3m Innovative Properties Company

Minnesota Mining and Manufacturing Company

Charles W Haggans

Wayne Francis Varner

Harmeet Singh

Jau-Sheng Wang

A single-mode optical fiber that includes: (a) a core that includes silica and is characterized by a first refractivity that changes upon exposure to actinic radiation of a predetermined wavelength; and (b) a cladding surrounding the core that also includes silica and is characterized by a second refractivity different from the first refractivity that changes upon exposure to actinic radiation of a predetermined wavelength. At least one of the core and the cladding further includes boron, the relative amounts of boron in the core and cladding being selected such that the first refractivity and the second refractivity change by substantially the same amount upon exposure to actinic radiation of a predetermined wavelength.

Boron-doped optical fiber

An optical fiber filter including a length of single mode fiber having an operating wavelength .lambda..sub.0. Fiber designs may include a depressed inner clad fiber, a photosensitive matched inner clad fiber or a photosensitive depressed inner clad fiber. The length of fiber includes a core, an inner cladding, an outer cladding and an azimuthally asymmetric grating. The core allows the existence of a LP.sub.01 core mode having an effective index of n.sub.eff,01 and the cladding allows the existence of a LP.sub.1m cladding mode, m.gtoreq.1. The core has an index of refraction n.sub.co and a radius A. The inner cladding has an index of refraction n.sub.ic, an inner radius A, an outer radius AB, a thickness W, where W=AB-A, and a refraction difference .DELTA.n-, where .DELTA.n- is the difference between n.sub.ic and n.sub.oc and n.sub.co &gt;n.sub.oc &gt;n.sub.ic. The inner cladding may be photosensitive to a radius R.sub.grat and have a fractional photosensitivity .gamma.. The outer cladding generally laterally surrounds the inner cladding and has an inner radius AB, an outer radius B, and an index of refraction n.sub.oc, where .DELTA.n.sub.+ is the difference between n.sub.co and n.sub.oc. The grating has an effective tilt angle .theta. and a period (.LAMBDA.), where .LAMBDA..ltoreq.(.lambda..sub.0 cos .theta.)/(2n.sub.eff,01), the maximum relative coupling coefficient for the cladding mode max(RCC.sub.1m) being greater or equal to 0.2 and the ratio of peak reflectivities for the cladding mode and the core mode RR being greater or equal to 1.

Waveguide narrowband rejection filter

A waveguide, such as an optical fiber waveguide for guiding light waves, which can provide a strongly reflective grating (e.g., a Bragg grating) at a specified wavelength while maintaining very low losses at adjacent wavelengths. The waveguide includes a core, an inner cladding laterally surrounding the core, an outer cladding laterally surrounding the inner cladding, and a grating pattern. The core has a refractive index n.sub.co and a first transverse dimension 2A. The inner cladding has a width W and a refractive index n.sub.ic. The outer cladding has a refractive index n.sub.oc. The relation between the refractive indexes, n.sub.co &gt;n.sub.oc &gt;n.sub.ic and 0.5&lt;A/(A+W)&lt;1, define a narrow depressed well region for limiting cladding losses.

Growing community of inventors

Woodbury, MN, United States of America

Charles W Haggans