Electro-optic modulators incorporating quantum dots
First Claim
1. A modulator device formed of a semiconductor material which utilises the electro-optic effect to achieve a change in the refractive index of the material (Δ
- n) under the influence of an applied field, F, in accordance with the equation;
Δ
n=−
½
n03[rF+sF2]≡
Δ
nL+Δ
nQwhere n0 is the refractive index of the material at zero field, and Δ
nL and Δ
nQ are the linear and quadratic contributions to the change in refractive index respectively, r is the linear electro-optic coefficient of the material and s is the quadratic electro-optic coefficient of the material incorporating a plurality of quantum dots and operating in a wavelength region where the value of rF is sufficiently greater than the value of sF2 so as to operate with the dominant effect on Δ
n being contributed by the linear effect.
2 Assignments
0 Petitions
Accused Products
Abstract
A modulator is formed of a semiconductor material which utilises the electro-optic effect to achieve a change in the refractive index Δn of the material under the influence of an applied electrical field F (251), in accordance with the equation: Δn=−½ n03 [rF+sF2]≡ΔnL+ΔnQ where n0 is the refractive index of the material at zero field, and ΔnL and ΔnL and ΔnQ are the linear and quadratic contributions to the change in refractive index respectively, r is the linear electro-optic coefficient of the material and s is the quadratic electro-optic coefficient of the material incorporating a plurality of quantum dots and operating in a wavelength region where the value of rF is sufficiently greater than the value of sF2 so as to operate with the dominant effect on the refractive index Δn being contributed by the linear effect. In this way, a device with a wide bandwidth is achieved by appropriately separating the band-gap wavelength (λg) and the operating wavelengths (λ).
20 Citations
21 Claims
-
1. A modulator device formed of a semiconductor material which utilises the electro-optic effect to achieve a change in the refractive index of the material (Δ
- n) under the influence of an applied field, F, in accordance with the equation;
Δ
n=−
½
n03[rF+sF2]≡
Δ
nL+Δ
nQwhere n0 is the refractive index of the material at zero field, and Δ
nL and Δ
nQ are the linear and quadratic contributions to the change in refractive index respectively, r is the linear electro-optic coefficient of the material and s is the quadratic electro-optic coefficient of the material incorporating a plurality of quantum dots and operating in a wavelength region where the value of rF is sufficiently greater than the value of sF2 so as to operate with the dominant effect on Δ
n being contributed by the linear effect.- View Dependent Claims (2, 3, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
- n) under the influence of an applied field, F, in accordance with the equation;
-
4. An integrated optical device including a path carrying an incoming optical signal of a wavelength λ
- , means for directing at least part of the signal via a modulation region, and a path for an optical signal;
the modulation region being formed of a semiconducting material incorporating a plurality of quantum dots and exhibiting an electro-optic response thereby to permit variation of the refractive index of at least part of the modulation region;
the band-gap of the semiconducting material incorporating the quantum dots being such that the corresponding wavelength λ
g is less than λ
. - View Dependent Claims (5, 6, 7)
- , means for directing at least part of the signal via a modulation region, and a path for an optical signal;
-
8. An integrated optical device including a path carrying an incoming optical signal of a range-of wavelengths between λ
-
1 and λ
2, means for directing at least part of the signal via a modulation region, and a path for an optical signal;
the modulation region being formed of a semiconducting material incorporating a plurality of quantum dots and exhibiting an electro-optic response thereby to permit variation of the refractive index of at least part of the modulation region;
the band-gap of the semiconducting material incorporating the quantum dots being such that the corresponding wavelength λ
g is less than both λ
1 and λ
2 by an amount sufficient that the change in refractive index at λ
1 and λ
2 is substantially the same. - View Dependent Claims (9, 10)
-
1 and λ
Specification