WO2002077687A2 - Spectrometre optique integre a haute resolution spectrale et procede de fabrication - Google Patents
Spectrometre optique integre a haute resolution spectrale et procede de fabrication Download PDFInfo
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- WO2002077687A2 WO2002077687A2 PCT/FR2002/001042 FR0201042W WO02077687A2 WO 2002077687 A2 WO2002077687 A2 WO 2002077687A2 FR 0201042 W FR0201042 W FR 0201042W WO 02077687 A2 WO02077687 A2 WO 02077687A2
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J3/2803—Investigating the spectrum using photoelectric array detector
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/0205—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
- G01J3/0218—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows using optical fibers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/0256—Compact construction
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/0291—Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B6/12007—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind forming wavelength selective elements, e.g. multiplexer, demultiplexer
- G02B6/12009—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind forming wavelength selective elements, e.g. multiplexer, demultiplexer comprising arrayed waveguide grating [AWG] devices, i.e. with a phased array of waveguides
- G02B6/12019—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind forming wavelength selective elements, e.g. multiplexer, demultiplexer comprising arrayed waveguide grating [AWG] devices, i.e. with a phased array of waveguides characterised by the optical interconnection to or from the AWG devices, e.g. integration or coupling with lasers or photodiodes
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B6/12007—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind forming wavelength selective elements, e.g. multiplexer, demultiplexer
- G02B6/12009—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind forming wavelength selective elements, e.g. multiplexer, demultiplexer comprising arrayed waveguide grating [AWG] devices, i.e. with a phased array of waveguides
- G02B6/12026—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind forming wavelength selective elements, e.g. multiplexer, demultiplexer comprising arrayed waveguide grating [AWG] devices, i.e. with a phased array of waveguides characterised by means for reducing the temperature dependence
- G02B6/1203—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind forming wavelength selective elements, e.g. multiplexer, demultiplexer comprising arrayed waveguide grating [AWG] devices, i.e. with a phased array of waveguides characterised by means for reducing the temperature dependence using mounting means, e.g. by using a combination of materials having different thermal expansion coefficients
Definitions
- the present invention relates to an optical spectrum analyzer also called a “spectral analysis device” or, more simply, an “optical spectrometer”.
- This spectrometer is particularly applicable to infrared radiation, for example in the field of high speed optical telecommunications.
- Other applications of the invention, in particular optical metrology, will be mentioned below.
- Optical telecommunications have enabled a considerable increase in information rates thanks to spectral and time coding.
- speeds of the order of 40 Gigabits / s are obtained on a single optical fiber.
- DWDM or dense wavelength multiplexing (“Dense Wavelength Division Mul tiplexing")
- the information rate exceeds 1 terabit / s.
- the increase in speeds which is necessary for establishing information transfer protocols (in particular on the Internet), requires simultaneously increasing the spectral width of the telecommunications band and reducing the spectral interval between canals.
- This approach is limited by the wavelength routing capacities, by the power available for the amplifiers and by the non-linear effects such as the stimulated Raman effect, the stimulated Brillouin effect and especially the four-wave mixing. which constitutes a limit for the wavelength separation.
- the first is around 800 nm; it is used for local networks with multimode fibers.
- the second spectral window is located around 1280 nm to 1350 nm (corresponding to a minimum of dispersion in silica); it is currently little used because the optical amplifiers with fibers doped with praseodymium (PDFA), which were developed for this window, have never reached the performance of fiber amplifiers doped with erbium (EDFA) for the band. at 1.55 ⁇ m.
- PDFA praseodymium
- EDFA erbium
- the third window is located around
- Band C (“C-band”) is the spectral band amplified by traditional EDFA optical amplifiers; it extends from 1528 nm to 1565 nm and therefore over 37 nm.
- the L-band (“L-band”) extends from 1561 nm to 1620 nm, and therefore over 59 nm, and corresponds to EDFA optical amplifiers with “Raman” amplification.
- ITU International Telecommunication Union
- International Telecommunication Union International Telecommunication Union
- ITU grid that is to say the set of wavelengths defined by the ITU, begins at 1528.77 nm (196.1 THz) to reach 1563.86 nm (191.7 THz). It has 45 wavelengths which extend over approximately 36 nm.
- the growing need for transmission capacity means that a channel interval of 0.4 nm (50 GHz) becomes likely, although the non-linear effects currently limit the transmission range.
- New optical amplifiers with fibers doped with thulium make it possible to cover the spectral range which extends from 1470 nm to 1500 nm.
- This domain which is currently called “S-band” (“S-band”) thus completes the third window (the spectral band located at 1510 nm + 10 nm comprising supervision channels).
- optical amplifiers are studied using amplification mechanisms by stimulated Raman effect.
- the amplification is provided in a distributed and not a pointwise manner (as is the case in EDFA amplifiers).
- the noise factors obtained using a Raman amplification are better than those that one obtained with EDFA amplifiers, which makes it possible to reduce the transmitted optical powers and therefore to reduce the spectral interval between channels.
- stimulated Raman effect amplifiers make it possible to amplify a much wider spectral band by means of a suitable assembly of pumping lasers.
- a Raman amplifier can thus cover all wavelengths between 1300 nm and 1660 nm, that is to say much more than the bands currently covered by doped fiber amplifiers.
- the current DWDM transmission spectrum extends over a hundred nanometers (C and L bands) for a spectral separation between channels of 0.8 nm.
- the TDFA amplifiers can be improved for the S band, which would make it possible to cover a total spectral band of approximately 150 nm (S, C and L bands).
- optical spectrum analyzer it is important to have an optical spectrum analyzer in order to check the wavelength allocations and to maintain a low error rate on all the channels. It is also important to measure the intensity of optical signals with a good signal-to-noise ratio.
- the separating power of this spectrometer is approximately equal to or greater than 30000 and that the observed wavelength range makes it possible to satisfy the future bandwidth standard (between 120 nm and 180 nm).
