Faraday Rotator, Optical Isolator, Polarizer, and Diamond-Like Carbon Thin Film

Abstract

A diamond-like carbon (DLC) film having refractive indices distributed in a pattern oriented within the plane of the film or on a bias with respect to the thickness of the film. Such films may be useful in low-cost Faraday rotators, in polarizers (analyzers), and in magnetic substances, and in Faraday rotators and optical isolators that can handle a plurality of wavelengths. The refractive index structure may be imparted to the DLC film, for example, by irradiating at least one region of the film with either a particle or energy beam.

Description

BACKGROUND OF THE INVENTION [0001] 1. Technical Field [0002] The present invention relates to Faraday rotators, optical isolators, polarizers and diamond-like carbon thin films, and more particularly relates to—in optical communications fields—Faraday rotators for rotating light-wave polarization planes, optical isolators for blocking return beams from a light source, polarizers for transmitting only a given polarized component of light, and to diamond-like carbon thin films utilized as materials in optical communications fields. [0003] 2. Description of the Related Art [0004] In optical communications systems constituted from optical fibers and optical elements, reflected light from optical-connector junctions and optical circuit components is sometimes reintroduced to the light source. Noise produced by beams returning to a light source—especially to a semiconductor laser—often turns out to be a major problem in designing optical communications systems and optical devices. [0005] ...

AI Technical Summary

Benefits of technology

[0014] Given the foregoing, objects of this invention are: first, to miniaturize and hold down the cost of, respectively, Faraday rotators, polarizers, analyzers, magnetic bodies, and optical isolators in which these are the constituent elements; second, to enable a Faraday rotator and an optical isolator to handle a plurality of wavelengths; and third, a new material useful in miniaturizing and in lowering the cost and enhancing the performance of polarizers to begin with, and of various optical devices.

[0034] Accordingly, under this invention, miniaturizing and moreover holding down the costs of Faraday rotators, polarizers, analyzers, magnetic parts, and optical isolators having these as their constituent elements, is made possible. Likewise, manufacturing Faraday rotators and optical isolators that can handle plural wavelengths is made possible. Furthermore, a new material useful in miniaturizing and in lowering the cost and enhancing the performance of polarizers to begin with, and of various sorts of optical devices, can be provided.

Problems solved by technology

Noise produced by beams returning to a light source—especially to a semiconductor laser—often turns out to be a major problem in designing optical communications systems and optical devices.

What is more, with conventional isolators especially—whose basic constituent elements are a Faraday rotator, a polarizer (analyzer) and a magnetic part—has been the problem of being large-sized overall.

Meanwhile, Faraday rotators, polarizers (analyzers) and magnetic bodies are expensive, making conventional optical isolators in which these are the constituent elements cost all the more.

A further problem has been that because the individual constituent elements in conventional optical isolators are independent, their assembly process is complex, adding that much more to the cost.

The consequent problem too with conventional optical isolators having a conventional Faraday rotator as a constituent element has been that they basically can handle only a single wavelength.

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