Tunable edge-emitting microlaser on photonic crystal slab

Abstract

A tunable edge-emitting microlaser is realised by a chirped line-defect photonic crystal waveguide. A tunable range of 57 nm is obtained experimentally.Introduction: Photonic crystals can effectively modulate the density of photon states and manipulate the light on a nanometre scale [1,2]. Many optical devices based on photonic crystal have been realised [3 -8]. Particularly, the photonic crystal microlaser has attracted more attention not only because it possesses an ultra-low threshold and ultra-small mode volume but also because it is a potential light source for future photonic integrated circuits [4][5][6][7][8]. A highly efficient edge-emitting microlaser based on slow light effect has been realised in our group, which is suitable for planar integration [9]. In many applications such as optical communication, information processing, optical sensors and spectrum analysis, the tunable laser is crucial. Several groups [10,11] have attempted to obtain multiple wavelengths lasing in microcavities, however till now only PC laser arrays have been achieved. Apparently the laser arrays have the disadvantage of having to be integrated with other photonic crystal components. In this Letter, we propose a single output port PC laser device in which the resonant build up depends on the cavity position. From the single output port, multiple wavelength lasers are expected. Such a tunable edge-emitting microlaser was designed and fabricated based on a chirped photonic crystal waveguide [9]. A tunable range of 57 nm was obtained.

Semiconductor photonic crystal laser

“…[26][27][28] So far, people have proposed various kinds of PC laser structures at a single wavelength, whereas multiwavelength lasers are only limited to the structure of the array. [29,30] Zheng et al [31,32] realized multiwavelength lasing based on one PC laser (see Fig. 2(a)).…”

“…(c) Lasing spectrum of the tunable edge-emitting microlaser. The broad line shows the gain spectrum of the material [31,32].…”