Two comparative blue emitting InGaN/GaN multiple quantum well (MQW) structures, for lighting and laser diode
applications, with and without pre-strained layer, were grown by MOCVD. Temperature dependent photoluminescence
(TDPL) and time-resolved (TR) PL were used to study their optical and transient properties. PL signals from InGaN
MQWs were divided into two parts: one is the band to band transition of InGaN; the other is the broad defect band. It is
indicated that the InGaN/GaN MQW structure with prestrained layer has larger activation energy. TRPL measurements
were performed in 10-300 K and with the detection wavelength cross over the emission peak. It is found that the MQW
sample with prestrained layer has deeper localization depth. Temperature dependence of PL decay time shows an
interesting behavior of an increase from 10K to 30K and then a decrease till 300K.
Optical en/decoder is one of the key components in Optical Code Division Multiple Access (OCDMA) systems.
Therefore, the improvement of performance of en/decoder is very necessary for improving the whole performance of
OCDMA system. Among all kinds of factors which affecting the performance of en/decoder, the compatibility between
optical source and en/decoder is proved to be an inevitable item. In this paper, as to equivalent phase shift super-structured
FBG (EPS-SSFBG), an advanced en/decoding technology, both optimum pulse width and proper central
wavelength deviation between optical source and EPS-SSFBG based en/decoder are first investigated, which lead to a
novel method of optimizing the compatibility between optical source and en/decoder. The simulation results show that
there exists an optimum pulse width, not the narrowest one, fit for EPS-SSFBG based en/decoder, what's more, it is
proved advisable that proper central wavelength deviation would be beneficial when pulse width is relatively wide.
Simulation and experimental results prove the feasibility and effectivity of the proposed method.
Combined DLP algorithm and sampled theory, super-narrow FBG filter for arbitrary shaping spectrum can be
successfully synthesized, and the process of design and fabrication using one uniform mask are demonstrated. A novel
method for a single stage illumination to fabricate dc-free apodized sampled FBG is proposed based on the chirp of
sample period. Above design and fabrication method are testified by simulation and experiment results, and a super-narrowband
triangle shaping FBG filter with 25pm 3dB bandwidth and side lobes suppression beyond 20dB is