Shinyoung Yoon

A Novel Low-Cost Fiber In-Line-Type Bidirectional Optical Subassembly

A novel low-cost fiber in-line-type bidirectional optical subassembly using a tilted fiber Bragg grating has been developed for fiber-to-the-home applications. We successfully realized a low-cost subassembly by reducing the number of components and simplifying the packaging process. The extinction ratio of 14.8 dB, receiver minimum sensitivity of -26.5 dBm at a bit-error rate of 10-12 and frequency response of 2.7 GHz were experimentally obtained. The electrical crosstalk between transmitter and receiver part was less than -86 dB up to 2.5 GHz.

Highly efficient, wavelength-selective out-coupling of cladding mode using tilted fiber grating and micro-etched cladding

A highly efficient, wavelength-selective detection through micro-etched groove on cladding of tilted fiber gratings (TFGs) is proposed and experimentally demonstrated. More than 88% power of the cladding mode is out-coupled into an optical power detector

Experimental and theoretical characterization of optical signal out-coupling through V-grooved optical fiber cladding

We demonstrate a highly efficient in-fiber out-coupling device. The core mode is coupled to the cladding by a tilted fiber Bragg grating and then the cladding mode is out-coupled from the optical fiber through V-grooved cladding. The light emitting characteristics are investigated experimentally and a maximum out-coupling efficiency of 54.8% is obtained.

Wavelength-Switching Erbium-Doped Fiber Laser with a Multimode Fiber Bragg Grating and Faraday Rotator Mirror

Without polarization dependent gain, a multimode fiber Bragg grating (MMFBG)-based wavelength-switching erbium-doped fiber laser (EDFL) as a case of optical source in WDM communication system is demonstrated. By varying spatial-launching position of the single-mode fiber against the MMFBG, discrete single-wavelength lasing are obtained.

Erbium Doped Superfluorescent Fiber Source with Mean Wavelength Stability on Pump Wavelength

Using the double-pass forward configuration, the mean wavelength stability of erbium doped Suprfluorescent Fiber Source (SFS) is demonstrated and investigated. The dependence of the mean wavelength on pump wavelength was negligible, which was measured to be 1.4 ppm/nm when this source is pumped at 1480 nm wavelength.

Depolarization of external optical feedback on VCSEL and variation of relative intensity noise

By using of optical depolarizer, polarization dependence of external optical feedback on VCSEL is drastically reduced. Relative intensity noise and transmission characteristics of VCSEL are experimentally investigated under various polarization states of external optical feedback.

Proposal of WDM receiving structure using tilted FBGs

Tilted fiber Bragg grating can couple light both to backward propagating core modes and cladding modes. We propose a WDM receiving device with high cladding and/or radiation mode coupling efficiency using etched cladding parts and tilted Fiber Bragg gratings(TFBGs) which are key components for doing wavelength selective operations. Each channel exhibits the cladding and radiation mode coupling efficiency of approximately 20%.

Optimization of tilted fiber Bragg grating and micro-etched cladding for high efficient out-coupling of cladding mode

The cladding mode generated by the tilted fiber Bragg grating is out-coupled to optical power detector by the total internal reflection at the micro-etched cladding. Optimization of the tilted fiber Bragg grating and micro-etched cladding for high efficient out-coupling of cladding mode was discussed theoretically. Over 32 % power of the cladding mode is out-coupled by the micro-etched cladding. In addition, as much as 90 % power of the input power is experimentally detected using the avalanche photodiode.

Fiber-in-line optical transceiver structure using silicon V-groove and tilted-fiber gratings

A novel fiber-in-line optical transceiver structure by focusing the outgoing radiation from a tilted and chirped fiber Bragg grating is proposed. The chirped gratings with 45° tilted angle is designed for an optimum input coupling at 1.55 μm and a FDTD method is used for analysis. Experimental results on beam focusing are shown. We expect this novel design can be used for a low-cost receiver in the bi-directional fiber-in-line optical transceiver.