- the total number of measurement points is therefore at least of the order of 2400 to 3600 and preferably close to 7200.
- Such a spectrometer becomes vital for future DWDM networks and would be widely used for optical checks at each node of a network (“network”) comprising a wavelength add-drop device), a terminal or amplifier.
- diffraction gratings spectrometers with single or double passage
- Fabry-Perot interferometric cavities with free space scanning or Fourier Transform spectrometers based on Michelson interferometers.
- multiplexers / demultiplexers could be used as optical spectrum analyzers, but these devices do not make it possible to perform optical spectrum measurements and only perform the multiplexing functions compatible with the ITU 50 GHz standard.
- optical spectrometer having the following qualities: "wavelength separation better than the interval between channels (0.4 nm), that is to say at least 0.05 nm ( spectrometer resolution power greater than 30,000),
- phasears optical phase arrays
- AWGs arrayed Waveguide
- the present invention aims to remedy the drawbacks mentioned above and to provide optical spectrometers having all or part of the qualities mentioned above and in particular an ability to separate wavelengths very close to each other, a wide spectral band of operation and the possibility of being compact and obtained in integrated form to be portable.
- the subject of the present invention is an optical spectrometer comprising at least one elementary optical spectrometer, this elementary optical spectrometer being characterized in that it comprises: an optical phase network comprising a set of micro-guides, this network of optical phase being formed on a planar optical guide which is cleaved, - reflection means capable of successively reflecting radiation from all of the microguides, with a view to propagation of this radiation in folded form and in free space,
- the reflecting means are adapted to enable propagation of radiation in folded form, first in the planar optical guide then in free space, above this planar optical guide, in a plane which is parallel to the latter.
- the optical phase grating is designed to operate by reflection and the planar optical guide has a plurality of cleaved sides, made reflective with respect to radiation from the set of microguides and vis-à-vis radiation intended to penetrate this set.
- the set of microguides ends at one of the cleaved sides and the optical phase grating comprises a focusing zone which leads to at least one of these cleaved sides.
- the optical phase network is designed to operate by reflection and the planar optical guide has a cleaved side, which is made to reflect vis-à-vis radiation from the set of microguides and vis-à-vis the radiation intended to penetrate this assembly and to which all of the microguides ends, as well as other cleaved sides capable of reflecting this radiation, this radiation being intended to arrive on these other cleaved sides with angles of 'incidence large enough to lead to a total reflection of these radiations.
- the microguides form, for example, arcs of concentric circles.
- the optical phase network is designed to operate by transmission.
- the reflection means comprise:
- a prism which is provided for reflecting the radiation from the set of microguides in a plane parallel to the planar optical guide on which the optical phase network is formed, and - at least one mirror provided for reflecting the radiation propagating in this plan towards the photodetection means.
- the optical spectrometer which is the subject of the invention may further comprise a support on which the optical phase grating, the reflection means and the photodetection means are positioned in relation to each other.
- this support is obtained by molding or hot stamping of a plastic material, from a mold obtained by a molding technique by lithography and electro-forming.
- the optical spectrometer which is the subject of the invention further comprises means for compensating for modifications undergone by the optical phase network due to variations in temperature.
- these compensating means preferably comprise a bar having a coefficient of preferably high thermal expansion, this bar being made integral with the mirror to generate, by thermal expansion, changes in the orientation of the mirror, capable of compensating for the changes undergone by the optical phase grating.
- the planar optical guide is obtained by an integrated optical technique on glass or on a semiconductor, in particular silicon or indium phosphide.
- the present invention also relates to an optical spectrometer comprising a plurality of elementary optical spectrometers according to the invention, intended to cover in a modular manner a determined spectral range and optically coupled to an input optical fiber by means of wavelength separation.
- this spectrometer further comprises polarization separation means which connect these wavelength separation means to the elementary optical spectrometers.
- this spectrometer further comprises power separation means and polarization means which connect these wavelength separation means to the elementary optical spectrometers.
- the present invention also relates to an advantageous method of manufacturing the spectrometer which is the subject of the invention, in which the optical phase grating is of the folded type, to operate by reflection, and manufactured in several copies, by head-to-tail pairs, according to the techniques. integrated optics, from the same substrate which is then cleaved to obtain the various optical phase networks thus manufactured and to form an elementary optical spectrometer with each of these.
- each optical phase network from a substrate and to form cleavage marks at the same time as the optical phase network microguides on this substrate.
- the present invention further relates to a spectral analysis device for high speed optical telecommunications using dense wavelength division multiplexing, this device comprising the spectrometer object of the invention, which comprises the plurality of elementary optical spectrometers, for provide a real-time indication of channel placement in the range from 1528.77 nm to 1563.86 nm, in a modular fashion and adaptable to the needs of users.
- the present invention also relates to a Bragg grating optical metrology device, this device comprising the spectrometer which is the subject of the invention, which comprises the plurality of elementary optical spectrometers, for measuring Bragg wavelengths.
- This spectrometer is for example intended to detect optical signals coming from at least one Bragg grating sensor.
- the dispersive device that the elementary optical spectrometer comprises is a component of integrated micro-optics called an optical phase network, or also phasar, which comprises a plurality of waveguides, each of which introduces a phase shift compared to the one preceding it; such a phasar generates a “mono-dimensional” set of electrical signals
- a spectrometer may include one or more elementary spectrometers mounted in parallel, arranged in multiple stages; the optical spectrum sought is then obtained by concatenating all the elementary spectra coming from each of the phasars; this parallel assembly makes it possible to resolve the physical contradiction between obtaining a good spectral resolution (that is to say a high dispersion), a large spectral range and a minimum bulk for the spectrometer ; - in addition, to minimize congestion, each phasar can be a phasar operating in transmission or a half-phasar "folded" (to operate in reflection) thanks to an interface forming a mirror, located in the area of phase shifting microguides; moreover, the adaptation of the phasar dispersion properties to the dimensions of the photo-detector arrays leads to “folding” the focusing area a plurality
- the optical spectrometer of the invention comprises half-phasars "folded" at the level of the micro-guides by an interface forming a mirror and the focusing area is therefore identical for entry and exit (unlike conventional phasars);
- the focusing zone can also be "folded" in part on the substrate where it is formed and also in free space, by optical means assembled on a support preferably obtained by pre-forming according to the technique called LIGA, this support being capable of including temperature self-compensation means;
- Such a multi-stage optical spectrometer with “folding” makes it possible to solve the problems posed in the field of DWDM telecommunications.
