Method of controlling the optical power output of a laser, and circuit for carrying out the method

US4833680A · kind A · utility

Assignee

• Alcatel N.V. · NL

Inventors

• Norbert Kaiser · Markt Taschendorf, DE
• Martin Mittrich · Bad Liebenzell, DE

Key dates

• Filing date: Mar 18, 1987
• Grant date: May 23, 1989
• Expiry date: Mar 18, 2007

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01S5/06835
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

An optical transmitter for digitally transmitting data by using NRZ pulses. The transmitter has a laser diode whose operating current consists of a bias current and a modulation current. A photodiode measures the optical performance of the laser diode. Also provided is a regulating device having a multiplier for multiplying the alternating component of a measuring signal transmitted by the photodiode with a signal beat, the latter having the frequency of the bit rate corresponding to the NRZ pulses, with the output signal of the regulating device setting the bias current via a control member to a value which is smaller, by a predetermined amount, than the laser threshold current.