Abstract: This invention relates to a method and system to detect hysteresis/unstable regions of multi-section lasers. The method comprises the steps of obtaining a first set of measurement values for the output of the laser diode by increasing a first current through a range of values in a positive direction, increasing a second control current by a step, obtaining a second set of measurement values for the output of the laser diode by decreasing the first control current through a range of values in a negative direction, and increasing a second control current by a step. The process is repeated until a sufficient range of the second control currents has been used to provide resultant data which can then be processed in order to identify regions of hysteresis of the laser diode.

Abstract: The invention relates to a method and system for providing a set of continuous tuning regions from a discontinuously tuned laser, by providing a wavelength reference having at least first and second resonance peaks, sweeping the laser across a pre-determined wavelength range of the wavelength reference, and defining, within the laser sweep, one or more regions of continuous tuning operation of the laser, each of the regions corresponding to a response of the laser between adjacent resonance peaks of the wavelength reference. The advantage of the invention is that it provides a way for stitching together continuous regions of a multi-section tunable laser in an efficient and accurate manner.

Abstract: A system in which the controller (24) of a multi section diode laser such as a SG-DBR (10) is configured so that the laser can be swept rapidly in a pre-determined frequency direction through a series of frequency points by asserting a pre-calibrated series of sets of control input values to the sections of the diode laser, wherein the frequency points are obtained from cavity modes in a plurality of different supermodes, and the sets of control input values are pre-determined to take account of thermal transients that are known to arise from jumps in the output modes that occur when sweeping through the pre-calibrated series of sets of control input values in the pre-determined frequency direction.

Abstract: The invention provides a method to compensate for degradation in a tunable laser and ensure its performance by tracking the degradation and adjusting the control information accordingly. This is accomplished by performing some measurements of the output of the tunable laser at an initial setup or calibration procedure. Then, by effecting a periodic repetition of these measurements and using a comparison between these two measurements the present invention provides for a compensation factor for the operating conditions, primarily in the form of a look up table of operating points of the laser. These measurements show how much the operating points of the laser have drifted over the period since the last set of measurements, which provide control informatIon to compensate for degradation in the laser.

Abstract: A distributed packet switch to control data packet flows in a network is described. The distributed packet switch includes a means for operating over an asynchronous burst optical closed fiber medium. The distributed packet switch also includes at least one control system provided at a node to control data packet flow characteristics, such that the switch is configured to operate dependent on at least one efficiency parameter.

Abstract: A method relating to the calibration of tuneable lasers is described. The method provides for the provision of correct control currents so as to achieve each of desired output frequencies from the laser. The correct currents are determined by forming a matrix of the output characteristics of the laser at specific tuning currents and processing that matrix to determine stable operating points within the matrix.

Abstract: The invention relates to a method and system for providing a set of continuous tuning regions from a discontinuously tuned laser, by providing a wavelength reference having at least first and second resonance peaks, sweeping the laser across a pre-determined wavelength range of the wavelength reference, and defining, within the laser sweep, one or more regions of continuous tuning operation of the laser, each of the regions corresponding to a response of the laser between adjacent resonance peaks of the wavelength reference. The advantage of the invention is that it provides a way for stitching together continuous regions of a multi-section tunable laser in an efficient and accurate manner.