Modeling of a high-performance multimode interference optical switch using reconfigurable image modulated region

Abstract

Modeling and detailed performance analysis is carried out to realize a multimode interferometer optical switch by inserting an appropriate image-modulated (IM) region. The concept of self-imaging characteristics of multimode waveguides has been utilized in order to drive the designed device as a photonic switch. Transition losses in the waveguides of the structure are maintained at low levels by selecting appropriate dimensions to increase overall performance of the switch. It has been observed that by inserting an additional IM region, switching losses and corresponding crosstalk levels can be reduced significantly. The device performance is checked for a wider range of index variation in the IM region with respect to other regions for a test wavelengh of 1.55 μm. With rigorous and repetitive simulation, a crosstalk level better than −22.2 dB for either case of polarization state (transverse electric and transverse magnetic) of input has been achieved. The design also possesses a design tolerance in the range of AE0.25 to AE0.5 μm, within which variation in the imaging length and its subsequent adverse effects on device performance remains less than 1.5%.

Design of GaSb-based monolithic passive photonic devices at wavelengths above 2 µm

“…MMI couplers based on the self-imaging effect [22], are crucial in PICs as they provide a wide range of possible input and output ports that control the splitting/combining capabilities. MMI couplers are preferred when fabrication constraints are considered compared to other types of splitters [23]. Our GaSb-based MMI power splitter has a multimode region whose width, W MMI = 15 µm as shown in figure 3(a).…”

“…By the EME method, L 1×2 is obtained as 176 µm thus a correction of ∆L = 16.7 µm is required to compensate for the Goos-Hänchen effect [24]. A linear taper at the input and output waveguides helps reduce the excess loss by decreasing the waveguide and multimode region mode mismatch [23]. A taper at the input and output sections of the MMI with length L t and width, W t are optimized, which are 50 µm and 5.37 µm, respectively.…”

Optimization of a thermally tuned silicon-based reconfigurable optical power splitter with thermal isolations

“…13 Fortunately, the optical power splitters can sufficiently offer us reconfigurable functionality and introduce further flexibility. The MMI-based optical power splitter is very suitable for achieving the reconfigurable function, 14,15 which may derivate novel integrated and compact photonics. 16 By designing the MMI structure and modulating the refractive index of specific multimode (self-images) areas, the phase shifts in the MMI coupler can be accurately controlled, [17][18][19] and different splitting ratios at the output ports can then be realized.…”