Method for temperature compensating an optical filter

Details Method for temperature compensating an optical filter Method for temperature compensating an optical filter

1999-06-23

2001-05-22

Scott, Jr., Leon (Department: 2881)

Coherent light generators

Particular beam control device

Optical output stabilization

C372S034000, C372S038060

Reexamination Certificate

active

06236667

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to laser tuning and, more particularly, to a method for temperature compensating an optical filter (e.g. etalon).
2. Description of the Related Art
Generally, lasers can be tuned by varying the wavelength or, equivalently, the laser frequency while minimizing other undesirable or unwanted effects. However, when tuning a currently available distributed feedback (DFB) laser, it may not be possible to vary the wavelength without causing other undesirable effects. In addition, optical frequency or wavelength stabilization of lasers is required for dense wavelength division multiplexing (DWDM) applications. Stable optical filters such for example, as etalons, are used for wavelength stabilization.
Since the laser wavelength is a function of temperature, lasers are currently tuned with temperature. Unfortunately, when tuning using temperature other parameters such as optical power also change, thus requiring an optical power control system. Generally, power control is present in the laser system, so that this requirement does not present a major problem. Thus, the wavelength control system feeds a control current or control voltage to a control terminal which changes the laser wavelength. A thermoelectric cooler (TEC) coupled to the wavelength control system receives this control signal and responds thereto by changing the temperature of the laser and thereby the wavelength.
Due to space limitations, and for cost and packaging considerations, the optical filter associated with the laser is located in a butterfly package on the same TEC as the laser, and therefore may also experience a change in temperature as a result of the temperature tuning. This change in temperature of the optical filter results in an additional limitation in performing wavelength stabilization, because optical filters have temperature characteristics that provide optimal functioning within a specified temperature range. Specifically, each optical filter inherently has a temperature coefficient or constant that indicates its optimal operating temperature. Thus, the optical filter's temperature stability is of integral concern since temperature tuning will be used in the first generation of frequency (wavelength) stabilized laser products.
SUMMARY OF THE INVENTION
In accordance with a preferred embodiment of the present invention, a method for temperature compensating an optical filter comprises the steps of determining a temperature coefficient of the optical filter, and selecting a feedback resistor in a transimpedance preamplifier having a temperature dependence value and corresponding sign and magnitude selected to offset any changes in transmission through the optical filter resulting from variations in temperature caused by temperature tuning of the laser.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.


REFERENCES:
patent: 4243952 (1981-01-01), Patterson
patent: 4375067 (1983-02-01), Kitamura
patent: 4710631 (1987-12-01), Aotsuka et al.
patent: 5019769 (1991-05-01), Levinson
patent: 5946334 (1999-08-01), Ema et al.
patent: 5999551 (1999-12-01), Yoshizawa
patent: 6023053 (2000-02-01), Nakayama et al.
patent: 6145474 (2000-11-01), Yoshida

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