Rx Power en -18 dBm y Tx 1.94 dBm: Decoding Critical Optical Link Failure in POF Systems

In this technical breakdown, “Rx Power En -18 DBm Y tx 1.94dbm” exposes a 7.6 dB deficit versus the receiver’s operational limit. The N-well/P-substrate photodiode generates only 0.16 µA photocurrent—63× below the 10 µA needed for 1e⁹ BER (Table 1).

We dissect connector losses, fiber attenuation (0.2 dB/m), and misalignment fixes using empirical data from Yonsei University’s POF prototype.

Based on the provided research paper and technical analysis, here’s a breakdown of “rx power en -18 dbm y tx 1.94dbm”:

Technical Interpretation of rx power en -18 dbm y tx 1.94dbm

1. Rx Power: -18 dBm
   • Meaning: Received optical power at the detector is -18 dBm (decibels relative to 1 milliwatt).
   • Context:
     • The paper’s CMOS receiver requires -10.4 dBm sensitivity for reliable 150-Mb/s operation (Fig. 7).
     • -18 dBm is 7.6 dB below this sensitivity threshold.
   • Implications:
     • Bit Error Rate (BER) will exceed 1e⁻⁹ (likely catastrophic errors).
     • Signal is too weak for detection at 150 Mb/s due to insufficient photocurrent generation.
2. Tx Power: 1.94 dBm
   • Meaning: Transmitted optical power from the LED is 1.94 dBm.
   • Context:
     • Paper specifies a typical LED output of 0 dBm at room temperature (Table 1).
     • Worst-case Tx power due to temperature/aging is -1.94 dBm.
   • Discrepancy:
     • 1.94 dBm is higher than typical (0 dBm), suggesting:
       • Non-standard LED (e.g., overdriven or different model).
       • Possible measurement error (paper never reports >0 dBm output).

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Link Budget Analysis for rx power en -18 dbm y tx 1.94dbm

Using parameters from the paper for the rx power en -18 dbm y tx 1.94dbm:

Parameter	Value	Notes
Tx Power	1.94 dBm	Query value (atypical)
Rx Sensitivity	-10.4 dBm	Required for 150 Mb/s (Fig. 7)
Power Margin	12.34 dB	1.94 dBm - (-10.4 dBm)
Connector Losses	2 dB	(Table 1)
POF Loss (650 nm)	0.2 dB/m	(Section II)
Max Distance	~51.7 m	(12.34 dB - 2 dB) / 0.2 dB/m

Key Issue:

• Despite sufficient Tx power (1.94 dBm), the Rx power (-18 dBm) is critically low.
• Probable causes:
  • Excessive fiber length (>30 m).
  • Misalignment or connector damage (Section III).
  • Dirty fiber end-face reduces coupling efficiency just like Mirai Intex.

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Why rx power en -18 dbm y tx 1.94dbm Matters

• Receiver Operation Threshold:
  The N-well/P-substrate photodiode needs ≥10 μA photocurrent for 1e⁻⁹ BER (Table 1). At -18 dBm:textPhotocurrent = Responsivity × Optical Power = 0.1 A/W × 10^(-18/10) mW ≈ 0.16 μA → 63× lower than required (10 μA).
• System Impact:
  • Eye diagrams collapse (Fig. 8).
  • Signal detector may disable post-amplifiers (Section 2.3).

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Solutions to Fix Rx Power

1. Increase Tx Power:
   • Use LEDs with >3 dBm output (beyond paper’s specs).
2. Reduce Losses:
   • Clean connectors, minimize bends, use high-quality POF.
3. Shorten Distance:
   • Keep fiber ≤30 m (per paper’s design).
4. Amplifier Modifications:
   • Increase TIA gain beyond 60 dBΩ (Section 2.3).

Note: The notation “en” may be a typo for “=” (e.g., “rx power = -18 dBm”). “y” likely means “and” (Spanish/abbreviation context).

Summary

“rx power en -18 dbm y tx 1.94dbm” describes a failing POF link:

• Transmitter outputs strong signal (1.94 dBm), but receiver gets critically low power (-18 dBm).
• Result: No data recovery due to violated sensitivity limits of the CMOS optical receiver.
• Fixes require optimizing link loss or upgrading components beyond the paper’s design.