- FIG. 1 is a block diagram of a DWDM spectrometer according to the invention
- FIG. 2 is a block diagram of another DWDM spectrometer according to the invention, using polarization splitters,
- FIG. 3 is a block diagram of another DWDM spectrometer according to the invention, using optical fiber polarizers,
- FIG. 4 schematically illustrates an example of a masking diagram for a half-phasar in integrated optics on glass, usable in the invention
- Figure 5 is an optical diagram corresponding to half phasar shown in Figure 4,
- FIG. 6A is a schematic view of an assembly of an elementary micro-spectrometer according to the invention, using the technique called LIGA for "Lithography Galvanoformung Abformung",
- FIG. 6B is the section AA in FIG. 6A
- FIG. 7A is a schematic view of an assembly of another elementary micro-spectrometer according to the invention, also using the LIGA technique,
- FIG. 7B is the section AA in FIG. 7A
- FIG. 8 schematically illustrates a mechanism for passive self-compensation of the thermal dependence of a phase network usable in the invention
- FIG. 9 schematically illustrates another mechanism for passive self-compensation of the thermal dependence of a phase network usable in the invention
- FIG. 10 schematically illustrates an example of a masking diagram of two half-phasars in integrated optics on glass, usable in the invention
- FIG. 11A is a schematic view of an assembly of another elementary micro-spectrometer according to the invention, using the LIGA technique,
- FIG. 11B is the section AA in FIG. 11A,
- FIG. 12 schematically illustrates an application of a device according to the invention to the measurement of deformations, pressures and temperatures using Bragg gratings forming transducers
- FIG. 13 schematically illustrates a wafer of 8 inches (about 20 cm) in integrated silica on silicon optics as well as an example of a masking scheme of phasar components according to the elementary mask described with reference to the figure 10.
- An objective of the present invention is the production of a compact spectrometer, at optimized cost, which makes it possible to cover the useful spectrum for the third telecommunications window (conventional band, or C band, and long band or L band).
- the spectral band to cover to satisfy the current telecommunications market is around 120 nm.
- the current ITU grid is 50 GHz, which corresponds to a separation of approximately 0.4 nm between channels (the number of channels being equal to 300).
- phasars are used for reasons of dispersion (phasars having a high diffraction order), compactness and crosstalk performance.
- sizing calculations show that it is not easy to manufacture a single phasar for the entire wavelength range because the number of micro-guides required to satisfy the spectral resolution criterion is very high: it is greater than 2500.
- the dimensioning of such a component leads to a value of focal focal length output much greater than the size of a semiconductor wafer. This is why, in the invention, it is preferable to "fold" the beam diffracted by the micro-guides one or more times in the focusing zone and mount a plurality of phasars in parallel using a “multi-stage” approach
- d g is the interval between two micro-guides at the entrance to the exit focusing zone, n s the index of the planar guide, n c the index of the guide (which is often the same) , the angles ⁇ i and ⁇ 0 are the diffracted angles respectively in the input focusing zone and in that of the output, ⁇ L is the length offset from one guide to the other, and n is the diffraction order.
- the wavelength ⁇ 0 is the central wavelength of the phasar which is written:
- ns sin ⁇ i + sin ⁇ o n.
- the phasar demultiplexes the wavelengths from one of the input guides to the output guides. The phasar allows you to perform this function from any input guide; the spectrum received at the output is then shifted proportionally to the location of the input guide considered.
- This property can be used in order to achieve temperature self-compensation by fixing the input optical fiber on a mechanical support whose displacement induced by thermal expansion compensates for the spectral shift due to the thermal dependence of the component.
- this property is also applicable in the case of the use of a half-phasar (folded) in order to offset an input fiber from a photodetector array located in the same plane, as is the case. will see further.
- phase grating for spectrometry applications firstly requires adjusting the maximum possible diffraction order (and the length offset between each microguide) by considering the spectral range observed
- the minimum number of micro-guides is chosen to guarantee the desired resolving power.
- the focal length of the output is calculated according to the characteristics of the photodetector array. To remove any ambiguity, the spectral overlaps from an i order to a following order i + 1 or previous i-1 are avoided. For this, the free spectral interval, denoted ISL, is chosen at best equal (or greater) to the observed spectral range, denoted ES. This defines a condition on the phasar diffraction order:
- n the diffraction order and M the ⁇ number of micro-guides.
- ⁇ corresponds to the spectral width of the "Airy spot"; we try to have 0.05 nm in order to be able to distinguish the channels within the ITU grid.
- the micro-guides are made up of arcs of circles.
- n s is the effective index of the focusing area and f the length of this area which corresponds to the focal length of the output.
- focal length f is therefore little different from ns : g . L.
- the interval d g cannot be reduced as much as desired; it is limited by the crosstalk between the guides. This value being fixed, the focal distance only depends on the length of the bar.
- the focal distance in the glass (index 1.46) is greater than the focal distance in the air (index 1) due to the self-focusing at the exit of the planar guide. .
- focal length of exit 250 mm in the glass (index 1.46), from where a path of 50 mm in the glass added to 140 mm in the air (equivalent to 200 mm in the glass) [example which s 'applies to the assembly shown in Figures 6A and 6B] or 175 mm in the air [example which applies to the assembly shown in Figures 7A and 7B].
- Beam Propagation Method takes into account the dispersion of the materials used in the precise definition of the optical dimensioning of the component to be produced.
