A semiconductor tunable ring laser including a laser cavity having a closed loop optical path, and an optical filter that is arranged within the laser cavity. The optical filter includes a first MZI-based tunable frequency filter section including a 13 MMI input splitter providing a first non-zero fraction, T.sub.1, of optical radiation at a first optical output port of the 13 MMI for wavelength locking and/or power monitoring purposes outside of the laser cavity, a second fraction, T.sub.2=(1T.sub.1)/2, of optical radiation at a second optical output port of the 13 MMI, and a third fraction, T.sub.3=(1T.sub.1)/2, of optical radiation at a third optical output port of the 13 MMI. A PIC including the semiconductor tunable ring laser, and to an opto-electronic system including such a PIC.

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.

There is provided an external cavity laser, including: a photonic integrated platform including a gain chip providing a gain medium and at least one reflector chip, the photonic integrated platform including first and second functional layers made of different materials; a resonant cavity optically coupled to the gain medium and including a first and a second micro-ring resonators (MRR) in a Vernier configuration, the first MRR and second MRR extending within respective ones of the first and second functional layers made of different materials and having corresponding group indices, the first and second MRRs having different radii selected in view of said corresponding group indices; and a tuning mechanism for tuning a spectral response of at least one of the first and second MRR.

Provided are a silicon-based tunable filter, laser and an optical module. The tunable laser comprises a semiconductor optical amplifier and a silicon photonic integrated chip, wherein a first coupler, a phase regulator and a tunable filter are provided on the silicon photonic integrated chip; the tunable filter comprises a flat-top band-pass filter structure, a Mach-Zehnder interferometry (MZI) structure and a micro ring resonation (MRR) structure, which are cascaded; gain light emitted by the semiconductor optical amplifier is coupled to the silicon photonic integrated chip by means of the first coupler, and a narrowband filtered optical signal is output by means of the tunable filter; and the phase of the gain light is regulated by means of the phase regulator so as to output single-peak narrowband laser light with a tunable target wavelength.