A method of forming an imaging fibre apparatus comprises arranging rods to form a plurality of stacks each comprising a respective plurality of rods, wherein: for each stack, the respective plurality of rods comprises rods having different core sizes, the rods of different core sizes being arranged in a selected arrangement, and the rods of different core sizes being arranged such that each stack has a respective selected shape; wherein the selected shape or shapes are such that the stacks stack together in a desired arrangement; the method further comprising: drawing each of the plurality of stacks; stacking together the plurality of drawn stacks together in the desired arrangement to form a further stack; drawing the further stack; and using the drawn further stack to form an imaging fibre apparatus, wherein the selected arrangement of the rods in each stack and the selected shape or shapes of the stacks are such that the further stack comprises a repeating pattern of rods of different core sizes.

A method of forming an imaging fibre apparatus comprises arranging rods to form a plurality of stacks each comprising a respective plurality of rods, wherein: for each stack, the respective plurality of rods comprises rods having different core sizes, the rods of different core sizes being arranged in a selected arrangement, and the rods of different core sizes being arranged such that each stack has a respective selected shape; wherein the selected shape or shapes are such that the stacks stack together in a desired arrangement; the method further comprising: drawing each of the plurality of stacks; stacking together the plurality of drawn stacks together in the desired arrangement to form a further stack; drawing the further stack; and using the drawn further stack to form an imaging fibre apparatus, wherein the selected arrangement of the rods in each stack and the selected shape or shapes of the stacks are such that the further stack comprises a repeating pattern of rods of different core sizes.

A flexible light guide that has a homogeneous light emission with high luminance is provided. The flexible light guide is provided by a side-emitting light guide. The side-emitting light guide includes a light-guiding fiber designed as a side-emitting fiber so that light guided in the fiber is scattered out along a longitudinal direction in a distributed manner. The guide also includes a tube that surrounds the fiber. The tube is designed to be light-scattering and translucent so that light emitted from the fiber can traverse the tube with scattering. The tube is surrounded by a cladding. The tube and cladding are made of plastic.

An apparatus for concentrating light from a light source includes a plurality of fibers that are substantially parallel with one another. Each fiber includes a light-receiving end and a light-transmitting end. The light-receiving end is configured to receive the light from the light source. The light-transmitting end is configured to transmit the light from the fiber. The light-receiving ends the fibers extend different distances from a plane that is perpendicular with respect the fibers.

According to one aspect, the invention concerns a device for transporting and controlling light pulses for lensless endo-microscopic imaging and comprises: a bundle of N monomode optical fibers (F.sub.1) arranged in a given pattern, each monomode optical fiber being characterized by a relative group delay value (Ax) defined relative to the travel time of a pulse propagating in a reference monomode optical fiber (F.sub.0) of the bundle of fibers (40), an optical device for controlling group velocity (50) comprising a given number M of waveplates (P.sub.j) characterized by a given delay (8t.sub.j); a first spatial light modulator (51) suitable for forming from an incident light beam a number N of elementary light beams (B.sub.i) each of which is intended to enter into one of said optical fibers, each elementary beam being intended to pass into a given waveplate such that the sum of the delay introduced by said waveplate and the relative group delay of the optical fiber intended to receive said elementary light beam is minimal in absolute value; a second spatial light modulator (52) suitable for deviating each of the N elementary light beams such that each elementary light beam penetrates into the corresponding optical fiber perpendicularly to the entrance face of the optical fiber.

According to one aspect, the invention concerns a device for transporting and controlling light pulses for lensless endo-microscopic imaging and comprises: a bundle of N monomode optical fibers (F.sub.1) arranged in a given pattern, each monomode optical fiber being characterized by a relative group delay value (Ax) defined relative to the travel time of a pulse propagating in a reference monomode optical fiber (F.sub.0) of the bundle of fibers (40), an optical device for controlling group velocity (50) comprising a given number M of waveplates (P.sub.j) characterized by a given delay (8t.sub.j); a first spatial light modulator (51) suitable for forming from an incident light beam a number N of elementary light beams (B.sub.i) each of which is intended to enter into one of said optical fibers, each elementary beam being intended to pass into a given waveplate such that the sum of the delay introduced by said waveplate and the relative group delay of the optical fiber intended to receive said elementary light beam is minimal in absolute value; a second spatial light modulator (52) suitable for deviating each of the N elementary light beams such that each elementary light beam penetrates into the corresponding optical fiber perpendicularly to the entrance face of the optical fiber.

A waveguide is provided for transmitting electromagnetic waves, in particular for transmitting image information, from a proximal end to a distal end, along a transport direction running between the ends and a via a cross-section running transversely to the transport direction. The waveguide has a plurality of structural elements, wherein at least two different types of structural elements have a first type with a first refractive index and a second type with a second refractive index. Each of the structural dements extends along the transport direction and over a part of the cross-section of the waveguide such that a plurality of cross-sectional regions are defined in the cross-section of the waveguide, each cross-sectional region corresponding to the cross-section of an individual structural element.

A waveguide is provided for transmitting electromagnetic waves, in particular for transmitting image information, from a proximal end to a distal end, along a transport direction running between the ends and a via a cross-section running transversely to the transport direction. The waveguide has a plurality of structural elements, wherein at least two different types of structural elements have a first type with a first refractive index and a second type with a second refractive index. Each of the structural dements extends along the transport direction and over a part of the cross-section of the waveguide such that a plurality of cross-sectional regions are defined in the cross-section of the waveguide, each cross-sectional region corresponding to the cross-section of an individual structural element.

An intravascular or other 2D or 3D imaging apparatus can include a minimally-invasive distal imaging guidewire portion. A plurality of thin optical fibers can be circumferentially distributed about a cylindrical guidewire core, such as in an spiral-wound or otherwise attached optical fiber ribbon. A low refractive index coating, high numerical aperture (NA) fiber, or other technique can be used to overcome challenges of using extremely thin optical fibers. Coating and ribbonizing techniques are described. Also described are non-uniform refractive index peak amplitudes or wavelengths techniques for FBG writing, using a depressed index optical cladding, chirping, a self-aligned connector, optical fiber routing and alignment techniques for a system connector, and an adapter for connecting to standard optical fiber coupling connectors.

An intravascular or other 2D or 3D imaging apparatus can include a minimally-invasive distal imaging guidewire portion. A plurality of thin optical fibers can be circumferentially distributed about a cylindrical guidewire core, such as in an spiral-wound or otherwise attached optical fiber ribbon. A low refractive index coating, high numerical aperture (NA) fiber, or other technique can be used to overcome challenges of using extremely thin optical fibers. Coating and ribbonizing techniques are described. Also described are non-uniform refractive index peak amplitudes or wavelengths techniques for FBG writing, using a depressed index optical cladding, chirping, a self-aligned connector, optical fiber routing and alignment techniques for a system connector, and an adapter for connecting to standard optical fiber coupling connectors.