The invention concerns a Photonic Crystal Fiber (PCF) a method of its production and a supercontinuum light source comprising such PCF. The PCF has a longitudinal axis and comprises a core extending along the length of said longitudinal axis and a cladding region surrounding the core. At least the cladding region comprises a plurality of microstructures in the form of inclusions extending along the longitudinal axis of the PCF in at least a microstructured length section. In at least a degradation resistant length section of the microstructured length section the PCF comprises hydrogen and/or deuterium. In at least the degradation resistant length section the PCF further comprises a main coating surrounding the cladding region, which main coating is hermetic for the hydrogen and/or deuterium at a temperature below Th, wherein Th is at least about 50° C., preferably 50° C.<Th<250° C.

The invention discloses a preparation method and device of active microcrystalline fiber, place the prefabricated rod in the drawing furnace for wire drawing, the drawn fiber is induced by magnetic field in uncoated state and combined with laser treatment technology, the laser beam is focused on the fiber and recrystallized after laser treatment to obtain active microcrystalline fiber. Appropriate laser processing power directly affects the silicate glass fiber in the crystal structure, type, degree of crystallinity, grain size, content, and how much residual phase of glass. Induced by external magnetic field, the thermodynamics and dynamics of crystallization process are changed, make the crystal size distribution is better and uniform, reduce the phenomenon of condensation and makes the grain size is smaller.

The invention discloses a preparation method and device of active microcrystalline fiber, place the prefabricated rod in the drawing furnace for wire drawing, the drawn fiber is induced by magnetic field in uncoated state and combined with laser treatment technology, the laser beam is focused on the fiber and recrystallized after laser treatment to obtain active microcrystalline fiber. Appropriate laser processing power directly affects the silicate glass fiber in the crystal structure, type, degree of crystallinity, grain size, content, and how much residual phase of glass. Induced by external magnetic field, the thermodynamics and dynamics of crystallization process are changed, make the crystal size distribution is better and uniform, reduce the phenomenon of condensation and makes the grain size is smaller.

It is an object of the present invention to allow a furnace core tube used for a heat treatment apparatus of a porous glass base material to be used for a long period of time.

A heat treatment apparatus includes: a furnace core tube made of silica glass; a heater provided adjacent to the furnace core tube, the heater heating a heating region; and a moving mechanism supporting a porous glass base material and relatively moving the porous glass base material with respect to the heater in the furnace core tube in a state where the heating region is heated by the heater to make the porous glass base material pass through the heating region. The heat treatment apparatus includes a thin-walled part provided in a region adjacent to a portion located in the heating region in the furnace core tube, the thin-walled part having a thickness of glass less than that of the portion located in the heating region.

It is an object of the present invention to allow a furnace core tube used for a heat treatment apparatus of a porous glass base material to be used for a long period of time.

A heat treatment apparatus includes: a furnace core tube made of silica glass; a heater provided adjacent to the furnace core tube, the heater heating a heating region; and a moving mechanism supporting a porous glass base material and relatively moving the porous glass base material with respect to the heater in the furnace core tube in a state where the heating region is heated by the heater to make the porous glass base material pass through the heating region. The heat treatment apparatus includes a thin-walled part provided in a region adjacent to a portion located in the heating region in the furnace core tube, the thin-walled part having a thickness of glass less than that of the portion located in the heating region.

Embodiments include an optical fiber cable comprising a length extending between a first end and a second end, a central cooling tube, a plurality of optical fibers disposed radially around the cooling tube, each optical fiber comprising a fiber core and a cladding disposed around the fiber core, an outer protective cover, and an inner thermal filler disposed between the outer protective cover and the central cooling tube and surrounding each of the optical fibers, wherein each of the central cooling tube, the outer protective cover, the inner thermal filler, and the plurality of optical fibers extend the length of the cable. Various systems and methods for removing imperfections from individual optical fibers and for distributing power across long distances using the optical fiber cable are also provided.

The invention discloses a preparation method and device of active microcrystalline fiber, place the prefabricated rod in the drawing furnace for wire drawing, the drawn fiber is induced by magnetic field in uncoated state and combined with laser treatment technology, the laser beam is focused on the fiber and recrystallized after laser treatment to obtain active microcrystalline fiber. Appropriate laser processing power directly affects the silicate glass fiber in the crystal structure, type, degree of crystallinity, grain size, content, and how much residual phase of glass. Induced by external magnetic field, the thermodynamics and dynamics of crystallization process are changed, make the crystal size distribution is better and uniform, reduce the phenomenon of condensation and makes the grain size is smaller.

The invention discloses a preparation method and device of active microcrystalline fiber, place the prefabricated rod in the drawing furnace for wire drawing, the drawn fiber is induced by magnetic field in uncoated state and combined with laser treatment technology, the laser beam is focused on the fiber and recrystallized after laser treatment to obtain active microcrystalline fiber. Appropriate laser processing power directly affects the silicate glass fiber in the crystal structure, type, degree of crystallinity, grain size, content, and how much residual phase of glass. Induced by external magnetic field, the thermodynamics and dynamics of crystallization process are changed, make the crystal size distribution is better and uniform, reduce the phenomenon of condensation and makes the grain size is smaller.

A Photonic Crystal Fiber (PCF) a method of its production and a supercontinuum light source comprising such PCF. The PCF has a longitudinal axis and includes a core extending along the length of said longitudinal axis and a cladding region surrounding the core. At least the cladding region includes a plurality of microstructures in the form of inclusions extending along the longitudinal axis of the PCF in at least a microstructured length section. In at least a degradation resistant length section of the microstructured length section the PCF includes hydrogen and/or deuterium. In at least the degradation resistant length section the PCF further includes a main coating surrounding the cladding region, which main coating is hermetic for the hydrogen and/or deuterium at a temperature below T.sub.h, wherein T.sub.h is at least about 50° C., preferably 50° C.<T.sub.h<250° C.

A Photonic Crystal Fiber (PCF) a method of its production and a supercontinuum light source comprising such PCF. The PCF has a longitudinal axis and includes a core extending along the length of said longitudinal axis and a cladding region surrounding the core. At least the cladding region includes a plurality of microstructures in the form of inclusions extending along the longitudinal axis of the PCF in at least a microstructured length section. In at least a degradation resistant length section of the microstructured length section the PCF includes hydrogen and/or deuterium. In at least the degradation resistant length section the PCF further includes a main coating surrounding the cladding region, which main coating is hermetic for the hydrogen and/or deuterium at a temperature below T.sub.h, wherein T.sub.h is at least about 50° C., preferably 50° C.<T.sub.h<250° C.