U.S. Philips Corporation

Giok D Khoe

Antonius J Nicia

Adrianus J Franken

Cornelis M Jochem

Lambertus J Meuleman

Dieter Kuppers

Johannes H Van Leest

Kieran G Wright

Gerard Kuyt

Hans-Jurgen Lydtin

Peter K Bachmann

Hendrikus G Kock

Cornelis J Potters

Henricus M De Vrieze

Robert G Gossink

Tullio E Rozzi

Johannes M Van Esdonk

Coen T Liedenbaum

Pieter W Hooijmans

John J Reid

Christiaan H Velzel

Hendricus F Smulders

Peter J De Waard

Gerard A Acket

Bernhard Schmidt

Pol A Gustin

Abram Van De Grijp

Lodewijk J Van Ruyven

Martinus L Thoone

Gijsbrecht C Wirtz

Johannes H Angenent

Johannes T Kluitmans

Ching K Wong

Laurentius C Vroomen

Antonius H Swemmers

Friedrich Krahn

Cornelis H Van Den Brekel

Henricus W Smulders

Johannes H Van Heuven

Louis M Faessen

Joannes P Gieles

Jacob Langerhorst

Franciscus M Coolen

Karl H Schelhas

Paul D Kuppers

Josephus H Poulissen

Dieter Rittich

Cathal J Mahon

Mahon, Cathal J

Andreas H Hoovers

Gathal J Mahon

In an optical soliton transmission system an optical transmitter (2) generating short pulses is coupled to a glass fiber cable (4) comprising sections of glass fiber (7, 9, 11, 13, 15) with interspaced semiconductor laser amplifiers (8, 10, 12, 14). An optical receiver (6) is connected to the end of the glass fiber cable (15). In optical soliton transmission Erbium doped fiber amplifiers and dispersion shifted fiber are currently used in the 1.5 .mu.m wavelength region. However, by utilizing standard fiber in the 1.3 .mu.m wavelength region it is possible to use a lower soliton power compared with a state-of the-art transmission system.

Optical soliton transmission system

A device for optical heterodyne detection is described, using only two adjustable elements influencing the state of polarisation and having a limited control range (51, 52) in order to realize an endless polarisation control. In a first embodiment a temporary loss of signal intensity of at most 3 dB is accepted. This signal loss is avoided if a circuit of non-adjustable optical components (81, 82, 83) is incorporated in the heterodyne detection device.

Device for optical heterodyne or homodyne detection of an optical signal

In an optical telecommunication system having a direct-access optical transmission medium, a plurality of send/receive terminals may communicate with each other on different optical carriers. In order to make it possible for a terminal which is already in communication with a second terminal to also transmit to or receive a message from a third terminal, each terminal includes modulation and demodulation circuits for modulating/demodulating particular message signals on particular subcarriers. Signals received from different terminals can thereby be distinguished from each other on the basis of their respective subcarriers.

Coherent optical telecommunication network wherein each send/receive

An optical coherent receiver including apparatus for preventing radiation from the local oscillator (40) from being reflected in the transmission fibre (10). As a result this radiation, after reflection on imperfect couplings (11, 12, 13) in the transmission fibre, is prevented from reaching the receiver again and from detrimentally influencing the received signal. Reflection of local oscillator radiation is prevented by obliquely polishing entrance and exit faces of fibres (51, 52, 61, 62), by providing anti-reflection coatings (50', 60', 53', 54', 63', 64') on the appropriate faces and by arranging an optical isolator behind the input (20) of the coherent receiver.

Optical coherent receiver

In an optical heterodyne or homodyne receiver an optical system (140) is used in which the local oscillator beam (L) is combined with the signal beam (S). Simultaneously, these beams are split into orthogonally polarized sub-beams. For this purpose the optical system (140) comprises polarization-sensitive beam-splitting layers (141a and 141b) and neutral beam-splitting layers (142a and 142b) which function as beam-combining elements. In order to align the directions of the exit sub-beams of the signal beam (.sub.11, S.sub.12, S.sub.2, S.sub.22) and the local oscillator beam (L.sub.11, L.sub.12, L.sub.21, L.sub.22), the angles (.alpha., .beta., .gamma., .delta.) enclosed by the beam-splitting faces are chosen to be such that two angles located opposite each other have a combined magnitude of 180.degree.. This is realised by providing the layers (141a, 142b and 141b, 142a) on side faces of one prism (140a, 140b).

Device for optical heterodyne detection and mirror system suitable for

An optical heterodyne or homodyne receiver comprises an integrated optical component (140) in which the local oscillator beam and the signal beam are combined and simultaneouly split into orthogonally polarized sub-beams. The optical component comprises a polarization-sensitive beam-splitting layer in a first face (141) and a second beam-splitting layer in a second face (142) which is perpendicular thereto. This second layer functions as a beam-combining element in the optical receiver and has two distinct portions (142a and 142b), one portion (142a) of which passes and reflects one state of polarization (s) to the desired extent and the other portion (142b) having this property for the other state of polarization (p).

