This paper describes a design method for a 446 Mb/s optical repeater with four kinds of monolithic integrated circuits. It is mainly concerned with the circuit division, optical receiver and timing amplifier design methods. Repeater circuit is divided based on maximum allowable gain and power consumption. Allowable gain determined by IC package crosstalk characteristics at 400 MHz transmission band is presented here. Allowable maximum power consumption of 1 W/chip is also determined. Effective amplification bandwidth adjustment methods for the optical receiver and the d.c. drift control (DCFB) system design method, specific in the d.c. coupled monolithic integrated optical receiver, are described. Finally, a useful design method for small-phase-shift timing amplifier is proposed. This is a circuit parameter optimizing method which monitors operating point dependence of small signal amplification bandwidth. The 446 Mbit/s submerged optical repeater has successfully been developed using these design methods.

The characteristics of an optical functional integrated circuit and its applications are discussed. This circuit is based upon a Mach-Zehnder interferometer type waveguide device employing thermo-optic effect. This circuit is compact, cost-effective and practical. One proposed application is an optical loopback circuit to test both OCU loop 1 and DSU loop C. This optical loopback circuit with an attenuator and space switches is formed on a common silicon substrate, and using this circuit both loopback and line tests are independently available at the same access point. The other is an optical selector. This optical selector with WDM-MUX/DMUX and space switches is formed on a common silicon substrate, and using this selector, wavelength selection from medium density WDM (MDWDM) signal can be performed. Each MDWDM signal carries both AM and FM-FDM video signals modulated by Subcarrier Multiplexing (SCM) techniques. This selector can be wired in point-to-multipoint configurations to home video appliances.

A fiber-optic transmission system for linking radio base stations to the mobile communication center is developed, and its performance is evaluated. The introduction of this system yields two main improvements: optimum zone allocation to increase radio frequency utilization efficiency and the elimination of service quality issues such as dead zones and traffic imbalance. Being optical, the system suffers from the interferometric noise and distortion created by multiple reflections within the fiber. Moreover, because system response is much different from that of optical CATV systems, we clarify the optical parameter selection criteria and hypothetical return loss model for an embedded fiber infrastructure. An optical multiplexing method is also introduced that reduces the quantity of fiber and connectors, as well as splicing and cable installation costs. A new ternary optical multiplexing architecture combined with a cost-effective self-tuning type WDM technique and a high isolation type circulator are proposed for the 1.3µm wavelength region. The performance of low distortion high power common amplifiers is measured with the aim of reducing the size and weight of back-up batteries, and to improve the packaging density of the typical base station.