FR2734650A1 - DEVICE FOR CONNECTING INTEGRATED OPTICAL COMPONENTS AND APPLICATION OF THE DEVICE - Google Patents

Abstract

Device characterized in that the substrates (10, 20) and the integrated optical components (11, 21) to be connected are superimposed, the integrated optical components (11, 21) have, at the level of the ends to be connected, in the optical path, side surfaces (12, 22) inclined relative to each other and the side surfaces (12, 22) are inclined so that light from the first integrated optical component (11) radiates to the first inclined side surface (12) to be reflected there and arrives on the inclined second side surface (22) to be reflected there towards the second integrated optical component (12).

Description

State of the art.

  The invention relates to a device for connecting

  integrated optical components provided on different substrates

  rents. The invention also relates to the application of this device.

  According to the state of the art, circuits are known.

  integrated optical circuits having optical waveguides and

  passive optical components such as beam splitters

  ceaux, derivations or selective components vis-à-vis

  wavelengths. Other integrated optical circuits

  carry active optical components such as amplification waveguides doped with erbium. In some

  case, for technical reasons, it is not possible to

  briquetting optical components of very different natures on the same substrate. Thus, for example, to manufacture amplifier waveguides doped with erbium, it

  other glass substrates are needed than those used in the manufacture

  tion of optical couplers, taps or dividers

bundles.

  This is why an optical device comprising

  integrated optical components produced using incom-

  different or different substrate materials requires at least two substrates with integrated optical components, the optical paths of which must be connected. According to the state of the art, an optical link is thus required by coupled fibers or

  by coupling the front surfaces.

  The connection by optical fibers is very complicated.

  quée because, for each optical path, it is necessary to couple twice each fiber. In the case of a frontal surface coupling of

  two integrated optical substrates we can certainly couple in

  with several optical paths, but for this you need a supp-

  very precise common port to connect the two substrates, to meet the necessary coupling tolerances and to

  sufficient mechanical strength.

  Based on this state of the art, the present

  object of the invention is to create a device allowing

  to link the integrated optical components, which is of simple construction and ensures a high degree of coupling; the invention has

  also aim an application for this device.

  To this end, the invention relates to a device of the type defined above, characterized in that the substrates and the integrated optical components to be connected are superimposed, the

  integrated optical components present, at the extremities

  tees to connect, in the optical path, lateral surfaces inclined with respect to each other and the lateral surfaces are inclined so that the light from the first integrated optical component radiates to the first inclined lateral surface to be reflected therein and arrives on the second inclined side surface to be reflected therein towards the second integrated optical component. According to other advantageous characteristics of the invention: - at least one of the inclined lateral surfaces is provided with a reflecting surface, - the lateral surfaces are inclined so that the light from the integrated optical components undergoes total reflection,

  - the optical paths of the optical components

  tégrés are in parallel planes at the ends to be connected and that the sum of the angles of inclination of the inclined side surfaces is 90 relative to one of the parallel surfaces, - the transparent substrates include adjustment marks for the active adjustment, cavities and complementary bosses on the substrates allow passive adjustment,

  - the substrates have cavities for receiving

  see adjustment elements allowing passive adjustment, - the substrates are arranged one on the other, - the substrates are fixed one on the other by gluing or bonding, - the substrates are fixed one to the other by a

middle layer.

  The invention also relates to an application of a

  such a device, characterized in that the first substrate comprises

  carries passive integrated optical components and the second

  substrate has an integrated optical waveguide structure

  active rig connected to passive components.

  The present invention relates to a device

  putting to connect at least two substrates with optical components

  integrated, following a very solid and weak link

  ble optical damping, for the optical paths to be connected.

  Adjustment marks allow active precision adjustment. Passive adjustment is carried out if in the substrates additional structures or cavities are provided for

receive adjustment elements.

  The device according to the invention makes it possible to connect several substrates which are appropriately superimposed.