- micro-spectrometer comprises a single phasar or a plurality of phasars
- the design mode (1) (respectively (2)) is a special case of the design mode (3)
- design modes (2) and (4) have the advantage of using phasars of simpler design (without polarization compensation), which are for example formed by means of an integrated optics technique on silicon, and allows to realize a polarization control spectrometer.
- phasars of simpler design without polarization compensation
- the design modes (1) and (2) are respectively identical to the design modes (3) and (4) but without a wavelength separator.
- this wavelength separator is to perform a first separation of the bands observed by each of the elementary micro-spectrometers. It can be a network demultiplexer of the kind that is marketed under the STIMAX brand by the Jobin-Yvon Company or else an integrated optical device such as a commercial phasar.
- FIG. 1 represents the optical block diagram of such a micro-spectrometer, applied to the DWDM technique and comprising a wavelength separator 2 as well as three blocks, namely three elementary micro-spectrometers whose references are Ml respectively , M2 and M3, depending on the design mode (3).
- FIGS. 2 and 3 represent optical block diagrams of a micro-spectrometer made up of six blocks, namely six elementary micro-spectrometers whose references are Mlx and Mly,
- This design mode may involve a wavelength separator 4 (for example, a phasar having a bandwidth of 40 nm) and three polarization separation couplers C1, C2, C3 (see Figure 2) which use preferably birefringent crystals to effect the separation of the polarizations because the crosstalk is then low.
- Another solution is to use the wavelength separator 2 of the FIG. 1, three couplers with power separation Pi, P2, P3 and six polarizers integrated on fibers, namely three pairs of polarizers Px and Py, Px allowing polarization in a direction x and Py in a direction y perpendicular to x.
- the optical fibers for connection between the polarization separation couplers or the polarizers and the elementary microspectrometers are fibers with polarization maintenance 6.
- each polarization-maintaining fiber 6 is placed parallel to the surface of the substrate on which the associated microspectrometer is formed (this surface being for example parallel to the direction x).
- the second neutral axis of this fiber 6 is placed perpendicular to this surface (and therefore parallel to the y axis in the example considered).
- the light signal to be analyzed by the microspectrometer reaches it by an input optical fiber FE; the wavelength separator 2
- each of the couplers PI, P2, P3 is connected to the two associated polarizers Px and Py by two optical fibers fx and fy.
- Three possible techniques for manufacturing a phasar which can be used in the invention are: the integrated optical technique on semiconductor or the integrated optical technique on silicon - or the ion exchange technique on glass.
- Si0 2 / Si guiding layers in Si0 2 , SiON or Si 3 N 4
- the processes used in this case are based on vapor deposition (essentially chemical vapor deposition) or hydrolysis with a flame and on reactive ion etching for the production of the patterns.
- the optical substrate is a layer of silica of sufficient thickness to isolate the light from the silicon (6 ⁇ m for a wavelength of 0.8 ⁇ m and
- the guiding layer is a phosphorus doped silica layer (with a thickness of 2 ⁇ m to 5 ⁇ m depending on the wavelength) and the covering layer, or superstrate, is equivalent, from the point of view from the optical index, to the substrate, with a thickness of 6 ⁇ m to 10 ⁇ m.
- the dimensions of the channels are of the order of 4 ⁇ m x 4 ⁇ m with doping with 1 germanium oxide making it possible to achieve an index jump of the order of 2 ⁇ 10 ⁇ 2 in order to ensure a strong confinement of the mode and to limit crosstalk between guides.
- OFC Optical Fiber Communications
- a larger index jump, of the order of 3 ⁇ 10 -2 , can be achieved by depositing SiON.
- An important advantage of integrated optics on silicon is to be able to simultaneously engrave V-grooves or V-grooves for positioning single-mode optical fibers.
- Another advantage of this technique lies in controlling the slope of the etching flanks (to limit parasitic reflections at the ends of the guides, reflections which generate crosstalk).
- This technique is well suited for producing the component shown in FIG. 4.
- the technique used is that of the thermal exchange of ions such as Na + , K + or Cs + , possibly assisted by an electric field.
- This well-known technique consists in exchanging alkaline ions (for example Na + ions), already present in the glass, with other ions such as Ag + or Tl + which have the effect of locally increasing the refractive index. glass.
- the optical losses due to the fiber / guide connection and attenuation in the guide have been considerably reduced thanks to the technique of buried guides.
- the latter consists in diffusing the first doping into the substrate (under an electric field) or else in performing a second thermal diffusion of sodium ions.
- Guides are thus obtained characterized by quasi-circular doping sections, having a mode conforming to that of a single-mode optical fiber -on optimizes modal overlap- and having much lower linear attenuations due to the virtual disappearance of diffusion surface: it is typically less than 0.1 dB / cm.
- Another advantage of this technique is to be able to produce guides having a very low dependence on polarization, and thus having a less costly design: there is no longer any need to compensate for the effects of birefringence by means of '' a half-wave blade inserted in the middle of the microguides area for example.
- the first masking scheme corresponds to a folded half-phasar (therefore operating in reflection), with a focusing zone of the input beam in a guiding layer, this input beam coming from an optical fiber (see FIGS. 4 and 5).
- the second masking scheme corresponds to a phasar operating in transmission (and therefore not folded), without focusing area in integrated optics: this focusing takes place in free space.
- the first (respectively second) masking scheme corresponds to a suitable housing which is shown in FIGS. 6A and 6B (respectively 7A and 7B).
- FIG. 4 shows a mask of a half-phasar folded according to the first masking scheme.
- the substrate used is a glass disc 8 60 mm in diameter and 1.5 mm thick.
- the useful area, delimited by a dotted circle 10, is restricted to a disc 50 mm in diameter.
- the microguides 12 and the planar guide 14 are obtained by burying the guide layer.
- At least four half-phasars of the kind which is shown in FIG. 4 can be produced by plate.
- plates 8 inches (that is to say about 20 cm) in diameter it becomes possible to form, on a single substrate, eight half-phasars of the kind shown in FIG. 4, and therefore to further reduce manufacturing costs.
