structure formed by photolithography is described as having a number of potential functions. These constitute single quantum well structures that are optically pumped to multiple quantum well structures, and also two-port and three-port devices that function, for example, as detectors, data amplifiers and ammeters.
Further, the output is either modulated or unmodulated, as described in col. 6, lines 3-23 of this patent, but the general description (e.g., "subtleties about cancellation of unmodulated output" Apart from such destructive phase interference "), there is no teaching of how to perform the modulation, or even how it can be modulated at high speeds. Further work on this approach will result in practical modulators at some point in the future, but will face obstacles due to the need for matching to fiber optic waveguides, such as cost and insertion loss. There will be problems with proper performance.

Application for US Pat. No. 5,878,070 (inventor: Ho, et.al.) (“Photonic W
ire Microcavity Light Emitting Devices ") describes a somewhat related approach. The inventor also found that a U-shaped low index waveguide material sandwiched between InGaAsP layers less than 1 micron thick. Arc surrounds a ring of optically active material and has a taper on its side arm (see FIG. 9) InGa
A WGM microcavity with an As gain medium is described. According to this configuration, a photon tunnel effect due to resonance occurs from the active material of the gain cavity to the output coupling waveguide that serves as the core of this structure. The possibility of modulation by changing the pumping energy of the active medium outlet portion has also been suggested (column 15, lines 54-58), but the specific implementation method is not described. This method is individually and specific active waveguide core,
Obviously, there are the same problems as mentioned in the McCall patent because of the use of an arc-shaped member of low index waveguide material which works in concert with it as an output waveguide.

[0008] Not only is the use of fiber optic systems rapidly increasing, but there is a continuous evolution of technology towards higher density wavelength division multiplexing and higher data rates per channel. This means that factors such as spectral bandwidth frequency stability, compactness and reproducibility have more significant meaning, further increasing the requirements for the new approach.

Therefore, an all-fiber modulator that ensures continuity of light wave energy propagating along an optical waveguide has a sufficient dynamic range, high data rate handling capability, and minimal insertion loss. If it can be provided in a form that suppresses it, it has a great potential advantage. Obviously, such a device, if sensitive to wavelength, can also be used as an on / off switch or as a switchable bandpass filter, depending on the particular application. For complex switching and routing systems with a large number of channels, it is preferable to be able to manufacture units according to the same concept with microlithography or microfabrication techniques.

[0010]

[Outline of the Invention]

The above and other objects of the invention are achieved by energy transfer structures and modes of operation that variably attenuate (modulate) or completely block (switch off) propagation energy in a portion of an optical waveguide. To this end, a short portion of the optical waveguide is modified to couple energy into an adjacent high-Q resonant microcavity, where energy is stored by recycling lightwave energy in a resonant mode in the microcavity. Energy is returned to the optical waveguide. In the first possible mode of operation, the resonator-optical waveguide coupling loss is greater than the other losses of the resonator, due to the optical loss after one round trip in the resonator. This is called an over-coupling state. In this state, the attenuation of the resonant optical energy incident from the waveguide by the resonator is minimized, and as a result, the propagation by the waveguide is maximum. When the resonator loss for each round trip is increased (the coupling loss of the resonator-waveguide is made constant) and balanced with the coupling loss of the resonator-waveguide, the state changes from excess coupling to critical coupling (energy propagation through the waveguide). Is 0).
This causes the propagation rate of the light wave along the waveguide to be essentially modulated from 1 to 0. To do this, it is necessary to make very small changes to the round trip loss introduced by the control element, which is external to the resonator or which takes advantage of changes in the characteristics of the resonator itself. Due to such modulation, there is no discontinuity, and it is not necessary to combine with dissimilar elements,
It is possible to obtain a very high data rate in a propagation structure consisting of all optical fibers with a minimum insertion loss. It is also possible to operate between the critical and under-coupled states to obtain the modulation. In this second mode of operation, the modulator-
The round-trip coupling loss of the waveguide is balanced with the resonator loss before increasing the resonator loss due to the control element. In this state, the propagation through the waveguide is 0 as described above. Increasing the resonator loss and passing the equilibrium state results in an under-coupled state in which the propagation through the waveguide recovers to a value close to unity. It is possible to realize both the first and second modes of operation using negative optical loss (or optical gain), but the direction in which the optical gain is obtained is the same as the direction of positive optical loss. The opposite. For example, in the first mode of operation, due to losses, a critical coupling state exists before applying optical gain. The control element then applies optical gain to generate the over-coupling state, which modulates the propagation rate from essentially zero to essentially one.

The third and fourth modes of operation change between a super-coupled state and a critical coupled state (modes 1 and 3), or a critical coupled state and a poorly coupled state (modes 2 and 4). It is comparable to the first and second modes of operation in that it is used to modulate the propagation through the waveguide. However, in these operating modes, the modulator-waveguide coupling loss changes (not the constant), while the other resonator losses remain constant. In these cases, the control element changes the resonator-waveguide coupling loss. Alternatively, the operating principle is essentially the same as modes 1 and 2.

In the fifth mode of operation, the loss causes the resonator to be critically coupled to the waveguide. Modulation is obtained by changing the optical path length of the resonator such that the resonant frequency of the resonator shifts in or out of resonance with the desired light wave. The change in optical path length is obtained, for example, by changing the dielectric constant of the resonator electro-optically or optically nonlinearly.

Since the assembled elements are very small and frequency specific, multiple units can be used in combination with separate controllers to provide high density wavelength division multiplexing. The switching system and multiple modulators can be arranged with or without a signal source or amplifier in the fiber, depending on the particular application.

According to the invention, the optical waveguide or optical fiber is a known core / cladding structure with a short section of very narrow cross section by a taper. In this part, the core only leaves a trace and the energy is confined within the reduced diameter cladding and in a limited radial direction around it. The perimeter of the WGM resonator is in the external electric field of the narrowed constriction to allow electric field coupling, and the resonator is such that essentially total internal reflection occurs at the internal equatorial plane and / or a light guiding effect is obtained. Have a geometric shape. This creates a lightwave recirculation path with a high Q within the circumference of the resonator. Energy is transferred into the resonator by electric field coupling, but the resonator does not completely confine the light wave and returns a part of the energy to the optical waveguide as an output. On the resonator,
Loss control mechanisms in internal or adjacent locations that affect the external or internal electric field further increase the loss, which affects the energy propagated through the optical fiber. As the loss control mechanism, it is advantageous to use an arbitrary type of converter whose light transmission characteristic changes with a signal at a selected wavelength. As an example, a combination of an optically active layer of a semiconductor material is arranged on a resonator or a position adjacent to the resonator, and dimensions, efficiency, and signal response are appropriately selected so that desired control can be obtained. These materials may be bulk or quantum well materials, whose absorption is altered by optical pumping, injection current or applied voltage. As another example, a variable coupling mechanism that couples the energy of the resonator to a separate structure, such as another waveguide, may be arranged to couple the energy from the resonator and vary its round trip loss. Good.

The resonator element is a silica microsphere, on the order of about 1 to 1000 microns in diameter, dimensioned to have a resonant mode at one or more selected wavelengths.
(microsphere), disk-shaped or ring-shaped. The diameter of the equator is chosen not only for Q but also for data rate and spectral linewidth, but it should be very small (eg, 30 microns) to accommodate current and expected conditions. is necessary. Similarly, the shape and size of the resonator affects the frequency spacing between adjacent resonant modes. This frequency spacing should, at a minimum, exceed the desired modulation rate or signal bandwidth, but in practice should be large enough to encompass the spectral spread of the light waves that co-propagate in the optical waveguide. For this purpose, eccentric resonator structures such as oblate spheres, disks, rings and ellipses are desirable. Diameter 1
For example, a loss controllable transducer can be affixed directly to the opposite side of the optical fiber for placement and retention in proper relation to the waisted portion of the optical fiber, which is 0 microns or less.

In theory and in practice, the effective range of loss control is only between over-coupled states where the propagation rate is 1 or slightly less and critical-coupled states where the propagation rate is attenuated by 90% or more. It indicates that change is needed. Since this is in fact obtained with only small changes in the losses introduced by the loss control mechanism, this method changes the resonance frequency while maintaining the behavior and critical coupling between the critically coupled and the under-coupled states. Preferred over operation. In the latter case, it is necessary to recognize different dynamic ranges for both control and energy.

The modulator is polarization sensitive, but this is not critical if it can be located close to the source laser that provides the polarized output. If it is desired to be insensitive to polarization, two resonators such as silica microspheres may be arranged at positions orthogonal to the central axis of the optical fiber. The geometry of the resonator itself and the materials used can be varied as long as the desired Q factor and resonator mode frequency spacing are maintained. In particular, oblate spheres, rings, disks, ellipses, ellipses, rings and polygons are known and can be used for this purpose.

