Multi-port optical filter with cascaded isolation
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Solution Overview
Problem
Current optical wavelength multiplexing and add/drop devices face challenges in achieving high reflection channel isolation, leading to signal interference and loss due to residual signals, particularly at large incident angles, which complicates wavelength separation in fiber optic networks like FTTH applications.
Innovation Solution
The use of multiple optical filters with band-pass spectra to sequentially minimize residual signals, ensuring that reflected light beams pass through additional filters to reduce interference and enhance channel isolation between the T-channel and R-channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single optical filter is used in a three-port device, then the device structure is simple and compact, but the reflection channel isolation is insufficient due to residual signals
Solution Approach 1:
The patent divides the filtering function into multiple independent optical filters (first optical filter and second optical filter) arranged in sequence. Each filter handles a specific filtering task, with the first filter providing initial wavelength selection and the second filter eliminating residual signals. This segmentation improves channel isolation by reducing signal residuals while maintaining a relatively simple overall structure.
2Reliability
If multiple optical filters are used to improve channel isolation, then signal quality improves, but the device footprint and manufacturing complexity increase
Solution Approach 1:
The patent combines multiple optical filters and beam directing elements into an integrated optical device structure. The first and second optical filters are positioned in sequence within a compact arrangement, with beam directors (such as mirrors or prisms) efficiently routing the light path. This merging approach achieves high channel isolation and signal quality while minimizing the overall device footprint through spatial optimization.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces signal residuals, improving channel isolation and minimizing errors, thereby enhancing signal quality, reducing footprint, and lowering manufacturing costs while maintaining a broad operating wavelength range.
Implementation Method 1
a first optical filter configured to transmit a first selected wavelength and reflect all other wavelengths
Implementation Method 2
the first optical filter, being not perfect and producing a reflected signal with a residual of a signal at the first selected wavelength
Data Source
AI summary
Techniques for designing optical devices with high isolation are disclosed. The high isolation is achieved by causing a reflected light signal to go through another filter. According to one embodiment, an optical apparatus comprises a first optical filter configured to transmit a first selected wavelength and reflect all other wavelengths, a second optical filter the second optical filter configured to transmit a second selected wavelength and reflect all other wavelengths. The first optical filter, being not perfect and producing a reflected signal with a residual of a signal at the first selected wavelength, the residual of the signal is minimized by the second optical filter when the reflected signal is impinged upon the second optical filter.