- this half-phasar has five cleaved and polished sides cl, c2, c3, c4 and c5.
- 800 microguides 12 separated by 19.8 micrometers from each other form arcs of circles of 60 °.
- the minimum radius of curvature is' 4 mm and the maximum radius of curvature is 19.8 mm.
- the focusing zone F integrated on the planar guide 14 and delimited by the sides c, c 3 and c 2 (FIG. 5), makes it possible to extend all the light emitted of an optical fiber 16 (FIG. 5) on all the microguides without additional focusing optics.
- the numerical aperture of the single-mode optical fibers traditionally used in optical telecommunications is of the order of 0.15 to 0.17 in air, hence a half-angle of divergence of approximately 9 ° to 10 ° in air and about 6 ° to 7 ° in the glass.
- the end of the fiber 16 is thus approximately 55 mm from the interface of the micro-guides. It is specified that this end of the fiber 16 is optically coupled to the planar guide by micrositioning and bonding (“pigtail” technique).
- the sides cl, c2 and c3 must behave as reflectors. To do this, the side cl to which the respective ends of the respective microguides 12 orthogonally end forming concentric arcs of a circle, and possibly the sides c2 and c3 receive a reflective deposit R which may be a metallization or, preferably, a dielectric multilayer whose reflection spectrum is centered on the wavelength domain analyzed.
- a reflective deposit R which may be a metallization or, preferably, a dielectric multilayer whose reflection spectrum is centered on the wavelength domain analyzed.
- the side c5 can receive an anti-reflection multilayer deposit A (in the useful spectral band along the path from the glass to the air).
- the microguide outputs are distributed along a circle with a radius of 250 mm corresponding to the diameter of the Rowland circle on which the image points are dispersed.
- a small image distortion (carried on a circle with a radius of 125 mm) is therefore observed on the flat array of photodetectors, used with the half-phasar (see Figures 6A and 6B), and does not exceed half a pixel at the edge of the field, which therefore allows a flatness correction in the spectral measurement.
- the sides c2, c3 and c4 allow the incident light beam 18 coming from the injection optical fiber 16 to be folded back (FIG. 5). This beam 18 is then naturally extended over all the inputs of the microguides.
- Fiber 16 is offset from the output field.
- the fiber 16 is a single-mode optical fiber of 125 ⁇ m and digital aperture 0.16 and this fiber can be placed close to the axis of the wafer and oriented at about 13 ° relative to this axis.
- the incident wavefront is therefore offset from the front of the microguides and the wavelength ⁇ o defined above then corresponds to the lowest wavelength of the spectrum and no longer to the central wavelength (corresponding in case the fiber is placed in the center).
- the reference 20 designates a separating zone which results, for example, from a diffusion of chromium or cobalt (absorbent at 1.55 ⁇ m).
- the phasar is similar to that which has been described with reference to Figures 4 and 5, except that it is not folded and therefore operates in transmission.
- it has four precisely cleaved sides which are parallel in pairs and an additional cleaved side.
- a first cleaved side corresponding to the entry of the micro-guides makes an angle of 120 ° with a second cleaved side corresponding to the exit of the micro-guides and the third and fourth cleaved sides are respectively parallel to the first and second cleaved sides.
- the additional cleaved side connects the first cleaved side to the fourth and the cleavage of this additional side makes it possible to accommodate a cylindrical lens in the support of a microspectrometer using this phasar as seen in FIG. 7A.
- a spectrometer according to the invention is an assembly of several blocks of elementary micro-spectrometers as we saw above, each elementary micro-spectrometer making it possible to cover a spectral range of 40 nm.
- the superposition of several of these blocks makes it possible to cover a larger spectral range which can be adjusted according to the applications.
- the focusing of the beam at the exit of the spectrometer can be carried out in different ways. It is possible to align several guiding layers by superimposing planar substrates connected together by a 45 ° polishing forming a reflective prism or by a ribbon of single-mode optical fibers.
- the recommended assembly technique consists in placing the planar substrate (comprising the phasar) and the reflective prism as well as the lens and the array of photodetectors in a molded substrate or support, developed by a lithography and electro-forming molding technique, called "LIGA technique" (for Lithography Galvanoformung Abformung).
- LIGA technique for Lithography Galvanoformung Abformung
- the LIGA process allows mass production, and therefore at an optimized cost, of elementary detection blocks, that is to say elementary micro-spectrometers.
- a metal mold is formed by electro-forming (hence an electrolytic growth of the mold) after a high resolution lithography (of the order of l ⁇ m).
- the LIGA X process a special case of the LIGA process, consists in exposing a photosensitive resin ("photoresist"), for example PMMA, through a membrane mask carrying a layer of gold which absorbs X-rays. exposed parts, a layer of metal is deposited by electro-forming until it covers the PMMA pattern and forms a mold which is used to form the final parts by molding or hot stamping of a plastic, techniques suitable for mass production.
- photoresist for example PMMA
- the elementary spectrometer corresponding to a first assembly in accordance with the invention uses the first masking scheme (see FIGS. 4 and 5).
- the planar substrate 22, carrying the half-phasar, is placed guiding layer below and comprises the input focusing part (injection optical fiber 16 - planar guide 14) integrated on the planar substrate 22.
- the light beam diffracted by these micro-guides is recovered at the exit of the planar guide 14 by a reflective prism 24 then focused on a photodetector array 26 by a cylindrical lens 28 whose focal distance is approximately 6 mm.
- Three mirrors 30, 32 and 34 allow the beam to be reflected towards the bar 26, over a distance of 140 mm in free space.
- the diffracted beam coming from the prism is reflected on the mirror 30 then on the mirror 32 which is perpendicular to this mirror 30 then on the mirror 34 which is perpendicular to this mirror 32 and the mirror 34 reflects the beam towards the bar 26.
- the edge of the substrate is at a distance of 6.27 mm from the center of the lens for a focal distance of 6 mm.