To utilize the concept of simultaneously modulating signals of different wavelengths multiplexed on the same optical fiber, a series of resonators / losses along one narrowed portion of the optical fiber or each separate taper portion is used. All that is required is to arrange the combination of controllers. Each resonator responds only to its own selected wavelengths, which are modulated separately with minimal crosstalk. It is also possible to perform optical pumping in the same or opposite directions with an in-fiber laser source such as a DFB fiber laser. Integrating a number of resonator modulators into a wavelength division multiplexing system results in a wavelength addressable propagation system.

As described above, in order to simultaneously modulate wavelengths that are simultaneously propagated and to modulate one wavelength that is simultaneously propagated together with other wavelengths by specifying the wavelength, it is necessary to arrange between adjacent resonators. Maintaining proper frequency spacing prevents unintended interference.
In addition, the spacing between adjacent mode frequencies of a resonator that supports multiple modes at different frequencies is such that it exceeds the total bandwidth of the frequency range of interest, such as the total bandwidth determined by the number of WDM channels on the optical waveguide. To be selected. The resonator geometry can be determined to meet these requirements.

[0020]

[Detailed Description of Examples]

1 and 2, the lightwave energy modulator of the present invention receives lightwave energy of a single frequency from a light source 10 such as a semiconductor laser. Since the dielectric microcavity resonator, which is the device of this example, is sensitive to polarization, the polarization characteristics of the light wave can be determined by arranging the device relatively close to the laser 10 or between the light source 10 and the dielectric microcavity. Is maintained by using a polarization maintaining fiber. To this end, a fiber optic waveguide 12 of conventional diameter, such as about 92-125 microns, is used.
The short length portion of the includes a very small diameter integral waisted region 14, typically 1-10 microns. The constricted region 14 is a transition from the optical fiber 12 at both ends thereof via the tapered portions 15 and 16 which are integrally converged and flared. The exit length portion of the normally sized optical fiber 18 carries the modulated signal.

A high Q cavity modulator 20 operating as a WGM device in the waisted region 14 of the waveguide is either in contact with the surface of the small waisted region 14 or spaced from it by a distance on the order of a few microns. It is arranged. The diameter of the high Q resonator 20 is sized and shaped to have at least one resonant mode at the selected signal frequency. Other resonant modes exist in the resonator 20, but have no effect on the different single frequency signals. If the incident light wave contains more than one frequency, the resonator remains transparent to all frequencies other than the selected frequency as long as the modes are far from the frequency of the light wave.
As an example, assuming a communication signal wavelength of 1550 nanometers is selected, the diameter of the silica microsphere, the dielectric resonator 20 of this example, is in the range of about 1-100 microns. WGM resonators with very low losses and thus very high Q are provided, which is a disadvantage for use with moderate spectral linewidths and high data rates. Although fiber optic systems face other problems such as group velocity dispersion at very high data rates, system builders are constantly motivated to improve data rate performance. Therefore, at the velocities currently used of about 2.5 to 10 Gbit / sec, the linewidth of WGM resonators needs to be widened to enable these velocities. Illustratively, the resonator 20 has a diameter of 30 microns to obtain a data rate in the range of 1 to 10 Gbit / sec for a 1550 nanometer signal. In general, the spectral width of the WGM mode should be greater than or equal to twice the desired information bandwidth. The spectrum width of the measured propagation energy (WGM line width of the resonator) has the following relationship with the index of merit of the resonator, that is, Q.

Q = υ ₀ / Δυ Expression (1) In the above expression, Δυ is the half width in the maximum half, and υ ₀ is the WGM center line frequency. For a WGM resonator with a typical communication wavelength of 1550 nanometers and a data rate of 10 gigabits per second (5 GHz bandwidth in NRZ format), the required optical bandwidth is about 10 GHz and Q is 19000. Or less. Laboratory experimental data has shown that diameters of 30 microns or less can, by chance, achieve the required properties because of the high degree of compactness and density that can be achieved. Reduce the round-trip propagation time in the resonator (ie reduce the size of the resonator) or increase the resonator-waveguide coupling loss to match the preferred mode of operation in the range of over-coupling to critical coupling. By doing so, it is necessary to reduce Q and thus increase the spectral linewidth. The coupling loss either increases the spatial overlap of the resonator mode with the electric field outside the constricted portion of the optical fiber, or improves the phase matching condition between the resonator mode and the Taper mode, or their Both can increase.

To stabilize the position, the microspheres 20 in this example directly adhere to the constricted area 14 of the optical fiber. A tightly juxtaposed controllable loss converter 22 on the side of the silica microsphere 20 opposite the constricted portion 14 controls the absorption of light wave energy circulating in and around the resonator 20 and makes one round trip. It is driven by the modulation signal source 24 in order to add the loss coefficient for each. If the control signal is an analog signal between limits, the energy signal propagating in the waveguide is modulated. If the loss control varies between the maximum propagation state and zero, the unit acts as an on / off switch or digital modulator.

The taper portions 15, 16 of the waveguide and the constricted portion 14 therebetween are, as is well known, optical fibers provided by one or more fixed or movable heat sources (eg, torches). It can be formed by stretching with softness and controllable tension. At the manufacturing site, commercially available machines can be used for this purpose. As the diameter decreases on the order of about 1 or more, the size and function of the central core of the optical fiber's core / cladding structure is markedly reduced, and the core can no longer carry most lightwave energy. Instead, the light wave energy within the full diameter portion of the optical fiber migrates to the waisted region without significant loss, where the energy is contained within the diameter-reducing cladding material, as shown fragmentarily in FIG. And is confined in the electric field generated around it. After propagating through the waisted region 14, the external lightwave energy is again thinned in the diverging taper region 16 and propagates in the exit fiber section 18 with low loss.

The silica microspheres forming the high-Q resonator 20 of this example are coupled with the energy guided outwardly around the waisted region 14 of the waveguide. That is, as shown in FIG. 4, there is always a binding interaction from the main optical fiber to the inside of the microsphere. The resonator 20 additionally recycles energy with low loss by the whispering gallery mode, returning some of that energy to the constricted portion 14 of the waveguide. With each round trip, a coupling is made to the controllable loss converter 22. When resonance is present at the selected wavelength, the resonator 20 internally undergoes total internal reflection with minimal internal attenuation and radiation loss. However, the emitting portion of the lightwave energy is still confined and is coupled back into the waisted region 14 of the waveguide. This whispering gallery mode, which appears to have been first explained by Rayleigh in the 1912 paper "The Problem of the Whispering Gallery", has extremely high Q values (8 billion values have been observed).
Since then, this phenomenon has been theoretically (ML Gorodetsky, et al., In Optics Lette
rs 21, 453, 1996), and in various practical examples, as shown in the aforementioned McCall and Ho patents. Various WGM devices, including disc, ring, polygonal, oblate, and oblate shapes have been described and studied in the technical literature. Furthermore, since the WGM effect exists in non-concentric boundary structures such as elliptical or racetrack structures, concentricity or near concentricity is not needed in some cases.

The controllable loss device 22 can be made with a controllable electrically or optically variable light absorber. The quantum well structure having controllable photon absorption characteristics includes a transducer 22 and an active material (for example, InGaAs-22 ′) arranged on or near a part of the circumferential surface of the microsphere 20, and a buffer. Layer (InGaAsP-22
)) And the photon absorption can be changed within a range controlled by an electric signal, which is particularly preferable. Such a structure is suitable for the above-mentioned McCall and H.
It is described in detail in both patents.

Other available methods of substantially absorbing light waves are, for example, semiconductor materials having a bandgap that is (1) greater than the signal wave photon energy or (2) less than the signal photon energy. Is the method to use. In either case, as shown in FIG. 7, the semiconductor can be deposited as a layer 30 over a portion of the resonator 32 or placed in the vicinity of the resonator, and a semiconductor light source such as a laser 36 can be used. Irradiate. In the former example, carriers are generated in the semiconductor layer 30 by optical pumping from the laser 36, free carriers of light waves are absorbed, and the resonator shifts from an excessive coupling state to a critical coupling state (assuming a preferable operation mode). Transitions and reduce propagation through the modulator. The modulation rate is determined by the carrier lifetime, but this parameter can be shortened by introducing defects in the semiconductor.

In the latter case, the carriers generated by the optical pumping from laser 36 reduce the optical absorption by filling the band. In this case, the modulator characteristics are designed to give the maximum absorptance (critical coupling) in the absence of optical pumping, which means that the device has the maximum absorptivity designed into it during manufacture. It is advantageous because Therefore, the coupling relationship of the lightwave energy becomes over-coupled when optical pumping is applied, increasing the output propagation. As described above, the modulation rate depends on the carrier lifetime.

