Browse Prior Art Database

Protocol for Class-3 Laser Start-Up On a Serial I/O Link

IP.com Disclosure Number: IPCOM000120100D
Original Publication Date: 1991-Mar-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 5 page(s) / 134K

Publishing Venue

IBM

Related People

Fredericks, KJ: AUTHOR

Abstract

Disclosed is a method, using serial-I/O architected sequences, to start-up a class-3 laser transmitter. The sequences are transmitted as incremental pulses for the bring-up procedure of a class-3 laser transmitter. Disclosed is a protocol which handles both ends of a serial-I/O link simultaneously performing the laser bring-up procedure.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Protocol for Class-3 Laser Start-Up On a Serial I/O Link

      Disclosed is a method, using serial-I/O architected
sequences, to start-up a class-3 laser transmitter.  The sequences
are transmitted as incremental pulses for the bring-up procedure of a
class-3 laser transmitter. Disclosed is a protocol which handles both
ends of a serial-I/O link simultaneously performing the laser
bring-up procedure.

      A safe method of bringing-up power on a laser transmitter is
described in (*).  The referenced disclosure provides for an
increasing sequential transmission of incremental pulses to allow
safe operation of the laser transmitter.

      Serial-I/O architecture has defined the offline sequence and
the offline procedure as a mechanism by which one end of a link can
stop transmission of light through the fiber-optic link without
causing detection of link errors or a link failure at the other end
of the link.  The offline sequence consists of eight consecutive
ordered sets of K28.5-D24.2 transmission characters.

      For the safe operation of a class-3 laser transmitter, the unit
of transmission (one-increment pulse) is defined as eight consecutive
offline sequences (that is, 64 consecutive offline ordered sets of
K28.5-D24.2 transmission characters).  The serial-I/O bring-up
procedure starts with transmission of eight consecutive offline
sequences which takes 6.4 microseconds, keeps the laser transmitter
power turned off for at least 57.6 microseconds, and waits for the
appropriate incremental-pulse response from the other end of the
link.  When the appropriate incremental-pulse response is received,
the bring-up procedure continues with the appropriate incremented
number of consecutive offline sequences transmitted and the reduction
of the time that the transmitter power is off.  The period between
each transmitted incremental pulse (consecutive offline sequences) is
at least 64 microseconds.  After the tenth incremental pulse is
received, the end of the link can keep power on its transmitter and
can continuously transmit the offline sequence.

      The basic bring-up procedure described in (*) specifies that
the end of the link receiving the one-increment pulse sends a
two-increment pulse, then the end of the link that sent the
one-i...