Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Adiabatic Expander for Frustrating Fiber Mode Coupling

IP.com Disclosure Number: IPCOM000010968D
Publication Date: 2003-Feb-05
Document File: 3 page(s) / 55K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that consists of an index matched region of free space in which a fiber facet is immersed. The disclosed method suppresses the coupling of ghost reflections generated on the free space launch or by the extraction of light from a fiber. Benefits include a simplified way to frustrate mode coupling efficiency to arbitrary values.

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 50% of the total text.

Adiabatic Expander for Frustrating Fiber Mode Coupling

Disclosed is a method that consists of an index matched region of free space in which a fiber facet is immersed. The disclosed method suppresses the coupling of ghost reflections generated on the free space launch or by the extraction of light from a fiber. Benefits include a simplified way to frustrate mode coupling efficiency to arbitrary values.

Background

Current techniques for suppressing on fiber waveguides include anti-reflection coatings and angle polished fibers. An alternate technique is the use of an auxiliary component (isolator) to suppress ghost images. Anti-reflection coatings reduce the amplitude of the ghost reflection, but not the mode matching. In addition, it is difficult to achieve antireflection coatings on fiber better than 0.1%, because of material properties and film thicknesses.

Angle polished fiber does reduce mode coupling efficiency; however, there are significant alignment issues when launching a mode into or from free space, because of the need to couple to an angle non-parallel to the optical axis. Optical isolators are effective for rejection at approximately 30 dB and 60 dB; however, isolators that have significant dispersion in temperature and wavelength: generate additional stray reflections that must be carefully controlled, are affected by magnetic fields, require significant volume for packaging, and are costly.

General Description

The disclosed method places the air interface in the fiber far field, which enables surface contamination to happen in a more graceful degradation. This is similar to the effect achieved in optical data storage with the protective substrate. When the interface occurs directly at a fiber cleave, a single defect of 10 microns causes a catas...