Integrated semiconductor diode laser and photodiode structure
AssigneeInternational Business Machines Corporation
InventorsPeter L. Buchmann, Christoph S. Harder, Otto Vogeli
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Abstract
An integrated semiconductor structure with optically coupled laser diode (11) and photodiode 12A, both devices having etched, vertical facets (16A, 21). The photodiode has a spatially non-uniform sensitivity profile with respect to the incident light beam (18A) emitted by the laser. This is due to the varying distance from the laser facet and/or to variations in the angle of incidence and results in photocurrents produced by the photodiode that depend on the intensity distribution of the light beam. The spatially non-uniform sensitivity profile allows the measurement of the far-field intensity distribution of the laser and thus on-wafer screening of lasers with respect to their mode stability.
Claims16
An integrated semiconductor device, comprising:
- a semiconductor substrate;
- laser diode means with at least one mirror facet on said semiconductor substrate for emitting an impinging light beam;
- at least one photodiode means on said semiconductor substrate optically coupled to said laser diode means and provided with an etched mirror photodiode facet, said at least one photodiode means producing a photocurrent in response to said impinging light beam emitted by said laser diode means;
- and
- whereby said at least one photodiode means has a spacially non-uniform sensitivity profile with respect to said impinging light beam.
A method of on-line wafer testing of the far-field beam characteristics of a plurality of laser diodes, comprising the steps of:
- a) providing on a semiconductor wafer a plurality of laser diodes, each of said laser diodes integrated with at least one photodiode, having a spacially non-uniform facet, optically coupled with one of said laser diodes such that, said photodiode, when activated, produces a photocurrent in response to an impinging light beam emitted by said laser diode;
- b) successively applying operating voltage to said laser diodes, resulting in the emission of an impinging light beam;
- and
- c) activating said optically coupled photodiode in order to convert said impinging light into a photocurrent, thus providing a test signal with an amplitude that is a function of the far-field intensity distribution of the impinging light beam.
Dependencies are inferred from the claim text.