  An exemplary embodiment of the invention will be shown

  crit below in more detail using the accompanying drawings in which: - Figure 1 is a cross section of a device according to the invention with waveguide structures, - Figure 2 is a top view of the device of FIG. 1, the substrates being transparent, FIGS. 3 to 5 show known devices with an optical fiber amplifier of bi-directional transmission and wavelength multiplexing systems, - FIGS. 6a 6c represent the application of a

  device according to the invention to an optical fiber amplifier for bi-directional transmission systems.

  According to the figures, the device consists of a substrate 10 having a waveguide structure 11 and on this a second substrate 20 with a waveguide structure 21. The substrates are fixed by a contact surface common 40 so that the faces of the waveguide structures are opposite one another. Each of the substrates has at least one front face 12, 22 at an angle at an angle a ,, c2 such that: 35 a1 + a2 = 90 The front faces at an angle 12, 22 are turned

  towards each other and together form a rectangular 30

  convex surface for the overall structure formed of the substrates 10 and 20. The ends to be coupled of waveguide structures 11 and 21 abut on the oblique front surfaces 12, 22 and are superposed there in the case where the light guides to both are perpendicular to the edge of the substrate. When the waveguide structure 11 'of the lower substrate 10 makes an angle y, with respect to the normal of the edge of the substrate (see FIG. 2), the waveguide structure 21' must be coupled, in the upper substrate 20, make an angle Y2 = -y ,. The projections of the axes of the waveguide structures 11 'and 21' on the connection surfaces 40 between the substrates

  and 20 intersect along edge 30.

  The light beam guided by the structure 11 is reflected by the front surface 12 as a free beam

  13, upwards through the connecting surface 40 to reach

  worm in the substrate 20 and fall on the front surface 22.

  This again reflects the beam in the structure 21 to guide it. As the surfaces of the substrates 10 and 20 which carry the waveguide structures 11 and 21 are opposite one another, the path of the free beam 13 is very short. Even in the case of buried waveguides, whose

  axes are located up to 10 gm below the surface of each

  as substrate, the optical path of the free beam 13 is only 20 gm long. For a free beam with a Gaussian type profile and a radius adapted to a single mode fiber, of 5 μm, for a refractive index of the substrate ns = 1.5 and a length

  wave in the air equal to 1.55 gm, we have a yield of

  98.3% range, which corresponds to a coupling loss of

  -0.074 dB. The optical path coupling of the elementary substrate

  upper cover 20 in the lower elementary substrate 10

is possible in the same way.

  The device according to the invention has the advantage

  compact construction with no more clutter -

  ment on the surface for two substrates than for one substrate. Attachment over the entire surface for the two substrates 10, 20

  gives a very solid construction. The adjustment of the two subs-

  trats relative to each other can be done, either actively or passively, and for this one can use adjustment marks 16 and 26 provided on the two surfaces to

  unite and that we see simultaneously in the substrates in giant

  transparent or by using a milking system

ment of images.

  Another method for aligning the two substrates 10 and 20 consists in producing cavities 17 and complementary bosses 27 on the surfaces or alternatively cavities 18 and 28 in the two surfaces and using adjustment elements

  19, distinct, such as balls or cylinders very pre-

  cis. Fixing the two substrates 10 and 20 to each other

  can be done according to the state of the art by gluing or bonding

  its anodic, possibly with an intermediate layer, if necessary. It is only important that this connection is transparent for the wavelengths used, at least

  less at the level of the free beams 13 to be coupled.

  In the optical information transmission technique, optical fiber amplifiers are required to compensate for the power losses and the distribution losses downstream of the beam splitters. For this, amplifying fibers doped with erbium are used or alternatively optical waveguides integrated with doping with erbium; the useful signal to be amplified and the pumping light are injected therein by the beam splitters. Corresponding systems use the wavelength X1 = 1550 nm, which is pumped by wavelengths C = 850 nm, 980 nm or 1480 nm, for the direction of flow from the central to the subscribers. For the return direction, for example, a wavelength X2 =

1300 nm.