Device for optical heterodyne detection and optical component suitable

An optical fibre of the single-mode type in which light travels in one polarization mode is formed from a single-mode quadruple-clad fibre, in which the dimension of the light-transmitting part of the fibre in a first direction perpendicular to the axis of the fibre differs from the dimension of the light-transmitting part in a second direction perpendicular to the axis of the fibre and the first direction.

Polarization-maintaining single-mode optical fibre and method of making

A ball lens connector part having low total reflections as well as a method of manufacturing such a ball lens connector part are described. The total reflections can be limited to less than -60 dB by means of the present ball lens connector part. The ball lens connector part comprises a fiber with an inclined fiber end in a tubular housing which housing further comprises a ball lens. If the ball lens comprises a flat surface, the total reflections can be lower than -80 dB. By subjecting the end of the housing to a machining treatment, the center line of the said end is moved in such a manner that it coincides with the optical axis of the emanating light beam.

Low-reflection ball lens connector part

An optical heterodyne or homodyne receiver includes a single constructively integrated optical component which combines a local oscillator beam with a signal beam to derive oppositely phased combined beams and further splits each of the combined beams into orthogonally polarized sub-beams. The integrated optical component has a polarization-sensitive beam-splitting layer in a first plane and a polarization-insensitive beam-splitting layer in a second plane, the two planes being perpendicular or parallel to each other.

Optical heterodyne detection and integrated optical component suitable

In an optical transmission device comprising a plurality of semiconductor lasers (.lambda..sub.1, . . . , .lambda..sub.N) for transmitting an equal plurality of information streams, the wavelengths of the radiation beams from the lasers are stabilised by successively selecting them and then measuring them by means of a wavelength meter (20) and subsequently by correcting them. Since the wavelength of the radiation emitted by each laser may vary within limits imposed by neighbouring wavelengths, a high measuring rate of the wavelength meter is not required.

Optical transmission device

The connector comprises two coupling elements (1) in each of which end parts of light conducting fibres (9) are secured mutually in parallel beside each other in such a manner that the centers of their end faces (15) are situated on one line (17) in an end face (19) of the coupling element (1). The connector further comprises a connector housing (25) for receiving the two coupling elements (1). Each coupling element (1) has a cylindrical outer surface (20) the axis of which coincides with the axis of the light conducting core of one of the fibre end parts (9) secured therein (preferably the central one) and which is capable of cooperating with a centring member (27) of the connector housing (25). Each coupling element furthermore has an orientation element (23) which is capable of cooperating with an orientation member (29) of the connector housing (25). As a result of this the cylindrical outer surfaces (20) of the two coupling elements (1) are located with their axes in the elongation of each other and the lines (17) on which the centers of the fibre end faces (15) are located are mutually parallel. As a result of this an optimal coupling between each pair of light conducting fibres (9) is ensured.

Connector for the detachable connection of light conducting fibres

A device is described for optically coupling a radiation source unit to at least one optical monomode transmission fiber. The fiber core has a tapered end portion by which it can be connected to a known radiation source housing without very stringent requirements on the positional accuracy of the fiber relative to the optical components in the housing.

Device for optically coupling a radiation source to an optical

A monomode optical transmission fibre (1) is described, having a tapered end portion (5) on which a lens (10) is arranged. This lens is obtained by immersing the fibre end in a transparent liquid material (7) whose melting temperature is lower than that of the fibre materials and whose refractive index is substantially equal to that of the fibre core (2), and by allowing the drop which adheres to the fibre after withdrawal to solidify.

Monomode optical transmission fibre having a tapered end portion

The device comprises at least a carrier (1) with a flat surface, in which centering grooves (5) are provided for the play-free take-up of an end section (13) of a light-conducting fibre (3) from which its protective cover (11) has been removed. The length of the centering groove (5) is at most equal to five times the diameter of the light-conducting fiber (3) without protective cover (11) and in the line with the centering groove a supporting groove (7) linking up with the centering groove is provided, the width of which is between 5 and 10 .mu.m greater than that of the centering groove. The supporting groove (7) serves to take up with play a second section (15) of the fibre (3) linking up with the end section (13) and from which the protective cover has likewise been removed. Thanks to the short length of the centering groove (5) temperature changes have no significant effect on the position of the end section (13) in spite of the different coefficients of expansion of the carrier (1) and the fibre (3).

Light-conducting fibres connecting device with reduced temperature

An optical transmission system is described which comprises a radiation source (30) and a multiple-clad monomode optical transmission fibre (10) with a negative-step index profile. In order to improve the efficiency of coupling the radiation from the source into the transmission fibre a single-clad-monomode transmission fibre (20), whose end portion which faces the source is tapered, is arranged between the source and said fibre.

Optical transmission system comprising a radiation source and a

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Eindhoven, Netherlands

Giok D Khoe