# US 2024/0201523 A1 · Phase shifter for low optical loss in optical communications systems

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- Number: US 2024/0201523 A1
- Document ID: US20240201523A1
- Status: Published application
- Kind: A1
- Application number: 18/162,106
- Filed: 2023-01-31
- Published: 2024-06-20
- Earliest claimed: 2022-12-14
- Assignees: X Development LLC
- Applicants: X Development LLC
- Inventors: Simon Bilodeau
- Web page: https://patentgrep.com/patent/US20240201523A1

## CPC

- G02F 1/025: in an optical waveguide structure (G02F1/017, {G02F1/2257} take precedence)
- G02F 1/2257: {the optical waveguides being made of semiconducting material}
- H04B 10/6165: {Estimation of the phase of the received optical signal, phase error estimation or phase error correction}
- G02F 2203/50: Phase-only modulation
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- H04B: TRANSMISSION

## Abstract

Aspects of the disclosure provide phase shifters as well as systems and methods in which those phase shifters may be utilized. For instance, a system may include a first communications terminal. The first optical communications terminal may include an optical phased array (OPA) architecture including a plurality of phase shifters configured to receive an optical communications beam from a second communications terminal. The plurality of phase shifters includes a first phase shifter consisting of silicon having a slab-contacted NPN junction scheme geometry. The first phase shifter may have a PN junction distance from waveguide center within a range 100 nm to 2 μm, inclusive, and a waveguide core width dimension within a range 500 nm to 2 μm, inclusive. The system may also include the second optical communications terminal.

## Claims

### Claim 1

A phase shifter consisting of silicon, the phase shifter having:
a slab-contacted NPN junction scheme geometry;
a PN junction distance from waveguide center within a range 100 nm to 2 μm, inclusive: and
a waveguide core width dimension within a range 500 nm to 2 μm, inclusive.

### Claim 2 (depends on 1)

The phase shifter of claim 1, wherein the phase shifter is configured to operate under depletion modulation.

### Claim 3 (depends on 1)

The phase shifter of claim 1, wherein the phase shifter includes a maximum optical loss on the order of 3 dB (decibels) or less.

### Claim 4 (depends on 1)

The phase shifter of claim 1, wherein the slab-contacted NPN junction scheme geometry includes a single rib portion protruding from a slab portion.

### Claim 5 (depends on 4)

The phase shifter of claim 4, wherein the rib portion and the slab portion each include each of which include continuous Na and Na regions.

### Claim 6 (depends on 1)

The phase shifter of claim 1, wherein the phase shifter has a doping density in a range of 1010 cm−3 to 1017 cm3.

### Claim 7 (depends on 1)

The phase shifter of claim 1, wherein the phase shifter has a dynamic switching energy of the phase shifter is less than 0.1 mWatt.

### Claim 8 (depends on 1)

The phase shifter of claim 1, wherein the phase shifter has an acceptor concertation NA which ranges from 1016 to 1018 cm3 inclusive.

### Claim 9 (depends on 8)

The phase shifter of claim 8, wherein the phase shifter has a donor concentration Np which ranges from 1016 to 1018 cm−3, inclusive.

### Claim 10

A system comprising:
a first communications terminal comprising:
an optical phased array (OPA) architecture including a plurality of phase shifters configured to receive an optical communications beam from a second communications terminal, wherein the plurality of phase shifters includes a first phase shifter consisting of silicon, the first phase shifter having:
a slab-contacted NPN junction scheme geometry;
a PN junction distance from waveguide center within a range 100 nm to 2 μm, inclusive; and
a waveguide core width dimension within a range 500 nm to 2 μm, inclusive

### Claim 11 (depends on 12)

The system of claim 12, further comprising the second optical communications terminal, the second optical communications terminal having a second OPA architecture including a plurality of phase shifters configured to receive an optical communications beam from the first communications terminal, wherein the plurality of phase shifters includes a second phase shifter consisting of silicon.

### Claim 12 (depends on 11)

The system of claim 11, wherein the second phase shifter has a PN junction distance from waveguide center within a range 100 nm to 2 μm, inclusive and a waveguide core width dimension within a range 500 mn to 2 μm, inclusive.

### Claim 13

A method comprising:
receiving, at a first communications terminal, light through an aperture;
passing the received light to a phase shifter of an OPA architecture, the phase shifter consisting of silicon and having (1) a slab-contacted NPN junction scheme geometry, (2) a PN junction distance from waveguide center within a range 100 nm to 2 μm, inclusive, and (3) a waveguide core width dimension within a range 500 nm to 2 μm, inclusive;
providing, using the phase shifter, the received light to receiver components including a sensor;
receiving, using the phase shifter, light to be transmitted; and
transmitting the light to be transmitted through the aperture and to a second communications terminal.