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Browse Prior Art Database

Adaptive Optical Link

IP.com Disclosure Number: IPCOM000118991D
Original Publication Date: 1997-Oct-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Etzold, KF: AUTHOR

Abstract

Disclosed is a system for optical communication between two data processing devices. Instead of the usual wide angle optical radiator, a directional link using spatially confined beams is used between receiver and transmitter. Initialization takes place during the boot period and position updates are made during quiescent periods of the system.

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This is the abbreviated version, containing approximately 52% of the total text.

Adaptive Optical Link

      Disclosed is a system for optical communication between two
data processing devices.  Instead of the usual wide angle optical
radiator, a directional link using spatially confined beams is used
between receiver and transmitter.  Initialization takes place during
the boot period and position updates are made during quiescent
periods of the system.

      When digital systems are interconnected using free space
optical links the range or data rate are often severely limited due
to the limited amount of optical power available.  This is due to the
need to distribute the transmitted radiation isotropically over a
large solid angle, typically between pi and 2pi.  Similarly, the
receiver must  have isotropic sensitivity over a similar solid angle.
These wide angular  ranges are necessary to cover all possible
orientations between the transmitter and receiver.

      The invention consists of a system in which the solid angles
of the radiators and detectors are limited and the beams are adjusted
automatically when the system is set up and automatically updated
after that.  For instance, in a computer the beam geometry can be
optimized while the machine is booting.  A system with narrow solid
angle light sources and receivers is necessarily sensitive to ambient
disturbances related to moving obstacles, rearrangements, etc.
However, a new configuration can be found quickly which reestablishes
the connection.  This is achieved by reorienting the transmitter and
receiver or both (in most cases both ends of the link will actually
have a transmitter-receiver pair).  It will also often be true that
the required  bandwidth in one direction is significantly larger than
in the other (this will be true for instance in the link between a
printer and the computer system).  In such an asymmetric situation,
one can relax the reorientation requirements in the slow direction,...