- the height of the image beam on the photo-detectors is approximately 120 ⁇ m.
- calibrated spacers 36, 38 and 40 which are respectively arranged on the cleaved sides cl, c4 and c5 of the planar substrate 22, between these sides and the support 42 molded by the LIGA technique, make it possible to position this planar substrate in height and to guarantee that it is parallel to the detection strip 26.
- the three mirrors 30, 32 and 34 as well as the strip 26 rest in notches, such as the notches 44 provided in the support 42.
- the planar guide 14 is buried at a known distance from the upper surface of the planar substrate 22, this surface serving as a reference.
- the elementary spectrometer corresponding to a second assembly in accordance with the invention uses the second masking scheme mentioned above.
- the planar substrate of this second assembly is also placed as a guide layer below.
- the focusing of the light coming from the single mode optical fiber 16 is not done in integrated optics but in free space.
- the fiber is aligned with passively in a groove -46.
- the support 48, intended to receive the planar substrate 50 is formed with the LIGA technique, provided with this groove 46 as well as all the notches which are needed.
- the divergent light beam 52 (whose half-angle of divergence is 8 °) is filtered by a circular opening 54 and then focused by a cylindrical lens 56 of equal focal length at 22 mm placed at equal distance (22 mm) from the planar guide and the fiber.
- the light beam is reflected towards the microguides 60 by a mirror 58 placed at 35 ° and the fiber is inclined by 10 °.
- the focusing parameters are defined by the Gaussian optical conjugation relationships for a guided mode having a half-width (“waist”) of 2.2 ⁇ m.
- the transmitted beam, diffracted by the microguides 60, is recovered at the exit of the planar guide by a reflective prism 62 and then focused on the photodetector array 64 by a cylindrical lens 66 with a focal distance approximately equal to 8 mm.
- This lens 66 can be a piano-convex lens or a Fresnel lens.
- the edge of the planar substrate 50 is at a distance of 8.5 mm from the center of the lens 66 for a focal distance 8 mm.
- the height of the image beam is approximately 100 ⁇ m on the photo-detectors.
- Three mirrors 68, 70 and 72 make it possible to reflect the beam towards the bar over a distance of 175 mm in free space. More precisely, the diffracted beam coming from the prism 62 is reflected on the mirror 68 then on the mirror 70 then on the mirror 72 and the latter reflects the beam towards the bar 64.
- the first mirror 68 makes an angle of 15 °
- the second mirror 70 makes an angle of 75 °
- the third mirror 72 makes an angle of 48 , 75 ° (its normal being oriented by 41.25 ° along the vertical).
- calibrated spacers 74, 76 and 78 which are arranged on cleaved sides of the planar substrate 50, between these sides and the molded support 48, as is seen in FIG. 7A, make it possible to position this planar substrate 50 in height and to guarantee that it is parallel not only to the detection strip 64 but also to the part of the fiber which is in the groove 46 and to the axis of the cylindrical lens 56.
- An elementary micro-spectrometer according to the first assembly (FIGS. 6A and 6B) is capable of occupying a volume of 60 ⁇ 60 ⁇ 9 mm 3 .
- a micro-spectrometer comprising a stack of four elementary blocks makes it possible to cover a spectral range of more than 150 nm (at a wavelength of 1.55 ⁇ m) by superposition according to the following distribution:
- a phasar is sensitive to temperature regardless of the technology with which it is made. This results in variations in the central wavelength ⁇ o of the phasar as a function of temperature, these variations resulting from the thermal expansion of the phasar material and ' variations in the refractive index of this material as a function of the temperature (thermo-optical effect). The central wavelength increases with temperature.
- the thermal dependence of the central wavelength is order of 10 pm / ° C.
- Each of the two proposed assemblies can be temperature controlled by a heating resistor, in order to guarantee the stability of the spectral measurements over time, and the sealing of the assembly can be provided to guarantee the resistance of this assembly to humidity and also guarantee a constant air pressure.
- Another solution consists in providing a mechanical element for compensating for this angular offset.
- a compensation solution consists in actuating one of the mirrors for "folding" the output beam, advantageously the first mirror 30 (FIG. 6A) or 68 (FIG. 7A ) although this principle is adaptable to each of the mirrors.
- This mirror 30 or 68 is engaged, by one of its ends, in a positioning groove 80 ( Figure 8) or 82 ( Figure 9) which serves as a pivot and this mirror 30 or 68 is actuated by a lever arm 84 (figure 8). or 86 ( Figure 9) attached to the other end of the mirror.
- this lever arm is an aluminum bar, engaged in a groove 88 or 90, the coefficient of thermal expansion of which is approximately 23 ⁇ 10 -5 " / ° C.
- the extension by thermal expansion of this bar tilt the mirror and compensate for the angular offset induced by the temperature variation in the planar substrate.
- An inclination of approximately 2.5 ⁇ 10 -5 " rad / ° C. is necessary and performed, for example, by a 20 mm long bar placed 20 mm from the pivot according to FIGS. 8 and 9 which correspond respectively to the first and second assemblies).
- the total distance traveled by light within the spectrometer is around 10 cm, resulting in a loss of propagation of 1 dB (considering an attenuation of 0.1 dB / cm). Connectivity losses and losses at interfaces must be added. Let us therefore consider a total optical loss of the spectrometer of 6 dB.
- An external optical fiber is connected to the planar guide 14 (FIG. 5) so as to be subsequently welded or connected to the optical circuit incorporating one or more sensitive optical fibers.
- This fiber external thus constitutes the optical interface with the external environment (accessible by the end user).
- this external optical fiber is single mode at the wavelength of use (typically 1300 nm, 1550 nm or even 820 nm).
- the fiber-guide connection can be ensured by the V-groove technique.
- the fibers can be connected to the guides by gluing (for example with an adhesive that can be polymerized by ultraviolet radiation) or by laser welding.
