A 13-channel, InP-based arrayed waveguide grating(AWG) is designed and fabricated in which the on-chip loss of the central channel is about-5 dB and the crosstalk is less than-23 dB in the center of the spectrum response. However,the central wavelength and channel spacing are deviated from the design values. To improve their accuracy, an optimized design is adopted to compensate the process error. As a result, the central wavelength 1549.9 nm and channel spacing1.59 nm are obtained in the experiment, while their design values are 1549.32 nm and 1.6 nm, respectively. The route capability and thermo–optic characteristic of the AWG are also discussed in detail.
The experimental optimization of a 10 GHz optoelectronic oscillator (OEO) based on a 1.55 μm directly modulated distributed feedback (DFB) laser is demonstrated in this paper. The phase noise of the directly modulated laser (DML) based OEO is significantly reduced by proper selection of the laser's bias current and by using a dispersion shifted fiber as a delay line. The phase noise performance of the DML OEO achieved after optimization is close to that of a conventional OEO constructed using a commercial DFB laser and a LiNbO 3 Mach-Zehnder modulator. The DML based OEO is most promising for future realization of a miniature OEO architecture with the components integrated on a semiconductor substrate.
WANG LiXianZHU NingHuaLIU JianGuoLI WeiZHU HongLiangWANG Wei
A monolithic integrated variable attenuator multiplexer/demultiplexer is demonstrated. It is composed of a 16-channel 200 GHz silica-based arrayed waveguide grating and an array of Mach–Zehnder interferometer thermo-optic variable optical attenuators. The integrated device is fabricated on a quartz substrate, which eliminates the process of depositing the undercladding layer and reduces the power consumption compared with a device fabricated on a silicon substrate. The insertion loss and crosstalk of the integrated device are 5 d B and less than 22 d B, respectively. The power consumption is only 110 m W at the attenuation of 20 d B per channel.
