Methods for robust channel switching of widely-tunable sampled-grating distributed bragg reflector lasers
First Claim
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1. A method of switching an output wavelength of a multi-section laser containing two or more current-controlled, tunable, wavelength-selective elements, comprising:
- (a) selecting front and back mirror currents for the laser to tune the laser'"'"'s output to a wavelength of a target channel based on a feedback signal combined with a mode map, wherein the feedback signal results from a selection of one or more sets of tuning currents intermediate between those of an initial channel and the target channel, and the mode map comprises a two-dimensional grouping of the front and back mirror currents corresponding to cavity modes of the laser as measured at an earlier time.
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Abstract
The present invention describes methods and apparatus for reliably assuring that correct mirror currents are selected during a channel switch to achieve the desired wavelength channel, based on feedback from either internal or external means combined with a mode map obtained at a time zero calibration.
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Citations
78 Claims
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1. A method of switching an output wavelength of a multi-section laser containing two or more current-controlled, tunable, wavelength-selective elements, comprising:
(a) selecting front and back mirror currents for the laser to tune the laser'"'"'s output to a wavelength of a target channel based on a feedback signal combined with a mode map, wherein the feedback signal results from a selection of one or more sets of tuning currents intermediate between those of an initial channel and the target channel, and the mode map comprises a two-dimensional grouping of the front and back mirror currents corresponding to cavity modes of the laser as measured at an earlier time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An apparatus for switching an output wavelength of a multi-section laser containing two or more current-controlled, tunable, wavelength-selective elements, comprising:
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(a) a multi-section laser containing two or more current-controlled, tunable, wavelength-selective elements; and
(b) means for selecting front and back mirror currents to tune the laser output to a wavelength of a target channel based on a feedback signal combined with a mode map, wherein the feedback signal results from a selection of one or more sets of tuning currents intermediate between those of an initial channel and the target channel, and the mode map comprises a two-dimensional grouping of the front and back mirror currents corresponding to cavity modes of the laser as measured at an earlier time. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. A method for switching from an initial channel to a target channel for an output beam of a laser, comprising:
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(a) ramping front and back mirror currents for the laser in a coordinated manner based on a traversal of a mode map along a path leading from the initial channel to the target channel, wherein the mode map comprises a two-dimensional plot of the front and back mirror currents that identifies one or more cavity modes for the laser;
(b) detecting cavity mode boundaries as the front and back mirror currents for the laser are ramped; and
(c) comparing the detected cavity mode boundaries with the cavity mode boundaries in the mode map in order to provide incremental corrections to the traversal of the mode map. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54)
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55. An apparatus for switching from an initial channel to a target channel for an output beam of a laser, comprising:
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(a) means for ramping front and back mirror currents for the laser in a coordinated manner based on a traversal of a mode map along a path leading from the initial channel to the target channel, wherein the mode map comprises a two-dimensional plot of the front and back mirror currents that identifies one or more cavity modes for the laser;
(b) means for detecting cavity mode boundaries as the front and back mirror currents for the laser are ramped; and
(c) means for comparing the detected cavity mode boundaries with the cavity mode boundaries in the mode map in order to provide incremental corrections to the traversal of the mode map. - View Dependent Claims (56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68)
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69. A method for switching from an initial channel to a target channel for an output beam of a laser, comprising:
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(a) setting front and back mirror currents for the laser to an estimate of the front and back mirror currents for the target channel obtained from a mode map, wherein the mode map comprises a two-dimensional plot of the front and back mirror currents that identifies one or more cavity modes for the laser;
(b) measuring a wavelength of the output beam to determine a wavelength error resulting from the setting step; and
(c) converting the wavelength error to corrections for the front and back mirror currents. - View Dependent Claims (70, 71, 72, 73)
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74. An apparatus for switching from an initial channel to a target channel for an output beam of a laser, comprising:
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(a) means for setting front and back mirror currents for the laser to an estimate of the front and back mirror currents for the target channel obtained from a mode map, wherein the mode map comprises a two-dimensional plot of the front and back mirror currents that identifies one or more cavity modes for the laser;
(b) means for measuring a wavelength of the output beam to determine a wavelength error resulting from the setting step; and
(c) means for converting the wavelength error to corrections for the front and back mirror currents. - View Dependent Claims (75, 76, 77, 78)
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Specification