In both of these examples, electrical excitation rather than optical excitation can generate carriers in the semiconductor and cause modulation (or switching).

Another effect of using the semiconductor layer 40 on or near the resonator 42 can be understood with reference to FIG. Here, a resonator 42 is interposed between small parallel plate capacitors 44, and a variable electric field that can be modulated at high speed is applied to the semiconductor layer. In this example, the energy gap is chosen to be close to, but slightly larger than, the photon energy of the signal. The resonator is initially overcoupled and therefore the propagation of lightwave energy in the optical waveguide 46 is maximal. To increase the absorption, an electric field is applied to the semiconductor layer 40 through the capacitor 44, and the Franz-Keltish effect increases the light wave absorption in the resonator 42 to bring the resonator into a critically coupled state. As a result, the propagation from the optical waveguide 46 to the resonator 42 is reduced, and it can be used for modulation (or switching) of energy in the optical waveguide 46.

The loss can be changed by using a resonator made of a variable loss material, changing the relative positions of the resonator and the optical fiber, or transferring the energy from the resonator to another structure such as a second waveguide. This can be accomplished by other methods including utilizing coupling elements. In the case of coupling to the second waveguide, the coupling loss can be obtained by changing the phase-matching state to the second waveguide, for example, by using an electro-optical material,
It could be changed. The relatively gradual changes achievable by mechanical devices or temperature changes are perfectly acceptable as loss control elements in some applications.

FIG. 9 shows a combination of a common resonator 50 and two optical waveguides. The narrowed portions 52, 53 and two fiber optic waveguides 55, 56 are shown, but the input source and output circuits (not shown) utilize the bidirectionality of the waveguides 55, 56 and the resonator 50. Is configurable. Both the waveguides 55 and 56 are connected to the control source 5 as described above.
It is coupled to the resonator 50 as well as the loss converter 58 which is changed to the critical coupling range by 9. This coupling couples the constricted portions 52, 53 to essentially the same mode of resonator 52, thereby allowing the transfer of resonant energy from one waveguide to the other under the control of loss converter 58. It will be possible. This coupling is symmetrical about the two waisted portions 52, 53, and if the coupling loss between the associated resonator and the waveguide is greater than the other losses of the resonator, then the resonator 50 is critically coupled to each waveguide. The state becomes possible, and almost complete transfer of energy from one waveguide to the other waveguide becomes possible at the time of resonance. In this energy transfer, the loss of the resonator is the loss converter 5
If substantially increased by 8, it will be compromised and the resonator 50 will be undercoupled. In this case, the transfer of energy is interrupted and resonant energy is sent to the respective waveguide 55, 56 at the constricted portion 52 or 53 at a transmissivity of approximately 1. In this way, the device acts as a wavelength-addressable 2 × 2 switch that can control the destination of the signal. In either case, the wavelength-multiplexed signal that is out of resonance with the mode of the resonator 50 transparently passes from the incident side to the emitting side. This 2 × 2 loss conversion element is essentially the same as that described for the modulator (1 × 1 type switch) except that the 2 × 2 type switch nominally operates from critical coupling to under coupling. Is. Other design factors regarding bandwidth, modal frequency spacing and modulator structure are the same as for the modulator.

The coupling and control principles of the present invention are substantially and clearly different from previous research and literature on WGM devices. From these, it is known that there is a slight coupling between the light beam incident on the prism and the light beam internally reflected from one surface at the point where the WGM microsphere is located outside. This prism subtly couples some of its lightwave energy into the recirculation passages within the microsphere when its frequency falls within one of the resonant modes of the microsphere. It is also known that the incident light wave is sent out in a state where the energy is not essentially reduced except for the minimum point within the resonance range. As disclosed, a similar effect exists for a combination of a tapered fiber optic waveguide and an adjacent dielectric WGM resonator.

However, in order to be able to take advantage of the recirculation resonance modes and coupling effects, it is necessary to understand a number of control conditions and use them appropriately. Whether it is modulation or switching, varying the propagating energy output between substantially perfect and near-zero propagating states requires understanding and controlling a number of parameters, including the source of the resonator loss. . There are many distinct sources of loss experienced by circulating light waves, including: (1) Loss associated with the portion of the WGM electric field that is internally reverse coupled from the microsphere to the taper portion. (2) Distribution loss associated with the unique properties of the microspheres such as optical absorption, surface defects and surface contamination of the microsphere material. However, with careful material selection and processing, pure silica microspheres or disks with smooth surfaces can be prepared with very low distribution loss. (3) Parasitic losses, such as due to unintentional coupling of lightwave energy into modes that are not returned to the optical waveguide, eg radiative modes. Observations have shown that the loss is very low if the proper conditions for binding are observed. (4) Losses intentionally introduced into the microspheres (not associated with coupling to the taper portion of the waveguide) to provide modulation or switching.

When the only source of loss is the coupling loss [(1) above], 100% of incident energy is propagated and emitted according to the law of energy conservation. According to past research and development and practical results, the non-coupling loss [(2) and (3) above] can be made small. Therefore, the following analytical model shown in the graph of FIG. It can be neglected based on the following coupled linear equations of complex electric field amplitudes using the quantities shown.

4-port scattering equation E _st = κE _i + t′E _si formula (2) E _t = κ′E _si + tE _i formula (3) Round-trip propagation state in a sphere E _si = E _st αe ^iθ , where θ = ΚC Equation (4) In Equation (4), α gives the resonator attenuation of the amplitude of each round trip associated with one round trip propagation in the sphere, θ is the phase associated with that propagation, and κ is It is the propagation constant of the excitation mode, and C is the circumference of the sphere. Further, in the equation (4), κ and κ ′ are amplitude coupling coefficients from the waveguide to the resonator or vice versa, and are different depending on device parameters including electric field overlap between the resonator and the waveguide and phase matching. , T, t ′ are the 4-port propagation amplitudes on the waveguide side and the resonator side (not to be confused with the propagation of the modulator). This model makes it possible to calculate the maximum value of propagation attenuation as a function of loss from unspecified sources other than the loss factors inherent in the microsphere / waveguide system. The curve shown in FIG. 5 shows the calculation results assuming the numerical values of the model's coefficients that match the Q measurements in the test of the tapered fiber optic-microsphere system. These values are exemplary only. The horizontal axis gives the amplitude attenuation per round trip, α generated by unspecified loss (α = 1 corresponds to the case where there is no additional loss). At α = 1, the transmissivity of the resonant lightwave energy is 1.

The additional loss-introducing effect shown in FIG. 5, in which the coupling loss increases to the left of the horizontal axis, increases the attenuation until the propagation energy becomes zero. In this respect, the additional loss per round trip is the only reason for the overall loss reduction in this model, and in the example used in FIG. 5, α is approximately 0.9997. In such a state, known as "critical coupling" in microwave theory, only a small loss needs to be added to cause a large change in the propagation energy of the waveguide. By changing the state of the recirculation type resonator in this way, the basis of the embodiment of the present invention can be obtained. In addition, the resonant modes provide accurate frequency selectivity.

The calculation results of the model shown by the curve in FIG. 5 are completely confirmed by the experimental measurement values of the optical fiber / microsphere resonator with a taper as shown in FIG. These measurements are placed at a variable position adjacent the microsphere to controllably increase the coupling loss introduced by the constriction of an optical fiber about 3 microns in diameter, the microsphere about 300 microns in diameter. And a movable microprobe. Due to the nature of the study, the horizontal axis is related to linewidth rather than α and the curves are reversed, but evidence of critical coupling is clear. Importantly, there is a critical coupling with a very small deviation of α, and the observed total loss at α = 1.000 is small. This is also significant in other respects, as it shows that the measured distribution loss and parasitic loss of the structure are also lower than the coupling loss from the tapered fiber to the microspheres. Thus, if one does not intentionally add loss, an "over-bond" condition naturally exists. This experiment further experimentally shows that the properties of the model for adding coupling loss are reliable.

As described above, the operation of the optical modulator or the switch using the microresonator can be confirmed in the presence of the under-coupling state, but the attenuation value is greatly widened, and the low dynamic range is likely to occur. Will need energy. However, modulation from the critical coupling portion to the over-coupling region is preferred because it requires less attenuation and allows the loss-controlled converter or device to be of very small size and minimal effect on the converter mode. . In addition, energy consumption is minimized in this mode of operation. Depending on whether the attenuator is non-absorptive or absorptive in the absence of the control signal, the modulator or switch will be inverting or non-inverting, respectively.

