For instance, should stage 608 calculate a laser slope efficiency similar to that shown in FIG.
It is understood that the drawings are diagrammatic and schematic representations of exemplary embodiments of the invention, and are not limiting of the present invention nor are they necessarily drawn to scale.As used herein, the term âdiagnostic dataâ will refer to both environmental parameters and operational parameters, whether the parameter is provided as raw data or processed data. sensing data relating to laser transmit power and laser bias current at a plurality of laser bias current levels;by a processor, calculating a slope efficiency of the laser using the data by comparing a ratio of bias current to transmit power data for a plurality of bias current levels of the laser;by the processor, determining a desired modulation current for the laser using the slope efficiency; andif needed, modifying the modulation current of the laser to match the desired modulation current.acquiring data relating to the laser transmit power at both a laser bias current level that is greater than an average light level bias current and a laser bias current level that is less than the average light level bias current.sensing the laser transmit power by a photodiode positioned in relation to the laser; andsensing the laser bias current by a resistor placed in series with a laser bias current signal line.at least temporarily storing the data in a memory that is accessible by the processor.calculating the laser transmit power corresponding to at least one of a logic â1â and a logic â0â power level.17. Thus by configuring transceivers with the dynamic ability to compensate for such age-related changes, the transceiver can be left in use a relatively longer period of time when compared with a transceiver having no such functionality.The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. by operating on the active mediumStabilisation of laser output parameters by monitoring or fixing the threshold current or other specific points of the L-I or V-I characteristicsCalculation of laser slope efficiency in an optical transceiver module These issues have stirred within me an interest in laser slope efficiency . A processor is then employed to calculate a slope efficiency of the laser using the data. One particularly useful application of the above is in older transceivers, as it is well known that such transceivers tend to fall out of compliance in terms of allowable parameter ranges (e.g., extinction ration, OMA) as they age.
I am interested in how SEchanges at temperatures above room temperature, which I will define here as 25 °C. Other parameters that are critical to proper operation of a laser and that are affected by LSE include extinction ratio (âERâ), which is a ratio of 1) the difference between a âdark levelâ of the laser, i.e., a point at which no light is produced by the laser, and the low light (logic â0â) level; and 2) the difference between the dark level and the high light (logic â1â) level. The slope efficiency is the slope of this line. It varies from part-to-part and with temperature. This makes it applicable to pulsed lasers. Among the disadvantages is the fact that the compensation table used by the controller must be predefined during optical transmitter manufacture, and as such, is not capable of dynamic laser modification according to present operating requirements. Diagnostic data can be provided in analog or digital form. Laser … I have spent much of my summer dealing with issues related to the high temperature characteristics of lasers.
60/641,117, entitled âOPTICAL TRANSCEIVER MODULE END OF LIFE INDICATION,â filed Jan. 3, 2005, which is incorporated herein by reference in its entirety.Maintenance of the laser modulation current within acceptable parameter ranges according to the method Additionally, practice of embodiments of the present invention enables the life expectancy of certain transceivers to be extended over what would otherwise be possible.
In another attempt, laser controllers have been employed that include pre-set laser current or power compensation tables based on digital measurement. One of these factors is laser temperature.
(a) varying a bias current of the laser to at least two bias current levels;(b) sensing analog data relating to transmit power and bias current of the laser for the at least two bias current levels;(c) calculating a slope efficiency of the laser using the digital data by comparing a ratio of bias current to transmit power data for a plurality of bias current levels of the laser;(d) determining a desired modulation current for the laser according to the slope efficiency;(e) if needed, setting the modulation current for the laser according to the desired modulation current; andsetting the modulation current for the laser according to the desired modulation current such that at least one of an extinction ratio and an optical modulation amplitude of the laser is maintained within acceptable parameter ranges.varying the bias current from a current level sufficient to sustain an average light level.at least temporarily storing data relating to the slope efficiency in the optical transmitter.reporting at least some of the stored data to a host system in operable communication with the optical transmitter. This application claims the benefit of U.S. patent application Ser.