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Proceedings Paper

Wavelength stabilisation of a DFB laser diode using measurement of junction voltage
Author(s): A. Asmari; J. Hodgkinson; E. Chehura; S. E. Staines; R. P. Tatam
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Paper Abstract

Laser diode wavelength stability is vital for applications such as spectroscopy and data communication, and the emitted wavelength is a function of temperature. In a conventional system, the laser diode temperature is controlled using a Peltier element with a temperature-sensing thermistor, the latter placed at a short distance from the laser diode chip. Despite the use of good thermal design and a case, a change in ambient temperature may cause a change to internal thermal gradients, resulting in a systematic error in the laser diode wavelength. In this paper we describe a novel system to measure the temperature of the laser diode junction via measurement of the junction voltage. The method has been applied to a 1651 nm DFB laser diode for use in tunable diode laser spectroscopy (TDLS) of methane. The wavelength stability of both thermistor- and voltage- control systems are compared over a period of 30 minutes and with different ambient temperatures. Over 30 min at constant ambient temperature, thermistor control provided a precision of ± 0.4 pm (40 MHz) and junction voltage control gave a similar ± 0.6 pm (70 MHz). For an ambient temperature change of 20°C, conventional thermistor control suffered a wavelength change of 76 pm (8.4 GHz), whereas junction voltage control reduced this to 0.6 pm (70 MHz), at or below the level of long-term wavelength precision.

Paper Details

Date Published: 1 May 2014
PDF: 8 pages
Proc. SPIE 9135, Laser Sources and Applications II, 91351A (1 May 2014); doi: 10.1117/12.2052449
Show Author Affiliations
A. Asmari, Cranfield Univ. (United Kingdom)
J. Hodgkinson, Cranfield Univ. (United Kingdom)
E. Chehura, Cranfield Univ. (United Kingdom)
S. E. Staines, Cranfield Univ. (United Kingdom)
R. P. Tatam, Cranfield Univ. (United Kingdom)


Published in SPIE Proceedings Vol. 9135:
Laser Sources and Applications II
Jacob I. Mackenzie; Helena JelÍnková; Takunori Taira; Marwan Abdou Ahmed, Editor(s)

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