A plastic optical fiber for a medical device lighting decreases the cost of a lens and simplify the design of a lighting apparatus, wherein the plastic optical fiber for a medical device includes a core composed of a (co)polymer containing methyl methacrylate as a main component and is characterized by including a cladding material composed of a copolymer having a fluorine weight composition ratio of 60 to 74%, and by having a theoretical numerical aperture, NA, of 0.48 to 0.65 and, thus, the plastic optical fiber has a high numerical aperture and also has excellent translucency and flexibility.

A method for adjusting the properties of a photonic circuit such that they fit with expected properties, the photonic circuit including a waveguide which includes a light propagation region, is provided. The method includes a step of modifying the refractive index of at least one zone of the region, the step being implemented by an ion implantation in the at least one zone. It extends to a waveguide the light propagation region of which has at least one zone with a refractive index modified by ion implantation in which the light remains confined, as well as a photonic circuit incorporating such a guide.

Provided is an optical isolator including a semiconductor substrate, an optical attenuator and an optical amplifier aligned with each other on the semiconductor substrate, an input optical waveguide connected to the optical attenuator, and an output optical waveguide connected to the optical amplifier, wherein a gain of the optical amplifier decreases based on an intensity of light incident on the optical amplifier increasing, wherein a first input light incident on the optical attenuator through the input optical waveguide is output as a first output light through the output optical waveguide, and a second input light incident on the optical amplifier through the output optical waveguide is output as a second output light through the input optical waveguide, and wherein when an intensity of the first input light and an intensity of the second input light are equal, an intensity of the first output light is greater than an intensity of the second output light.

A photonic integrated chip is configured as a transmitter-receiver chip. The photonic integrated chip includes a light emitter, a light detector, a multi-mode interference coupler, and a mode-filed adapter. The light emitted by the light emitter is guided to a core layer formed below the multi-mode interference coupler, and further to the mode-filed adapter for transmission of light to an optical fiber coupled with the photonic integrated chip. Similarly, light received by the mode-filed adapter from the optical fiber propagates to the core layer, and is guided by the multi-mode interference coupler into the light detector. The photonic integrated chip is utilized to realize a single-unit transmitter-receiver module for a fiber optic gyroscope circuit based on monolithic integration of photonics components via wafer fabrication on a substrate. The photonic integrated chip has a low fabrication cost, low size, and is robust.

Disclosed herein are configurations and methods to produce very low loss waveguide structures, which can be single-layer or multi-layer. These waveguide structures can be used as a sensing component of a small-footprint integrated optical gyroscope. By using pure fused silica substrates as both top and bottom cladding around a SiN waveguide core, the propagation loss can be well below 0.1 db/meter. Low-loss waveguide-based gyro coils may be patterned in the shape of a spiral (circular or rectangular or any other shape), that may be distributed among one or more of vertical planes to increase the length of the optical path while avoiding the increased loss caused by intersecting waveguides in the state-of-the-art designs. Low-loss adiabatic tapers may be used for a coil formed in a single layer where an output waveguide crosses the turns of the spiraling coil.

An aluminosilicate glass having a composition according to the following formula (I):

(100−(1+a.sub.1+b.sub.1).Math.x)SiO.sub.2.Math.(x)Al.sub.2O.sub.3.Math.(a.sub.1.Math.x)MO.Math.(b.sub.1.Math.x)R (wt %)  (I)

in which MO is alkaline earth metal oxide, the alkaline earth metal M being one or more of Mg, Ca, Sr, and Ba, R comprises alkali metal oxide, the alkali metal being one or more of Li, Na, and K, x is at least 15, a.sub.1 is at least 0.35, b.sub.1 is at least 0.55, and wherein the product of a.sub.1 and b.sub.1 is at least 0.22.

A Group III-Nitride quantum well laser including a distributed Bragg reflector (DBR). In some embodiments, the DBR includes Scandium. In some embodiments, the DBR includes Al.sub.1-xSc.sub.xN, which may have 0<x≤0.45.

Photonic devices having a photonic waveguiding layer, and a cladding layer, disposed on the photonic waveguiding layer, and where the cladding section is a material comprising Scandium. The cladding layer may include a material comprising Al.sub.1-xSc.sub.xN material where 0<x≤0.45.

An in-plane photonic device is provided for transmission of an optical signal across a gap, in particular an in-plane photonic device for use in a photonic integrated circuit with one or more in-plane crossings of electrical connections and photonic waveguides. One embodiment relates to an in-plane photonic device for use in a photonic integrated circuit with in-plane crossings of electrical connections and photonic waveguides, including: at least one input optical waveguide; and at least one output optical waveguide; wherein the at least one input optical waveguide and the at least one output optical waveguides are positioned such that a gap between them separates the input and the output optical waveguide(s), and wherein the input and the output optical waveguides are configured for optical mode matching across the gap, such that an optical signal can be transmitted from the input optical waveguide to the output optical waveguide across the gap.

A photonic integrated chip is configured as a transmitter-receiver chip. The photonic integrated chip includes a light emitter, a light detector, a multi-mode interference coupler, and a mode-filed adapter. The light emitted by the light emitter is guided to a core layer formed below the multi-mode interference coupler, and further to the mode-filed adapter for transmission of light to an optical fiber coupled with the photonic integrated chip. Similarly, light received by the mode-filed adapter from the optical fiber propagates to the core layer, and is guided by the multi-mode interference coupler into the light detector. The photonic integrated chip is utilized to realize a single-unit transmitter-receiver module for a fiber optic gyroscope circuit based on monolithic integration of photonics components via wafer fabrication on a substrate. The photonic integrated chip has a low fabrication cost, low size, and is robust.