  This light must not pass through the am-

  plifiers in the direction of return, because the light would be too strongly attenuated. This is why it is necessary to plan for the

  return direction, either a second fiber, or for a transmission-

  in both directions with the same fiber, a deviation around the optical amplifier by selective wavelength coupling. When the bit rates are low for the return direction and there is a low division ratio with very few subscribers, it is possible to suppress the amplification of the signals from the subscribers to the central office for the return direction. If there are many subscribers with bit rates

  high in the return channel, it requires an amplification

signal property.

  According to the state of the art, optical amplifiers are also known for signals with a wavelength of 1300 nm with then pumping with light with a wavelength of 1017 nm. If the direction of return must also be amplified optically according to the state of the art,

  either use such an optical amplifier in the se-

  conde fiber for the return, either use a fiber for both directions with a deflection around the amplifier

optics for the forward direction.

  These solutions are shown in Figures 3 and 4.

  FIG. 3 shows an amplifying installation for two separate fibers for the forward direction with the fiber F1 of wavelength X1 and for the return direction the fiber F2 and the wavelength X2- The signal for the forward direction is amplified by l optical amplifier Vl into which the light of

  wavelength pumping Pl. Similarly, the direction signal

  turn is amplified by the amplifier V2 in which we inject

  pumping light of wavelength X2-

  FIG. 4 shows a damping device with only one transmission fiber F12 for the forward direction and the return direction. Return direction signals bypass

  amplifier V1 by the two wavelength couplers

  lective K1, K2 and are amplified by the amplifier V2.

  Optical amplifiers can be used at the same time for forward and backward amplification for a single transmission fiber.30 Figure 5 shows the block diagram of such a

  device. The wavelength X1 for the forward direction and the long

  feeder X2 for the return direction are close enough to

  allow their joint amplification in the op amplifier

  tick V12. For the forward direction, the signal to be amplified coming from the central by the transmission fiber F12Z on the side of the central (wavelength k1) arrives by the input port E in the amplifier device; this signal is amplified there by the optical amplifier V12 pumped by the pumping light of wavelength C; the signal arrives through the output port A in the transmission fiber F12T corresponding to the side of the subscribers. The return signal sent by the subscribers, coming from the transmission fiber of the F12T subscribers, is transmitted from the port A via a first coupler K1 selective with respect to wavelengths, a first bypass U1 and a second selective coupler at wavelengths K2 at the input of the optical amplifier V12. The return signal y

  is amplified at the same time as the go signal.

  The amplified return signal is coupled by a

  third wavelength selective K3 coupler, the

  second branch U2 and the fourth wavelength selective coupler K4, in the transmission fiber F12Z on the side of the power plant. The many passive components required such as selective wavelength couplers and taps are produced by fiber optic components

  or by integrated optical components. The solution of the

  The integrated optical health has the advantage of being more compact, weaker and easier to handle and in particular for

  the integration of many components the solution is less cost-

teuse and easier to reproduce.

  Similarly, for the realization of the amplified part

  catrice, next to the known solution using op-

  we proposed an optical amplifier waveguide using a special glass with doped waveguides

with erbium.

  For technical reasons, for the manufacture of integrated passive optical components such as leads,

  beam splitters, injectors or couplers

  wavelength readings, other glasses are required than for the manufacture of amplifier doped waveguides by

  erbium. The necessary meeting in itself of all the compo-

  Passive and active health on the same glass substrate is therefore not possible for technical reasons. According to

  the invention a solution is proposed for an optical amplifier.

  than using two different glass substrates but offering the same compactness as if all active and passive components

  were integrated into a single substrate.

