Optical device and optical transceiver

Patent metadata

Field	Value
Publication number	US-12066737-B2
Application number	US-202217591395-A
Country	US
Kind code	B2
Filing date	Feb 2, 2022
Priority date	Mar 11, 2021
Publication date	Aug 20, 2024
Grant date	Aug 20, 2024

Abstract

An optical device includes a substrate W, a RF modulating unit, and a phase adjustment unit 220 . The RF modulating unit is provided on the substrate W and modulates light in accordance with a RF signal. The phase adjustment unit 220 is provided on the substrate W and adjusts the phase of an optical signal modulated by the RF modulating unit. The phase adjustment unit 220 includes a heater 2200 and a to-be-heated optical waveguide 2201 . The to-be-heated optical waveguide 2201 is provided between a thin film LN substrate 32 and a buffer layer 33 of the substrate W, and is formed of a material having a thermo-optical effect. The heater 2200 is provided at a position opposite the to-be-heated optical waveguide 2201 , with the buffer layer 33 therebetween on the substrate W, and heats the to-be-heated optical waveguide 2201.

First claim

What is claimed is:

1. An optical device comprising:
a substrate in which a first buffer layer, a thin film having an electro-optic effect and including a second optical waveguide, and a second buffer layer are formed in this order;
a RF modulating unit that is provided on the substrate and that modulates light propagating through the second optical waveguide in accordance with a RF signal, the second optical waveguide having an electro-optic effect; and
a phase adjustment unit that is provided on the substrate and that adjusts a phase of an optical signal modulated by the RF modulating unit, wherein
the phase adjustment unit includes
a first optical waveguide that is provided between the second buffer layer and the thin film, that is formed of a material having a thermo-optical effect, and through which light that has been modulated or that is to be modulated by the RF modulating unit is allowed to pass, and
a heater that is provided at a position opposite the first optical waveguide, with the second buffer layer therebetween, and that heats the first optical waveguide.

2. The optical device according to claim 1 , wherein
the second optical waveguide is formed as a projected section,
the RF modulating unit modulates the optical signal propagating through the second optical waveguide,
the first optical waveguide is disposed so as to continue in an extending direction of the second optical waveguide, and
an end surface of the first optical waveguide in an extending direction of the first optical waveguide is in contact with an end surface of the second optical waveguide in the extending direction of the second optical waveguide.

3. The optical device according to claim 2 , wherein the thermo-optical effect of the first optical waveguide is larger than the electro-optic effect of the second optical waveguide.

4. The optical device according to claim 1 , wherein a refractive index of the first optical waveguide is larger than a refractive index of the thin film.

5. The optical device according to claim 2 , wherein
a width of an end portion of the second optical waveguide in the extending direction of the second optical waveguide is narrower as the end portion of the second optical waveguide is closer to the end surface of the second optical waveguide that is in contact with the first optical waveguide, and
the width of the end surface of the second optical waveguide that is in contact with the first optical waveguide is narrower than a width of the end surface of the first optical waveguide that is in contact with the second optical waveguide.

6. The optical device according to claim 2 , wherein
a thickness of the first optical waveguide is thinner than a thickness of the second optical waveguide.

7. The optical device according to claim 1 , further comprising a second optical waveguide that is a projected section is formed on the thin film, wherein
the RF modulating unit modulates the optical signal propagating through the second optical waveguide, and
the first optical waveguide is provided between the second optical waveguide and the heater.

8. The optical device according to claim 7 , wherein
a width of an end portion of the first optical waveguide in an extending direction of the first optical waveguide is narrower as the end portion of the first optical waveguide is closer to a leading end of the first optical waveguide.

9. The optical device according to claim 8 , wherein
a width of a second optical waveguide at a portion in which the first optical waveguide is provided is wider than a width of the second optical waveguide at a portion in which the first optical waveguide is not provided.

10. The optical device according to claim 9 , wherein
the width of the second optical waveguide at the portion in which the first optical waveguide is provided is gradually narrower toward a position that is associated with the leading end of the first optical waveguide in the extending direction of the first optical waveguide.

11. An optical transceiver comprising:
the optical device according to claim 1 that functions as an optical transmission device that transmits the optical signal modulated in accordance with the RF signal; and
an optical reception device that receives the optical signal and that outputs an electrical signal according to the received optical signal.

Assignees

• Fujitsu Optical Components Ltd

Inventors

• Sugiyama Masaki

Classifications

• G02F1/0147 Primary

  based on thermo-optic effects (G02F1/132 takes precedence) · CPC title

• G02F1/212 Primary

  Mach-Zehnder type · CPC title

• H04B10/40

  Transceivers · CPC title

• H04B10/25759

  Details of the reception of RF signal or the optical conversion before the optical fibre · CPC title

• G02F1/035

  in an optical waveguide structure · CPC title