Nanjing University

Xiangfei Chen

Jun Lu

Yuechun Shi

Song Tang

Lianyan Li

Yunshan Zhang

A tunable distributed feedback (DFB) semiconductor laser based on a series mode or a series and parallel hybrid mode. A grating structure of the laser is a sampling Bragg grating based on the reconstruction-equivalent chirp technology. DFB lasers with different operating wavelengths based on the reconstruction-equivalent chirp technology are integrated together by a sampling series combination mode or a series/parallel hybrid mode, one of the lasers is selected to operate via a current, and the operating wavelength of the laser can be controlled by adjusting the current or the temperature, so that the continuous tuning of the operating wavelengths of the lasers can be realized. Various wavelength signals in parallel channels are coupled and then output from the same waveguide. An electrical isolation area (-) is adopted between lasers connected in series or lasers connected in series and connected in parallel to reduce the crosstalk between adjacent lasers.

Tunable semiconductor laser based on reconstruction-equivalent chirp and series mode or series and parallel hybrid integration, and preparation thereof

A method for manufacturing a multi-dimensional target waveguide grating and volume grating with micro-structure quasi-phase-matching. An ordinary waveguide grating is used as a seed grating, and on this basis, a two-dimensional or three-dimensional sampling structure modulated with a refractive index, that is, a sampling grating, is formed. The sampling grating comprises multiple shadow gratings, and one of the shadow gratings is selected as a target equivalent grating. A sampled grating comprises Fourier components in many orders, that is, shadow gratings, a corresponding grating wave vector is [Formula 1], and the grating profile of all the shadow gratings changes with the sampling structure [Formula 2]. In a case where a seed grating wave vector [Formula 3] and a required two-dimensional or three-dimensional grating wave vector do not match, a certain Fourier periodic structure component of the Fourier components of the sampling structure is used to compensate for the wave vector mismatch. The manufacturing method may be applied to design and manufacture a multi-dimensional target waveguide grating and volume grating for any grating profile, and may simplify the grating manufacturing process and also make possible a variety of grating-based photon devices.

Method for manufacturing multi-dimensional target waveguide grating and volume grating with micro-structure quasi-phase-matching

Using sampled Bragg grating structure, the present invention proposes a distributed feedback (DFB) semiconductor laser based on reconstruction-equivalent-chirp technology. Namely, the Bragg grating in the said DFB semiconductor laser cavity is a sampled Bragg grating, in which there is an equivalent grating corresponding to the original ordinary DFB grating as feedback for lasing. The laser wavelength of the said semiconductor laser located within the operation bandwidth of the said equivalent grating. The said equivalent grating is designed and fabricated using REC technology and has equivalent chirps, one equivalent phase shift or multiple equivalent phase shifts. The said sampled Bragg grating has multiple ghost gratings and the wavelength spacing between neighboring ghost gratings is inversely proportional to the sampling period and the effective refractive index of the said semiconductor laser. Only one ghost grating except the ghost grating related to the center wavelength is selected to be as equivalent grating. In semiconductor laser fields, only based on sub-micron precision, the present invention provides a method to realize various complex equivalent chirps and equivalent phase shifts in the resonant cavity of the said semiconductor laser. These equivalent chirps and equivalent phase shifts have the same functions with the corresponding true chirps and true phase shifts, so as to avoid the processes of fabrication of grating structure with complex true chirps and true phase shifts.

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Nanjing, China

Xiangfei Chen