  Figure 6a shows in section the two substrates S1

  with the WL1 waveguide structure for the op-

  passive ticks and S2 with an amplified waveguide structure

  active ficatrice WL2. The two substrates are brought together so that the faces with the waveguide structures are facing each other

  one from the other. On at least one lateral surface Sp of the subs-

  trat If we have the ports for input E, outputs A1, An and

  the pumping light source P. At least one side surface

  rale Skl of the substrate Si and at least one lateral surface Sk2 of the substrate S2 are polished at an angle and lie opposite one another so that the two lateral surfaces at an angle Skl and

  Sk2 form a right angle between them.

  Figure 6b shows a waveguide structure

  passive WL1 in the substrate Si and Figure 6c shows the struc-

  amplification waveguide structure WL2 in the substrate S2.

  The coupling of the light between the waveguide structures WL1 and WL2 is done by a total double reflection or, if necessary, by reflection on the mirror layers at the level of the biased lateral surfaces Skl, Sk2 in the connection ports.

  VAl and VE1 or VA2 and VE2 aligned with each other.

  The WL1 light guide structure according to fig.

  gure 6a contains all the coupling and connection elements

  liabilities required for optical amplifiers as an

  integrated optical elements whose purpose has been described in connection with the

  figure 3. In addition, we have a beam splitter according to the ratio

  port l / n, bearing the reference Tn; this divider Tn presents n

  Al ... An output ports, integrated.

  As an example, Figure 6c shows a structure

  amplifying waveguide structure in the form of a spi-

  rale. One can also envisage other waveguide structures making it possible to arrive at the necessary wavelength without exceeding the minimum curvature imposed on the waveguide; optical path intersections and reflections on

  appropriate reflection surfaces, as well as on the edges

  substrates are allowed.

Claims (9)

R E V E N D I C A T IONS   1) Device for connecting integrated optical components provided on different substrates, characterized in that the substrates (10, 20) and the integrated optical components (11, 21) to be connected are superimposed, the integrated optical components (11, 21) have, at the ends to be connected, in the optical path, lateral surfaces (12, 22) inclined with respect to each other and - the lateral surfaces (12, 22) are inclined so that the   light from the first integrated optical component (11) radiates up to   than at the first inclined lateral surface (12) to be there   bent and arrives on the second inclined lateral surface (22) to be reflected there towards the second integrated optical component (12).   2) Device according to claim 1, characterized in that at least one of the inclined side surfaces (12, 22) is   provided with a reflective surface.   3) Device according to claim 1, characterized in that   the lateral surfaces (12, 22) are inclined so that the light   integrated optical components (11, 21) undergo a total flexion.   4) Device according to one of claims 1 to 3,   characterized in that the optical paths of the integrated optical components are in parallel planes at the ends to be connected and that   the sum of the angles of inclination of the inclined lateral surfaces   born (12) is 90 relative to one of the parallel surfaces the.    ) Device according to any one of claims 1 to 4,   characterized in that the transparent substrates (10, 20) have marks   adjustment (16, 26) for active adjustment.   6) Device according to one of claims 1 to 4,   characterized by cavities (17) and complementary bosses (27) on the   substrates (10, 20) allowing passive adjustment.   7) Device according to any one of claims 1 to 4, characterized in that   the substrates (10, 20) have cavities (18, 28) for   have adjustment elements (19) allowing the adjustment not sif.   8) Device according to any one of claims 1 to 7, characterized in that   the substrates (10, 20) are arranged one on the other.   9) Device according to any one of claims 1 to 7,   characterized in that the substrates (10, 20) are fixed to each other by gluing or bond.    ) Device according to any one of claims 1 to   7, characterized in that the substrates (10, 20) are fixed to each other by an intermediate layer.   11) Application of a device according to any one of the re-   vendications 1 to 10, to an optical amplifier for systems   mes of bi-directional transmission, characterized in that   the first substrate (S1) comprises integrated optical components   passive sandstone (WL1) and the second substrate (S2) has an active integrated optical waveguide structure (WL2) connected passive components (WL1).