IP Library › Granted Patent US 12663319
Granted Patent B2
US 12663319 · App. 18/341,543 · Granted Jun 23, 2026

Local silicon-photonics temperature sensor

Inventors: Sujit Handanhal Ramachandra (Allentown, PA); Abhishek Bhat (Allentown, PA); Prajwal M. Kasturi (Breinigsville, PA)
Assignee: Cisco Technology, Inc.
G01K7/183G02F1/0147H04B10/40
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Quick Facts
Patent No.
US 12663319
App. No.
18/341,543
Granted
Jun 23, 2026
Kind
B2
Abstract

The present disclosure describes systems and methods for detecting temperature in an electro-optical circuit (e.g., an electro-optical transceiver). According to an embodiment, an electro-optical circuit includes a photonic integrated circuit and an electronic integrated circuit. The photonic integrated circuit includes an optical component and a first resistor positioned by the optical component. The electronic integrated circuit determines a temperature for the optical component based on a first resistance of the first resistor.

Claims (42)

1 . An electro-optical circuit comprising:

a photonic integrated circuit arranged in a package, the photonic integrated circuit comprising:

an optical component; and

a first resistor positioned by the optical component; and

an electronic integrated circuit arranged in the package, the electronic integrated circuit positioned on the photonic integrated circuit and arranged to determine a temperature for the optical component based on a first resistance of the first resistor.

2 . The electro-optical circuit of claim 1 , wherein the electronic integrated circuit comprises:

a first oscillator arranged to generate a first signal with a first frequency based on the first resistance of the first resistor; and

a second oscillator arranged to generate a second signal with a second frequency based on a second resistance of a second resistor.

3 . The electro-optical circuit of claim 2 , wherein the electronic integrated circuit further comprises:

a first frequency divider arranged to produce a third signal with a third frequency based on the first signal; and

a second frequency divider arranged to produce a fourth signal with a fourth frequency based on the second signal.

4 . The electro-optical circuit of claim 3 , wherein the electronic integrated circuit is further arranged to determine a difference between the third frequency and the fourth frequency, wherein the temperature for the optical component is determined based on the difference between the third frequency and the fourth frequency.

5 . The electro-optical circuit of claim 2 , wherein the electronic integrated circuit comprises a filter arranged to calibrate the second oscillator.

6 . The electro-optical circuit of claim 5 , wherein calibrating the second oscillator comprises adjusting a resistance of a variable resistor of the second oscillator.

7 . The electro-optical circuit of claim 1 , wherein the first resistor comprises doped silicon.

8 . The electro-optical circuit of claim 1 , wherein the first resistor is electrically connected to the electronic integrated circuit by a via, a metal layer, and a solder bump of the photonic integrated circuit.

9 . A method comprising:

determining, by an electronic integrated circuit, a first resistance of a first resistor positioned in a photonic integrated circuit and by an optical component of the photonic integrated circuit, wherein the electronic integrated circuit is positioned on the photonic integrated circuit; and

determining, by the electronic integrated circuit, a temperature for the optical component based on the first resistance.

10 . The method of claim 9 , wherein determining the first resistance comprises:

generating, by a first oscillator in the electronic integrated circuit, a first signal with a first frequency based on the first resistance; and

generating, by a second oscillator in the electronic integrated circuit, a second signal with a second frequency based on a second resistance of a second resistor.

11 . The method of claim 10 , wherein determining the first resistance further comprises:

producing, by a first frequency divider in the electronic integrated circuit, a third signal with a third frequency based on the first signal; and

producing, by a second frequency divider in the electronic integrated circuit, a fourth signal with a fourth frequency based on the second signal.

12 . The method of claim 11 , wherein determining the first resistance further comprises determining a difference between the third frequency and the fourth frequency, and wherein the temperature for the optical component is determined based on the difference between the third frequency and the fourth frequency.

13 . The method of claim 10 , further comprising calibrating, by a filter in the electronic integrated circuit, the second oscillator.

14 . The method of claim 13 , wherein calibrating the second oscillator comprises adjusting a resistance of a variable resistor of the second oscillator.

15 . The method of claim 9 , wherein the first resistor comprises doped silicon.

16 . The method of claim 9 , wherein the first resistor is electrically connected to the electronic integrated circuit by a via, a metal layer, and a solder bump of the photonic integrated circuit.

17 . A system comprising:

a photonic integrated circuit comprising:

an optical component; and

a first resistor positioned by the optical component; and

an electronic integrated circuit positioned on the photonic integrated circuit, wherein the electronic integrated circuit is arranged to determine a temperature for the optical component based on a first resistance of the first resistor.

18 . The system of claim 17 , wherein the electronic integrated circuit comprises:

a first oscillator arranged to generate a first signal with a first frequency based on the first resistance of the first resistor; and

a second oscillator arranged to generate a second signal with a second frequency based on a second resistance of a second resistor.

19 . The system of claim 18 , wherein the electronic integrated circuit further comprises:

a first frequency divider arranged to produce a third signal with a third frequency based on the first signal; and

a second frequency divider arranged to produce a fourth signal with a fourth frequency based on the second signal.

20 . The system of claim 19 , wherein the electronic integrated circuit is further arranged to determine a difference between the third frequency and the fourth frequency, wherein the temperature for the optical component is determined based on the difference between the third frequency and the fourth frequency.