屋脊棱镜具有转折光路、图像旋转、定向反射、缩短系统光路等作用, 被广泛用在各种观瞄系统中。在目视光学仪器的光学系统中, 为了得到“完全一致像”, 常常采用屋脊棱镜转像。采用屋脊棱镜转像, 比用其他的棱镜组或者透镜组转像具有体积小的优点。高精度屋脊棱镜在其角度误差、面形误差和表面粗糙度等方面都具有较高的要求, 如何获得较高的精度, 降低生产成本, 是近些年光学制造行业研究探索的一道难题。着重介绍了一种控制屋脊角精度的抛光工艺, 从光胶胶盘方式、屋脊面面形对屋脊角的影响、屋脊面返工方法等方面进行分析, 对高精度屋脊棱镜屋脊角精度的控制进行了阐述。

A scheme that utilizes the 4-level pulse-amplitude-modulated (4PAM) signal as the re-modulated signal of colorless optical network units (ONUs) based on reflection semiconductor optical amplifiers (RSOAs) is proposed. The system with 10-Gb/s non-return-to-zero (NRZ) downstream and 5-Gb/s 4PAM upstream signals is theoretically analyzed and experimentally verified. Simulation and experimental results reveal that the 4PAM re-modulated signal yields better performance than the NRZ signal in the upstream. A receiver power penalty of 1.6 dB is also improved by the 4PAM signal at back-to-back (BtB) transmission, whereas another receiver power penalty of 1.5 dB improved after 30-km single mode fiber transmission, where 4PAM signals are used as upstream signal.

Pulse position modulation (PPM) is introduced downstream of the reflective semiconductor optical amplifier (RSOA)-based single-fiber full-duplex bidirectional wavelength division multiplex passive optical network (WDM PON) to suppress the interference brought by the remodulation effect in the RSOA, Rayleigh backscattering, and reflection of the connection devices. In addition, because of the power-efficient characteristic of the PPM-encoded signals, the power budget shows clear improvement. As the experimental tests indicate, with ~6 dB extinction ratio (ER) in the downstream signal, the receiving sensitivity of the PPM-encoded channel is ~2.6 and ~3 dB higher than that of the NRZ (Non-return to zero)-encoded channel in the downlink and uplink, respectively.

A scheme of flexible colorless remote note with reflective semiconductor optical amplifier (RSOA) assisted Michelson interferometer is proposed. This is capable of generating an optical carrier suppressed signal at a specific radio frequency to suppress the penalty brought about by Rayleigh backscattering and reflection in a full-duplex single fiber transmission network. Simulations are conducted, and the validation of the proposal is discussed by observing the penalty eye opening factor. The results are useful for designing cost-effective multi-wavelength passive optical network (PON) or radio-over-fiber (RoF) systems.