Browse Prior Art Database

Fault-Tolerant Scheme for Differential Optical Link

IP.com Disclosure Number: IPCOM000116429D
Original Publication Date: 1995-Sep-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Li, C: AUTHOR [+2]

Abstract

Disclosed is a fault tolerant optical link to provide graceful degradation of the link performance when either the laser or the fiber/waveguide fails during the lifetime of a link.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 57% of the total text.

Fault-Tolerant Scheme for Differential Optical Link

      Disclosed is a fault tolerant optical link to provide graceful
degradation of the link performance when either the laser or the
fiber/waveguide fails during the lifetime of a link.

      Optical interconnects for board-to-board or on-board
applications require high fault tolerance to survive possible link or
device failures.  Existing single-ended optical link architectures,
however, does not provide this fault tolerance and is vulnerable to
single-laser and/or single-link failure.

      In this invention, a new optical interconnect architecture is
proposed to provide sufficient redundancy to overcome single-laser
or/and single-link failures.  The system architecture, as shown in
the Figure, consists of a differential laser driver, two laser
diodes, two fiber/waveguides, two photodetectors, and a differential
preamplifier.  Complementary optical signals are generated at the
output of the laser transmitter.  The photodetectors are connected so
that the sensitivity of the preamplifier benefits from the
complementary optical signals under normal operating conditions.
When any one of the laser diodes or/and one of the fiber/waveguide
fails, the interconnect can still operate with reduced sensitivity.
As shown in the Figure, three different receiver configurations are
possible to satisfy the fault tolerant requirement.  The first
configuration (1(a) has been used in coherent optical receiver.  In
both...