Loading patent…
AssigneeFujitsu Limited
InventorKazunori Nishizono
Estimating the term…
An amplification circuit used in an optical communication apparatus includes a first amplifier for generating a first voltage signal corresponding to an input current, a second amplifier for amplifying the first voltage signal and generating a second voltage signal, a gain control circuit for generating a gain control signal for adjusting the gain of the first amplifier based on the second voltage signal, and a bias control circuit for generating a bias control signal for adjusting the bias current at the output of the first amplifier based on the gain control signal. The bias control signal stabilizes the bias voltage of the first amplifier during gain adjustment of the first amplifier.
An amplification circuit for receiving an input current, the amplification circuit comprising:
An optical communication apparatus for receiving signal light, the optical communication apparatus comprising:
An optical communication apparatus comprising:
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
From the US filing history. Foreign family members aren’t listed.
Backward citations are indexed for grants only.
In amplifiers having semiconductor devices: in receivers or transmitters for electromagnetic waves other than radiowaves, e.g. lightwaves
With semiconductor devices only: controlled by light
Control of amplification
Amplifiers
Term end not estimated
This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2002-118233, filed on Apr. 19, 2002, the entire contents of which are incorporated herein by reference.
The present invention relates to an amplification circuit, and more specifically relates to an amplification circuit provided in an optical communication apparatus.
In recent years, electronic devices such as portable telephones, and portable terminals such as personal digital assistants (PDAs) have been provided with infrared data communication functions. Computers have been provided with optical communication apparatuses for sending and receiving data over optical fiber. These optical communication apparatuses include an amplification circuit as an optical receiver amplifier (amp).
The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings, in which:
FIG. 1 is a circuit diagram of a first example of a conventional optical receiver amp;
FIG. 2 is a circuit diagram of a second example of a conventional optical receiver amp;
In the drawings, like numerals are used for like elements throughout.
As shown in FIG. 6, an optical communication apparatus 30 of a first embodiment of the present invention includes a light-emitting diode LD, a photodiode PD, and a transmission-reception circuit 31. The transmission-reception circuit 31 includes an optical transmitter amp 32 as an amplification circuit and transmission circuit, and an optical receiver amp 33 as an amplification circuit and a reception circuit.
The optical transmitter amp 32 receives a transmission signal TX and supplies a pulse-like transmission current ILD corresponding to the transmission signal TX to the light-emitting diode LD. The optical transmitter amp 32 repeatedly emits and quenches in accordance with the transmission current ILD.