Browse Prior Art Database

LED for Optical Link Card Laser Bring-Up

IP.com Disclosure Number: IPCOM000103360D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 50K

Publishing Venue

IBM

Related People

Becker, DJ: AUTHOR [+2]

Abstract

A fiber optic light source sequencer was developed for test applications involving a fiber optic card assembly which contains circuitry to detect an open fiber. As such, it requires a specific bring-up sequence and handshake operation with like circuitry in its normal operation. In normal operation, this sequencing time is long relative to any desired test times for the hardware in a manufacturing environment. The controllable light source shown in the figure allows the normal sequencing/ handshake time to be eliminated.

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LED for Optical Link Card Laser Bring-Up

      A fiber optic light source sequencer was developed for test
applications involving a fiber optic card assembly which contains
circuitry to detect an open fiber.  As such, it requires a specific
bring-up sequence and handshake operation with like circuitry in its
normal operation.  In normal operation, this sequencing time is long
relative to any desired test times for the hardware in a
manufacturing environment.  The controllable light source shown in
the figure allows the normal sequencing/ handshake time to be
eliminated.

      Since the open fiber detector circuitry looks for a light
signal in the optical receiver, this technique suggests using a
separate controllable light source (F), such as a fiber optic LED.
This light source would be coupled into the optical receiver along
with the laser light present in the optical data path (D) during
testing.  This allows tester software complete control of the
specific timing light sequences required to satisfy the handshake
expected by the fiber optic card and thus entering an operational
status.  A fiber optic coupler/splitter (E) performs the coupling as
shown in the figure.

      A combination of AC and DC light needs to be present at the
optical receiver or the laser on the card will not be allowed on.  An
oscillator was used to drive the LED providing an AC component of the
LED light.  Tester control can provide the DC component of light
using a NAND logic...