- the detection unit is a set of photodiodes or an array of InGaAs photodiodes produced by epitaxy. Bars such as those sold by Thomson can be used.
- the useful detection area is approximately 5 ⁇ m; it is separated by two passivated zones of 8 ⁇ m, hence a period of 13 ⁇ m.
- a high frequency bandwidth (100 kHz) can be achieved by operating the photodiodes in photoconductive mode and by inserting these photodiodes into an electronic assembly of the transimpedance type for example.
- the photodetectors can be directly incorporated into the circuit.
- a matrix of photo-detectors making it possible to form images in two dimensions can also be used instead of several linear bars.
- a polynomial correction between pixel and wavelength is generally implemented due to the distortion of the field observed on the bar.
- 96 (respectively 98) of 800 microguides forming arcs of circles of 60 ° is delimited, on one side, by a cleavage 100 (respectively 102), the side resulting from this cleavage being provided with a reflective deposit 104
- a reflective deposit is not necessary on the cleavage 116 (respectively 118) because, in the example of the figure
- the angle of incidence is sufficient for there to be total reflection for the incident and refracted beams.
- the two half-phasars are first separated by a cleavage 124 before any other operation.
- marks marking the axis of this cleavage for example marks m at the two ends of this axis, can advantageously be photoetched at the same time as the masking for the diffusion of the guide.
- An upper cleavage 126 and a lower cleavage 128 are also formed for mechanical reasons, as seen in FIG. 10.
- the third assembly schematically represented in FIGS. 11A and 11B incorporates the optical component 91 described with reference to FIG. 10, an optical fiber 130 connected to this component by traditional techniques and a mechanical support 132, molded by the LIGA technique and supporting all the optical elements (reflective prism 134, cylindrical lens 136, folding mirrors 138, 140 and 142 and array of photo-detectors 144). It is specified that, in this assembly, the light coming from the optical component 91 is reflected by the reflective prism 134 then focused by the cylindrical lens 136 on the array of photo-detectors 144 after reflection on the folding mirrors 138, 140 and 142 .
- the optical principle of this assembly is identical to that of the first assembly (FIGS. 6A and 6B).
- the cylindrical lens 136 is however placed between the reflective prism 134 and the planar optical component 91 but the distance between the lens and this component is the same as for the first assembly.
- This component also rests on three spacers 146, 148 and 150.
- the optical fiber 130 is advantageously made of germanosilicate, its core (“core”) has a very small diameter (approximately 2 micrometers) and it has a very high index jump (greater than or approximately equal to 0.05).
- This fiber is assembled to the planar substrate 152 of the component 191 by bonding. Fibers of this kind are used for non-linear optics or optical amplification, applications for which a very high light intensity is sought.
- This optical fiber 130 is welded to another optical fiber 154, of the kind used in telecommunications in the wavelength band of 1.55 micrometers. These fibers have a heart of the order of 9 micrometers in diameter and a jump in index of approximately 5 ⁇ 10 -3 .
- An adaptation of the mode of the fiber 130 to the mode of the fiber 154 is carried out in order to weld these fibers 130 and 154 with a minimum of losses.
- the fiber 130 is locally heated to diffuse the dopant (germanium in the example considered) outwards and thus create a progressive variation in the diameter of the core until it adapts to that of fiber 154.
- This technique is known as TEC for Thermally-diffused Expanded Core.
- the optical fiber 130 therefore comprises, at one end, a portion of diffused core fiber 156 onto which the fiber 154 is traditionally welded.
- a spectrometer makes it possible to provide a user with a visual indication of the optical placement of the channels.
- DWDM It is possible to provide feedback signals to laser diode control modules in order to correct a possible drift in the wavelengths of the transmitters.
- This control mode corresponds to pixel-by-pixel addressing. It allows for a dynamically reconfigurable multi-channel receiver.
- Such a spectrometer is compatible with future DWDM specifications. It is characterized by a small footprint, an optimized cost (resulting from collective manufacture) and a large bandwidth, which typically ranges from a few kilohertz to a few hundred kilohertz and depends only on the photodetectors, with or without analysis of the state of polarization.
- the monomode fibers used support two polarization modes due to the birefringence of the silica. These two modes are characterized by two slightly different effective indices.
- the light pulse received is therefore formed of two pulses according to two polarization states, the delay of which changes over time, in particular because of the constraints in the optical cables, these constraints resulting for example from temperature variations.
- Chromatic dispersion has long limited time multiplexing.
- polarization mode dispersion constitutes a new limitation in terms of modulation capacity.
- the large PMD values are defined by the spectral resolution of the spectrometer that is used, while the low PMD values are defined by the spectral range of the observed spectrum.
- a broadband optical source is used and the wavelengths reflected by the various Bragg gratings multiplexed in wavelengths along the measurement line are analyzed.
- Measurement and demultiplexing are carried out simultaneously by addressing to a photodetector array at an optimized cost and with a high frequency bandwidth, all these parameters being important in order to be able to use this type of metrology in the industrial environment.
- an optical micro-system for measuring deformations or temperatures comprising photoaggregated Bragg grating transducers as shown diagrammatically in FIG. 12.
- Such a micro-system can also comprise a balanced four-way coupler (with 50% transmission on the two output channels) which has the reference 158 in Figure 12.
- An optical source 160 with a broad spectral band which can be a superfluorescent source with erbium-doped fiber or else a superluminescent diode, is then connected to an input arm of the coupler 158 while the micro-spectrometer 162 conforms to the The invention is connected to the other input arm of the coupler.
- One of the two output arms of the coupler is, for its part, connected to the end of a sensitive optical fiber 164 on which have been photo-registered several Bragg networks transducers 166 and the other end of which has a cleavage at an angle 168.
- FIG. 12 also shows the means 170 for supplying the source 160, the photodiodes array 172 which is associated with the micro-spectrometer and the electronic means 174 for detecting the signals supplied by the photodiodes array.
- a device according to the invention therefore applies to the monitoring in real time, at high bandwidth (1 kHz), of several constraints or pressures applied to a sensitive optical fiber incorporated in a structure, for example made of composite material.
