Hybrid multimode resonators based on grating-assisted counter-directional couplers

Abstract

Research thrusts in silicon photonics are developing control operations using higher order waveguide modes for next generation high-bandwidth communication systems. In this context, devices allowing optical processing of multiple waveguide modes can reduce architecture complexity and enable flexible on-chip networks. We propose and demonstrate a hybrid resonator dually resonant at the 1st and 2nd order modes of a silicon waveguide. We observe 8 dB extinction ratio and modal conversion range of 20 nm for the 1st order quasi-TE mode input.

Silicon chip-scale space-division multiplexing: from devices to system

“…A large tolerance of >20 nm width deviation is obtained, while it is only a few nanometers for conventional ADCs. To enable WDM grid to be compatible, a micro-ring resonator (MRR) was introduced into ADCs having wavelength-selective features [40][41][42] as shown in Figure 4( grating-assisted couplers are used to realize contra-directional coupling and band-pass filtering [43,44].…”

Electro-optic tunable grating-assisted optical waveguide directional coupler in lithium niobate

“…To solve this phase mismatch issue, it is suggested to introduce a grating into the ADC to compensate the phase mismatch between the two modes so as to achieve e cient mode coupling [2]. According to the grating type and the propagation direction of the coupled modes, GADC can be divided into Bragg grating assisted contra-directional couplers [3][4][5][6][7][8][9][10][11][12][13][14][15][16] and long period gratings (LPG) assisted codirectional couplers [17][18][19][20][21][22][23][24].…”

“…GADC provides a new way to improve the performances of the coupler and the grating. Due to its compact structure, easy integration, versatility, and good wavelength selectivity, GADC is now widely used in various scenarios, such as codirectional coupler [3,4], optical add-drop lter [5][6][7][8]18], polarization splitter [9], microring resonator [10], multimode resonator [11], tunable delay line [12], wavelength division multiplexer [13,14,19], mode division multiplexer [15,16,23], lter [17,20,21], mode lter [22], optical sensing [23], and so on.…”

Grating-Assisted Directional Coupler in Lithium Niobate for Tunable Mode Filtering

“…A grating-assisted directional coupler (GADC) consists of two parallel dissimilar waveguides and a Bragg grating [8][9][10][11][12] or a long-period grating [13] formed along one of the two waveguides. Such a coupler enables the coupling between the two same order modes of the two dissimilar waveguides since the introduction of the grating is able to compensate for the phase mismatch of the two coupled modes.…”

“…Such a coupler enables the coupling between the two same order modes of the two dissimilar waveguides since the introduction of the grating is able to compensate for the phase mismatch of the two coupled modes. Up to now, GADCs have been proposed as contra-directional coupler [8], add-drop filter [9], polarization splitter [10], resonator [11], or a mode (de)multiplexer [12,13]. In this paper, we propose and demonstrate an electro-optic (EO) tunable mode filtering functionality implemented with a long-period GADC (LPGADC) in lithium niobate (LN) for the first time, to the best of our knowledge.…”