Optical waveguide element and optical modulator

Abstract

An optical waveguide element is provided with a rib-type waveguide having a core that has a rib portion, and a pair of slab portions including a first slab portion and a second slab portion that are connected respectively to both ends of the rib portion so as to sandwich the rib portion. The rib portion has a cross-sectional dimension that allows the propagation of light of a basic mode and a high-order mode in a preset single polarization state, and has a first P-type semiconductor and a first N-type semiconductor that form a PN junction. The first slab portion has a second P-type semiconductor and a P-type conductor that are connected to each other, the second P-type semiconductor being connected to the first P-type semiconductor of the rib portion. The second slab portion has a second N-type semiconductor and an N-type conductor that are connected to each other, the second N-type semiconductor being connected to the first N-type semiconductor of the rib portion.

Description

technical field [0001] The present invention relates to a high-speed optical waveguide element with low optical loss and an optical modulator including the optical waveguide element. [0002] This application claims the priority of Japanese Patent Application No. 2012-283964 for which it applied in Japan on December 27, 2012, and uses the content here. Background technique [0003] In recent years, studies have been conducted on the use of optical integrated circuits such as substrate-type optical waveguides in devices for optical fiber communication, especially for long-distance wavelength division multiplexing optical fiber communication. [0004] Patent Document 1 discloses a single-mode silicon ridge waveguide that has a PIN junction in the lateral direction and controls the refractive index by changing the carrier density in the PIN junction. [0005] The following optical modulator is described in Patent Document 2. The optical modulator is a silicon ridge waveguide w...

AI Technical Summary

Problems solved by technology

As a result, if the high-order mode component is superimposed on the intensity modulation signal or the phase modulation signal, the extinction ratio of the intensity modulation or the Q value (Q-factor) of the phase modulation will decrease, and the bit error rate will increase, making it impossible to construct a good optical communication system

[0012] In the silicon Mach-Zehnder type waveguide having a PN diode disclosed in Non-Patent Document 1, it is necessary to reduce the optical loss to less than 10 dB in the wavelength region including the C-band (1530-1565 nm) and the L-band (1565-1625 nm). very difficult

Therefore, the low optical loss required for optical components for long-distance wavelength division multiplexing optical fiber communication cannot be realized

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