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Optical modulator that includes optical waveguide formed in ferroelectric substrate

A technology of optical modulator and optical waveguide, which is applied in the fields of instruments, optics, nonlinear optics, etc., and can solve the problems of quality degradation of modulated optical signals, etc.

Inactive Publication Date: 2016-08-10
FUJITSU OPTICAL COMPONENTS LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the quality of the modulated optical signal generated by the optical modulator degrades

Method used

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  • Optical modulator that includes optical waveguide formed in ferroelectric substrate
  • Optical modulator that includes optical waveguide formed in ferroelectric substrate
  • Optical modulator that includes optical waveguide formed in ferroelectric substrate

Examples

Experimental program
Comparison scheme
Effect test

no. 1 approach

[0054] Figure 7 The configuration of the light modulator according to the first embodiment is illustrated. According to the optical modulator 100 of the first embodiment, by following the Figure 5 The illustrated light modulator is constructed in the same manner including the substrate 1 . In the substrate 1, an input optical waveguide 2a, a pair of straight optical waveguides 2b and 2c, and an output optical waveguide 2d are formed. That is, an optical waveguide constituting a Mach-Zehnder interferometer is formed near the top surface of substrate 1 . in accordance with Image 6 In the same manner as in the illustrated configuration, buffer layer 5 and semiconductive film 7 are formed on the top surface of substrate 1 . Signal electrodes 3 x and 3 y , ground electrodes 4 , and DC electrodes 6 a and 6 b are formed on semiconductive film 7 . Note that the light modulator 100 includes a DC electrode 6e and a DC electrode 6f instead of Figure 5 The illustrated DC electro...

no. 2 approach

[0066] Figure 10 The configuration of the light modulator according to the second embodiment is illustrated. The configuration of the light modulator 200 according to the second embodiment is the same as Figure 5 with Image 6 The configurations of the illustrated light modulators are almost the same. However, the resistance of the semiconductive film 31 of the light modulator 200 is lower than Image 6 The resistance of the semiconductive film 7 is illustrated. For example, semiconductive film 31 is formed such that the resistance value between DC electrode 6 a and DC electrode 6 d and the resistance value between DC electrode 6 b and DC electrode 6 c are less than or equal to 1 megohm. In addition, the semiconductive film 31 is realized by, for example, a Si film whose resistivity is adjusted.

[0067] When the resistance of the semiconductive film 31 is small, such as Figure 10 As illustrated, charges generated by the pyroelectric effect due to temperature change m...

no. 3 approach

[0073] Figure 12 The configuration of the light modulator according to the third embodiment is illustrated. The light modulator 300 according to the third embodiment includes a pair of light modulator elements arranged in parallel to each other. Each light modulator element generates a modulated light signal. A pair of modulated optical signals generated by the pair of optical modulator elements are combined and output. Therefore, the optical modulator 300 is capable of generating a QPSK modulated optical signal.

[0074] Near the top surface of the substrate 1, an optical waveguide for the first light modulator element and an optical waveguide for the second light modulator element are formed. The optical waveguides used for the individual optical modulator elements can be used with Figure 5 to Figure 11 The illustrated optical waveguides 2a-2d are substantially identical. In addition, a ground electrode 4 is formed on the top surface of the substrate 1 .

[0075] In ...

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Abstract

Disclosed is an optical modulator that includes optical waveguide formed in a ferroelectric substrate. The optical modulator includes: a ferroelectric substrate in which an input optical waveguide, first and second optical waveguides, and an output optical waveguide are formed; a first electrode formed in a vicinity of the first optical waveguide and to which a first DC voltage is applied; a second electrode formed in a vicinity of the second optical waveguide and to which a second DC voltage is applied; a third electrode electrically connected to the first electrode and formed on both sides of the second electrode; and a fourth electrode electrically connected to the second electrode and formed on both sides of the first electrode. A first gap between the first electrode and the fourth electrode is approximately the same as a second gap between the second electrode and the third electrode. A gap between the third electrode and the fourth electrode is 1-5 times greater than the first gap.

Description

technical field [0001] Embodiments discussed herein relate to optical modulators including optical waveguides formed in ferroelectric substrates. Background technique [0002] Ferroelectrics, which have a strong electro-optic effect, are used in optical devices that convert electrical signals into optical signals. For example, optical modulators constructed by including a LiNbO3 (lithium niobate) substrate are widely in practical use. Optical modulators constructed by including a LiNbO3 substrate are sometimes referred to as LN modulators. The chirp effect is small in the LN optical modulator and the LN optical modulator is capable of high-speed modulation. [0003] Figure 1A and Figure 1B An example of the configuration of the light modulator is illustrated. Figure 1A is a top view of the light modulator seen from above. Figure 1B is instantiated Figure 1A Cross-sectional view of the A-A section of the illustrated light modulator. [0004] The substrate 1 is a Z-c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G02F1/05
CPCG02F1/0508G02F1/0516G02F1/0036G02F1/0316G02F1/225G02F1/2255G02F2202/20G02F2202/22G02F1/212
Inventor 土居正治吉田宽彦久保田嘉伸川岛由匡
Owner FUJITSU OPTICAL COMPONENTS LTD