Kinichiro Ogawa

Considerations for Optical Receiver Design

The low dispersion and low attenuation properties of fibers between 1.3 μm and 1.6 μm make them more attractive for optical fiber transmission applications. In the absence of efficient avalanche photodiodes in this wavelength range, considerable research and development efforts on detectors as well as on the lownoise amplifier devices have been carried out. This paper reviews the present status of optical detectors and low-noise amplifier devices and discusses the low-noise amplifier design process by using a couple of examples at DS-1 and DS-4 bit rates.

A high-sensitivity APD receiver for 10-Gb/s system applications

In this paper, we will report the performance of a high-sensitivity (-28.7 dB) avalanche photodiode (APD) receiver, constructed with a low-noise superlattice APD, for l0-Gb/s applications. This receiver sensitivity value is only about 4-5 dB away from that of a commercially realizable optical pre-amplifier receiver at this bit-rate. Using this receiver and a transmitter with an output optical power of only -4 dB, we are able to transmit data over 61 km of standard fiber, including system operational margins, without using any optical amplifiers.

Chapter 8 Semiconductor Laser Noise: Mode Partition Noise

Publisher Summary Semiconductor laser diodes exhibit two fundamental types of noise: (1) the quantum shot noise associated with the total power fluctuation and (2) mode partition noise carried by each longitudinal mode. This chapter discusses mode partition noise, its theoretical background, its effects on system performance, and its distribution function. The quantum shot noise should be considered one of the significant noise sources for optical systems requiring high signal-to-noise ratio, such as analog television transmission systems or coherent optical systems that must take into consideration AM or FM noise. The performance of optical fiber digital systems employing direct modulation will not be degraded by this quantum shot noise unless the reflection from the fiber enhances greatly this quantum shot noise. However, mode partition noise plays a key role in the performance limitation of any optical system. It is caused by the instantaneous fluctuation of the power distribution among the laser longitudinal modes while the total power of all longitudinal modes is kept constant. This partitioning fluctuation among the longitudinal modes is a common problem for multifrequency cavity oscillators, such as gas lasers and early magnetrons.

Coherent communication systems research and development at AT&T Bell Laboratories, Solid State Technology Center

Research and development effort on a field deployable coherent lightwave system at Bell Laboratories is reviewed. Detailed features and design of a 1 . 7 Gb/s FSK single filter heterodyne detection system and its performance in a one-month transmission field trial are described. Long distance transmission experiments of such a system with Er-doped fiber amplifiers at 1 . 7 Gb/s and 2. 5 Gb/s are presented. I.