Abstract: Provided is a device which includes a method for the coherent detection of an optical signal, including the following steps of providing a vertically illuminable photodiode; producing an optical reference signal; radiating the optical signal and the reference signal into the photodiode in such a way that the two signals at least partially interfere with each other. Radiating the optical signal into the photodiode is effected via a first side of the photodiode, and radiating the reference signal into the photodiode is effected via a second side of the photodiode, or, vice versa, the reference signal is radiated into the photodiode via the first side of the photodiode and the optical signal is radiated into the photodiode via the second side.

Abstract: The disclosure relates to a modulator arrangement, including an optical thin film lithium niobate Mach-Zehnder modulator with a first and a second waveguide arm arranged on a substrate. The first and the second waveguide arm each include an area formed of lithium niobate; an electrode arrangement for generating an electric field which at least sectionally acts on the first and the second waveguide arm. The electrode arrangement includes a first and a second signal line as well as a first and a second ground line. The first signal line at least sectionally extends above the first waveguide arm so that the first signal line—as seen in a direction perpendicular to the substrate—is aligned with the first waveguide arm. The second ground line at least sectionally extends above the second waveguide arm so that the second ground line—as seen in a direction perpendicular to the substrate—is aligned with the second waveguide arm; and a differential driver for providing a voltage for the Mach-Zehnder modulator.

Abstract: An optical assembly for optical signal processing including a first input for coupling in a first light signal; a second input for coupling in a second light signal; a first beam splitter for splitting the first light signal into a first part and a second part; a second beam splitter for splitting the second light signal into a first part and a second part; a superposing unit; a detector; an electronic signal processing unit; at least one actuating unit; and a delay line for generating a delay of the running time of the first part of the first light signal and of the first part of the second light signal up to the superposing unit. The delay line is configured such that the first part of the first light signal and the first part of the second light signal pass through the delay line in opposite directions.

Abstract: Provided is a photodiode, including a substrate formed by a III-V semiconductor material. The substrate is made of InP; at least one light absorption layer; and at least one doped contact layer. The absorption layer is to be illuminated through the contact layer. The contact layer includes a semiconductor material having an indirect band gap and has a thickness of at least 200 nm.

Abstract: An apparatus includes an input receiving a modulated optical data signal having components of at least first and second polarizations, a first optical detector receiving the data signal, the first optical detector being first polarization-selective or first polarization-sensitive, passing components of the data signal having the second polarization, and outputting a first electrical signal, a second optical detector coupled to the first optical detector to receive the components of the data signal having the second polarization, and outputting a second electrical signal, and a processor applying a Kramers-Kronig process to the first and second electrical signals, and outputting the data signal using the Kramers-Kronig processed first and second electrical signals.

Abstract: Provided is a device which includes a method for the coherent detection of an optical signal, including the following steps of providing a vertically illuminable photodiode; producing an optical reference signal; radiating the optical signal and the reference signal into the photodiode in such a way that the two signals at least partially interfere with each other. Radiating the optical signal into the photodiode is effected via a first side of the photodiode, and radiating the reference signal into the photodiode is effected via a second side of the photodiode, or, vice versa, the reference signal is radiated into the photodiode via the first side of the photodiode and the optical signal is radiated into the photodiode via the second side.

Abstract: A method for distance measurement by means of an active optical sensor system is disclosed, comprising: an initial pulse sequence with an initial frequency spectrum, which corresponds to a frequency comb, is generated using a laser source. Based thereon, a first pulse sequence and a first reference pulse sequence with a first frequency spectrum, which corresponds to a first part of the frequency comb, as well as a second pulse sequence and a second reference pulse sequence with a second frequency spectrum, which corresponds to a second part of the frequency comb, are generated. A first distance of the object is determined using a first heterodyne measurement based on the first reference pulse sequence and reflected portions of the first pulse sequence and a second distance is determined using a second heterodyne measurement based on the second reference pulse sequence and reflected portions of the second pulse sequence.

Abstract: An optical assembly for optical signal processing: including a first input for coupling in a first light signal; a second input for coupling in a second light signal; a first beam splitter for splitting the first light signal into a first part and a second part; a second beam splitter for splitting the second light signal into a first part and a second part; a superposing unit; a detector; an electronic signal processing unit; at least one actuating unit; and a delay line for generating a delay of the running time of the first part of the first light signal and of the first part of the second light signal up to the superposing unit. The delay line is configured such that the first part of the first light signal and the first part of the second light signal pass through the delay line in opposite directions.

Abstract: An apparatus includes an input receiving a modulated optical data signal having components of at least first and second polarizations, a first optical detector receiving the data signal, the first optical detector being first polarization-selective or first polarization-sensitive, passing components of the data signal having the second polarization, and outputting a first electrical signal, a second optical detector coupled to the first optical detector to receive the components of the data signal having the second polarization, and outputting a second electrical signal, and a processor applying a Kramers-Kronig process to the first and second electrical signals, and outputting the data signal using the Kramers-Kronig processed first and second electrical signals.

Abstract: A semiconductor photodiode, including a light-absorbing layer; an optical waveguide via which light can evanescently be coupled into the light-absorbing layer, and a doped contact layer arranged between the light-absorbing layer and the optical waveguide. The optical waveguide at least sectionally has a doping which produces a diffusion barrier counteracting a diffusion of dopant of the contact layer into the optical waveguide.

Abstract: A semiconductor photodiode, including a light-absorbing layer; an optical waveguide via which light can evanescently be coupled into the light-absorbing layer, and a doped contact layer arranged between the light-absorbing layer and the optical waveguide. The optical waveguide at least sectionally has a doping which produces a diffusion barrier counteracting a diffusion of dopant of the contact layer into the optical waveguide.

Abstract: A tunable DBR laser including: an amplifier section, a part-reflecting optical output, a connection section connected to the amplifier section, and at least two wavelength-selective reflectors optically coupled to the amplifier section via the connection section. The connection section includes at least one MMI coupler and several waveguides, so that different optical paths lead from the amplifier section to the wavelength-selective reflectors and each of the different optical paths leads through the at least one MMI coupler and through one of the waveguides. The wavelength-selective reflectors differ from one another by having different reflection spectra and each of the wavelength-selective reflectors is connected to one of several outputs of the at least one MMI coupler. By activating a phase shifter, arranged in a course of at least one of the waveguides, the DBR laser can be switched between different resonators.

Abstract: A tunable DBR laser including: an amplifier section, a part-reflecting optical output, a connection section connected to the amplifier section, and at least two wavelength-selective reflectors optically coupled to the amplifier section via the connection section. The connection section includes at least one MMI coupler and several waveguides, so that different optical paths lead from the amplifier section to the wavelength-selective reflectors and each of the different optical paths leads through the at least one MMI coupler and through one of the waveguides. The wavelength-selective reflectors differ from one another by having different reflection spectra and each of the wavelength-selective reflectors is connected to one of several outputs of the at least one MMI coupler. By activating a phase shifter, arranged in a course of at least one of the waveguides, the DBR laser can be switched between different resonators.