Matsushita Electric Industrial Co., Ltd.

Takeshige Ichida

Katsuyuki Fujito

Hiroaki Nakata

Kunihiko Hontani

Tetsuro Hanaoka

Yoshiki Nishino

An optical transmission system is disclosed wherein a multiplexed analog signal is supplied to a laser diode to modulate the intensity of a long-wavelength laser beam. A single mode optical fiber transmission medium has a first inclined end face at a proximal end and a second inclined end face at a distal end. The laser beam is coupled to the proximal end of the transmission medium by a coupling means including a single mode optical fiber connecting medium having one end connected to the laser diode and an opposite end having a third inclined end face complementary to the first inclined end face and a coupler for coupling the first and third inclined end faces in abutment relation. An optoelectrical transducer having a light receiving face is located adjacent the distal end of the transmission medium, the light receiving face being parallel to the second inclined end face of the transmission medium to divert rays of light reflecting from the transducer away from the angle of reentry to the transmission medium.

Analog optical transmission system

An optical transmission apparatus is provided which has an LD of single longitudinal mode. A bias current of the LD is set at its threshold current. A current obtained by amplitude modulation of a signal to be transmitted is superposed on the bias current. The LD is then set in the multimode, so that the apparatus can transmit a high-quality signal with reduced modal noise and distortion during multimode fiber transmission.

Optical transmission apparatus

A DPCM coding apparatus adapted for directly coding a composite color television signal is disclosed which carries out a so-called two-dimensional prediction using horizontal and vertical signals from a predetermined earlier period as predict value for DPCM while taking the color sub-carrier wave into consideration. The two-dimensional prediction allows immediate restoration after dropout of the coded signal should this occur.

Growing community of inventors

Osaka, Japan

Takeshige Ichida