Disclosed is a self-locked laser system, including: a semiconductor substrate; a laser diode including a first semiconductor part disposed on the semiconductor substrate, and which generates an optical signal; an unidirectional Whispery Gallery Mode (WGM) resonator including a second semiconductor part disposed on the semiconductor substrate; and a structure emitting an optical signal self-locked by the optical signal of the laser diode, in which the laser diode and the resonator are optically coupled on the semiconductor substrate.

An optical device capable of suppressing a reflected light at an end of an optical waveguide regardless of the width of the optical waveguide is provided. An optical device includes an optical waveguide and a terminator. The optical waveguide is formed on a substrate. The terminator is formed on the substrate in such a way that the terminator is connected to one end of the optical waveguide, includes a curved optical waveguide having such a curvature that it causes a bending loss in an input light input from the optical waveguide, the input light decaying as it propagates through the curved optical waveguide.

A semiconductor light source including a planar optical component that focuses long-wavelength (e.g., infrared) light emitted in a resonant cavity into a nonlinear crystal, which then converts the long-wavelength light into light having a shorter wavelength (e.g., visible light) by frequency doubling. A wavelength-selective reflection layer on the nonlinear crystal reflects the long-wavelength light back into the resonant cavity to form an external cavity and transmits the light having the shorter wavelength out of the external cavity. The resonant cavity includes an active region that emits the long-wavelength light at a high efficiency. The planar optical component includes a micro-lens formed in semiconductor layers or a gradient refractive index lens formed in the nonlinear crystal.

A grating coupler having first and second ends for coupling a light beam to a waveguide of a chip includes a substrate configured to receive the light beam from the first end and transmit the light beam through the second end, the substrate having a first refractive index n1, a grating structure having curved grating lines arranged on the substrate, the grating structure having a second refractive index n1, wherein the curved grating lines have line width w and height d and are arranged by a pitch Λ, wherein the second refractive index n2 is less than first refractive index n1, and a cladding layer configured to cover the grating structure, wherein the cladding layer has a third refractive index n3.

Methods for wavelength determination of widely tunable lasers and systems thereof may be implemented with solid-state laser based photonic systems based on photonic integrated circuit technology as well as discrete table top systems such as widely-tunable external cavity lasers and systems. The methods allow integrated wavelength control enabling immediate system wavelength calibration without the need for external wavelength monitoring instruments. Wavelength determination is achieved using a monolithic solid-state based optical cavity with a well-defined transmission or reflection function acting as a wavelength etalon. The solid-state etalon may be used with a wavelength shift tracking component, e.g., a non-balanced interferometer, to calibrate the entire laser emission tuning curve within one wavelength sweep. The method is particularly useful for integrated photonic systems based on Vernier-filter mechanism where the starting wavelength is not known a-priori, or for compact widely tunable external cavity lasers eliminating the need for calibration of wavelength via external instruments.

Provided is a tunable laser source including a plurality of optical waveguides, at least three optical resonators provided between the plurality of optical waveguides and optically coupled to the plurality of optical waveguides, the at least three optical resonators having different lengths, and at least one optical amplifier provided on at least one of the plurality of optical waveguides, wherein a ratio of a first length of a first optical resonator of the at least three optical resonators to a second length of a second optical resonator of the at least three optical resonators is not an integer.

Systems and methods for a self-injection locked SBS laser are provided herein. In certain embodiments, a system includes a pump laser source providing a pump laser; an SBS resonator receiving the pump laser through a first port and scattering some of the pump laser to provide an SBS laser through the first port, wherein a frequency shift of Brillouin scattering within the SBS resonator is an integer multiple of a free-spectral range for the SBS resonator; a filter receiving the pump laser on a first filter port and the SBS laser on a second filter port, wherein the pump laser is output through the second filter port and the SBS laser is output through a drop port; and a pump laser path coupling the output pump laser into the pump laser source, wherein a frequency of the pump laser becomes locked to a resonance frequency of the SBS resonator.

In various embodiments, laser apparatuses include thermal bonding layers between various components and creep-mitigation systems for preventing or retarding movement of thermal bonding material out of the thermal bonding layers.

A wavelength-tunable laser device includes: a wavelength-tunable light source part; an optical filter; a light receiving element; and a control device. Further, the control device includes: a monitor value calculating part configured to calculate a monitor value; a storage part configured to store wavelength control information; a target value calculating part configured to calculate a control target value; and a wavelength control part configured to control the wavelength of the laser beam to be the target wavelength, and the wavelength control information is information in which a wavelength, a control reference value, and mode identification information are associated with each other, and the target value calculating part calculates the control target value based on the wavelength control information stored in association with the same mode identification information when the same wavelength as the target wavelength is different from the wavelength control information stored in the storage part.

A semiconductor optical integrated device in which a forward-bias optical device and a semiconductor laser are monolithically integrated on a semiconductor substrate, includes: a passive waveguide portion that is arranged between the forward-bias optical device and the semiconductor laser; and a ground electrode that is arrange on a lower surface of the semiconductor substrate. Further, the semiconductor laser includes a mirror having a length on a side closer to the forward-bias optical device, the forward-bias optical device includes a forward-bias optical-device electrode on a side opposite to a side in contact with the semiconductor substrate, the passive waveguide portion includes a passive waveguide electrode on a side opposite to a side in contact with the semiconductor substrate, and the passive waveguide electrode is electrically connected to the ground electrode.