Abstract:
A method for sweeping an electromagnetic radiation source (12) to produce single mode operation having an optimized side-mode suppression ratio over a continuous range of wavelengths within a prescribed temporal profile, the electromagnetic radiation source is configured to output electromagnetic radiation at a given wavelength based upon parameters. The method includes determining a set of parameter combinations that satisfy a condition for a desired set of wavelengths and a maximum side mode suppression ratio over the range of wavelengths. The set of parameter combinations define sub-paths for transitioning from one wavelength to another wavelength. Combinations of select sub-paths provide a multivariate path for transitioning over the range of wavelengths. The method also includes controlling the semiconductor laser to emit electromagnetic radiation over the range of wavelengths by traversing the multivariate path in a desired manner.
Abstract:
The present invention concerns tunable distributed Bragg reflector (DBR) semiconductor lasers, in particular a DBR laser with a branched optical waveguide 5 within which a plurality of differently shaped lasing cavities may be formed, and a method of operation of such a laser. The laser may comprise a phase control section (418), gain section (420, 422), a sampled graiting DBR (412) giving a comb-line spectrum and two tunable, chirped DBRs (414, 416) fro broadband frequency training and a coupling section (410).
Abstract:
A system in which the controller (24) of a multisection 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:
A semiconductor laser comprising an optical generation section and a heat balancing region, wherein each region of the optical generation section is paired with associated means in a corresponding region of the heat balancing section and is in thermal communication with such associated means. In operation the total input electrical power applied to said region and its associated means is constant and independent of the electrical power applied to the other regions and their respective associated means. Preferably, each region and its associated means have substantially identical structures.
Abstract:
A method is described for qualifying a multisection semiconductor laser (100) using measurements of excursions from stable operating conditions (61) to neighbouring mode boundaries (52, 142) at which the laser undergoes mode-hopping. These excursions are measured when the laser is characterised to provide a measure of the stability and hence the quality of the laser, and to facilitate statisctical analysis of the quality of a batch of lasers from a given wafer. The values of the excursions may be re-measured during the life of the laser using a curtailed version of the characterising procedure rapidly to monitor aging or other deterioration of the laser (100).
Abstract:
Controller calibration methods for use with sampled grating distributed Bragg reflector SGDBR laser (102) is presented. An exemplary method includes conducting a two-dimensional mirror current scam of each front mirror current setting and back mirror current setting for a sampled grating distributed Bragg reflector SGBDR laser(102) to produce laser setting data corresponding to each front mirror current setting and back mirror current setting to generate a reference optical signal (114) of the SGDBR laser (102). A channel operating point is determined for each channel within thetwo-dimensional scan data. A fix up of the operating point to substantially minimize wavelength and power error can also be perfo rmed. A two-dimensional control surface is characterized at the channel operating point for each channel. A lookup table for controlling the SGDBR (102) laser is generated from the operating point currents, locker values and two-dimensional control surface data from each channel.
Abstract:
A laser assembly includes an epitaxial structure formed on a substrate. A separately controllable tunable laser resonator and external optical amplifier are formed in the epitaxial structure. At least a portion of the laser and amplifier share a common waveguide, which may have non-uniform optical or geometrical properties along the waveguide centerline or across a normal to the centerline.
Abstract:
A wavelength converter assembly includes a substrate. An epitaxial structure is formed on the substrate with areas of different optical properties. A laser and a photodetector are formed in the epitaxial structure. The photodetector generates a first electrical signal in response to an optical signal. A conditioning circuit is coupled to the laser and the photodetector. The conditioning circuit receives the first electrical signal and provides a second electrical signal to the laser to modulate its optical output.
Abstract:
A tunable laser comprised of a gain section for creating a light beam by spontaneous emission over a bandwidth, a phase section for controlling the light beam around a center frequency of the bandwidth, a cavity for guiding and reflecting the light beam, a front mirror bounding an end of the cavity, and a back mirror bounding an opposite end of the cavity. The back mirror has a kappa effB approximately equal to alpha Tune, where kappa effB is an effective coupling constant and alpha Tune is the maximum amount of propagation loss anticipated for an amount of peak tuning required, and a length of the back mirror is made to produce greater than approximately 80 % reflectivity.