Another approach to modulation / switching (mode 5 of operation outlined) is to reduce the optical path length of the dielectric resonator itself under constant resonator loss and coupling conditions necessary to obtain critical coupling. It is realized by changing. With reference to Figures 11 and 12, this effect changes the propagation loss of the waveguide by shifting the resonant frequency of the resonator 60 towards or away from the propagating lightwave energy frequency. In the illustrated example, the surface of the resonator 60 is coated with a polymeric material 62 that changes its index of refraction in response to the electric field applied by the associated electrode pair 64,65. The electric field is controlled by the signal source 66 to change the refractive index of the coating 62, which shifts the resonant frequency of the resonator 60. As a result, as shown in FIG. 11, the given optical frequency from the laser light source stays at a constant value, but the WGM line center frequency that gives the maximum resonance shifts, and the light wave that changes depending on the degree of shift has a certain degree. Be absorbed. In this example, the resonator 60 is designed so that complete absorption occurs when ν _L and ν _o completely match (critical coupling), as shown in FIG.

The WGM resonant frequency can be modulated by other methods as well. For example,
The resonator material can be optically or electrically excited to change the refractive index. If the modulation rate is very slow, it is possible to take advantage of temperature changes.

Microlithography fabrication techniques based on a number of different principles, suitable for the fabrication of optical waveguides and microcavities, are currently available. As shown in the McCall and Ho patents noted above, the electro-optical WGM structure using layered materials forms a controllable electro-optical device with variable absorption (or gain) characteristics. As can be seen from FIG. 13, a thin planar waveguide 70 whose waveguide characteristic is comparable to that of an optical fiber with a taper is
Similarly, it is formed in a slight coupling relationship with the edge portion of the WGM disk 74 formed on the substrate 72. The loss control element responsive to electrical signals or optical pumping is also the substrate 7
It can be provided adjacent to the disc 74 on the two. Alternatively, disk 7
The dielectric constant of 4 may be varied to change the resonant mode of disk 74, as described above. To this end, a region 76 of the substrate 72 is provided below and in contact with the disk 74 to shift the dielectric constant on the disk 74 in response to a control source 78 of a modulating or switching signal. Although it is possible to manufacture microlithographic devices with high reliability on a production basis, by accurately arranging a large number of devices, it is possible to satisfy the mounting conditions of a complicated DWDM system. Since they can be serially coupled onto the substrate, a substantial number of couplings to the propagating optical fiber are unnecessary.

There are many system configurations that require multiple frequencies to be separately modulated or switched, and combinations of tapered constrictions 80 of a single optical fiber 82 and multiple modulators as shown in FIG. Each modulator / resonator 84a, 84b, 84c,
84d resonates at different frequencies corresponding to one of the WDM signals on optical fiber 82 and is spaced apart along the waist 80. Each modulator / resonator 8
4a-84d are separately modulated (or switched on / off) by different loss control means 86a-86d, and the system changes the WDM components separately, but so as not to interfere with each other. It will be appreciated that sharing these constricted areas is not a requirement and can be located at different locations along the length of the fiber optic propagation line. In the example of Figure 15, the same concept is extended to the system using the two tapered waveguides of Figure 9. The constricted portions 52 ', 53' of the two spaced waveguides are different modulator / resonators 84a'-84, respectively.
Greater flexibility in system design is also obtained for d'and because they can interact with each other as described above.

The concept of WDM utilization just described is the use of an active device, such as a tandem fiber optic laser (eg DFB fiber laser), in series with a number of resonators / modulators for all fiber type multimodulation of modulator and light source. It can be extended to form a wavelength system. Referring to FIG. 16, each includes a controlled microcavity modulator 90,
Selected wavelengths λ ₁ , λ ₂ , λ ₃ . ． ． Fibers having tapered portions (not shown) responsive to λ _n-1 , λ _n are interleaved with fiber optic DFB lasers 94 operating at similar wavelengths. This forms a wavelength division multiplexed signal source having N channels. If N is not too large, then a single opto-pumping diode 94 can be used to pump the laser 94 in the opposite direction (or in the same direction) as shown. The modulators and fiber lasers are interleaved as shown, but they may be placed in a series set as they do not generate interfering signals in any case.

WGM resonators resonate at a number of frequencies, and the spacing between those frequencies is, in part,
It depends on the requirements of any associated multi-frequency system. Therefore, the frequency spacing between the resonators should be large enough so that the light waves that are propagated with the modulated light wave do not undergo unintended modulation. In WDM systems, this spacing must cover the bandwidth of all channels on the optical waveguide. For example, in a WDM system with 16 channels having a channel spacing of 100 GHz, the resonator / modulator should have a modal frequency spacing over a bandwidth of approximately 1.5 THz. As the number of light waves co-propagating on the WDM waveguide increases, the interval between modal frequencies inevitably increases. Such issues affect the choice of resonator as well as the microcavity geometry. For example, to satisfy such a spacing condition,
Disk and ring shapes are preferred over microspheres.

The value of a fully in-line multiplexing system will be apparent to those skilled in the art.
Given the frequency selectivity of modulators coupled with their transparency to all other signals and assuming that all components are on the order of microns in size, all conditions of simplicity, no mismatch and compactness are required. Are satisfied at the same time.

The propagating function of WGM microcavity is polarization dependent because it needs to be oriented around the equator of the microcavity for electromagnetic mode recycling. This is usually not a problem because it can be placed in a suitable relationship near the laser source that produces the polarized lightwave with the resonator as output. In systems where this is not possible, or where other factors affect the polarization, a configuration such as that shown in FIG. 17 can be used. The above-described tapered optical fiber 100 having a narrow constricted region cooperates with two resonators 102 and 103, which are microspheres here, which are arranged so as to be orthogonal to each other with the optical fiber 100 as the center. The resonators are properly oriented and work with different loss transducers 104, 105 that are subject to changes by the loss controller 108. In some cases, separate loss controllers are used. Regardless of the vector direction of polarization or any state, this configuration modulates or switches lightwave energy as in the previous example.

It will be appreciated that a substantial number of other methods are possible since frequency selective energy control is possible according to the concepts of the present invention. For example, if the incident light wave energy itself is modulated, the transfer of energy in the resonator can be translated into a function as a detector. This means that the incident light wave in the WDM signal can be selectively converted into an electric signal without introducing discontinuity in the light propagation line.

It will be appreciated that it is also possible to change the critical coupling in the modulator by optical gain (negative loss) rather than loss (see summary section).

Although various embodiments and modifications have been described above, it is obvious that the present invention is not limited to them and includes all modifications and design changes included in the claims of the initial document. Ah

[Brief description of drawings]

FIG. 1 is a simplified block diagram of an all-fiber lightwave energy control device according to the present invention.

2 is a fragmentary and idealized view of a controllable loss element, an optical fiber with a taper, and a microsphere that can be used in the configuration of FIG. 1;

FIG. 3 is a simplified cross-sectional view of a light absorbing means that can be used as a loss element of the converter of FIG.

FIG. 4 is a fragmentary diagram showing the interaction between the electric fields of electromagnetic energy in the example of FIGS. 1 and 2.

FIG. 5 is a graph showing the relationship between the propagation through the waveguide and the calculated value of the attenuation of the resonator amplitude for each round trip (an index of the round trip loss of the resonator).

FIG. 6 is a graph showing the propagation value with respect to the mode line width obtained in the experiment, which confirms the calculated value of FIG.

[Figure 7]   FIG. 7 is a diagram showing a first configuration for controlling the resonator loss.

[Figure 8]   FIG. 8 is a diagram showing a second embodiment for controlling the resonator loss.

FIG. 9 shows a variant in which two optical waveguides interact with and interact with a single resonator.

FIG. 10 is a schematic diagram showing phase amplitude and coupling coefficient for modeling a control system using a resonator.

FIG. 11 shows a simplified system for varying waveguide propagation by shifting the resonant mode frequency.

FIG. 12 is a graph showing a relationship between attenuation due to propagation and shift of a center frequency of a resonator mode.

FIG. 13 is a fragmentary perspective view of a modulator of the present invention using a planar waveguide and a disk resonator.

FIG. 14   FIG. 14 is an example showing a number of modulators that can be used with a common light guide.

FIG. 15   FIG. 15 shows a system in which two waveguides and multiple resonators interact.

FIG. 16   FIG. 16 shows an example of an all-fiber light source / modulator system.

