Linghui Jia

A Multiexposure Technology for Sampled Bragg Gratings and its Applications in Dual-Wavelength Lasing Generation and OCDMA En/Decoding

In this letter, a multiexposure technology for sampled Bragg gratings is proposed and investigated for the first time. Combined with reconstruction-equivalent-chirp technology, the useless zeroth-order channel can be eliminated and the plusmn1st-order channels can be enhanced significantly. The proposed method is applied experimentally to achieve a dual-wavelength fiber laser and is studied both numerically and experimentally in two ways for the optical code-division multiple access en/decoding system. Its properties may lead to more efficient design and fabrication of grating-based optical devices.

Fabrication and performance of an index-coupled DFB laser with sampled grating

An index-coupled DFB laser with a sampled grating has been designed and fabricated. The key concept of the approaches is to utilize the +1st-order reflection of the sampled grating for laser operation, and use a conventional holographic exposure combined with the usual photolithography to form the sampled grating. The typical threshold current of the sampled grating DFB laser is 25 mA, and the optical output is about 10 mW at the injected current of 100 mA. The lasing wavelength of the device is 1.5314 mu m, which is the +1st-order peak of the sampled grating.

Dual-wavelength DFB fiber laser based on equivalent phase shift and double exposure method

A special sampling structure based on the double exposure technology is proposed to achieve dual-wavelength lasing in the distributed feedback (DFB) fiber laser. This structure is composed of two grating pitches in one sampling period, which could be realized by changing the fibers length in the fabrication. And through employing an equivalent phase shift, only a submicrometer-level precision is required for precise phase control. Then a stable dual-wavelength laser with the spacing of 400pm is obtained in the experiment successfully. The output power is 30.46uW and the SMSR is 46dB under a pumped power of 146mw.

Application of sampled grating to control the lasing wavelength in complex-coupled DFB laser

A complex-coupled DFB Laser with the sampled grating has been designed and fabricated. The +1st order reflection of the sampled grating is utilized for laser single mode operation, which is 1.5387μm in the experiment. The typical threshold current of the device is 30mA, and the optical output power is about 10mW at the injected current of 100mA.