A Mach-Zehnder interferometer (MZI) filter comprising one or more passive compensation structures are described. The passive compensation structures yield MZI filters that are intrinsically tolerant to perturbations in waveguide dimensions and/or other ambient conditions. The use of n+1 waveguide widths can mitigate n different sources of perturbation to the filter. The use of at least three different waveguide widths for each Mach-Zehnder waveguide can alleviate sensitivity of filter performance to random width or temperature variations. A tolerance compensation portion is positioned between a first coupler section and a second coupler section, wherein the tolerance compensation portion includes a first compensation section having a second width, a second compensation section having a third width and a third compensation section having a fourth width, wherein the fourth width is greater than the third width and the third width is greater than the second width.

A frequency diverse distributed Mach-Zehnder Interferometer may include an optical modulator on a chip, with the modulator comprising a plurality of diodes arranged along a waveguide and with each diode driven by two or more drivers. An optical signal may be received in the waveguide, and a first modulating electrical signal may be applied to a first of the plurality of diodes using a first driver and a second modulating electrical signal may be applied to the first of the plurality of diodes using a second driver. The first electrical signal may be different from the second modulating electrical signal. The second electrical signal may have a larger voltage swing than the first electrical signal. The first electrical signal voltage swing may be 0.85 volts and the second electrical signal voltage swing may be 1.5 volts, for example. The first and second electrical signals may have different frequencies.

An achromatic optical subassembly is suitable for connecting with an optical fiber. The achromatic optical subassembly includes a light-emitting unit, a light guide unit and an achromatic unit. The light-emitting includes a light source with broad spectral width used for optical fiber, wherein the spectral width of the light source with broad spectral width is at least greater than 30 nm. The light guide unit is disposed opposite the light-emitting unit and includes a ferrule for the optical fiber to pass through. The achromatic unit is disposed between the light-emitting unit and the guide unit, wherein the light source with broad spectral width passes through the achromatic unit, after which the different wavelengths of the light source with broad spectral width traveling along the respective optical paths are brought to the same focus and incident on the optical fiber in the light guide unit.

An optical waveguide includes a core, a first cladding, a second cladding, and a heater. The first cladding configured to cover the core. The second cladding disposed over the first cladding. The heater disposed over the second cladding to heat the core. The first cladding and the second cladding are silicon oxide films. A first fixed charge density of the first cladding is lower than a second fixed charge density of the second cladding.

A planar wave guide (PWG) having a first end for coupling to a light pump and a second end opposite to the first end and including a first cladding layer; a second cladding layer; and a uniformly doped core layer between the first cladding layer and the second cladding layer, wherein the core layer is tapered having a smaller thickness at the first end and a larger thickness at the second end, and wherein a ratio of the core thickness to thickness of the cladding layers is smaller at the first end and larger at the second end.

Provided is an optical wavelength multi/demultiplexing circuit with a high rectangular transmission loss spectrum that is able to secure loss flatness of a transmission band, maintain/reduce a guard bandwidth of wavelength channel spacing, and broaden a transmission bandwidth. The circuit uses a multimode waveguide for a connecting part between a field modulation device and an AWG. The field modulation device is constituted by a common input waveguide, an optical branching unit, optical delay lines, a multiplex interference unit, and a mode converter/multiplexer.

An asymmetric optical resonator comprises a waveguiding element forming a closed loop. A first circumference of the loop is different from a second circumference, the first circumference being measured at one end of the loop in a plane perpendicular to a cavity axis. The second circumference is measured at the opposite end of the loop in a plane perpendicular to the cavity axis. An effective refractive index of the waveguiding element varies along a circumferential direction of the loop.

A Michelson interference optical fiber temperature sensor for detecting fringe contrast change is provided. It includes a light source, an optical fiber coupler connected to a first optical fiber and a second optical fiber, a coarse wavelength division multiplexer, a first photodetector, a second photodetector, a display device, and a processing circuit connected to the display device. The light source, optical fiber coupler and coarse wavelength division multiplexer are connected sequentially in that order. The coarse wavelength division multiplexer is connected to the first photodetector and the second photodetector individually. The first photodetector and the second photodetector are connected to the processing circuit. An end of the first optical fiber or the second optical fiber facing away from the optical fiber coupler is connected to a semiconductor. It has advantages of simple and fast manufacturing process, safe and reliable sensor, stable signal, low cost, high sensitivity and high precision.

An optical radiation detection system (100) comprising: an optical medium (1) structured to define a region (5) suitable for transmitting an optical radiation and being associated to at least one electric parameter varying as a function of the optical radiation concerning said region; at least one electrode (2, 3) electrically coupled to the optical medium (1), and spaced from said region (5), an electric power generator (4) connected to said at least one electrode (2) and structured to provide an electric signal (Se) to be applied to the optical medium. Further, the system comprises an electric measuring circuit (50) connected to said at least one electrode (2) and structured to provide a measuring electric signal (SM) representing a variation of said at least one electric parameter.

An optical modulation device configured of a planar optical waveguide, includes: a light incidence unit which allows light to be incident on the planar optical waveguide; a Mach-Zehnder interferometer which includes a first optical splitter section branching the light incident on the light incidence unit, two arm portions guiding the light branched by the first optical splitter section, a phase modulation unit linearly disposed on each of the two arm portions, and a first optical coupler section combining the light guided from the two arm portions; a light launching unit which launches the light combined by the first optical coupler section from the planar optical waveguide; and a traveling-wave electrode which includes an input unit and an output unit, and applies a voltage to the phase modulation unit.