Optical equalizer for signal-transmission system using multimode light guides

• US 4,094,578 A
• Filed: 02/18/1977
• Issued: 06/13/1978
• Est. Priority Date: 02/19/1976
• Status: Expired due to Term

• Current Assignee: CSELT Centro Studi e Laboratori Telecomunicazioni SpA (Telecom Italia S.p.A.)
• Original Assignee: CSELT Centro Studi e Laboratori Telecomunicazioni SpA (Telecom Italia S.p.A.)
• Inventors: DiVita, Pietro, Vannucci, Riccardo
• Primary Examiner(s): Corbin, John K.
• Assistant Examiner(s): Hille, Rolf
• Application Number:
  US05/770,232
• Time in Patent Office: 480 Days
• Field of Search: 350/96 C, 350/96 WG, 350/293, 350/294, 350/169, 250/209, 250/227
• US Class Current: 385/51
• CPC Class Codes: G02B 6/14 Mode converters
• CPC Class Codes: G02B 6/264 with optical elements between opposed fibre ends which perform a function other than beam splitting having lens focusing means G02B6/32; utilising prism or grating G02B6/34
• CPC Class Codes: G02B 6/29376 coupling light guides for controlling wavelength dispersion, e.g. by concatenation of two light guides having different dispersion properties dispersion managed optical transmission systems H04B10/25253
• CPC Class Codes: G02B 6/29394 Compensating wavelength dispersion G02B6/29376 takes precedence; dispersion compensated optical transmission systems H04B10/2507

Abstract

Signals, especially short pulses, are transmitted by way of a series of light guides with internally reflecting boundaries (i.e. fibers or foils) angularly adjoining one another, each junction being encased in an external body having the same index of refraction as the light guides. Within the body the light rays exiting from one guide are intercepted by one or two mirrors reflecting them to the other guide, each mirror having a cross-section in the form of a segment of an ellipse whose foci are the center points of the two guide ends in a common axial plane of the guides. Each segment terminates in two points represented by the intersection of a respective guide axis with the path of a limiting ray from the other guide.

Claims

1. A system for the optical transmission of signals, comprising:

a first and a second light guide with internally reflecting boundaries respectively connected to a transmitter and a receiver of luminous signals, said light guides having proximal ends respectively emitting and collecting bundles of light rays with axes angularly intersecting in a common plane, each bundle being bounded by a pair of limiting rays on opposite sides of the respective axis; and

a mirror confronting said proximal ends for reflecting light rays from said first light guide to said second light guide, said mirror having a cross-section in said common plane in the shape of a segment of an ellipse whose foci are the center points of said proximal ends within said common plane, said segment extending between the intersection of the axis of said first light guide with the position of a limiting ray of said second light guide and the intersection of the axis of said second light guide with the position of a limiting ray of said first light guide.

2. A system as defined in claim 1, further comprising a body of transparent material having substantially the same index of refraction as said light guides, said proximal ends and said mirror being embedded in said body.

3. A system as defined in claim 1, comprising another mirror confronting said proximal ends for reflecting light rays from said first light guide to said second light guide, said other mirror having a cross-section in said common plane in the shape of a segment of an ellipse whose foci are said center points and which extends between the intersection of the axis of said first light guide with the position of the other limiting ray of said second light guide and the intersection of the axis of said second light guide with the position of the other limiting ray of said first light guide.

4. A system as defined in claim 1 wherein said light guides are two individual fibers, the reflecting surface of said mirror being a segment of an ellipsoid of revolution.

5. A system as defined in claim 1 wherein said light guides have a width transverse to said common plane less than their width in said common plane, the reflecting surface of said mirror being a segment of an elliptical cylinder with generatrices perpendicular to said common plane.