High speed semiconductor optical modulator and fabricating method thereof
First Claim
1. A high speed semiconductor optical modulator, the optical modulator formed by stacking an n-type light-wave guiding layer, a light absorbing layer, a p-type light-wave guiding layer, a p-type clad layer, and a p-type ohmic contact layer on a substrate successively, the optical modulator having a ridge structure wherein the optical modulator is an electric-field absorbing type, and wherein width of the light absorbing layer is less than that of the p-type ohmic contact layer.
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Abstract
The present invention relates to an electrical field absorbing semiconductor optical modulator, more particularly, to a high speed semiconductor optical modulator and a fabricating method thereof. The present invention includes a high speed semiconductor optical modulator, the optical modulator formed by stacking an n-type light-wave guiding layer, a light absorbing layer, a p-type light-wave guiding layer, a p-type clad layer, and a p-type ohmic contact layer on a substrate successively, the optical modulator having a ridge structure wherein the optical modulator is an electric-field absorbing type, and wherein width W3 of the light absorbing layer is less than the width W1 of the p-type ohmic contact layer. Accordingly, the present invention enables to provide high speed optical modulation of tens of giga rate of which modulating characteristics are excellent by reducing contact resistance and capacitance, which are the major problems of ruining the characteristics of an optical modulator, simultaneously.
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Citations
8 Claims
- 1. A high speed semiconductor optical modulator, the optical modulator formed by stacking an n-type light-wave guiding layer, a light absorbing layer, a p-type light-wave guiding layer, a p-type clad layer, and a p-type ohmic contact layer on a substrate successively, the optical modulator having a ridge structure wherein the optical modulator is an electric-field absorbing type, and wherein width of the light absorbing layer is less than that of the p-type ohmic contact layer.
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3. A method of fabricating a high speed semiconductor optical modulator, comprising the steps of:
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a first step of forming a ridge structure by stacking an n-type light-wave guiding layer, a light absorbing layer, a p-type light-wave guiding layer, a p-type clad layer, and a p-type ohmic layer on a substrate successively;
a second step of etching the p-type ohmic contact layer to have a width W1;
a third step of etching vertically the n-type light-wave guiding layer, the light absorbing layer, the p-type light-wave guiding layer, the p-type clad layer, and the p-type ohmic layer to have width W2; and
a fourth step of side-etching the light absorbing layer to have a width W3 which is narrower than the width W1.
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- 5. The method of fabricating a high speed semiconductor optical modulator according to claim 5, wherein the fourth step is carried out during a predetermined time enough to etch completely a test pattern of which width is equal to a difference between the widths W2 and W3.
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