A warm-white light-emitting diode (LED) without blending of different kinds of phosphors is demonstrated. An approach that consists of a blue LED chip and a wavelength-conversion phosphor is carried out. The phosphor is a newly developed yellowish orange CaEuSiAlON ceramic phosphor with high efficiency. The CIE1931 chromaticity coordinates (x, y) are (0.458, 0.414), the color temperature is 2750 K, and the luminous efficacy of this LED is 25.9 lm/W at room temperature and with a forward-bias current of 20 mA. The chromaticity of the assembled LED is more thermally stable than that of a LED with a conventional oxide phosphor (YAG:Ce) because of the better thermal stability of the oxynitride phosphor.

In the hybrid optical code division multiple access (OCDMA) architectures using different types of optical encoder/decoder (E/Ds) between an optical line terminal and optical network units, a hybrid 40G-OCDMA-PON with a single multiport and super-structured fiber Bragg grating (SSFBG) E/Ds is studied as a candidate system beyond next-generation PON stage 2 (NG-PON2). In this paper, we have developed uniformed and sampled SSFBG E/Ds with different refractive index profiles and have compared their code performances in a hybrid 40G-OCDMA-PON system. The experimental results show that the sampled profile improves the code dependent performances presented in many OCDMA systems. We have also demonstrated a full-duplex 4-user × 40 Gb/s hybrid OCDMA-PON system by applying the sampled SSFBG E/Ds. An asynchronous full-duplex 50 km transmission with a total capacity of 160 Gb/s (4-user × 40 Gb/s) has been achieved for the first time. Furthermore, we focus on major requirements in NG-PON2 and discuss several issues to introduce the hybrid 40G-OCDMA-PON for optical access networks.

In this paper, a simultaneous strain and temperature measurement method using a polarization maintaining and absorption reducing (PANDA) fiber is applied to a distributed sensing system based on optical frequency domain reflectometry (OFDR). A fiber Bragg grating (FBG) whose length is 100 mm is inscribed into a PANDA fiber to form a long-length PANDA-FBG. We demonstrated simultaneous measurements of strain and temperature distributions experimentally. In experiments the long-length PANDA-FBG was bonded on a steel plate and various strains and temperatures were applied at the same time to the plate. Consequently strain and temperature were successfully discriminated. However, larger errors were observed for distributed measurement results.

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