Strongly influenced by the advances in the semiconductor industry, the miniaturization and integration of optical circuits into smaller devices has stimulated considerable research efforts in recent decades. Among other structures, integrated interferometers play a prominent role in the development of photonic devices for on-chip applications ranging from optical communication networks to point-of-care analysis instruments. However, it has been a long-standing challenge to design extremely short interferometer schemes, as long interaction lengths are typically required for a complete modulation transition. Several approaches, including novel materials or sophisticated configurations, have been proposed to overcome some of these size limitations but at the expense of increasing fabrication complexity and cost. Here, we demonstrate for the first time slow light bimodal interferometric behaviour in an integrated single-channel one-dimensional photonic crystal. The proposed structure supports two electromagnetic modes of the same polarization that exhibit a large group velocity difference. Specifically, an over 20-fold reduction in the higher-order-mode group velocity is experimentally shown on a straightforward all-dielectric bimodal structure, leading to a remarkable optical path reduction compared to other conventional interferometers. Moreover, we experimentally demonstrate the significant performance improvement provided by the proposed bimodal photonic crystal interferometer in the creation of an ultra-compact optical modulator and a highly sensitive photonic sensor.

在半导体工业的进步的强烈影响下，近几十年来，光电路的小型化和集成到较小的设备中激发了相当多的研究努力。在其他结构中，集成式干涉仪在片上应用的光子设备开发中扮演着重要角色，这些应用范围从光通信网络到即时医疗点分析仪器。然而，设计极短的干涉仪方案一直是一个长期的挑战，因为完整的调制转换通常需要较长的相互作用长度。已经提出了几种方法，包括新颖的材料或复杂的构造，以克服这些尺寸限制中的一些，但是以增加制造复杂性和成本为代价。这里，我们首次展示了集成单通道一维光子晶体中的慢光双峰干涉行为。所提出的结构支持具有相同的极化的两种电磁模式，它们表现出较大的群速度差。具体而言，在简单的全介电双峰结构上实验表明，高阶模群速度降低了20倍以上，与其他传统干涉仪相比，光程显着降低。此外，我们通过实验证明了所提出的双峰光子晶体干涉仪在创建超紧凑型光学调制器和高灵敏度光子传感器方面提供了显着的性能改进。