FIG. 17 is a general example showing an optical modulator or switch that is polarization insensitive.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02F 1/015 505 G02F 1/03 505 5F073 1/017 505 1/313 1/03 505 1/35 1 / 313 H01S 3/10 A 1/35 5/50 630 H01S 3/10 G02B 6/12 A 5/50 630 J (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, K E, LS, MW, SD, SL, SZ, TZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, M), AE, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK , MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU, ZA, ZW (72) Inventor Yarib, Amon United States California 91108 San Marino Homet Road 2257 F Term (reference) 2H047 KA01 KA13 KB05 LA14 MA07 NA02 NA04 NA08 QA07 RA08 2H050 AC81 AC90 2H079 AA02 AA06 AA12 AA13 AA14 DA07 DA16 DA17 EA01 EA07 EA09 EB04 EB27 GA0 6 KA20 2K002 AA02 AB04 BA01 BA06 BA13 CA02 CA06 CA13 DA06 DA10 DA20 EA06 HA03 HA05 HA11 HA17 HA28 5F072 AK06 HH06 KK07 MM01 5F073 AB25 AB28 BA01 EA12

Claims (153)

[Claims] 1. A light wave energy control device for changing energy of at least one light frequency (that is, light wave carrier) propagated on a light wave energy propagation member, wherein the light energy of at least one light frequency of the propagation member is A light wave energy propagation member configured to propagate in a spatial mode extending outward from the circumferential surface, and to receive light wave energy from the propagation member and to give it to the propagation member,
At least one whispering gallery mode lightwave resonator arranged in a coupling relation with the spatial mode of the lightwave energy propagation member, and each of which is in an operative relationship with at least one different resonator, and propagated through the lightwave energy propagation member A lightwave energy control device comprising at least one control means for changing the round-trip loss of each resonator such that the level of lightwave energy is changed. 2. The lightwave energy control device of claim 1, wherein the control means is coupled to the resonator and absorbs lightwave energy from the resonator. 3. The light wave of the light wave energy control device according to claim 2, wherein the resonator and the propagation member have a loss introduced so that the resonator is in an excessively coupled state, and the loss introduced by the control means achieves critical coupling. Energy control device. 4. The lightwave energy control device according to claim 1, wherein the loss per reciprocation of the recirculation mode at the resonance frequency is maintained in the critical coupling region. 5. The resonator comprises a member having a diameter of less than about 1000 microns and having a substantially equatorial peripheral surface disposed with respect to the light wave energy propagating energy member, and coupled to the light wave energy of the carrier member to cause the resonance mode to equatorially. The lightwave energy control device according to claim 1, which is circulated in 6. The lightwave energy control device of claim 5, wherein the resonator has a Q selected according to the desired wavelength and bandwidth of the modified propagation member. 7. The light wave energy control device according to claim 5, wherein the frequency interval of the resonance mode is selected according to the spread of the spectrum over the frequencies propagating through the carrier member. 8. The lightwave energy control device of claim 7, wherein the cavity mode frequency spacing is greater than 200 GHz. 9. The lightwave energy controller of claim 6 wherein the resonator has a peripheral surface diameter less than about 100 microns and has a Q on the order of 20,000 in the 1550 nanometer communication band. 10. The lightwave energy control device according to claim 1, wherein the propagation member is a planar waveguide, and the resonator is a disk, a ring, or a closed loop. 11. The propagation member is an optical fiber having a thin length portion, and the resonator is a microsphere closely aligned with the thin length portion of the optical fiber.
Lightwave energy control device. 12. The propagating member is an optical fiber having a thin length and the resonator is selected from the group consisting of a disk, a ring and an aspheric surface in close juxtaposition with the thin length of the optical fiber. 1. Light wave energy control device. 13. The lightwave energy control device of claim 1, comprising a modulator responsive to a given optical frequency. 14. The lightwave energy control device of claim 1 comprising a switch responsive to a given optical frequency. 15. The lightwave energy control of claim 1 wherein at least one control means comprises a semiconductor device in close proximity with the resonator and variably absorbing lightwave energy circulating in the resonator in response to a control signal. apparatus. 16. The lightwave energy of claim 15, wherein the semiconductor device comprises a multi-layer photonic device of at least one layer of quantum well material that changes absorption characteristics in response to an applied signal and is insulated by a barrier layer. Control device. 17. The lightwave energy control device of claim 1, wherein the at least one control element comprises a semiconductor in contact with or adjacent to the resonator, and means for irradiating the semiconductor to change absorption and loss. 18. The lightwave energy of claim 1, wherein the at least one control means comprises a semiconductor in contact with or adjacent to the resonator and means for applying a controllable electric field to the semiconductor to change the optical properties. Control device. 19. The control means for changing the energy coupled to the resonator comprises:
2. The lightwave energy control device according to claim 1, comprising means for modulating propagation energy by changing the refractive index of the resonator to shift the frequency of the resonance mode of the resonator. 20. The light wave energy control device according to claim 19, wherein the means for changing the refractive index comprises an optical nonlinear means for the resonator and a means for irradiating the resonator to change the refractive index of the resonator. 21. The means for changing the refractive index comprises a material on the resonator whose refractive index changes with an electric field, and a refractive electric field of the resonator and a resonance mode frequency of the resonator by applying a variable electric field to the material. 20. The lightwave energy control device of claim 19 including means for varying. 22. The lightwave energy controller of claim 1 wherein the propagating lightwave energy is modulated with data at a selected data rate by monotonically varying the propagation energy between limits. 23. The lightwave energy control device according to claim 22, wherein the frequency interval between the modulation modes is selected according to the spread of the spectrum over the frequencies propagating in the propagating member. 24. The lightwave energy controller of claim 22, wherein the Q of the resonator is determined by a level determined by the wavelength of the modulating signal and the data rate / signal bandwidth. 25. The resonator is 20 in the communication band of 1550 nanometers.
23. The lightwave energy controller of claim 22 having a Q on the order of 000, the resonator having a diameter of less than 100 microns, and the modulating signal having a data rate on the order of 10 gigabits per second. 26. A light wave energy propagation member propagates a number of different frequencies, each of which resonates at a different propagation frequency, and a plurality of resonators coupled to the light wave energy propagation member, and a plurality of resonators each of which is different from each other. 2. The lightwave energy control device according to claim 1, further comprising a plurality of control means which are arranged opposite to each other to control the round-trip loss of the resonator to change the propagation energy of the selected frequency. 27. The light wave energy propagating means comprises an optical fiber waveguide having a coupling length portion having a small diameter so that a part of the light wave energy is propagated to the outside of the surface of the optical fiber, and a resonance of a propagation frequency different from each other. 27. The lightwave energy control device of claim 26, comprising a plurality of resonators having modes and arranged along a coupling length portion in a coupling relationship with a propagating member. 28. The optical energy propagation member comprises a planar waveguide having a coupling length portion having a small diameter so that a part of the light wave energy is propagated to the outside of the surface of the waveguide, and a waveguide having a propagation frequency different from each other. 3. A plurality of resonators having one resonance mode and arranged along a coupling length portion in a coupling relationship with a propagating member.
6. Light wave energy control device. 29. The control means alters the loss introduced between the substantially full propagation state and the substantially zero propagation state such that at least one optical frequency is switched on and off. 1. Light wave energy control device. 30. The light wave energy propagation member has a large number of resonators that propagate a large number of different frequencies in a wavelength division multiplexing mode, each resonator resonating at a different frequency,
2. The lightwave energy control device of claim 1, wherein the control means selectively switches (i.e., blocks or allows) frequencies in the multiplexed signal by varying the propagation of energy in each resonator. 31. A plurality of resonators and associated control means are arranged in-line with a lightwave energy propagating member, each resonator and associated control means operating at a different optical frequency within a set of optical frequencies. A plurality of laser light sources having a modulator and propagating the different frequencies of the set in a downstream direction on the propagating member in an in-line relationship with the optical energy propagating member, the modulator for each given frequency The lightwave energy control device according to claim 1, which is downstream of the laser light source of the frequency. 32. The lightwave energy control device according to claim 31, wherein the laser and the modulator are alternately arranged on the propagation member. 33. The lightwave energy control device of claim 31, wherein the light propagating member comprises an optical fiber waveguide and the laser comprises a fiber laser such as a fiber DFB laser. 34. The lightwave energy control device of claim 33, further comprising optical pumping means for the laser coupled to the propagation member. 34. The lightwave energy control device of claim 33, further comprising optical pumping means for the laser coupled to the propagation member. 35. The light wave energy propagating member comprises a single optical waveguide having a predetermined length with an electric field distributed to the outside, wherein at least one resonator responds to different frequencies, respectively, and extends along the predetermined length portion. 2. The lightwave energy control system of claim 1 comprising a plurality of resonators arranged in a plurality, the control means comprising a plurality of control means for varying round trip loss, each control means operable with a different resonator. 