ULTRA-RESPONSIVE PHASE SHIFTERS FOR DEPLETION MODE SILICON MODULATORS

• US 20160062156A1
• Filed: 08/31/2015
• Published: 03/03/2016
• Est. Priority Date: 05/14/2013
• Status: Active Grant

• Current Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Original Assignee: Coriant Advanced Technology, Llc (Infinera Corp.)
• Inventors: Baehr-Jones, Thomas, Liu, Yang
• Granted Patent: US 9,638,942 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02F 1/011 in optical waveguides, not otherwise provided for in this subclass
• CPC Class Codes: G02F 1/0113 Glass-based, e.g. silica-based, optical waveguides
• CPC Class Codes: G02F 1/015 based on semiconductor elements having potential barriers, e.g. having a PN or PIN junction G02F1/03 takes precedence
• CPC Class Codes: G02F 1/0152 using free carrier effects, e.g. plasma effect
• CPC Class Codes: G02F 1/025 in an optical waveguide structure G02F1/017, G02F1/2257 take precedence
• CPC Class Codes: G02F 1/035 in an optical waveguide structure
• CPC Class Codes: G02F 1/0353 involving an electro-optic TE-TM mode conversion
• CPC Class Codes: G02F 1/0356 controlled by a high-frequency electromagnetic wave component in an electric waveguide structure
• CPC Class Codes: G02F 1/2257 the optical waveguides being made of semiconducting material

Abstract

A novel phase shifter design for carrier depletion based silicon modulators, based on an experimentally validated model, is described. It is believed that the heretofore neglected effect of incomplete ionization will have a significant impact on ultra-responsive phase shifters. A low VπL product of 0.3V·cm associated with a low propagation loss of 20 dB/cm is expected to be observed. The phase shifter is based on overlapping implantation steps, where the doses and energies are carefully chosen to utilize counter-doping to produce an S-shaped junction. This junction has a particularly attractive VπL figure of merit, while simultaneously achieving attractively low capacitance and optical loss. This improvement will enable significantly smaller Mach-Zehnder modulators to be constructed that nonetheless would have low drive voltages, with substantial decreases in insertion loss. The described fabrication process is of minimal complexity; in particular, no high-resolution lithographic step is required.

Claims

1-27. -27. (canceled)

28. An optical modulator semiconductor device comprising:

an optical waveguide;

a p-type region of semiconductor material disposed within said optical waveguide, said p-type region having a p-type contact terminal;

an n-type region of semiconductor material disposed within said optical waveguide, said n-type region having an n-type contact terminal;

wherein said n-type region and said p-type region share a non-planar junction interface as viewed in a cross section taken perpendicular to said optical waveguide; and

wherein said non-planar junction interface is configured to enhance an overlap between an optical mode in said optical waveguide and said non-planar junction when said optical modulator semiconductor device is operational.

29. The optical modulator semiconductor device of claim 28 wherein said n-type region and said p-type region are designed to increase the length of the non-planar junction as viewed in said cross section.

30. The optical modulator semiconductor device of claim 28, wherein said non-planar junction interface comprises a curved surface having a convex side and a concave side.

31. The optical modulator semiconductor device of claim 30, wherein said curved surface resembles the English letter “

U”

.

32. The optical modulator semiconductor device of claim 30, wherein said curved surface resembles the English letter “

C”

.

33. The optical modulator semiconductor device of claim 30, wherein said curved surface resembles the English letter “

S”

.

34. The optical modulator semiconductor device of claim 30, wherein said p-type region is on said concave side of said non-planar junction interface and said n-type region is on said convex side of said non-planar junction interface.

35. The optical modulator semiconductor device of claim 30, wherein said n-type region is on said concave side of said non-planar junction interface and said p-type region is on said convex side of said non-planar junction interface.

36. The optical modulator semiconductor device of claim 28, wherein said semiconductor is silicon.

37. The optical modulator semiconductor device of claim 28, wherein said p-type region is doped with boron.

38. The optical modulator semiconductor device of claim 28, wherein said n-type region is doped with phosphorous.

39. The optical modulator semiconductor device of claim 28, wherein said n-type region is doped with arsenic.