Photodetector with split inputs
The present disclosure describes photodetectors with multiple inputs and methods of operating photodetectors with multiple inputs. An apparatus includes a substrate, an optical absorber, and an optical device. The optical absorber is positioned on the substrate. The optical absorber includes a first portion and a second portion coupled to the first portion along a line. The optical device produces a first optical signal and a second optical signal based on a received optical signal and directs the first optical signal through the first portion of the optical absorber in a direction substantially parallel to the line. The optical device also directs the second optical signal through the second portion of the optical absorber in the direction substantially parallel to the line.
1 . An apparatus comprising:
a substrate;
an optical absorber comprising a top surface and a bottom surface opposite the top surface, wherein the optical absorber is positioned on the substrate such that the bottom surface is positioned between the substrate and the top surface, and wherein the optical absorber comprises a first portion and a second portion coupled to the first portion along a line such that the first portion is positioned on a first side of the line and the second portion is positioned on a second side of the line different from the first side;
a first set of metal contacts positioned on the top surface such that the first set of metal contacts is arranged along the line;
an optical device arranged to:
produce a first optical signal and a second optical signal based on a received optical signal;
direct the first optical signal through the first portion of the optical absorber in a direction substantially parallel to the line such that the first optical signal passes through the optical absorber on the first side of the first set of metal contacts; and
direct the second optical signal through the second portion of the optical absorber in the direction substantially parallel to the line such that the second optical signal passes through the optical absorber on the second side of the first set of metal contacts.
2 . The apparatus of claim 1 , further comprising:
a second set of metal contacts arranged on the substrate; and
a third set of metal contacts arranged on the substrate, wherein the second set of metal contacts and the third set of metal contacts are arranged on opposite sides of the optical absorber.
3 . The apparatus of claim 1 , wherein the optical device is at least one of a directional coupler, a y-splitter, or a multi-mode interferometer.
4 . The apparatus of claim 1 , wherein the optical device abuts the optical absorber.
5 . The apparatus of claim 1 , wherein the optical device abuts the substrate.
6 . The apparatus of claim 1 , wherein the substrate comprises a first doped region and a second doped region, and wherein the first doped region and the second doped region extend beneath the optical absorber.
7 . The apparatus of claim 6 , wherein the substrate comprises an intrinsic region positioned beneath the optical absorber and between the first doped region and the second doped region.
8 . The apparatus of claim 1 , wherein the optical device is further arranged to:
introduce a first phase shift to the first optical signal before directing the first optical signal through the first portion of the optical absorber; and
introduce a second phase shift to the second optical signal before directing the second optical signal through the second portion of the optical absorber.
9 . A method comprising:
producing, by an optical device, a first optical signal and a second optical signal based on a received optical signal;
directing the first optical signal through a first portion of an optical absorber in a direction substantially parallel to a line, wherein the optical absorber comprises a top surface and a bottom surface opposite the top surface, wherein a first set of metal contacts is positioned on the top surface such that the first set of metal contacts is arranged along the line; and
directing the second optical signal through a second portion of the optical absorber in the direction substantially parallel to the line, wherein the second portion is coupled to the first portion along the line such that the first portion is positioned on a first side of the line and the second portion is positioned on a second side of the line different from the first side, wherein the first optical signal passes through the optical absorber on the first side of the first set of metal contacts, and wherein the second optical signal passes through the optical absorber on the second side of the first set of metal contacts.
10 . The method of claim 9 , wherein the optical absorber further comprises:
a second set of metal contacts arranged; and
a third set of metal contacts arranged, wherein the second set of metal contacts and the third set of metal contacts are arranged on opposite sides of the optical absorber.
11 . The method of claim 9 , wherein the optical device is at least one of a directional coupler, a y-splitter, or a multi-mode interferometer.
12 . The method of claim 9 , wherein the optical device abuts the optical absorber.
13 . The method of claim 9 , wherein the optical absorber is positioned on a substrate, and wherein the optical device abuts the substrate.
14 . The method of claim 9 , wherein the optical absorber is positioned on a substrate comprising a first doped region and a second doped region, and wherein the first doped region and the second doped region extend beneath the optical absorber.
15 . The method of claim 14 , wherein the substrate comprises an intrinsic region positioned beneath the optical absorber and between the first doped region and the second doped region.
16 . The method of claim 9 , further comprising:
introducing a first phase shift to the first optical signal before directing the first optical signal through the first portion of the optical absorber; and
introducing a second phase shift to the second optical signal before directing the second optical signal through the second portion of the optical absorber.
17 . An apparatus comprising:
an optical absorber comprising a top surface, a bottom surface opposite the top surface, a first set of metal contacts arranged along a first side of the optical absorber, a second set of metal contacts arranged along a second side of the optical absorber opposite the first side, and a third set of metal contacts arranged on the top surface along a line;
an optical device arranged to:
produce a first optical signal and a second optical signal;
direct the first optical signal through a first portion of the optical absorber between the first set of metal contacts and the third set of metal contacts on a first side of the first set of metal contacts in a direction substantially parallel to the line; and
direct the second optical signal through a second portion of the optical absorber between the second set of metal contacts and the third set of metal contacts on a second side of the first set of metal contacts different from the first side in the direction substantially parallel to the line.
18 . The apparatus of claim 17 , wherein the first and second sets of metal contacts are arranged in the direction parallel to the line.