36. The lightwave energy control device according to claim 1, further comprising a second lightwave energy propagation member having a coupling relationship with the resonator. 37. The light wave energy propagation member is an optical fiber having a tapered region each having a narrow constricted portion in coupling relation with the resonator, and the resonator is composed of a microsphere, an oblate surface, a disk or a ring. Item 36. The lightwave energy control device of item 36. 38. The light wave energy propagating member is a planar optical waveguide having a taper region having a narrow constricted portion each of which has a coupling relationship with the resonator, and the resonator is a microsphere, an oblate surface, a disk or a ring. 37. The lightwave energy control device of claim 36, comprising: 39. Two propagating members are coupled to substantially the same resonant mode, and the round trip loss of the resonator associated with the resonator-propagating member coupling is approximately between these resonator modes and each propagating member. 37. The lightwave energy control device according to claim 36, wherein a critical coupling state is generated. 40. The lightwave energy controller of claim 39 including means for varying loss by varying absorption of resonant modes. 41. The lightwave energy control device according to claim 39, wherein the means for changing the absorption comprises a semiconductor which is changed by applying an electric field or a voltage. 42. The lightwave energy control device of claim 39, wherein the means for changing absorption comprises a semiconductor that is changed by optical pumping. 43. The lightwave energy control device of claim 39 wherein the means for changing absorption comprises a semiconductor that is changed by the injection current. 44. The lightwave energy control device of claim 39, wherein the means for changing absorption comprises a quantum well semiconductor structure that is changed by applying an electric field or voltage. 45. The lightwave energy control device of claim 39, wherein the means for varying absorption comprises a quantum well semiconductor structure modified by optical pumping of the semiconductor. 46. The lightwave energy control device of claim 39, wherein the means for varying absorption comprises a quantum well semiconductor structure modified by an injection current. 47. The lightwave energy control device of claim 1 including a second member associated with the resonator, wherein the means for changing the energy level comprises means for changing the coupling of resonant mode energy to the second member. . 48. The lightwave energy control device according to claim 47, wherein the second member is a waveguide, and the means for changing the coupling of energy includes means for changing the phase matching of the waveguide with respect to the resonance mode. 49. The lightwave energy control device of claim 47, wherein the waveguide is made of an electro-optic material and the phase matching is changed by applying a voltage to the waveguide. 50. The lightwave energy control device of claim 47, wherein the waveguide comprises an optically non-linear material and the phase matching is altered by optical means. 51. At least one control means comprises means for changing a characteristic that is a component of a resonator's round trip loss associated with coupling from the resonator to a propagating member, the other source of the resonator's round trip loss. 48. The lightwave energy control device of claim 47, wherein is substantially constant. 52. The lightwave energy control device of claim 51, wherein the loss is varied by varying the amplitude coupled from the resonator to the propagating member. 53. The lightwave energy control device of claim 52, wherein the combined amplitude is varied by electro-optical means. 54. The combined amplitude of claim 52, wherein the combined amplitude is varied by optical means.
Lightwave energy control device. 55. The lightwave energy controller of claim 51 including means for varying the optical path length of at least one resonant mode. 56. The lightwave energy control device according to claim 55, wherein the means for changing the optical path length comprises means for changing the dielectric constant of the medium forming the resonator. 57. The lightwave energy control device according to claim 56, wherein the means for changing the dielectric constant comprises means for applying an electric field. 58. The light wave energy control device according to claim 55, wherein the means for changing the dielectric constant is a means for applying a light wave. 59. The lightwave energy control device according to claim 55, wherein the means for changing the dielectric constant comprises means for passing an electric current. 60. The lightwave energy control device of claim 55, wherein the means for changing the dielectric constant comprises thermal means associated with the resonator. 61. The lightwave energy control device of claim 51, comprising means for varying the negative round trip loss (optical gain) component of the resonator separate from the resonator loss associated with coupling to the propagation member. 62. The lightwave energy control device of claim 61, wherein the resonator comprises means for providing optical gain. 63. The lightwave energy control device of claim 61, wherein the optical gain causes overcoupling. 64. The lightwave energy control device of claim 47, wherein the loss associated with the control means causes undercoupling. 65. The lightwave energy control device of claim 1, wherein the at least one resonator includes at least two resonators, each resonator resonating at the same frequency and arranged in different quadrants around the length of the lightwave propagation means. .. 66. The propagating light wave is arbitrary polarized light, the resonator has an equatorial plane through which the WGM modes circulate, the equatorial planes are in mutually orthogonal planes, and the light wave energy propagating member is an optical fiber with a taper. 66. The lightwave energy control device according to claim 65. 67. A light energy control device, wherein a continuous length portion of the light wave energy propagation member, in which a slight electric field of the light wave extends to the outside, and a circumferential surface within the slight electric field of the propagation member. And at least one high-Q lightwave recirculation means for exchanging lightwave energy with the propagating member, and lightwave energy returned from the resonator to the lightwave energy propagating member in cooperation with the at least one lightwave recirculation means. A lightwave energy control device comprising: a lightwave control means for changing. 68. The recirculation means is a whispering gallery mode device, which is one member of the group of lightwave energy resonators consisting of spheres, disks, rings, ellipses, ellipses and polygons. 68. The lightwave energy control device of claim 67, wherein the energy transmitting member is included in the group consisting of optical fiber waveguides. 69. The recirculation means is a whispering gallery mode device, which is one member of the group of lightwave energy resonators consisting of spheres, disks, rings, ellipses, ellipses and polygons. 68. The lightwave energy control device of claim 67, wherein the energy transmitting member is included in the group consisting of optical fiber waveguides. 70. The lightwave energy control device according to claim 67, wherein the lightwave energy control means changes the lightwave energy returned from the recirculation means to the propagating member from excess coupling to critical coupling and from critical coupling to undercoupling. 71. An optical wave energy propagation control device for changing the propagation energy on an optical waveguide in-line, the peripheral surface coupling the optical energy from the optical waveguide and returning the optical energy to the optical waveguide. A low-loss light wave energy recirculation means provided adjacent to the optical waveguide and a discontinuity in the waveguide by operating together with the recirculation means to change the energy returned from the recirculation means to the optical waveguide. A lightwave energy propagation device comprising variable coupling means for changing the propagation energy on an optical waveguide without introducing it. 72. The variable coupling means, in order to bring a resonator that was previously in an excessively coupled state into a critically coupled state or to bring a resonator that was previously in a critically coupled state into an undercoupled state, at each recirculation reciprocation. 72. The lightwave energy control device of claim 71 which introduces losses. 73. The lightwave energy control device according to claim 72, wherein the variable coupling means interacts with the lightwave to be recirculated and absorbs a part of the lightwave energy to be recirculated every one round trip. 74. The light wave energy control device according to claim 71, wherein the variable coupling means changes the resonance frequency of the recirculation means by changing the refractive index of the recirculation means to change the propagation energy on the optical waveguide. 75. A method of varying the energy level of a single wavelength signal in an optical waveguide, wherein a portion of the energy propagated along the waveguide is transferred to a whispering gallery mode resonating at the propagation wavelength, An energy level changing method comprising the steps of changing the energy level of a propagating signal in an optical waveguide by returning energy from the whispering gallery mode to the optical waveguide and introducing a controllable loss in the energy of the whispering gallery mode. 76. Inherent losses in energy transfer and whispering gallery mode operation are insufficient to bring the energy level of the waveguide to zero, and are losses controllable to a greater extent than the intrinsic losses. Is changed.
