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A superluminescent diode (SLD) using J-shaped ridge waveguide and chirped multiple InAs quantum dots (QDs) with three different energy bandgap wavelengths, which are controlled by QD size, is demonstrated. The fabricated QD SLDs exhibit high continuous wave output power of 32 mW and wide spectral bandwidth up to 98 nm, covering the range 1084-1182 nm.

A simple scheme for the photonic microwave true-time delay with high tunability based on a tunable chirped fibre Bragg grating without centre wavelength shift is experimentally demonstrated. A large dynamic range of true-time delay from 20 to 200 ps was achieved for a microwave signal carried over an optical signal.

A novel and simple Raman amplifier based long-distance fibre Bragg grating (FBG) sensing system without any additional broadband light source is demonstrated. With the simplified system configuration recycling residual Raman pump power for generation of amplified spontaneous emission in an erbium-doped fibre (EDF), the high quality of remote strain sensing operation at a location of 50 km is achieved.

The authors report on the optical responses of a p-channel In/sub 0.49/Ga/sub 0.51/P/GaAs/In/sub 0.13/Ga/sub 0.87/As pseudomorphic MODFET with a gate length of 1 /spl mu/m. The photocurrent of the device is -0.36 mA at V/sub gs/=-0.2 V and V/sub ds/=-3.5 V, with incident optical power of 2.15 mW. A significantly high responsivity was obtained at low incident optical power range. Current gain cut-off frequency and maximum available gain cut-off frequency were increased by 20 and 10%, respectively, under optical illumination.