Miniature spectrometer and beam splitter for an optical coherence tomography on a silicon chip

Abstract

Optical coherence tomography (OCT) has enabled clinical applications that revolutionized in vivo medical diagnostics. Nevertheless, its current limitations owing to cost, size, complexity, and the need for accurate alignment must be overcome by radically novel approaches. Exploiting integrated optics, we assemble the central components of a spectral-domain OCT system on a silicon chip. The spectrometer comprises an arrayed-waveguide grating with 136-nm free spectral range and 0.21-nm wavelength resolution. The beam splitter is realized by a non-uniform adiabatic coupler with its 3-dB splitting ratio being nearly constant over 150 nm. With this device whose overall volume is 0.36 cm(3) we demonstrate high-quality in vivo imaging in human skin with 1.4-mm penetration depth, 7.5-µm axial resolution, and a signal-to-noise ratio of 74 dB. Considering the reasonable performance of this early OCT on-a-chip system and the anticipated improvements in this technology, a completely different range of devices and new fields of applications may become feasible.

A wafer-level miniaturized Michelson interferometer on glass substrate for optical coherence tomography applications

“…Table 1 provides key technical performance data on the macro OCT systems that are already available and used in medicine for ophthalmologic diagnosis. The typical state-of-the-art OCT operates in the frequency domain, either in the SD-OCT or the SS-OCT mode [13]. The standard use of OCT is currently limited by its high cost and the large dimensions of the instrument.…”

“…The use of OCT in biomedical applications is presently limited by its high cost and large instrument size. The integration of several complex optical devices as miniaturized components on a single microchip is a significant challenge in OCT development [12,13]. MEMS technologies offer a huge potential to achieve such a goal [14,15].…”

Development of a first-generation miniature multiple reference optical coherence tomography imaging device

“…Successful development of a miniature and affordable version of this technology opens the door to completely novel fields of application. Recently, other groups have reported the development of silicon-based integrated systems for SD-OCT 3,4 and SS-OCT. 5,6 However, swept source lasers and InGaAs cameras remain expensive, which is currently limiting the development of consumer-level SS-OCT and SD-OCT devices.…”

Waveguide-coupled micro-ball lens array suitable for mass fabrication

“…However, many applications require a collimated or focused light beam. Examples are on-chip optical coherence tomography (OCT) [1,2] and Raman spectroscopy [3]. A widely exploited approach is the use of one or more objective lenses to collimate or focus the light that emerges from the waveguide.…”