Method 5 77. The controllable loss introduced is varied between a critical coupling level at which the energy propagated in the waveguide is minimal and a level at which the energy propagated in the waveguide is not substantially attenuated. 77. The method of claim 76. 78. A part of electromagnetic energy is distributed outside a waveguide, energy outside the waveguide is coupled to a whispering gallery mode, and energy is controlled while coupling from the whispering gallery mode to the waveguide. 76. The method of claim 75, further comprising introducing a possible loss. 79. The energy propagated by the waveguide is unpolarized and the step of introducing controllable losses forms at least two whispering gallery modes in which the energy circulates in planes orthogonal to each other. 79. The method of claim 78, including. 80. A method of modulating or switching light of a single wavelength propagating along a continuous optical waveguide, wherein a portion of the light wave energy is propagated along but outside the waveguide, the outside of the waveguide. Transfer some energy to the high Q recirculation passage from which some energy is released, and return energy from the recirculation passage to the optical waveguide, thereby introducing loss into the recirculated energy. A method comprising modulating the energy propagated along the waveguide by controlling. 81. Energy propagates outside the waveguide by changing the cross section of the waveguide, and energy propagated along the waveguide imparts a critical coupling loss to the energy in the recirculation channel, thereby transferring the energy. 81. The method of claim 80, wherein the method is attenuated by a factor of 1 to over 90%. 82. The method of claim 81, further comprising limiting energy in the recirculation path to modes that resonate at one or more frequencies and increasing recirculated energy in resonant modes. 83. At least a portion of the propagated energy is coupled from the waveguide to at least one recirculating lightwave energy path that resonates at at least one frequency, and the recirculating lightwave energy is coupled back into the optical waveguide; A method of modulating lightwave energy in an optical waveguide comprising the step of modulating the lightwave energy propagating along the waveguide by controlling the energy absorbed from one recirculating lightwave energy path. 84. The method of claim 83, wherein the propagating lightwave energy comprises a signal of a single wavelength and the recycling step is resonant at that wavelength. 85. The method of claim 83, wherein the propagated lightwave energy comprises signals of at least two different wavelengths, and absorbing energy from at least one recirculation path comprises absorbing energy from different wavelengths. . 86. A signal amplitude modulator for use at an optical wavelength, the waveguide for propagating light wave energy, wherein the propagation energy is partially distributed in at least a portion in an adjacent portion, and adjacent to the waveguide. And a low-loss lightwave energy recirculation means that is arranged to combine a part of the energy distributed and recirculate and store the energy internally, and generate an external electric field for returning the energy propagating inside to the waveguide. A signal amplitude modulator comprising loss control means for changing the amplitude of light wave energy propagated along the waveguide by absorbing energy during recirculation in cooperation with the recirculation means. 87. The signal amplitude modulator of claim 86, wherein the recirculation means comprises a whispering gallery mode element selected depending on the wavelength and bandwidth of the signal. 88. The recirculating means has a Q of 1000 which resonates at a selected frequency.
87. The signal amplitude modulator of claim 86, which comprises more than 5 whispering gallery mode elements. 89. The signal amplitude modulator of claim 88, wherein the whispering gallery mode element is a dielectric microcavity selected from the group consisting of microspheres, oblate spheres, disks and rings. 90. The whispering gallery mode element has a diameter of 10
90. The signal amplitude modulator of claim 89, comprising a microsphere less than 00 microns, a ring, or a disk, the waveguide comprising an optical fiber having a narrowed region, and the microsphere secured to the constricted region. 91. An optical fiber has a constricted portion having a small diameter of about 10 microns or less, and a taper portion which is integral with the constricted portion and which is joined to both ends of the optical fiber waveguide. 90. The signal amplitude modulator of claim 89, including. 92. The incident lightwave energy is not necessarily polarized and at least two lightwave recycling means are adjacent to said portion of the waveguide in exchange relation with the energy distributed around said portion of the waveguide. 87. The signal amplitude modulator of claim 86, wherein the change in optical energy in the waveguide is polarization-independent because each is arranged and each lightwave recycling means is in an energy exchange relationship with the loss control means. 93. The signal amplitude modulator comprises a number of lightwave energy recycling means, each of which is arranged in energy exchange relationship with a distributed electric field along and along a lightwave distribution portion of the waveguide, 87. Responsive to signals of different wavelengths.
Signal amplitude modulator. 94. A modulator for use in a fiber optic propagation system, the fiber having a narrowed portion that distributes light wave energy having a selected nominal frequency around the exterior of the waveguide, and a resonator at the selected nominal frequency. Then, in order to generate an internal recirculation mode and return the energy to the optical fiber, an optical resonator placed close to the constricted part so as to have a communication relation with the energy outside the waveguide, and an internal resonator Is in a communication relationship with the energy that recirculates, and introduces losses into those modes to make the previously overcoupled resonators critically coupled, or
Or a modulator comprising loss control means for bringing a resonator that was previously in a critically coupled state into an undercoupled state. 95. The resonator comprises a whispering gallery mode element having an equatorial peripheral surface in which an electric field of recirculated energy is confined, and the electric field of recirculated energy is guided to spread outside the peripheral surface. 99. The modulator of claim 94, distributed in the open state. 96. The resonator comprises a microsphere, an oblate sphere, a ring or a disc, and the loss control means comprises a signal responsive semiconductor element within an external electric field of recirculated energy, the Q of the microsphere being used for propagation. 99. The modulator of claim 95, wherein the modulator is determined by setting the size of the microspheres according to the spectral linewidth required by the data rate. 97. The resonator comprises a microsphere of silica and the loss control means comprises a signal responsive semiconductor element within an external electric field of recycled energy, the Q of the microsphere.
96. The modulator of claim 95, wherein is determined by setting the size of the microspheres according to the spectral linewidth required by the data rate used for propagation. 98. A device for controlling the propagation of a number of different combinations of optical frequencies on an optical waveguide, wherein a portion of the propagating electric field is distributed outside the surface at the coupling portion and is capable of propagating different frequencies. A waveguide and a plurality of whispering gallery mode resonances disposed adjacent to and coupled to the coupling portion of the waveguide, each of which has a resonance mode of a different optical frequency and couples energy back into the waveguide. And a resonator, each coupled to a different resonator, which separately switches off the frequency according to the instruction by changing the loss in each resonator separately and changing the signal of the frequency returned to the waveguide. A propagation control device comprising a plurality of means. 99. The propagation controller of claim 98, wherein the resonator has a Q value selected according to a modal frequency spacing that depends on the signal frequency, bandwidth, and general spectral broadening of the optical frequency. 100. The propagation controller of claim 98, wherein the whispering gallery mode resonator is a microsphere. 101. A propagation control device according to claim 98, wherein the whispering gallery mode resonator is a disk, a ring, or an oblate sphere. 102. The propagation control device according to claim 98, wherein the waveguide is an optical fiber having a narrowed portion with a small diameter. 103. A system for generating and controlling optical signals of multiple different wavelengths on a single optical waveguide capable of propagating multiple wavelengths within a selected bandwidth, wherein a portion of the guided lightwave energy is An optical waveguide having at least two externally distributed integral lengths and at least two internal optical energy sources operating at different wavelengths within a selected bandwidth, each within the selected bandwidth At least two optical resonators that resonate at different wavelengths and are placed in a coupling relationship with different integral length portions of the optical waveguide, and at different wavelengths by optically coupling to each resonator to control optical loss. A system comprising control means for separately controlling the propagated energy in a single optical waveguide. 104. The optical waveguide is an optical fiber, and the at least two integral length portions comprise a narrow constriction portion having an integral taper portion with the optical fiber, and the resonator emits light waves at individual wavelengths selected. 104. The system of claim 103, which is an internal reflector of recirculating optical material, the edges being coupled to an externally distributed portion of the guided wave energy. 105. A system for controlling the amplitude level of a selected wavelength optical signal propagating along a polarization-undefined waveguide element, such that a portion of the guided light wave energy is distributed outward. The coupling length portion of the waveguide element having a size and shape is in a coupling relation with the light wave energy distributed outside, and the coupling length portion is in an orthogonal relation around the propagation axis of the coupling length portion of the waveguide element. A pair of resonators arranged along a line that resonate at a selected wavelength and a signal propagated in cooperation with each resonator to introduce a controllable loss into the lightwave energy that is recirculated in the resonator. A system consisting of loss control means that allow the s to be controlled independent of their polarization. 106. The waveguide element is an optical fiber having a narrowed portion in which guided light wave energy is distributed in and adjacent to the waveguide element, and the resonator is in a plane orthogonal to each other in a radial direction of the optical fiber. 106. The system of claim 105, which is a microcavity having an equatorial perimeter and whose amplitude level is controlled in response to a desired controllable loss independent of the direction of the polarization vector. 107. A device for varying an optical energy signal on an optical waveguide system, each having an interacting portion, wherein a portion of a light wave is guided outside thereof, said interacting portion being at least one selection. Separated first and second optical waveguides that propagate light wave energy of a selected frequency, operating in WGM mode, resonating at a selected frequency, and interacting between the first and second waveguides. And the energy of the light waves circulating in the microcavity means at a selected frequency, with the dielectric microcavity means located at, and in which the arc of the peripheral surface is in coupling relation with the interacting parts of both waveguides, and the microcavity means. A device for varying a lightwave signal comprising variable lightwave energy absorbing means for varying the level. 108. The microcavity means has an interacting equatorial recirculation path for energy at the resonant frequency, and the interacting portions of the first and second waveguides are in a common plane with the equatorial recirculating path. 108. The apparatus of claim 107, wherein the absorbing means changes the lightwave energy by introducing losses that vary in the critical coupling range. 109. The first and second waveguides are optical fibers, the interaction portion is a constricted region integrally formed in the optical fiber, and the microcavity means are disks, spheres, rings and aspherical surfaces. 109. The device of claim 108, which is a device selected from the group consisting of: 110. An apparatus for controlling a change in energy of an optical system in which variable lightwave energy is propagated adjacent to a WGM lightwave recirculator in an optical waveguide, the apparatus supporting WGM at at least one resonant frequency and at least 1 An energy change control device comprising a dielectric resonator including energy response means for changing the frequency of one resonance mode to change the propagation energy. 111. The control means of claim 110, wherein the energy responsive means comprises a material associated with a dielectric resonator that changes the dielectric constant in response to an external stimulus. 112. The material is a layer on a resonator responsive to external excitation,
