Fiber optic microbend phase shifter and modulator

Claim 1

An apparatus to shift the phase of light propagating in an optical fiber comprising: a first and second transducer block defining a passageway therebetween; a first single mode optical fiber disposed within said passageway; means disposed in said passageway for bending said optical fiber, said bending means including first and second sets of transversely extending teeth affixed to first and second transducer blocks respectively and positioned along said passageway in accordance with a fixed common spatial period Λ defined by the following equation ##EQU4## where λ is the wavelength of fill space, n e is the effective refractive index of the fundamental mode of said optical fiber, and n o is the refractive index of the cladding of the optical fiber and wherein said spatial period is within the range of 0.2 mm to 2 mm, said first set of teeth being interposed between said second set of teeth; and a second single mode optical fiber coupled to said first single mode optical fiber at two points, with an uncoupled area therebetween.

Claim 2

An apparatus to shift the phase of light propagating in an optical fiber comprising: a first and second transducer block defining a passageway therebetween; a first single mode optical fiber disposed within said passageway; means disposed in said passageway for bending said optical fiber, said bending means including first and second sets of transversely extending teeth affixed to first and second transducer blocks respectively and positioned along said passageway in accordance with a fixed common spatial period Λ defined by the following equation ##EQU4## where λ is the wavelength of fill space, n e is the effective refractive index of the fundamental mode of said optical fiber, and n o is the refractive index of the cladding of the optical fiber and wherein said spatial period is within the range of 0.2 mm to 2 mm, said first set of teeth being interposed between said second set of teeth; and a second single mode optical fiber coupled to said first single mode optical fiber at two points, with an uncoupled area therebetween.

Claim 3

An apparatus to modulate light in an optical fiber comprising: an optical fiber having a first an a second tapered end, and an untapered portion positioned between said first and second tapered ends, wherein said first and second tapered ends propagate light in one node and said untapered portion propagates light in at least two modes; a first and a second mode stripper each operably attached to one of said tapered ends of said optical fiber; a first and a second transducer block defining a passageway therebetween; said untapered portion of said optical fiber being disposed within said passageway; and means disposed within said pasasgeway and affixed to said first and second transducer blocks to bend said optical fiber, said bending means including a first and a second set of transversely extending teeth affixed to said first and second transducer blocks respectively and positioned along said passageway in accordance with a fixed common spatial period.

Claim 4

An apparatus to modulate light in an optical fiber comprising: an optical fiber having a first an a second tapered end, and an untapered portion positioned between said first and second tapered ends, wherein said first and second tapered ends propagate light in one node and said untapered portion propagates light in at least two modes; a first and a second mode stripper each operably attached to one of said tapered ends of said optical fiber; a first and a second transducer block defining a passageway therebetween; said untapered portion of said optical fiber being disposed within said passageway; and means disposed within said pasasgeway and affixed to said first and second transducer blocks to bend said optical fiber, said bending means including a first and a second set of transversely extending teeth affixed to said first and second transducer blocks respectively and positioned along said passageway in accordance with a fixed common spatial period.