Masahiro Mitsuda

Hybridly integrated optical transceiver module for access networks

Hybridly integrated optical transceiver modules for 1.3 /spl mu/m wavelength TDM (Time-Division-Multiplexing) bi-directional transmission and 1.3/1.55 /spl mu/m WDM (Wavelength-Division-Multiplexing) bi-directional transmission are demonstrated. Surface mounted laser diode and PIN photodiode are passively aligned to a fiber-embedded optical circuit. The module consists of a transmitting 1.3 /spl mu/m laser diode mounted on a silicon substrate with a V-groove for fiber attachment and a receiving photodiode surface mounted onto a glass substrate which has embedded in it a single mode fiber for input/output. Either power splitting 3 dB filter or wavelength selective WDM filter (1.55 /spl mu/m reflective) is inserted into the embedded fiber which directs the incoming signal light to the photodiode. The optical transceiver characteristics are as follows. The output power was greater than 2 mW for TDM transceiver and 4 mW for WDM transceiver, considering a 20% coupling efficiency to the single mode fiber. The responsivity of the photodiode were 0.97 A/W for WDM transceiver at 1.55 /spl mu/m, and 0.46 A/W for TDM transceiver at 1.3 /spl mu/m. Stable operation characteristics are obtained in the wide temperature range of -40/spl sim/85/spl deg/C.

Second-order distortion of amplified intensity-modulated signals with chirping in erbium-doped fiber

Second-order distortion produced in an erbium-doped fiber amplifier (EDFA) is investigated theoretically and experimentally. Rate equations for intermodulation products are led by the perturbation method. From numerical calculation, it is shown that optimum combinations of input power to EDFA and signal wavelength exist that give a distortion-free condition, Improvement of the composite second-order (CSO) distortion, which results from the cancellation of the laser distortion and the gain tilt induced distortion, was confirmed for VHF multichannel transmission. Furthermore, CSO distortion-free transmission in cascaded EDFAs has been demonstrated for a 42-channel AM-SCM signal by experimentally determining the optimum operating condition of the EDFA such that each amplifier generates no additive distortion.

Extremely low tail current optical transceiver module for passive double star TDMA networks

Summary form only given. We believe we have demonstrated extremely low tail current 1.3-μm laser diode/photodiode (LD/PD) transceiver module for OSU application for the first time. Also high performance is obtained over a wide temperature range from -40 C to +850 C. These features will help make PDS-TDMA architecture more attractive for subscriber loop networks.