Alcatel

Alcatel N.v.

Alcatel Sel Aktiengesellschaft

Ulrich Steigenberger

Gert Van Der Plas

Christiaan H Sierens

Klaus Braun

Werner Berger

Volker Hagele

Denis J Mestdeagh

Stephen Harnisch

A facility (VOR) is disclosed for combining and amplifying two broadband signals which are received from different transmission networks (NET1, NET2) and are transmitted in transmission channels separated in frequency. The facility (VOR) contains a broadband amplifier (BV), a preamplifier (VV), and a frequency filter unit (FW). The preamplifier (VV) and the frequency filter unit (FW) condition the signals to be amplified and establish an optimized signal-to-noise ratio between the two combined broadband signals: The preamplifier adapts the level of one of the signals to the level of the other signal, e.g., to the same value, whereby a linear and increased amplification is achieved in the broadband amplifier, and the filtering of the signals in the frequency filter unit prevents interfering signals, e.g., noise, contained in said one signal from getting into the frequency band occupied by the other signal and vice versa when the two signals are combined.

Facility for combining and amplifying two broadband signals

The compensation device is used in an optical network where signals are transmitted from a main station (M) to one or a plurality of user stations (US1 to US3). It compensates for analog optical signal distortion caused by laser chirp of a laser in the main station (M) which generates said analogue optical signal and fiber dispersion of the fiber link over which the optical signal is transmitted. The device includes a distance measuring device (R) generating a result signal (MS) indicative of the distance between the main station and the user stations and which is possibly already available in the network to perform ranging when the latter network is also used to transmit digital signals from the user stations to the main station using Time Division Multiple Access. It also includes a processing circuit (PC) which in response to a given laser chirp and the result signal, provides a tuning signal (V) to tune the bias voltage of a varactor diode (VD) which is part of the compensation circuit inserted in the electrical signal path. In an optimal implementation the measuring device (R) and the processing circuit (PC) are located in the main station (M), while the varactor diode (VD) is located in each user station.

Compensation device

An optical receiver receives a wideband input signal and separates the wideband input signal into at least a first narrowband signal (FB.sub.1) and a second broadband signal (FB.sub.2). A photodiode (3) receives the wideband input signal and generates a photo-current responsive to the wideband input signal. The photodiode has a first terminal (K) and a second terminal (A). First (1) and second (2) subcircuits respectively are coupled to receive the photo-current generated by the photodiode (3). The first subcircuit (1) includes an amplifier. The first narrowband signal (FB.sub.1) and the second broadband signal (FB.sub.2) are respectively separated from the wideband input signal with the first subcircuit (1) and the second subcircuit (2). The narrowband signal (FB.sub.1) includes a digital (telephone) signal and the broadband signal (FB.sub.2) includes a CATV signal which are both included in the wideband input signal.

Optical receiver with signal splitter

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Stuttgart, Germany

Ulrich Steigenberger