KudoZ home » English to German » Engineering (general)

monitor diode tracking loop

German translation: Regelkreis mit Monitordiode

Login or register (free and only takes a few minutes) to participate in this question.

You will also have access to many other tools and opportunities designed for those who have language-related jobs
(or are passionate about them). Participation is free and the site has a strict confidentiality policy.

01:28 Nov 21, 2011

English to German translations [PRO]
Tech/Engineering - Engineering (general) / optische Transmitter, Lasertreiber

English term or phrase: monitor diode tracking loop

Now referring to Figure 2, a block diagram of one embodiment of the present invention may be seen. Assume for the moment that the Burst Enable BEN is on. Accordingly the input data DATAIN is applied through the multiplexer M1 and the AND gate to a transconductance amplifier OUT and to a time delay circuit d. The output of the transconductance amplifier OUT is connected to external circuitry including laser diode LD, the transmitter laser diode for the system. Part of the light emitted by the laser diode LD is coupled to monitor diode MD, which provides a monitor diode output current proportional to the light coupled thereto. This provides an input to the programmable gain stage transimpedance amplifier I/V as one input to the block labeled MDTLs (***monitor diode tracking loops***). At the same time, the output of the time delay d is applied to transimpedance amplifier I/VDUPL through multiplexer M2. The transimpedance amplifier I/VDUPL amplifies the time delayed DATAIN signal to provide an output voltage dependent on the values of I1 and I0 fed back thereto, as determined by the state of the DATAIN signal.

The Average Power Target and the Extinction Ratio Target are provided as inputs to the system, specifically to the blocks labeled APC and ERC. These blocks update the laser bias current Ibias and the modulation current Imod, and provide the same to the transconductance amplifier OUT to drive the laser diode LD as previously explained. These currents are adjusted based on the outputs of the monitor diode tracking loops (MDTLs).
The purpose of the ***monitor diode MDTLs***, also referred to as a dynamic differential closed loop estimators, is to provide a measure of the monitor diode output to enable control of the transmitting laser diode LD to achieve target average optical power and extinction ratio. This is done by providing a first signal path for the output of the monitor diode MD and a second path for the delayed DATAIN signal, such that the signal waveforms of the signals Vin and Vref match each other. As previously pointed out, the monitor diode output has a much lower bandwidth than the laser diode LD and of course the DATAIN signal. Accordingly for waveform matching, Filterin and Filterref are provided. In a preferred embodiment these filters are programmable analog filters. Filterin and Filterref have very different transfer functions, Filterin preferably having some emphasis to extend the rolloff of the monitor diode MD signal out to higher frequencies, with Filterref providing rolloff so that the frequency response out of Filterref to the DATAIN signal is the same as the frequency response of the laser diode LD, the monitor diode MD and associated circuitry as provided by Filterin.

heimo KudoZ activity Questions: 743 (5 open) (25 without valid answers) (4 closed without grading) Answers: 33
Local time: 05:57

German translation:Regelkreis mit Monitordiode

Explanation:
Neben anderen möglichen Regelkreisen für den sicheren Laserbetrieb.
In einer optischen Achse mit dem aktiven Streifen des Lasers befindet sich gegenüber der hinteren Austrittsfacette eine Photodiode (Monitordiode), mit der ebenfalls über einen externen Regelkreis durch den Betriebsstrom die optische Leistung gesteuert werden kann.
http://books.google.de/books?id=ugBkUq6UCNQC&pg=PA556&lpg=PA...

--------------------------------------------------
Note added at 15 Stunden (2011-11-21 16:45:38 GMT)
--------------------------------------------------

Ich bin mir nicht sicher, ob es hier nur um die pure Nachführung geht, sondern vielleicht eher um die Vorhersage der Leistung aus den zurückliegenden Daten, also sozusagen die Projektion als Verlängerung der Leistungskurve (dem Track) - was dann eigentlich schon mehr eine compensation wäre, woraus sich in Grenzen eine Nachführregelung ableiten ließe.