112. The control means of claim 111 including variable control means for externally exciting said layer. 113. Propagation control means according to claim 111, wherein the resonator itself is made of an optically non-linear material and comprises control means for irradiating the resonator with radiation of variable intensity. 114. An apparatus for controlling a change in energy of an optical system for propagating variable light wave energy in an optical waveguide by coupling light wave energy with a WGM means, wherein the device responds to at least one resonance frequency and within an equatorial plane. A WGM resonator that recirculates the light wave of the frequency and emits the light wave energy guided from the peripheral surface, and one of the recirculated light wave energy in the distribution area of the light wave energy emitted from the resonator. A propagating energy control device comprising a light wave energy absorbing means for absorbing a portion and means for changing the absorption level of light wave energy which is coupled to the absorbing means and is recycled. 115. The propagation energy control device of claim 114, wherein the absorbing means comprises an optically active quantum well structure formed from a layer of barrier material and the means for varying the absorption level provides an electrical signal to the absorbing means. 116. The propagation energy control device according to claim 115, wherein the absorbing means is formed of an InGaAs active layer and the barrier layer is formed of InGaAsP. 117. The propagation of claim 114, wherein the absorbing means comprises a semiconductor material having a selected bandgap related to the photon energy of the signal light wave and the means for varying the absorption level comprises means for optically pumping the semiconductor material. Energy control device. 118. The absorbing means comprises a semiconductor material having a selected bandgap related to the signal light wave photon energy, and the means for varying the absorption level comprises:
115. The propagating energy control system of claim 114 comprising means for creating a variable electric field in the semiconductor material. 119. A system for controllably altering the propagation of a signal in an optical waveguide having no transitions for coupling to itself, the system releasing an outer portion of guided energy to an ambient environment. Distribution region of energy emitted from the waveguide, which has an optical coupling member, internally supports at least one WGM having at least one resonance frequency, and an optical waveguide selected from the group including an optical fiber and a planar optical waveguide. A dielectric optical microcavity member selected from the group consisting of microspheres, discs, and rings, and a microcavity member that extends inward and couples a portion of the lightwave energy into and out of the waveguide. A system consisting of means for changing the propagation of signals in an optical waveguide by working together to introduce losses in WGM. 120. A light wave energy control device for changing the energy of at least one light frequency (ie, an optical carrier) propagated by a light wave energy propagation member, wherein the light wave energy is propagated and guided at at least one light frequency. A light wave energy propagating member configured as described above, and selected light wave energy and frequency disposed in a coupling relationship with the propagating member to couple the light wave energy to or from the propagating member. At least one WGM lightwave resonator having a resonance relationship and at least one resonator each having a different relationship, and changing the characteristics of each resonator to change the energy level of the lightwave propagated through the lightwave energy propagation member. A lightwave energy control device comprising at least one control means for changing. 121. The lightwave energy control device of claim 120, wherein the altered characteristic is a component of the round trip loss of the resonator that is different from the loss of the resonator associated with coupling to the propagating member. 122. The lightwave energy control device of claim 121, wherein the loss is changed by changing the absorption of the resonator mode. 123. The lightwave energy control device of claim 122, wherein the absorption is generated by the semiconductor and is altered by applying an electric field or voltage to the semiconductor. 124. The lightwave energy control device of claim 122, wherein the absorption is generated by a semiconductor and is modified by optical pumping the semiconductor. 125. The lightwave energy control device of claim 122, wherein the absorption is generated by the semiconductor and is altered by injecting a current into the semiconductor. 126. The lightwave energy control device of claim 122, wherein the absorption is generated by a quantum well semiconductor structure and is modified by applying an electric field or voltage to the semiconductor. 127. The lightwave energy control device of claim 122, wherein the absorption is generated by a quantum well semiconductor structure and is modified by optically pumping the semiconductor. 128. The lightwave energy control device of claim 122, wherein the absorption is generated by a quantum well semiconductor structure and is modified by injecting a current into the semiconductor. 129. The lightwave energy control device of claim 121, wherein the loss is altered by altering resonant mode energy coupling to another member or structure. 130. The lightwave energy control device of claim 129, wherein said structure is a waveguide whose phase matching to resonant modes is varied to control energy coupling. 131. The lightwave energy control device of claim 130, wherein the waveguide is made of an electro-optic material and the phase matching is changed by applying a voltage to the waveguide. 132. The lightwave energy control device of claim 130, wherein the waveguide is composed of an optically nonlinear material and the phase matching is altered by optical means. 133. The changed characteristic is a component of the resonator round trip loss associated with the coupling of the resonator and the member, and the other source of the round trip loss of the resonator is constant.
20 lightwave energy control devices. 134. The lightwave energy control device of claim 133, wherein the loss is changed by changing the coupling amplitude of the resonator and the member. 135. The lightwave energy control device of claim 134, wherein the coupling is changed by electro-optical means. 136. The lightwave energy control device of claim 134, wherein the coupling is changed by optical means. 137. The lightwave energy control device of claim 120, wherein the property that is changed is the optical path length of the resonant mode. 138. The lightwave energy control device of claim 137, wherein the optical path length is changed by changing the dielectric constant of the medium comprising the resonator. 139. The lightwave energy control device of claim 138, wherein the dielectric constant is changed by applying an electric field. 140. The lightwave energy control device of claim 138, wherein the dielectric constant is changed by applying a lightwave. 141. The lightwave energy control device of claim 138, wherein the dielectric constant is changed by applying an electric current. 142. The lightwave energy control device of claim 138, wherein the dielectric constant is changed by thermal means. 143. The altered characteristic is a negative round trip loss (optical gain) component of the resonator that is different from the resonator loss associated with coupling to the propagating member.
0 lightwave energy controller. 144. The lightwave energy control device of claim 143, wherein the optical gain is provided by a resonator. 145. The lightwave energy control device of claim 121, wherein the resonator and the propagating member introduce a resonator round trip loss component such that the resonator is overcoupled and the losses associated with the control means cause critical coupling. 146. The lightwave energy controller of claim 121 wherein the resonator and the propagation member introduce a round trip loss component of the resonator such that the resonator is critically coupled and the loss associated with the control means causes undercoupling. . 147. The resonator of claim 133, wherein the resonator and the propagating member introduce a round trip loss component of the resonator such that the resonator is overcoupled and the losses associated with the control means are varied to produce a critical coupling. Lightwave energy control device. 148. The resonator and the propagating member of claim 133, wherein the resonator is critically coupled and introduces a round trip loss component of the resonator such that the losses associated with the control means are varied to produce undercoupling. Lightwave energy control device. 149. The lightwave of claim 133, wherein the resonator and the propagating member introduce a round trip loss component of the resonator such that the resonator is critically coupled and overcoupling occurs due to the optical gain associated with the control means. Energy control device. 150. The resonator of claim 133, wherein the resonator and the propagating member introduce a round trip loss component of the resonator so that the resonator is in an insufficiently coupled state, and critical coupling occurs due to an optical gain associated with the control means. Lightwave energy control device. 151. The lightwave energy propagating member propagates a number of different frequencies, each resonates at a different propagating frequency, and a plurality of resonators having a coupling relationship with the lightwave energy propagating member, and each resonator different from each other. 121. A lightwave energy control device as claimed in claim 120, comprising a plurality of control means arranged in a coupling relationship to change the propagation of energy of a selected frequency by controlling the characteristics of the resonator. 152. A modulator comprising a plurality of resonators and associated control means arranged in-line with a lightwave energy propagating member, each resonator and associated control means operating at a different frequency of the set of optical frequencies. And further has a plurality of laser light sources that are in line with the light wave energy propagation member and send out different frequencies of the set on the propagation member in the downstream direction, and each modulator is downstream of the laser light source of each frequency. 121. The lightwave energy control device of claim 120. 153. The light-wave energy-propagating member is an optical fiber, and coupling to at least one WGM light-wave resonator occurs in the taper region of the optical fiber.
20 lightwave energy control devices.