There has been a rapidly growing demand for low-cost, integrated single-shot spectrometers to be embedded in portable intelligent devices. Even though significant progress has been made in this area, two major problems are still remaining, namely the high temperature sensitivity and poor bandwidth-resolution ratio (BRR) that can’t meet the requirement of most applications. In this work, we present an integrated single-shot spectrometer relying on a silicon photonic circuit that has a footprint less than 3mm2, but could achieve broad operation bandwidth about 100 nm and high resolution up to 0.1 nm (with a BRR ~ 1000). Moreover, for the first time, we demonstrate an integrated spectrometer that could operate within a wide temperature range (between 10 and 70 degrees Celsius) without additional power consumption for temperature management.

为实现光栅耦合器与光纤的高效率耦合, 基于联合微电子中心有限责任公司(CUMEC)超低损耗氮化硅平台, 成功设计并开发了与互补金属氧化物半导体(CMOS)工艺兼容的低损耗、小尺寸氮化硅光栅耦合器。首先对光栅关键参数进行了仿真计算, 选择最优参数进行光栅耦合器的设计。然后, 基于CUMEC超低损耗氮化硅平台, 采用聚焦光栅结构, 极大地缩小了光栅耦合器的尺寸, 得到的氮化硅聚焦光栅耦合器小线宽结构制备良好。搭建了光学测试系统完成聚焦光栅性能表征, 测试结果表明, 损耗最优值为4.48 dB, 对应波长1548 nm, 1 dB带宽大于45 nm。

基于狭缝波导结构, 设计了工作波长在890 nm的聚合物基微环。从折射率传感的角度详细分析了狭缝波导的模场特性。分析了波导高度、宽度及狭缝宽度对灵敏度的影响。传统的狭缝波导具有较高的弯曲损耗, 这会影响微环谐振器的品质因子Q以及消光比。设计了非对称的狭缝结构, 保证波导模式位于波导中央传输, 降低弯曲损耗。为了条形波导与狭缝波导更好的耦合, 设计了基于多模干涉结构的条形-狭缝波导模式转换器。仿真表明设计的微环谐振器的传感灵敏度达到109 nm/RIU。

The polymer waveguide optical biosensor based on the Mach-Zehnder interferometer (MZI) by using spectral splitting effect is investigated. The MZI based biosensor has two unequal width sensing arms. With the different mode dispersion responses of the two-arm waveguides to the cladding refractive index change, the spectral splitting effect of the output interference spectrum is obtained, inducing a very high sensitivity. The influence of the different mode dispersions between the two-arm waveguides on the spectral splitting characteristic is analyzed. By choosing different lengths of the two unequal width sensing arms, the initial dip wavelength of the interference spectrum and the spectral splitting range can be controlled flexibly. The polymer waveguide optical biosensor is designed, and its sensing property is analyzed. The results show that the sensitivity of the polymer waveguide optical biosensor by using spectral splitting effect is as high as 104 nm/RIU, with an improvement of 2–3 orders of magnitude compared with the slot waveguide based microring biosensor.