Development of an Interference Filter-Stabilized External-Cavity Diode Laser for Space Applications

Linbo Zhang,Jun Liu,Guanjun Xu,Shougang Zhang,Chenhui Jiang,Long Chen,Tao Liu

doi:10.3390/photonics7010012

Abstract

The National Time Service Center of China is developing a compact, highly stable, 698 nm external-cavity diode laser (ECDL) for dedicated use in a space strontium optical clock. This article presents the optical design, structural design, and preliminary performance of this ECDL. The ECDL uses a narrow-bandwidth interference filter for spectral selection and a cat’s-eye reflector for light feedback. To ensure long-term stable laser operation suitable for space applications, the connections among all the components are rigid and the design avoids any spring-loaded adjustment. The frequency of the first lateral rocking eigenmode is 2316 Hz. The ECDL operates near 698.45 nm, and it has a current-controlled tuning range over 40 GHz and a PZT-controlled tuning range of 3 GHz. The linewidth measured by the heterodyne beating between the ECDL and an ultra-stable laser with 1 Hz linewidth is about 180 kHz. At present, the ECDL has been applied to the principle prototype of the space ultra-stable laser system.

Highlights

Compared to most other types of laser, diode lasers are cheap and simple to use; they have a high power and cover a large wavelength range
The objective of the present study is to develop and characterize a prototype of a 698 nm interference-filter external-cavity diode laser (IF-ECDL)
A semiconductor laser diode (LD) with a central wavelength of 698 nm is anti-reflection coated on its output facet and is combined with an external cavity, leading to a large tuning range for the wavelength

Summary

Introduction

Compared to most other types of laser, diode lasers are cheap and simple to use; they have a high power and cover a large wavelength range. They have become attractive light sources with versatile applications in many fields of optical technology and experimental physics, such as optical atomic clocks, precision measurement, astrophysics, and quantum communication [1,2,3,4,5].

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Conclusion