Abstract: The sensor includes an optical waveguide defined in a light-transmitting medium. The waveguide includes a sensing portion and an non-sensing portion. The light-transmitting medium included in the sensing portion has defects that provide the light-transmitting medium with a deep band gap level between a valence band of the light-transmitting medium and a conduction band of the light-transmitting medium. The deep band gap level is configured such that the waveguide guiding light signals through the light-transmitting medium in the sensing portion causes free carriers to be generated in the light-transmitting medium. A detector is configured to detect the free carriers in the sensing region of the waveguide.

Abstract: The sensor includes an optical waveguide defined in a light-transmitting medium. The waveguide includes a sensing portion and an non-sensing portion. The light-transmitting medium included in the sensing portion has defects that provide the light-transmitting medium with a deep band gap level between a valence band of the light-transmitting medium and a conduction band of the light-transmitting medium. The deep band gap level is configured such that the waveguide guiding light signals through the light-transmitting medium in the sensing portion causes free carriers to be generated in the light-transmitting medium. A detector is configured to detect the free carriers in the sensing region of the waveguide.

Abstract: The sensor includes an optical waveguide defined in a light-transmitting medium. The waveguide includes a sensing portion and an non-sensing portion. The light-transmitting medium included in the sensing portion has defects that provide the light-transmitting medium with a deep band gap level between a valence band of the light-transmitting medium and a conduction band of the light-transmitting medium. The deep band gap level is configured such that the waveguide guiding light signals through the light-transmitting medium in the sensing portion causes free carriers to be generated in the light-transmitting medium. A detector is configured to detect the free carriers in the sensing region of the waveguide.

Abstract: An electro-optic device includes a semiconducting layer in which is formed a waveguide, a modulator formed across the waveguide comprising a p-doped region to one side and an n-doped region to the other side of the waveguide, wherein at least one of the doped regions extends from the base of a recess formed in the semiconducting layer. In this way, the doped regions can extend further into the semiconducting layer and further hinder escape of charge carriers without the need to increase the diffusion distance of the dopant and incur an additional thermal burden on the device. In an SOI device, the doped region can extend to the insulating layer. Ideally, both the p and n-doped regions extend from the base of a recess, but this may be unnecessary in some designs. Insulating layers can be used to ensure that dopant extends from the base of the recess only, giving a more clearly defined doped region.

Abstract: The sensor includes an optical waveguide defined in a light-transmitting medium. The waveguide includes a sensing portion and an non-sensing portion. The light-transmitting medium included in the sensing portion has defects that provide the light-transmitting medium with a deep band gap level between a valence band of the light-transmitting medium and a conduction band of the light-transmitting medium. The deep band gap level is configured such that the waveguide guiding light signals through the light-transmitting medium in the sensing portion causes free carriers to be generated in the light-transmitting medium. A detector is configured to detect the free carriers in the sensing region of the waveguide.

Abstract: An integrated optical waveguide (1) having an in-line light sensor (2) integrally formed therewith for tapping off a small proportion of the signal transmitted along the waveguide (1). A first part (1A) of the waveguide leads to a photodiode portion (2) and a second part (1B) of the waveguide leads away from the photodiode portion (2), the photodiode portion (2) comprising one or more regions (14) of light absorbing material within the waveguide (1) arranged to absorb a minor proportion of light transmitted along the waveguide (1) and thereby to generate free charge carriers within the waveguide (1). Deep band gap levels (21) are introduced into photodiode portion by ion implantation to enable it to absorb selected wavelengths. The free charge carriers are detected by a p-i-n diode formed across the waveguide (1). Wavelength selective reflectors (11, 12) may be provided either side of the photodiode portion (2) so light passes repeatedly through the photodiode portion (2).

Abstract: An optic system including an integrated variable optical attenuating device for attenuating an input optical signal, the integrated optical variable attenuating device including a first electrically controllable attenuating element and a second electrically controllable attenuating element cascaded together, the first attenuating element having a first range of optical attenuation smaller than that of the second attenuating element but requiring less input power than the second attenuating element to switch between levels of attenuation within the first range of attenuation, and wherein the optic system further includes electrical circuitry for controlling the first and second attenuating elements in coordination with one another so as to achieve the desired level of total attenuation of the optical signal.