Abstract:
The temperature at different locations along a multiplexed laser array may be monitored by sensing temperature at two locations within a transmitter optical subassembly (TOSA) package housing the laser array. The temperature at the two locations is used to determine a temperature tilt across the laser array. Estimated temperatures may then be determined at one or more other locations along the laser array from the temperature tilt. The estimated temperature(s) may then be used to adjust the temperature proximate the other locations, for example, for purposes of tuning lasers at those locations along the laser array to emit a desired channel wavelength. The TOSA package may be used in an optical transceiver in a wavelength division multiplexed (WDM) optical system, for example, in an optical line terminal (OLT) in a WDM passive optical network (PON).
Abstract:
A projection apparatus (300) includes at least one laser diode (360) and a laser diode junction temperature estimator (310) to estimate the junction temperature of the at least one laser diode. Laser diode current drive values are modified in response to the estimated laser junction temperature. The modification of laser diode current drive values may occur as frequently as once per pixel.
Abstract:
The invention provides a dynamically swept tunable laser system and method for measuring sensor characteristics obtained from an array of optical sensors comprising means for dividing the total wavelength sweep of the laser into different regions in any particular order where each region contains single or multiple contiguous sweep segments and where each sweep segment is referenced by a start and a stop reference and can have different lengths compared to the other sweep segments. The sensor characteristics are determined from each region swept by the tunable laser. The invention provides for the tunable laser to be adapted to operate in a quasi-continuous mode to select segments in any order. The relative sweep rates of regions can be changed such that some regions can be swept more times than other regions.
Abstract:
There is provided a frequency tunable laser system (1) comprising a laser, frequency varying means (6) arranged for varying an optical frequency output of the laser (2), an intensity sensor (7m) arranged for receiving light (5b) from the laser (2), and a processor (8) arranged for controlling the frequency varying means (6) for varying the optical frequency output of the laser (2) and receiving an intensity signal (Sm) from the intensity sensor (7m) for monitoring the intensity output of the laser (2). The frequency tunable laser system (1) further comprises an external reflective surface (9), in use, fixedly arranged in a light path of the laser beam (5) outside the laser cavity (9) at a predefined distance (L) from the second reflective surface (2b) along the light path of the laser beam (5) to reflect part (5') of the emitted laser beam (5) back into the laser cavity (9). The processor (8) is further arranged for processing the intensity signal (Sm) and registering oscillations of the intensity output (I) caused by interference of the reflected part (5') of the laser beam (5) in the cavity (9) and responsive to a change in optical frequency and calculating the change in optical frequency output from the registered oscillations of the intensity output and predefined distance (L).
Abstract:
A laser chip having a substrate, an epitaxial structure on the substrate, the epitaxial structure including an active region and the active region generating light, a waveguide formed in the epitaxial structure extending in a first direction, the waveguide having a front etched facet and a back etched facet that define an edge- emitting laser, and a first recessed region formed in said epitaxial structure, the first recessed region being arranged at a distance from the waveguide and having an opening adjacent to the back etched facet, the first recessed region facilitating testing of an adjacent laser chip prior to singulation of the laser chip.