(EN) In polarization rotation circuits of the prior art, it was necessary to form a silicon nitride layer, a process not typically implemented when fabricating a silicon waveguide circuit. Implementing polarization rotation circuit functionality in an integrated optical circuit requires an additional process step for the exclusive purpose of forming the silicon nitride layer, leading to longer manufacturing times and more complicated manufacturing equipment. In this polarization rotation circuit, the waveguide width in the center core section of the polarization rotation circuit is constricted, whereby optical wave intensity does not become concentrated exclusively in the center core section, and there is greater susceptibility to structurally asymmetric effects. Due to the configuration of this polarization rotation circuit, polarization conversion can be brought about efficiently, despite a structure having a silicon waveguide only, and without forming a silicon nitride layer or the like. Moreover, through various configuration examples of mode conversion circuits in which the waveguide spacing is not excessively constricted, there may be provided configurations with which circuit length can be shortened, and tolerances during manufacture made looser.
(ZH) 在现有技术的偏振旋转回路中，一般需要形成并不适用于硅波导回路制作的氮化硅层。为了将偏振旋转回路的功能适用于光集成回路中，仅为此目的而追加形成氮化硅层的处理工序，导致制造时间的增加以及制造装置的复杂化。在本发明的偏振旋转回路中，使偏振转换回路的中央芯体部分的波导宽度变窄，由此，光波的强度不仅仅集中于中央芯体部分，使得更容易受到构造上的非对称性的影响。通过本发明的偏振旋转回路的构成，无需形成氮化硅层等，能够保持仅有硅波导的构造而高效地产生偏振转换。此外，通过并不使波导的间隔过度变窄的模式转换回路的各种构成例，提出能缩短回路长度、放宽制造时的公差的构成。
