Optical communications system for the subscriber area with optical amplifiers

Fiber-optic communications systems with a center (1) and a plurality of subscribers (T.sub.i) wherein the subscribers are connected to the center (1) via a multistar fiber-optic network (LA.sub.i, LB.sub.i, LC.sub.i), wherein fiber-optic amplifiers (10, 11) are provided between successive branch points of the fiber-optic network, and wherein the information signals, particularly television signals, to be distributed by the center (1) to the subscribers (T.sub.i), after being converted to a first frequency band (FB1), are transmitted as an optical signal having a first wavelength (.lambda..sub.1) over the fiber-optic network to the subscribers (T.sub.i), the optical signal being amplified by the fiber-optic amplifiers (10, 11), characterized in that

• means are provided for transmitting subscriber-assigned information signals, such as telephone signals, converted to a second frequency band (FB2) with subscriber-assigned frequencies, as an optical signal having the first wavelength (.lambda..sub.1) from the center to the subscribers, the optical signal being amplified in the fiber-optic amplifiers (10, 11);
• means are provided for transmitting subscriber-assigned information signals, such as telephone signals, converted to a third frequency band (FB3) with subscriber-assigned frequencies, as an optical signal having a second wavelength (.lambda..sub.2) from the subscribers over the same fiber-optic network to the center;
• at least one means (40, 41, 43;
• 51, 54, 52) are provided in the multistar fiber-optic network for extracting said optical signal having the second wavelength (.lambda.2) from the optical waveguide (LA.sub.4), amplifying it, and reinjecting it into the optical waveguide (LA.sub.4);
• and
• the means (51, 53, 54, 52) for extracting the optical signal having the second wavelength (.lambda..sub.2) to be transmitted to the center from the optical waveguide (LA.sub.4), amplifying it, and reinjecting it into the optical waveguide (LA.sub.4) are a wavelength-selective pump coupler (51) associated with the fiber-optic amplifier (10), an optical-to-electric transducer (54), and the pump source (52) associated with the fiber-optic amplifier (10), and said means are interconnected so that the optical signal having the second wavelength (.lambda.2) to be amplified and transmitted to the center is fed from one port of the pump coupler (51) to an input of the optical-to-electric transducer (54), and an electric output signal of said optical-to-electric transducer (54) modulates the pump light generated by the pump source (52).

Fiber-optic communications systems with a center (1) and a plurality of subscribers (T.sub.i) wherein the subscribers are connected to the center (1) via a multistat fiber-optic network (LA.sub.i, LB.sub.i, LC.sub.i), wherein fiber-optic amplifiers (10, 11) are provided between successive branch points of the fiber-optic network, and wherein the information signals, particularly television signals, to be distributed by the center (1) to the subscribers (T.sub.i), after being converted to a first frequency band (FB1), are transmitted as an optical signal having a first wavelength (.lambda..sub.1) over the fiber-optic network to the subscribers (T.sub.i), the optical signal being amplified by the fiber-optic amplifiers (10, 11), characterized in that

• means are provided for transmitting subscriber-assigned information signals, particularly telephone signals, converted to a second frequency band (FB2) with subscriber-assigned frequencies, as an optical signal having the first wavelength (.lambda..sub.1) from the center to the subscribers, the optical signal being amplified in the fiber-optic amplifiers (10, 11);
• means are provided for transmitting subscriber-assigned information signals, particularly telephone signals, converted to a third frequency band (FB3) with subscriber-assigned frequencies, as an optical signal having a second wavelength (.lambda..sub.2) from the subscribers over the same fiber-optic network to the center;
• at least one means (40, 41, 43;
• 51, 54, 52) is provided in the multistar fiber-optic network for extracting said optical signal having the second wavelength (.lambda.2) from the optical waveguide (LA.sub.4), amplifying it, and reinjecting it into the optical waveguide (LA.sub.4);
• and
• the means (51, 53, 54, 56, 58, 59) for extracting the optical signal having the second wavelength (.lambda.2) to be transmitted to the center from the optical waveguide (LA.sub.4), amplifying it, and reinjecting it into the optical waveguide are a wavelength-selective pump coupler (51) associated with the fiber-optic amplifier (10), an optical-to-electric transducer (54), and an electric-to-optical transducer (56), and a wavelength-selective fiber-optic coupler (59) which couples an optical output signal of the electric-to-optical transducer (56) into the optical waveguide (LA.sub.4).