Satoshi Okude

A novel temperature-insensitive long-period fiber grating using a boron-codoped-germanosilicate-core fiber

Long-period fiber gratings are promising components as gain equalizers for erbium-doped fiber amplifiers, band rejection filters and sensors. It has been reported that these devices have a high temperature sensitivity, typically 0.05 nm//spl deg/C at room temperature. Judkins et al., showed a method to eliminate the temperature sensitivity by optimizing the refractive-index profile of the host fiber. In this paper, we show a novel method to compensate the temperature sensitivity using a boron codoped germanosilicate core fiber as a host fiber.

Novel chirped fiber grating utilizing a thermally diffused taper-core fiber

Summary form only given. The usual fabrication method of the chirped grating is the phase-mask method using an expensive chirped phase mask. In this paper, we propose a novel fabrication technique of chirped gratings by using a standard unchirped phase mask.

PDL reduction of long-period fiber grating by rotating exposure method

We propose a novel fabrication method to suppress polarization dependent loss (PDL) of long-period-fiber gratings by a rotating exposure technique, with a theoretical consideration of the PDL origins of long-period fiber gratings.

Tunable second order dispersion compensator using fiber Bragg grating with double ring structure

Tunable second order dispersion compensator is realized utilizing linear chirped FBG with double ring structure. Tunable range from -100 to 100 ps/nm/sup 2/ is achieved in keeping center wavelength and first order dispersion constant.

Precise determination of local birefringence of optical fibers by long-period fiber grating analysis

We have proposed a novel and precise technique to determine the local birefringence of optical fibers by writing an LPFG in the fiber to be evaluated and analyzing the transmission loss and PDL of the LPFG. The accuracy of the determined local birefringence has been confirmed to be approximately 10/sup -8/, which is about 100 times better than the existing methods.

Athermalization of wideband EDFA gain profile using a phase-shifted long-period fiber grating

An EDFA gain profile was athermalized passively using a phase-shifted long period fiber grating with low background loss of 0.9 dB. Gain variation was suppressed to 0.25 dB/sub pp/ in the temperature range of 0-65/spl deg/C over 40 nm of C-band with 2.1 dB gain.

Optical pressure sensor utilizing a silica-based GRIN rod lens

An optical pressure sensor utilizing a silica-based GRIN rod lens is proposed and demonstrated. The major advantage of the sensor is inexpensive system configuration whose main part consists of low-cost components such as the rod lens, an LED light-source and photodiodes. The sensor also has two other superior characteristics. One is stability because the silica-based rod lens can be attached to the optical fiber directly by fusion splicing without adhesive or other materials. The other is flexibility because the sensitivity of the sensor can be varied by changing the rod lens length. In proposed method, optical power variations correspond to a displacement of a bellows is measured to detect the pressure. We have made two optical pressure sensors with different length rod lenses. Each lens is designed to measure up to 200 kPa and 10 kPa pressure. The displacement amounts of the bellows due to these pressure levels are 600 μm and 30 μm, respectively. The +/-0.2% accuracy of full scale is achieved for both sensors and +/-60nm displacement can be measured by this simple method.

Refractive index change and presensitization using 172-nm excimer lamp

Refractive index change and presensitization effect induced by irradiation of a xenon excimer lamp (λ=172nm) is studied. The refractive index changes over 0.005 and 0.003 are confirmed in hydrogenated and presensitized fibers respectively.

Low loss all-PANDA-fiber polartization beam splitter/combiner

A low loss all-fiber polarization beam splitter/combiner (AF-PBS/C) is proposed. Achieved insertion losses of slow and fast axis were as low as 0.1 dB and 0.3 dB, respectively. Crosstalk was less than -25dB. High reliability was also confirmed.