Optical Receiver Thermal Separation for Noise Reduction
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Solution Overview
Problem
In optical communication systems using wavelength division multiplexing, the thermal noise generated by the trans impedance amplifier (TIA) degrades the reception performance of the light receiving element, such as the avalanche photodiode (APD), due to their close proximity, leading to increased manufacturing costs and complex processes.
Innovation Solution
The optical receiver design thermally separates the light receiving element and the TIA by mounting them on substrates with different thermal conductivities, where the TIA is placed on a substrate for heat emission and the photodetector on a thermal separation substrate to block heat transfer, while using an optical demultiplexer and optical coupling lenses to direct and align the optical signals effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the TIA and photodetector are mounted on the same substrate for compact integration, then device integration is improved, but thermal noise increases due to heat interference from the TIA
Solution Approach 1:
The device is divided into two separate substrates: a first substrate for mounting the TIA and a second substrate for mounting the photodetector. This segmentation physically separates the heat-generating TIA from the sensitive photodetector, eliminating thermal noise interference while maintaining integration benefits through controlled wire bonding connections.
2Area of stationary object
If the TIA and photodetector are placed close together for compact design, then space utilization is improved, but heat transfer from TIA to photodetector increases
Solution Approach 1:
Wire bonding serves as an intermediary connection method between the TIA on the first substrate and the photodetector on the second substrate. This intermediary approach enables electrical connection while maintaining physical separation, allowing compact overall design without direct thermal contact between components.
3Reliability
If separate substrates are used for thermal separation, then thermal noise characteristics are improved, but manufacturing complexity increases
Solution Approach 1:
The connection between TIA and photodetector transitions from a planar two-dimensional layout to a three-dimensional stacked configuration using separate substrates. This dimensional change enables thermal separation in the vertical direction while maintaining compact footprint, and wire bonding provides aĉç manufacturing approach for inter-substrate connections.
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 thermal separation enhances the thermal noise characteristics and improves the reception performance by reducing heat interference between the TIA and photodetector, thereby increasing the reliability and efficiency of signal conversion in optical receivers.
Implementation Method 1
a reflector configured to change a progress direction of the divided optical signals transferred from the optical demultiplexer
Implementation Method 2
an optical coupling lens including, in an array form, light transmission lenses through which the divided optical signals reflected through the reflector are transmitted
Implementation Method 3
a plurality of photodetectors configured to mount on a photodiode (PD) substrate provided on the optical coupling lens, to receive the divided optical signals that are transmitted through the light transmission lenses of the optical coupling lens, respectively, and to convert the received optical signals to electrical signals
Implementation Method 4
The plurality of photodetectors and the plurality of trans impedance amplifiers are provided on substrates having different thermal conductivities to be thermally separate
Data Source
AI summary
An optical receiver includes: an optical demultiplexer to demultiplex an optical signal in which a plurality of wavelengths is multiplexed and divide the optical signal into optical signals corresponding to the plurality of wavelengths, respectively; a reflector to change a progress direction of the divided optical signals; an optical coupling lens including, in an array form, light transmission lenses through which the divided optical signals are transmitted, respectively; a plurality of photodetectors to mount on a photodiode (PD) substrate provided on the optical coupling lens, receive the divided optical signals that are transmitted through the light transmission lenses of the optical coupling lens, respectively, and convert the received optical signals to electrical signals; and a plurality of trans impedance amplifiers provided at desired intervals to electrically connect to the plurality of photodetectors through wire bonding and amplify the received plurality of electrical signals to be a desired magnitude.