Method for bandwidth reduction in writeable optical data storage apparatus

A method for reading data from an optical medium with reduced bandwidth, comprising the steps of:

• (a) producing a front facet monitor signal from a laser light beam;
• (b) producing first and second data signals from data read from the medium;
• (c) adjusting the gain of the front facet monitor signal to produce a gain adjusted from facet monitor signal;
• (d) producing a first gain adjusted data signal in response to the first data signal and the gain adjusted front facet monitor signal;
• (e) producing a second gain adjusted data signal in response to the second data signal and the gain adjusted front facet monitor signal;
• (f) producing a magneto-optic data signal in response to the first and second gain adjusted data signals, the magneto-optic data signal being a function of the difference between the first and second gain adjusted data signals;
• (g) producing a combined data signal in response to the first and second gain adjusted data signals, the combined data signal being a function of the sum of the first and second gain adjusted data signals;
• and
• (h) producing a write-once data signal in response to the gain adjusted front facet monitor signal and the combined data signal, the write-once data signal being a function of the difference between the gain adjusted front facet monitor signal and the combined data signal.

A method for reading data from a magneto-optic medium with reduced bandwidth, comprising the steps of:

• (a) producing a gain adjusted front facet monitor signal from a laser light beam;
• (b) producing first and second data signals from data read from the medium;
• (c) producing first and second gain adjusted data signals in response to the gain adjusted front facet monitor signal and first and second data signals, respectively;
• and
• (d) producing a magneto-optic data signal in response to the first and second gain adjusted data signals, the magneto-optic data signal being a function of the difference between the first and second gain adjusted data signals.

A method for reading data from a write-once optical medium with reduced bandwidth, comprising the steps of:

• (a) producing a gain adjusted front facet monitor signal from a laser light beam;
• (b) producing first and second data signals from data read from the medium;
• (c) producing first and second gain adjusted data signals in response to the gain adjusted front facet monitor signal and first and second data signals, respectively;
• (d) producing a combined data signal in response to the first and second gain adjusted data signals, the combined data signal being a function of the sum of the first and second gain adjusted data signals;
• and
• (e) producing a write-once data signal in response to the gain adjusted front facet monitor signal and the combined data signal, the write-once data signal being a function of the difference between the gain adjusted front facet monitor signal and the combined data signal.