Method for wavelength compensation in semiconductor photonic IC
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorsEskil Bendz, Lennart Lundqvist
Life of this patent
Estimating the term…
Abstract
The present invention relates to a method for manufacturing a plurality of semiconductor photonic integrated circuit comprising at least a laser and a modulator connected optically to one another. Each laser and modulator has a waveguide layer being implemented on a single substrate, where said modulator is formed by use of a selective area growth technique. By providing modulator masking parts with selectable width to compensate a difference in band-gap energy in the waveguide layer between the laser and the modulator a approximate uniform difference in band-gap energy between the optically connected laser and modulator may be obtained.
Claims10
A method for manufacturing a plurality of semiconductor photonic integrated circuits on a single semiconductor substrate, each of said integrated circuits comprising at least a first and a second photonic device connected optically to one another, said method comprising the steps of:
- (i) growing a first set of layers, including at least a first waveguide layer, to form said first photonic device on said substrate,
- (ii) providing an insulating film mask comprising masking parts covering each of said first photonic devices so as to define covered and exposed areas on said substrate,
- (iii) removing said first set of layers from said exposed areas,
- (iv) selecting an area for each second photonic device adjacent to and in a light transmission direction of each of said first photonic devices, and
- (v) growing a second set of layers, comprising at least a second waveguide layer, to form said second photonic device by use of a selective area growth process,
- wherein said method further comprises the steps of:
- (a) measuring variations in band-gap energy, across the substrate, in a waveguide layer corresponding to the second waveguide layer on a reference substrate, prior to step (ii), said variations resulting from the selective area growth process, which in turn causes a variation in detuning between the first and the second photonic device across the substrate, due to said variations in band-gap energy in the second waveguide layer,
- (b) providing said insulating film mask in step (ii) with at least one additional masking part adjacent to each of said areas, each additional masking part having a selected length and a selectable width, and being placed substantially in parallel to the light transmission direction of each respective first photonic device, and
- (c) selecting the width of each additional masking part, to correspond to said measured variations in band-gap energy, to at least partially compensate the variations in band-gap energy in the second waveguide layer across the substrate,
- thereby reducing the variation in detuning between the first and the second photonic device across the substrate.
Dependencies are inferred from the claim text.