- This device also applies to demultiplexing and to the measurement of several wavelengths, for example in the field of telecommunications multiplexed in wavelength.
- the great manufacturing flexibility of this device makes it particularly attractive for ultisectoral instrumentation, by easy adjustment of the Bragg wavelengths of the photoinscribed networks, an addressing being then carried out on the array of photo-detectors.
- Such phasars can be manufactured using integrated silica-on-silicon optics technology and a wafer 4 inches in diameter. With this technology we can also process slices of 8 inches (about 20 cm) in diameter. On such a support 175 (FIG. 13) it is possible to form 16 double-phasars 176 of the kind shown in FIG. 10 and therefore 32 phasar components simultaneously (collective manufacturing approach).
- the assemblies 176 are separated by sawing (using a metal blade or a diamond blade) according to an automated digital control procedure
- the saw cut is approximately 200 ⁇ m to 300 ⁇ m wide; it is not shown in FIG. 13.
- the sawing operation can for example start with a separation of bands 178 of double-phasars 176 according to the dotted lines 180 and then continue with an assembly of the bands thus separated and a recutting of these to isolate the patterns of double phasars 176
- the phasars can then be reassembled and sawn along their midline (not shown).
- polishing operations which follow the sawing operation can be carried out simultaneously on a very large number of substrates, which further reduces the cost. It is the same for the operation of forming a reflective deposit mentioned above in the description of Figures 4 and 5. It is also possible to form cleavage marks m as we have seen above, to define the various cleavage lines that are needed, in particular cleavage lines 180.
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Abstract
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Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
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CA002442528A CA2442528A1 (fr) | 2001-03-27 | 2002-03-26 | Spectrometre optique integre a haute resolution spectrale, notamment pour les telecommunications a haut debit et la metrologie, et procede de fabrication |
JP2002575686A JP2004523764A (ja) | 2001-03-27 | 2002-03-26 | 高いスペクトル解像度を有している集積型分光器および特に高速通信と高速測定とのための集積型分光器ならびにその製造方法 |
US10/471,749 US20040141676A1 (en) | 2001-03-27 | 2002-03-26 | Integrated optical spectrometer with high spectral resolution in particular for high-speed telecommunications and metrology and a method for manufactruing same |
EP02722382A EP1377857A2 (fr) | 2001-03-27 | 2002-03-26 | Spectrometre optique integre a haute resolution spectrale et procede de fabrication |
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FR0104080A FR2822949B1 (fr) | 2001-03-27 | 2001-03-27 | Spectrometre optique integre a haute resolution spectrale, notamment pour les telecommunications a haut debit et la metrologie, et procede de fabrication |
FR01/04080 | 2001-03-27 |
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PCT/FR2002/001042 WO2002077687A2 (fr) | 2001-03-27 | 2002-03-26 | Spectrometre optique integre a haute resolution spectrale et procede de fabrication |
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US (1) | US20040141676A1 (fr) |
EP (1) | EP1377857A2 (fr) |
JP (1) | JP2004523764A (fr) |
CA (1) | CA2442528A1 (fr) |
FR (1) | FR2822949B1 (fr) |
WO (1) | WO2002077687A2 (fr) |
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CN1217762C (zh) * | 2001-06-10 | 2005-09-07 | 山东威达机械股份有限公司 | 自锁钻夹头 |
US7254290B1 (en) * | 2004-05-10 | 2007-08-07 | Lockheed Martin Corporation | Enhanced waveguide metrology gauge collimator |
US20070086309A1 (en) * | 2005-10-16 | 2007-04-19 | New Span Opto-Technology Inc. | Method and Device for High Density Optical Disk Data Storage |
CN103314276B (zh) * | 2010-12-22 | 2016-08-10 | 奥姆尼森股份公司 | 布里渊光电测量方法和设备 |
US9464883B2 (en) | 2013-06-23 | 2016-10-11 | Eric Swanson | Integrated optical coherence tomography systems and methods |
US9683928B2 (en) | 2013-06-23 | 2017-06-20 | Eric Swanson | Integrated optical system and components utilizing tunable optical sources and coherent detection and phased array for imaging, ranging, sensing, communications and other applications |
US10606003B2 (en) * | 2013-08-02 | 2020-03-31 | Luxtera, Inc. | Method and system for an optical coupler for silicon photonics devices |
JP6395389B2 (ja) * | 2014-02-05 | 2018-09-26 | 浜松ホトニクス株式会社 | 分光器 |
JP6613063B2 (ja) * | 2015-07-07 | 2019-11-27 | 大塚電子株式会社 | 光学特性測定システム |
US11635344B2 (en) | 2019-02-01 | 2023-04-25 | Optikos Corporation | Portable optic metrology thermal chamber module and method therefor |
JP7198127B2 (ja) * | 2019-03-20 | 2022-12-28 | 株式会社アドバンテスト | インタポーザ、ソケット、ソケット組立体、及び、配線板組立体 |
CN113358571B (zh) * | 2021-07-06 | 2023-01-20 | 中国科学院物理研究所 | 一种光参量放大荧光光谱仪 |
US12085387B1 (en) | 2023-09-23 | 2024-09-10 | Hamamatsu Photonics K.K. | Optical coherence tomography system for subsurface inspection |
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- 2002-03-26 WO PCT/FR2002/001042 patent/WO2002077687A2/fr not_active Application Discontinuation
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Also Published As
Publication number | Publication date |
---|---|
US20040141676A1 (en) | 2004-07-22 |
WO2002077687A8 (fr) | 2004-06-10 |
EP1377857A2 (fr) | 2004-01-07 |
WO2002077687A3 (fr) | 2003-10-30 |
JP2004523764A (ja) | 2004-08-05 |
CA2442528A1 (fr) | 2002-10-03 |
FR2822949A1 (fr) | 2002-10-04 |
FR2822949B1 (fr) | 2004-01-09 |
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